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PC-SIG Diskette Library (Disk #2867)
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FILE2867.TXT
Disk No: 2867
Disk Title: TimeSet and RighTime
PC-SIG Version: S1.0
Program Title: TimeSet
Author Version: 6.00A
Author Registration: $35.00
Special Requirements: Modem.
For those who desire or require the "real time" on their computer,
TIMESET will set a computer clock to within five milliseconds of true
time through a six-second telephone call from your modem to the atomic
clocks of the U.S. Naval Observatory in Washington D.C. or the National
Institute of Standards and Technology in Boulder, Colorado. TIMESET can
then be complemented by RIGHTIME, a program that analyzes how much your
system clock drifts and then regularly resets it.
Highly regarded programs, TIMESET, along with RIGHTIME, are used by
organizations such as NASA, the Jet Propulsion Laboratories, power
companies, the military, radio and TV stations, etc. who depend on
time accuracy for technological or legal purposes. They are also used
by some of the rest of us who simply want a convenient way to set our
computer to a standard we know is right.
Program Title: RighTime
Author Version: 1.1
Author Registration: $25.00
Special Requirements: MSDOS 3.0+ and 100% compatible PC/AT.
RIGHTIME, a 3K TSR program for MSDOS v3.0+ and DRDOS, regulates both the
CMOS and DOS clocks, and can keep both clocks accurate to within a
fraction of a second for weeks at a time. Once loaded into memory,
RIGHTIME compares how far your CMOS clock is drifting from your more
accurate DOS clock, and then compares how both of them are drifting from
the "real time."
Real time, accurate to within five milliseconds, can be obtained by
using the program TIMESET that will call by modem the atomic clocks of
the U.S. Naval Observatory or the National Institute of Standards and
Technology. After your computer is set up with "real time" for a couple
of days and RIGHTIME has had a chance to analyze your system clocks,
RIGHTIME will automatically take steps to regularly set your CMOS clock.
(RIGHTIME supports only clock boards or computer motherboard clocks that
emulate the PC/AT hardware clock and its BIOS support precisely.)
PC-SIG
1030D East Duane Avenue
Sunnyvale Ca. 94086
(408) 730-9291
(c) Copyright 1989 PC-SIG, Inc.
GO.TXT
╔═════════════════════════════════════════════════════════════════════════╗
║ <<<< PC-SIG Disk #2867 TIMESET and RIGHTIME >>>> ║
╠═════════════════════════════════════════════════════════════════════════╣
║ To unzip the two programs, either copy the zipped files and PKUNZIP to ║
║ a diskette, or copy them to a subdirectory on your hard drive. (Note, ║
║ if you copy them to a 360K diskette, first unzip TIMESET and then ║
║ delete the TIMESET6.ZIP file. Then unzip RIGHTM11.ZIP. Otherwise, ║
║ there won't be enough room on the diskette.) ║
║ ║
║ After copying the files, unzip the programs by typing: ║
║ PKUNZIP [filename] (press Enter) ║
║ ║
║ After unzipping the files and before starting the programs according to ║
║ the instructions, print the documentation/instructions by typing: ║
║ ║
║ COPY TIMESET6A.DOC PRN (press Enter) ║
║ COPY RIGHTIME.TXT PRN (press Enter) ║
║ ║
║ ║
║ Copyright 1991, PC-SIG, Inc. ║
╚═════════════════════════════════════════════════════════════════════════╝
RIGHTIME.TXT
RighTime v1.1, TestTime v1.1 Copyright 1991, GTBecker
April 28, 1991 All Rights Reserved
Shareware Notice
This file (RIGHTIME.TXT) and evaluation program files RIGHTIME.COM and
TESTTIME.COM should be contained in the distribution file.
Neither evaluation program will run if the program file has been
modified in any way, including filename, length and content. A
fresh distribution file of the latest version is always available
on the SBE/DFW BBS, 214/647-0670.
These files are the copyrighted property of G.T. Becker and Air System
Technologies, Inc., of Dallas, Texas, USA, 75234.
Commercial shareware distributors must make arrangements with Air
System Technologies prior to distribution of these programs.
You may use these evaluation programs for up to one month, and you may
- and are encouraged to - pass the distribution file along to others for
their evaluation, but no one may modify, rename or sell the files or programs
to anyone under any circumstances. The programs will notify you when the
evaluation period has elapsed.
This document is a complete description of the programs, including the
license that will be granted upon registration. There are no surprises. If
you have questions or suggestions, or if you need assistance, you may call
the telephone number at the end of this document any time during evaluation.
We encourage you to register your use of RighTime. Registered RighTime
users receive a diskette containing the current version of the registered
programs, a printed user manual and license agreement, notification of new
releases, and enthusiastic support from the author when needed. The
registered version of RighTime is functionally identical to the shareware
distributed evaluation version, but it lacks registration reminders, it is
smaller in size, and it is serial numbered.
Beyond the immediate tangible benefits, registration also provides
support for the shareware software distribution concept. Shareware is not
free software, nor is it in the public domain. Shareware means quality
software that you try before you buy, generally at a far lower cost than a
similar retail product, if one exists. More happy shareware users mean more
happy shareware authors that produce more shareware distributed program
offerings. We all benefit, but only if the users do their ultimate part of
registering. If RighTime is a useful addition to your system, please
register your use.
To register, fill in the form at the end of this document and send it
with US $25 for a single machine to Air System Technologies, Inc., 14232
Marsh Lane, Suite 339, Dallas, Texas, 75234, USA. Site licensing is available.
Version 1.1
A number of new features have been added to RighTime since the previous
version (1.0a) was released, and problems that a few users encountered and
reported have been fixed. If you tried RighTime v1.0 or v1.0a and found that
you could not use the program, try again with v1.1. Please report any
difficulties you have. Sometimes your trouble can be remedied by a single
telephone call, but if not, your information can be valuable in improving
future releases of the programs.
RighTime v1.1 includes these new features:
* DRDOS 5.0 support;
* CMOS RAM requirement decreased to 12 bytes;
* Time trim provided in hundredths of a second;
* Permanent disable, temporary disable and reenable;
* Quiet mode silences beeps in error messages;
* Four termination codes testable by batch ERRORLEVEL;
* Automatic timeset request by two criteria;
* CMOS backup battery failure detection;
* Improved TestTime accuracy;
* New command line switches /H, /O, /T, /E, /K, /S, /Q.
What is RighTime?
RIGHTIME.COM is a TSR for MSDOS v3.0 and later and DRDOS which will
correct the PC/AT "CMOS"-type clock error up to about 5.5 minutes per day.
If RighTime is automatically and dependably installed via AUTOEXEC.BAT as
suggested below, the system clock will behave as properly and accurately as
one should hope the system clock of a computer would. Written in 80286
assembly language, the resident portion occupies about 3K of system memory.
First, here is what RighTime cannot do:
- RighTime cannot correct clock boards or computer motherboard
clocks that do not emulate the PC/AT hardware clock and its BIOS
support precisely. By far, the majority of current 80286, 80386
and 80486 machines are compatible, but systems like the AT&T PC
6300, some Tandy-manufactured machines, AST Six Pack equipped PCs
and XTs, ROM-socket and floppy-connector clocks and the like are
not supported.
- RighTime cannot properly correct an unstable clock; most clocks
are slow or fast and they are essentially unvarying. If your
clock wanders aimlessly, repair the hardware first.
RighTime exploits the better qualities of each of the two clocks in
your system and improves upon them by doing three fundamental things:
* RighTime slaves the DOS system clock (which has higher
resolution) to the hardware clock (which has higher stability),
* RighTime improves and maintains accuracy by regularly calculating
and applying corrections to both clocks, and
* RighTime monitors time set commands (and the equivalent system
calls from any program) to learn the hardware clock error rate.
RighTime intrinsically sets the hardware clock and solves the midnight
rollover date bug that exists in some DOS versions; this eliminates the need
for other utility programs or drivers that perform these functions. Unlike
DOS alone, the hardware clock seconds transition will be properly set by
RighTime and the time will be set to hundredths of a second resolution, and
these qualities will survive through rebooting.
Each time you set the time, RighTime will improve the accuracy of the
clock error corrections and will subsequently improve the accuracy of the
clocks. It should be easy to achieve a worst-case error of less than 0.5
second per day and under good conditions, less than 0.5 second per week;
typical results are much better. Command line options are provided that
allow fine tuning the correction process to your system. A trimming option
provides for offset adjustments in hundredths of a second.
An option is provided that assists in automatic timesetting by allowing
RighTime to notify the AUTOEXEC batch file when a specified number of days
has elapsed since the last timeset, or if the system has been inactive for
too long and requires a timeset.
Large time changes (larger than approximately 5.5 minutes) will not
affect the corrections, permitting standard time to daylight time and the
converse adjustments.
Some rogue programs apparently change the 8254 timer load constant,
resulting in a suddenly fast clock which usually requires a reboot to
correct. Reexecuting RighTime will load the right value (which will restore
the proper rate) and indicate the correct time without resetting the time if
it is done reasonably promptly.
If You Are In a Big Hurry, or If You Don't Read Manuals
You can't know how to take best advantage of a new product unless you
take the time to read the instructions, but if you insist on trying RighTime
before you understand what you're trying, here's a helping hand:
1) Make a new directory, for example:
MD \RT
2) Copy RIGHTIME.COM, TESTTIME.COM and RIGHTIME.TXT into the new
directory.
3) Set the date, if necessary.
4) Run from a DOS prompt:
\RT\RighTime /F /W /C
5) Set the system time very accurately with DOS's TIME command or,
far better, with a telephone timesetting program.
6) Add this command to your AUTOEXEC.BAT:
\RT\RighTime /F
7) Reboot.
8) For a few days, set the time accurately immediately before you
shutdown your system for the night, and immediately after booting
in the morning. If you never shutdown your system, set the time
accurately a few times each day.
9) There are other considerations, and there might be additional
features that are useful to you, so read the rest of this
document, perhaps twice.
Getting Started
To use RighTime, first decide where to store the corrections. There
are three options: disk file, unused CMOS RAM, or neither. In general, try
the disk file option first, if you can. If you have a hard disk, you can use
the disk file or probably the CMOS RAM option. If you have only floppies the
disk file option is impractical, so try the CMOS RAM option. A diskless
machine cannot use the disk option, unless it is equipped with a non-volatile
RAM disk which appears to the system as any other disk would.
The CMOS RAM option involves some initial bravado: although only the
first 52 bytes of CMOS RAM are defined by the IBM PC standard (presumably
leaving the last 12 bytes available), some modern BIOSs use these 12 bytes
for other functions. If you have adopted a user-specified hard disk format,
for example, your specification is probably stored there. Before attempting
to use the CMOS RAM option, be forewarned that CMOS RAM contains system setup
data that RighTime might inadvertently disturb; be prepared to reset the
setup data if the CMOS RAM option is unsuccessful on your system. See the
Hardware Compatibility List, below. If this dissuades you or if you are
otherwise reluctant, use the disk file option if you can.
If you choose the disk file option, RighTime will attempt to write to
its own program file from time to time, so write access must be allowed. If
the "disk" is actually a non-volatile RAM disk card, the card must remain in
the machine if this option is to work properly. If you use the disk file
option on a battery powered hard disk laptop, you might want to decrease the
update frequency to allow your hard disk to spin down after periods of
inactivity to increase the battery life (see the /U option, Command Line
Syntax, below). The disk file option causes RighTime to maintain an open
handle to its program file which might present a problem when running a file
defragmenting utility, but RighTime can be disabled during defragmentation
and restarted afterwards (see the /K option, Killing, Disabling and
Reenabling Resident RighTime, below).
RighTime can also be configured with no correction storage, with
consequential loss of some of its utility (see No Correction Storage Option,
below).
If you know how fast or slow your clock appears to run per day, you can
optionally speed the learning process of RighTime by suggesting a correction
to the program as a signed number in hundredths of a second - positive for a
slow clock, negative for a fast clock. For example, if your clock runs about
two minutes fast per day, the suggested correction should be -12000 (120
seconds times 100). There are actually two corrections that RighTime
normally applies, one while the system is running and warm, and another when
the system is turned off and cool. If you know the cool correction, you can
suggest it also. If you don't know one or either correction, RighTime will
determine them anyway; it'll just take a little longer for the corrections to
mature to good accuracy.
If you need to restart RighTime and it is currently resident and
running, you must first kill the resident program (see Disabling and
Reenabling Resident RighTime, below). If appropriate, the corrections that
RighTime has already learned can be suggested to the new program copy.
If you have been using another resident driver or TSR to correct the
weaknesses of your clock, remove all references to it from your CONFIG.SYS
and AUTOEXEC.BAT files and, once you are confident that RighTime is all it
purports to be, remove the other driver or TSR from your system.
To get started, place RIGHTIME.COM in some directory (dev:\path, which
does not need to be included in a PATH statement), and run it from the DOS
prompt:
if you choose the CMOS RAM option,
dev:\path\RighTime /R /Wwarm /Ccool
or
dev:\path\RighTime /R /W /C
if you choose the disk file option,
dev:\path\RighTime /F /Wwarm /Ccool
or
dev:\path\RighTime /F /W /C
As discussed above, the /W and /C switches are required, but the warm
and cool parameters are optional in this first execution.
Also, in your AUTOEXEC.BAT file, add:
if you choose the CMOS RAM option,
dev:\path\RighTime /R
if you choose the disk file option,
dev:\path\RighTime /F
Do not use the /W or /C switches in the AUTOEXEC.BAT invocation; if you
do, you will defeat the learning process. Use the /W and/or /C switches only
when starting - or restarting - the error correction learning process of
RighTime; normally this needs to be done only once, the very first time you
run RighTime from the DOS prompt. If you use other options to modify the
behavior of RighTime, these options must be included in the AUTOEXEC.BAT
invocation, and should be included in the initial DOS prompt invocation.
RighTime cannot be INSTALLed in the CONFIG.SYS file.
In the examples above and in those that follow, substitute your
appropriate device specification and the program file path.
For example, I put RIGHTIME.COM in C:\DOS\TIME, my clock runs about 1.5
seconds fast per day when warm, and I use the CMOS RAM option. I started by
running:
C:\DOS\TIME\RighTime /R /W-150 /C
and I added this line to my AUTOEXEC.BAT file:
C:\DOS\TIME\RighTime /R
Had I chosen the disk file option, I would have run:
C:\DOS\TIME\RighTime /F /W-150 /C
and I would have added this line to my AUTOEXEC.BAT:
C:\DOS\TIME\RighTime /F
If RighTime encounters difficulty during its installation, it will
report one of several messages and terminate (see Installation Error
Messages, below). A successful installation will display the corrections, a
copyright notice, and an "Installed" message.
Setting the Time
Now that RighTime is installed and running, set the date and time as
accurately as possible. If you have access to a time standard, use it. For
best accuracy, use a NIST telephone service time setting program such as
Professional TimeSet v6.0 by Peter Petrakis (register with him, too).
Alternatively, you can listen to WWV or CHU or a radio network news broadcast
and be prepared to set your clock when you hear the beep on the minute or
hour. Don't use a radio station that is airing a call-in talk show; the
audio is usually delayed six to ten seconds on such programs to allow for
profanity dumping, and so the beep will be equally late. An all-news format
station is probably not delayed. To be certain, call the radio station and
ask for engineering; they will know. Local telephone time services are
usually poor; don't trust that they are correct. What is important is
accuracy; RighTime needs a reference to initially learn from, and unless you
care to (and know how to) automate it, you are it.
From this moment on, RighTime will monitor each time set occurrence,
learning from your adjustments. Whenever you notice or suspect that the
indicated DOS system time is insufficiently correct to satisfy you, reset it
accurately. You will find that the clocks will become more and more accurate
and the need for adjustment will decrease, becoming infrequent; however, you
must set the time accurately at least once per month (an option is provided
to assist in automating this - see Errorlevels, below).
Allow sufficient time to elapse between time sets so that enough error
exists for RighTime to use in its correction calculations; the more time that
you allow, the better the correction factors that are determined. Time sets
that are separated by less than 30 minutes will be disregarded. Careless
timesets will result in poor correction or even wild clock behavior; remember
that you are "training" the program, so do it well. If you are eager, four
hours will probably be an adequate initial wait; of course, you can use your
system as you normally would during this time.
When you turn your computer on, allow it to boot and then, if it is
necessary, set the time accurately within ten minutes of boot. Time
adjustments that are performed within ten minutes of boot will affect the
cool correction; adjustments performed after that ten-minute period will
affect the warm correction.
Each time you reboot, RighTime will display the current corrections.
After a few days of your diligent time setting, the corrections should settle
to fairly constant numbers which will be true indications of the uncorrected
performance of your hardware clock. Once it is installed, you can also
display the current corrections by simply running RighTime again at a DOS
prompt (no parameters are required). The correction that is currently being
applied to the DOS clock will be displayed and a functional self test will
also be performed, verifying that RighTime is currently running properly on
your system (see Error Messages, below).
As long as RighTime is in use and you've been diligent in your
adjustments, and the corrections have matured, the hardware clock error will
not be more than 0.5 second, and the DOS clock will be much more accurate
than that. In fact, the DOS clock error can be less than 0.01 second; but
since DOS can't express the time any better than the 55 millisecond tick rate
permits, this accuracy might not be easily seen. Nevertheless, it is there.
A tool is provided with RighTime that allows verification and visualization
of RighTime's actions (see TestTime, below).
RighTime has limits of one week of inactivity, and one month between
time sets, that can be corrected to a maximum of 5 minutes, 27.67 seconds per
occasion; beyond that, all bets are off. In that case, unpredictable, and
probably incorrect, clock changes can occur, but RighTime will advise you of
its difficulty if it can. For example, if your clock runs two minutes slow
per day and you don't use the system for three full days, when you boot up
you will receive a message warning that the clock needs to be adjusted
manually (or automatically; see Errorlevels, below). The subsequent
adjustment will not affect the corrections.
Keep in mind that the date is the most significant part of the time.
If you change only the date, you are in fact making a very large change in
the time. The change will not affect the corrections due to its large size,
but it will very likely change the seconds synchronization, and that, in
turn, will create additional error at the next time set. A solution to this
problem is to set the time twice after you change the date; first,
deliberately set the time an hour off, and then set the time accurately.
Neither of these two timesets will affect the corrections due to their size.
No Correction Storage Option
If you have difficulty with both the CMOS RAM and disk file options or
you need or wish to use neither option, RighTime can still correct the clocks
for as long as the system runs continuously. What RighTime has learned will
be lost when you reboot or power down, and there can be no cool correction.
Otherwise, all of the comments above apply. If you suggest a good warm
correction and you set the clock after you boot, RighTime will serve well.
To run RighTime in this mode, add the following line in the
AUTOEXEC.BAT file:
dev:\path\RighTime /N /Wwarm
or
dev:\path\RighTime /N /W
You might want to follow this with a TIME command (perhaps preceded by
a DATE command) to remind you to set the clock at each boot.
Killing, Disabling and Reenabling Resident RighTime
Earlier versions of RighTime (which were running with the disk file
option) reportedly could cause occasional loss of data or system lockups
during high-speed communication sessions. If you encounter similar
difficulties with RighTime v1.1, you can temporarily suspend the function of
RighTime and reenable it later. The disabling and reenabling command lines
can be placed in a batch file surrounding the invocation of the offended
program. RighTime should not be disabled for an extended period.
In the Software Carousel environment, RighTime seemed to interfere with
the automatic partition starting process of the task switcher. This problem
was cured by installing and then immediately disabling RighTime in
AUTOEXEC.BAT, then reenabling RighTime when the last partition was started.
Once RighTime is resident, it can be disabled by running at a DOS
prompt:
dev:\path\RighTime /T
Resident RighTime can then be reenabled by running:
dev:\path\RighTime /E
Programs that defragment or reorganize the hard disk should always be
run with no open files. When using RighTime's disk file option, an open
handle is maintained to the program file, so before running a disk
reorganizing utility, RighTime should be killed. After the utility
completes, RighTime can be restarted with the same command line used in the
AUTOEXEC.BAT file. This precaution is not required when using the CMOS RAM
option.
RighTime can be irreversibly disabled (or "killed") by running:
dev:\path\RighTime /K
The /K switch will cause the function of RighTime to terminate, but the
memory that was allocated to RighTime will remain allocated and unavailable.
If you wish, another copy of RighTime can be started with different options.
In that case, a memory map will indicate multiple RighTime allocations, but
only one will be active.
If it is your intent to permanently remove RighTime from your system,
you can do so by killing the resident program and removing the RighTime
invocation in your AUTOEXEC.BAT. Rebooting is not immediately necessary.
Errorlevels
RighTime provides four unique termination codes. The termination code
can be tested in a batch file to guide subsequent operations.
Code value Indication
0 Installed normally, cool correction within range, last
timeset within specified elapsed period.
1 Installed, cool correction within range, but more than
the specified period has elapsed since a timeset.
2 Installed, but cool correction was out of range (the
system has been inactive too long), so a timeset is
externally required.
255 Not installed due to syntax error, insufficient memory,
incompatible hardware, etc.
These codes can be tested in the AUTOEXEC batch file with the
ERRORLEVEL batch command. For example, if the termination code is 1, then
more than 28 days have elapsed since the last timeset (this duration can be
changed with the /S option). It would be wise to have a NIST telephone
service time setting program such as Professional TimeSet v6.0 automatically
set the time in this situation to prevent RighTime from exceeding its one
month limit, or you could cause execution of the system DATE and TIME
commands to urge the user to set them manually.
Error Messages
RighTime might report one of the following messages:
"DOS version 3.0 or later is required"
The PC/AT "CMOS" hardware clock is not supported by earlier DOS
versions.
"System is not 80286 code compatible"
RighTime expects that the system processor is at least an 80286. The
80C286, 80386(DX), 80386SX, and the 80486 are also code compatible with
the 80286. Systems that use the 8086, 8088, 80186, 80188, and the NEC
V-series processors will not run RighTime.
"No AT hardware clock is present or clock is not running"
Either a hardware clock or BIOS failure prevents use of the clock, or
the clock chip is not installed in the system.
"System skipped a hardware clock alarm"
RighTime has not passed a self test, but this condition can
occasionally occur normally. Try again in a minute or so. If this
message persists, please notify the author.
"Alarm is not supported by BIOS"
The BIOS has reported an unsuccessful attempt to set the clock alarm
feature. The BIOS is not compatible with RighTime.
"Already installed"
RighTime is currently resident and running in the system.
"Correction storage switch is required"
Either the disk file (/F), CMOS RAM (/R) or no storage (/N) option must
be specified in the command line.
"Invalid switch"
An unrecognized option switch is present in the command line.
"Invalid parameter"
A value associated with an option is inappropriate.
"Program has been altered"
RIGHTIME.COM or TESTTIME.COM has been modified in some way. This
message might indicate the presence of a software virus in your system.
Immediately delete the program from your system and replace it with the
distributed program. If the original distributed copy displays this
message, notify the author. This message will also result from an
attempt to INSTALL RighTime in the CONFIG.SYS file.
"Enable resident RighTime first"
RighTime has been disabled with the /T switch. Reenable the program
with the /E switch.
"Hardware clock indicates low or no battery"
The hardware clock and CMOS RAM are powered by a battery during periods
when the system is turned off. Replace the battery or batteries or
replace the clock module if the battery is self-contained.
"Calculated correction is too large"
RighTime has determined that a single adjustment of more than about 5.5
minutes is required. The time must be set manually or via a subsequent
program that can be invoked within AUTOEXEC.BAT by testing the
termination code with ERRORLEVEL.
PC/AT and MSDOS Clock Esoteria
18.2
DOS historians say that the designers of the PC tried to do the DOS
system programmers a favor by dividing an hour into 65536 parts, or about
18.20444444 ticks per second, making the most significant 16 bits of the 32
bit tick count directly indicate the hour and theoretically simplifying the
system code. Somehow the hardware didn't turn out that way, resulting in
about 176 extra ticks per day. The 8254 timer/counter clock input of 1193180
Hz and its counter 0 load constant of 0 (effectively 65536), yielded a
hardware tick rate of approximately 18.20648193 ticks per second, and that
remains so today. That looks like a small difference, but it amounted to an
almost ten-second gain per day.
DOS designers corrected for the hardware error by redefining the number
of ticks per day to include the extra ticks, and a standard was set: the
exact ticker rate was defined by the quotient of the number of ticks per day
and the number of seconds per day (1573040/86400), which is approximately
18.20648148 ticks per second. When they did that, they made it possible to
convert from ticks to time and from time to ticks in two ways, each way
exact, but one according to the PC hardware implementation and one according
to the day-length standard definition.
Using only 16 bit integer arithmetic, the conversion that matches the
PC hardware requires multiplying the current time in hundredthseconds by
59659 (which is 1193180/20), dividing that product by 65536 (discard the
least significant 16 bits), then dividing that quotient by 5 to yield the
tick count. The resulting rate is approximately 0.1820648193 ticks per
hundredthsecond, which is the same as the hardware rate. The conversion for
the day-length standard can be accomplished by multiplying the current time
in hundredthseconds by 19663 (since 1573040/86400 = 19663/1080), dividing
that product by 10800, then dividing that quotient by 10 to yield the tick
count. The resulting rate is approximately 0.1820648148 ticks per
hundredthsecond, the correct day-length standard rate.
Ironically, MSDOS authors ignored their own day-length standard and
chose to match the hardware to determine the time. The resulting error
(compared to the day-length standard) is very small, only 0.039 tick per day,
but for some requirements that can be significant. For example, if the
resulting time is rounded or truncated to whole seconds, the two methods will
yield different results for some values. For most applications, though, the
choice won't matter.
Often, the number 18.2 or the period 55 milliseconds is used to
describe the system clock (interrupts 8 and 1Ch) tick rate. That is never
the correct number, but an approximation. Almost all PC "compatible"
machines use this 18.2 standard tick rate, but there are exceptions; the AT&T
6300, for example, uses 18.75.
Stability, Accuracy and Resolution
Frequently confused, these three qualities are different and are only
obliquely related, although each is required to exist in any good clock.
They can be prioritized with little difficulty. Stability is foremost. Even
if lacking in other qualities, a stable clock is useful if you know what to
expect of it; an unstable clock generates worthless noise. Accuracy can only
be meaningful if the clock is stable. Resolution is required only to meet
the requirements of the clock's task; to catch a train on time, for example,
you don't need hundredths of a second resolution, just an accurate, stable
clock that will tell the time to minutes, or maybe only hours.
Translation Gain, Resolution and Truncation Losses
Suppose that some accurate clock resolves only to minutes, and you read
the clock often at random, or asynchronous, times. Your time reading will be
correct if it is made at the instant the minutes have incremented from one
number to the next, but your reading will appear to be just under one minute
low if made at the instant before the next minute increment. If you do this
enough, the average or mean error of your readings will prove to be one-half
minute low. This is the mean resolution loss. An artifact of any finite
resolution, resolution loss is present when asynchronously reading any
accurate digital clock.
Some applications require resolution loss compensation, which can be as
simple as increasing the time by one-half of the unit of resolution of the
clock. Postcompensation can be applied when the time is read, or
precompensation can be applied when it is set. In the example, the range of
the compensated error would extend from 30 seconds low to 30 seconds high;
the mean resolution loss would be zero. More sophisticated compensation
schemes can synthetically increase the effective resolution of the clock, but
resolution loss, though smaller, remains unavoidable.
A similar effect, translation gain, occurs when asynchronously setting
a digital clock. The instant of time set can occur anytime between one
regular increment and the next. If set at the instant after an increment, no
error results; if set immediately prior to an increment, however, the clock
will be effectively set one unit too high. On the average, asynchronous
clock sets will produce a clock time that is one-half unit of resolution
high. Negative precompensation of one-half unit of resolution will
compensate for translation gain.
Truncation loss is an effect that results from the disregard of digits
of low significance. When converting from one time base to another, the
result is often not an integral number in the new time base. If the
fractional part is ignored, loss results. Arithmetic rounding to the nearest
unit of resolution is effective compensation and is easy to implement by
adding one-half unit of resolution; the fractional part of the sum is then
discarded by the time set function.
In the PC/AT, all of these compensations are useful and, when combined,
they are easy to implement. Translation and truncation errors are intrinsic
to the function of RighTime and are compensated. Since few application
programs - nor MSDOS itself - consider resolution loss, it is precompensated
by default; DRDOS 5.0, however, includes resolution loss compensation.
RighTime's /H0 option should be used on DRDOS systems.
TestTime
Included with RighTime is a program tool that can provide some
interesting insight into the relationship of the clocks in your system and
the function of RighTime. TestTime takes no command line parameters. It
will determine and express whether or not RighTime is running in the system,
and it provides a continuous single line display of the clock system status.
The status line is terse:
H[date:hh:mm:ss(:aa)] D[date:hh:mm:ss] corr diff distrib
where:
H is the hardware clock data. (:aa) is the alarm seconds data.
While RighTime is running, the alarm seconds will increment in
four second steps;
D is the DOS system clock data;
corr is the current correction being applied to the DOS
clock in hundredthseconds, if RighTime is resident;
diff is the signed time difference between the hardware and DOS
clocks in seconds. A positive difference indicates that the DOS
clock leads the hardware clock (it displays a higher, or later,
time). Since DOS can only express time to 55 millisecond
resolution in hundredthseconds, the difference is determined by
a 100-sample moving average method whose accuracy improves with
time. The last character of diff will initially be an approxima
(a wavy equal sign) to indicate that full accuracy has not been
achieved; it will change to an equal sign or a one-half sign when
the difference is accurate. A one-half sign indicates that the
difference value is between hundredths (an average of 5
milliseconds of resolution);
distrib contains three numbers corresponding to the percentage of
difference samples that are negative, zero, and positive. When
the average difference is zero, the distribution of differences
should ideally be balanced around zero. As the DOS clock drifts
away from the hardware clock, the balance will shift until all
samples are positive or negative.
An arrow to the left of each seconds data indicates which data last
changed.
You can use TestTime to learn much about the behavior of the two clocks
in your system. Try running it without RighTime installed and notice that
the DOS clock is never the same as the hardware clock. Set the time and run
TestTime again. If your DOS sets the hardware clock, check to see if the
seconds are synchronized, which is indicated by a diff value of zero. They
probably are not. Run TestTime some time later and see if the relationship
between the clocks has changed; there's a good chance that it will have.
Which, if either, is correct? Try these things with RighTime installed and
see the difference for yourself. If RighTime is doing its job, you should
see that corr and diff are essentially the same value - the former is the
cause, and the latter is the effect.
If the corr and diff values differ by some small, fixed amount, you can
trim RighTime with the /O option to achieve better accuracy. One way to
determine the proper trimming offset is by starting RighTime with a /W0
switch, then running TestTime. Making certain that the corr value is zero
(it should be, since you started RighTime with /W0), let TestTime run 100
seconds or more; the approxima will be replaced by an equal sign or one-half
sign. If the diff value is then not zero, use its complement value as the
trimming offset with the RighTime /O switch. For example, if the difference
is -00.02 second, the proper offset trim should be +2 hundredthseconds, so
the proper RighTime option expression would be /O+2.
Since TestTime measures the difference between the two clocks with a
moving average, the diff value will lag the corr value. For warm correction
values of 864 hundredthseconds per day or smaller this presents no problem,
but for larger daily correction values the current corr value will change
within the 100 second window of TestTime. TestTime will never "catch up"
with the correction, so the indicated diff value will be somewhat low under
these conditions.
Briefly, How RighTime Works
Every four seconds, RighTime reads the hardware clock time and
calculates and sets the proper system time tick count. As usual, DOS
continues to increment that count at each 55 millisecond timer tick interrupt
and uses the count to determine the time whenever it is requested.
When the user or an application program resets the time, RighTime
determines the sign and magnitude of the adjustment and uses this data to
modify correction factors that it maintains. RighTime normally stores these
corrections in CMOS RAM or in its own program file on disk.
Every two minutes, RighTime stores the current time so the period of
inactivity can be determined when the system is next booted. The proper
(cool) adjustment can then be calculated and the hardware clock can be
adjusted if it is required. If the cool adjustment spans midnight, the date
will be appropriately adjusted.
RighTime provides a plus or minus 500 millisecond correction range.
When the calculated system clock time and the hardware clock time differ by
500 milliseconds, RighTime advances or retards the hardware clock as needed
to keep the correction within range. This adjustment is automatic and will
not affect the DOS clock, which remains correct at all times.
RighTime takes interrupt 4Ah and hooks interrupts 8h, 1Ah, 21h, 28h and
2Fh, and it is TesSeRact compatible. Use of the features of the hardware
clock is central to the function of RighTime, so the hardware clock is
strongly guarded. While RighTime is installed, any attempt (via interrupt
1Ah) to set the hardware clock time, date or alarm time, or to disable the
alarm, will be ignored and will produce an error indication to the offending
program. If interrupt 4Ah is taken by another program, it will be recovered
by RighTime. The program is resistant to modifications.
Command Line Syntax
If you use other options to modify the behavior of RighTime, the
options (except options /W and /C) must be included in the AUTOEXEC.BAT
invocation, and should be included in the initial DOS prompt invocation.
Options /W and /C must be specified in the initial DOS prompt invocation and
must not be specified in the AUTOEXEC.BAT invocation. The options are not
case-sensitive (either /f or /F will work) and space between options is not
required. There must be no space between an option switch and its related
parameter.
RighTime [ [{/F | /R[addr] | /N}] [/W[[{+|-}]warm]] [/C[[{+|-}]cool]]
[/Dmin] [/Umin] [/H[{0|1}]] [/O[{+|-}]trim] [/Sn] [/Q] |
[{/K | /T | /E}] ]
where:
/F causes RighTime to store corrections in and retrieve corrections
from its own program file;
/R causes RighTime to store corrections in CMOS RAM;
/Raddr causes RighTime to store corrections in CMOS RAM at a specific
location other than the default address of 63. This location is
that of the last of 12 bytes. This option is potentially
harmful, since a careless value might allow RighTime to overwrite
setup data. Inadvertently changing a hard disk type, for
example, can lead to sadness. Be careful;
/N disables correction storage;
/W sets initial warm correction rate in hundredthseconds per day
(default 0, maximum +32767 or -32768);
/C sets initial cool correction rate, as above;
/D changes the cool adjust period allowance (after boot) from the 10
minute default. The valid range is 1 to 60. Consider this
option if your system exhibits a large difference in warm and
cool corrections and cabinet temperature is suspect. You should
also consider that the clock rate might be affected by lower
supply voltage when the system is off;
/U changes the CMOS RAM or disk file update period from the two
minute default. The valid range is 2 to 60, and the value should
be even. If you think the default is unnecessarily frequent, try
this option. Remember that this is part of the cool correction
process, and less frequency might affect correction accuracy in
severe situations;
/H sets positive half-tick compensation on (1) or off (0). The
default is on (1) for MSDOS systems. Off (0) should be used on
a DRDOS-equipped system, which includes its own compensation;
/O allows DOS clock offset trim in hundredthseconds. Default is 0; the
valid range is -99 to +99. This can be used to compensate for
fixed system overhead in the operating system, or to anticipate
relay and contactor actuation delays and motor start times in
process control system applications;
/T temporarily disables RighTime function;
/E reenables RighTime function;
/K irreversibly disables (kills) RighTime function. The memory that is
occupied by RighTime remains allocated and unavailable;
/S causes RighTime to set the program termination code, which can
be tested with ERRORLEVEL in the AUTOEXEC batch file if the
duration since the last timeset exceeds n days. The default is
28 days;
/Q will mute any error message beeps.
Hardware Compatibility
RighTime requires a hardware real time clock that is compatible with
the stock PC/AT part, an MC146818. The Dallas Semiconductor DS1287 is one
such part. Some modern PC/AT implementations provide an embedded hardware
clock, not a separate part, that is fully compatible.
The hardware clock and CMOS RAM usability depends upon the hardware and
the BIOS:
* The Tandy 1000TL hardware is not compatible.
* The Tandy 3000 and an unlabeled AT clone with an Award 286 BIOS
do not support the alarm feature of the hardware clock and are
not compatible with RighTime.
* Toshiba laptops will not allow the use of CMOS RAM but no ill
effects result from trying aside from a checksum error at the
next boot which requires only a key press to correct. Use the
disk file (/F) option.
* To date, all other AMI, DTK, Oak and Phoenix BIOS ROMs have
worked well.
If You Have Trouble
Please note the symptoms and circumstances as thoroughly as is
reasonably possible and contact
Tom Becker
Air System Technologies, Inc.
14232 Marsh Lane, Suite 339
Dallas, Texas 75234 USA
Telephone: 214/402-9660
SBEDFW BBS: 214/647-0670
Fidonet: 1:124/1213.0
CompuServe: 76436,3210
Software License Agreement
When you register, this will be the agreement between you (the user)
and Air System Technologies to which both parties are bound upon the payment
and acceptance of the license fee, which is part of the registration fee.
Grant of License
In consideration of the payment of each license fee by the user to Air
System Technologies, Air System Technologies will license to the user a
nonexclusive right to use one copy of each of the software programs (RighTime
and TestTime) on one computer at a time. The license is expressly for
program use only, per the terms of the license. No other rights are implied.
Ownership of Software
Air System Technologies is the owner of the software programs and holds
full title to them. The user may own the physical media on which the
software programs are recorded, including the original disk which is provided
by Air System Technologies to the user, but the user does not own the
software programs nor any copy of the software programs.
Copies
The software programs and the documentation are copyrighted and
therefore may not be copied without permission. Permission is granted to the
licensed user to make copies of the software programs and the documentation
as required in the conventional course of computer system data backup.
Permission is granted to copy the shareware distribution file in its
complete, unmodified form. No other permission to copy is granted.
Use and Transfer
The Grant of License applies only to one copy of each of the software
programs. Simultaneously functional resident copies of the software programs
each require licensing. You may not transfer any copy (except the shareware
distribution file) of the software programs to a computer which is not under
your control, nor may you rent, lease, sell or otherwise assign control of
the software programs to anyone.
Termination
The license is in effect until it is terminated. When the license is
terminated, the user's rights that are granted by the license are revoked.
The license is automatically terminated upon violation of any of its terms,
without notice.
Disclaimer of Warranty
No warranty of performance or suitability is expressed or implied.
Every effort has been made to make the software programs deliver as the
documentation describes, but the correctness for your application or
environment cannot be assured. Air System Technologies cannot assume
responsibility for the failure of the software programs, nor for any
consequence of their use.
RighTime Usage Registration Form Evaluation version 1.1
Fill out this form, enclose the required funds and mail to:
Air System Technologies, Inc.
14232 Marsh Lane, Suite 339
Dallas, Texas 75234 USA
I would like to register the use of RighTime.
Name:________________________________________________________________
Business name:_______________________________________________________
Address:_____________________________________________________________
_____________________________________________________________
City:______________________________ State:_________ Zip:_____________
Telephone:_________________________
Where did you get RighTime?__________________________________________
Registered RighTime programs are serial numbered. Registration is
required for each copy of RighTime that is simultaneously machine
resident. If you have, for example, three machines on which you want
to run RighTime, please register for three machines.
Single machine registration fee is $25.
Each additional machine registration fee is $20.
How many copies of the RighTime package do you want?_________________
On what media? 5.25"/360K______ 3.25"/720K______
Total enclosed: US$____________
Make your check or money order payable to Air System Technologies.
Does your business require an invoice?____________
Thank You!
TIMSET6A.DOC
TIMESET TM
Version 6.00A
A program to set computers to the world's most accurate clocks
Copyright 1987-1991, Life Sciences Software
8925 271st N.W., Suite 112
P.O. Box 1560
Stanwood, Washington 98292
206-387-9788
"TIMESET" is a trademark of Life Sciences Software TM
CONTENTS
FEATURES OF TIMESET 6.00A ii
SHAREWARE NOTICE iv
Toll-Free Registration by Modem -- using TSREGSTR iv
INTRODUCTION 1
CONFIGURATION 3
CONFIGURING TIMESET FOR HARDWARE CLOCKS 6
"Slotless Clocks" and Tandy's SmartClock 6
CMOS Clocks 6
Expansion Slot Add-On Clocks 6
Using CLKDRV10 7
RUNNING THE PROGRAM 9
Dialing 9
Standard and Daylight Time 9
Monitor Color 9
Pulse Generation 9
Changing the Configuration 10
Additional Help 10
THE TIME DATA STRINGS 12
The Naval Observatory's Data String 12
The NIST's Data String 13
LINE DELAY MEASUREMENTS 14
Line Delay Correction by NIST 14
Line Delay Correction with the Naval Observatory 16
When Should Line Delay Measurement Be Used? 16
A Note About MNP Modems 17
THE FINAL DISPLAY 19
MORE ABOUT ACCURACY 19
Recommendation: Get RIGHTIME.COM 20
TIMESET 6 AND THE WORDPERFECT LIBRARY 21
PROGRAMMING NOTE AND ACKNOWLEDGEMENTS 22
CUSTOM PROGRAMMING SERVICES AVAILABLE 23
DISCLAIMER 24
YOUR SUPPORT IS IMPORTANT 24
TIMESET 6 MAIL REGISTRATION FORM 25
- i -
FEATURES OF TIMESET 6.00A
Version 6.00A of Professional TIMESET is a top-to-bottom revision and
major enhancement of the classic program for setting computer clocks with
high accuracy and precision with a telephone call to the most accurate
time sources in the world. The program has many new features, but one of
the most notable is its ability to get time not just from one time source,
but from two. TIMESET 6.00A does alone what used to require two different
programs from two different suppliers. Yet the price has not changed,
it's still $35.
All the popular features of earlier TIMESET versions are still here,
including the big running time display, interactive or automatic
operation, immediate timesetting or after a countdown to zero seconds
(done offline), and rejection of noise-corrupted data strings.
The new features include:
1. Accurate time from two alternative sources. TIMESET 6.00A can set
the computer clock by calling cesium beam atomic clocks of either the
U.S. Naval Observatory in Washington, DC or the National Institute of
Standards and Technology (formerly the National Bureau of Standards)
in Boulder, Colorado. Previous versions could call and process time
signals only from the Naval Observatory. Correction for line delay
can be made with both services. If line delay is not requested,
estimated delay values are used for both services that are very close
to what could be measured for most localities in the continental
United States.
2. Line delay correction with any type of Hayes- compatible modem.
Previous versions could get this correction only through the Naval
Observatory with modems capable of remote digital loopback testing
through the &T6 and &T0 commands.
3. Very fast action. It normally takes only 2-6 seconds online,
depending on the service called, if no line delay measurement is
requested.
4. Very high accuracy. TIMESET 6.00A even measures the time it requires
to process the received data string, and it corrects for that
internal delay before setting the time. String processing is one of
the slowest things a computer does, and the time it takes is
measurable. Yet it's overlooked by every other timesetting program
we know of.
5. Self-configuration, with a detailed help screen available for each
configuration item and intuitive operation, making this the least
manual-dependent version of TIMESET so far. The help screens amount
to an online tutorial, and you may not even need the manual.
Previous versions of TIMESET needed a separate program to configure
for serial port, modem, time zone, time season, telephone dialing
- ii -
procedures, type of display, etc. All that is self-contained in
Version 6.00A and available at the press of a function key. The
configuration is written to TIMESET's own source file on disk (there
is no separate configuration data file). Most choices are made by
pressing arrow keys, and editing functions are available for the few
configuration items that require typing. Everything is done on a
single configuration screen.
6. One-key time season adjustment. The press of a single key toggles
the configuration between daylight or standard time and
simultaneously adjusts the computer clock to reflect the time season
change. Likewise, a single key lets you override the program's video
display configuration and toggle between color and forced monochrome
display (very useful for some laptop computers).
7. Numerous fixes, including substantial changes to eliminate connection
and synchronization problems with certain modems. The program now
works with PC, XT, AT, PS/2, and better computers -- on serial ports
1 to 4, at dialing speeds from 1200 to 38400 bps, with local modem
speed locked or unlocked. It automatically detects a PS/2 and
assigns the correct COM3/COM4 port addresses for that type of
computer.
8. Greatly reduced file size -- under 52 kbytes, less than half the
combined total of 105 kbytes for TIMESET plus CONFIGTS in version 5.3
and smaller than other programs that can call only one of the two
services.
9. Completely redesigned displays to convey more information, plus the
big running digital clock display that has always been part of the
program. TIMESET has always been a good-looking program, because
esthetics and functionality go hand in hand. This version is the
most esthetically pleasing yet and by far the most functional.
10. Advance notice of time season changes. Version 6.00A can notify you
weeks in advance when a time season change is coming. And each time
you use it on succeeding days it can tell you the number of days
remaining before the change actually takes effect. On the eve of the
season change it prints a special announcement to remind you that
it's almost time to reconfigure for daylight or standard time. On
the day of the change it tells you, in effect, "If you haven't
already reconfigured, you'd better do it now" (which you can do by
merely pressing a function key, with simultaneous automatic
adjustment of your clock).
We think all these enhancements put version 6.00A of Professional TIMESET
far ahead of any other program for computer timesetting. TIMESET 6.00A is
not a "bait" program intended to entice you to send away for something
we're holding back that's more complete, more professional, and expensive.
It IS the complete professional version. Nothing has been held back.
It's all here. You already have the maximum product. And it's still only
$35.
- iii -
SHAREWARE NOTICE
TIMESET Version 6.00A is a copyrighted commercial program developed and
owned by Peter L. Petrakis (doing business as Life Sciences Software of
Stanwood, Washington and formerly of Annapolis, Maryland) and is
distributed as shareware.
"Shareware" does not mean free and it does not mean public domain.
Shareware is a method of software distribution that lets you try a program
out and pass it along to others to try out. Those who don't find the
program useful are free to junk it (although they could pass it along to
somebody else). Those who like TIMESET, find it useful, and continue
using it after a reasonable trial period of 21 days are expected to pay
$35 for each copy in use (plus 8 percent sales tax for residents of
Washington State).
Payment makes you a registered user. Registration for TIMESET version
6.00A brings benefits of technical help by telephone, a printed manual, a
disk copy of the program containing any recent changes, and a 20 percent
discount on the next major upgrade.
Organizations such as corporations, other enterprises, government
agencies, educational institutions, etc. should not expect to pay $35 for
a single copy of TIMESET then put more than one copy into use. That is as
unfair to an author as buying a single copy of his book and using the
Xerox machine to duplicate it for the office staff. Payment of $35 is
required for each copy of TIMESET in use within an organization. That's
not unreasonable, and discounts are available for quantity.
If your organization requires the formality of purchase order and invoice,
don't let that be a deterrent to payment and registration; contact your
purchasing agent then let us know the procedures. We've worked that way
with several organizations. (Please contact us about a discount for
organizational use of more than six copies. The discounting rate will
depend on how many additional copies your organization plans to use.)
We concede that there is no practical way to make anyone pay for
shareware. Few shareware writers have the stomach for that sort of thing
anyway. Shareware is an honor system. And it's a valuable system that is
bringing many high-quality programs at modest prices from talented people
who work diligently to evolve and perfect their products. It should not
be exploited through abuse or forgetfulness.
Toll-Free Registration by Modem -- using TSREGSTR
Experience suggests that many people intend to pay for a shareware program
they continue using. But they postpone it. Then they forget to do it.
Eventually they might not even have the registration form and the address
around anymore. Because that's human nature, the TIMESET version 6.00A
- iv -
package includes a companion program, TSREGSTR, that lets you register by
modem -- with the phone call paid by us. It's simple, fast, and
convenient, allowing good intentions to be carried out promptly before the
memory cogs slip. All you need to do is type in some information -- your
name, address, phone number, etc. -- and press a key to send it to our
electronic mailbox automatically. A screen editor in TSREGSTR lets you
move around freely in the data entry field so you can make any necessary
corrections before pressing F10 to send the information. Your phone
number gives us a chance to call you back and confirm the order and take
care of problems such as a garbled transmission. We will then send you
the latest version of TIMESET, a printed manual, and an invoice.
It takes only a few seconds and the call is free, so there is no real
reason not to do it if you keep and use TIMESET.
To use TSREGSTR you need a 1200 or 2400 baud modem. To keep this limited
purpose program simple, we did not provide any support for serial ports
other than COM1 and COM2 or for high-speed locked dialing (although
TIMESET itself is much more versatile and can handle COM1-COM4 and locked
or unlocked dialing speeds up to 38,400 bps).
(NOTE: If you pass the TIMESET version 6.00A package along to others,
please be sure to include TSREGSTR.)
If you prefer to register by mail, using a check or money order, please
use the form at the end of this document.
Our voice line, if you have any general questions about registration,
licensing, quantity discounts, or the program's capabilities, is
206-387-9788.
- v -
INTRODUCTION
One of the least reliable components in any computer is the clock.
Computer clocks are notoriously inaccurate, gaining or losing as much as
several seconds a day, and it's not unusual for them to be off by minutes
within a few weeks or even days after they are set. This doesn't matter
to everyone who uses a computer, of course, but it matters a great deal to
a lot of people. This includes businesses that need an accurate record of
the time of data entry, sometimes for legal reasons. Technological and
research organizations need accurate time for numerous serious purposes
related to physical measurements. Radio and television stations and cable
TV systems need a dependable source of time so they can switch in and out
of networks or link up with remotes at the right time. These and many
other organizations have found previous versions of TIMESET not only
useful but necessary.
TIMESET is used in universities, NASA, the Jet Propulsion Laboratory,
the Federal Communications Commission, Federal Aviation Administration,
Veterans Administration, the military, police departments, municipal
agencies, the Federal Reserve Bank of New York, commercial banks, power
companies, Hewlett-Packard and similar high-tech companies, radio and TV
stations, cable networks, and by computer bulletin board operators,
satellite tracking hobbyists, professional and amateur astronomers, and
many people who simply want to know the time is at least close to what
their computer says it is.
There are many TIMESET users of all kinds in the United States and
abroad who are dismayed that the clock in their expensive computer, which
is driven by a high-frequency crystal-controlled oscillator, cannot keep
time nearly as well as a ten dollar wind-up watch from K-Mart. They think
a computer should provide a standard for setting other timepieces, not the
other way around, and they are right. Nor are all of them necessarily
interested in split-second accuracy for their computer clocks; many users
simply want a convenient way to set their computer to a standard they know
is right. TIMESET provides that convenience, and the Naval Observatory
and NIST clocks are as right as any clocks can be.
The first version of TIMESET was released to computer bulletin boards in
July 1987. It was to be the only version (it didn't even have a version
number), but the response was astonishing. Phone calls came day and
(alas) night from people all over the country who were either delighted
with the program or had problems getting it to work with their systems,
particularly their modems. That interest has stimulated continued
development ever since, and successive versions have been released to make
the program work reliably for more and more people and to add new
features, many of them suggested by users. It was very gratifying to see
Version 5.3, the most recent version until now, written up by PC/Computing
Magazine in its October 1990 issue in an article devoted to good ways to
enhance a DOS computer's operating environment.
- 1 -
Version 6.00A is a top-to-bottom revision that includes, for the first
time, the ability to get atomic time from either of the world's two
preeminent sources for timing by telephone -- the National Institute of
Standards and Technology (NIST) and the U.S. Naval Observatory. There are
programs,including previous versions of TIMESET, that can call one or the
other of these two services, but TIMESET 6.00A so far appears to be the
only one that can dial both of them (we expect to be corrected if that's
not right or ceases to be so) and make full use of the capabilities of
each. Thus users from one end of the country to the other can now reduce
phone costs by using the nearest service.
Users of previous versions will notice numerous other changes. The
program looks and feels completely different. Though it has more
features, it is much smaller on disk. Configuration procedures are now
built into the program itself (there is no external configuration data
file and no external configuration program) and are very easy to do. You
can enter configuration mode at any time to change things by pressing a
function key at the main menu. Help for each configuration item is
available by pressing another function key when the item is highlighted on
the configuration screen.
You can now toggle between standard and daylight time configuration by
pressing a function key at the main menu -- and it simultaneously sets the
computer clock one hour earlier or later depending on the season. You can
generate a usable pulse for synchronizing an external device at the
instant of timesetting by pressing another function key before dialing.
Command line options are displayed by typing TIMESET followed by a space
and a question mark at the DOS command. A quick overview of internal
command options is available by pressing a function key at the main menu.
Finally, TIMESET 6.00A can measure and correct for line delays with either
the Naval Observatory or the National Institute of Standards and
Technology.
CONFIGURATION
Because configuration data for TIMESET 6.00A are written directly to its
source file on disk, the program needs to know where its source file is;
it reads its configuration each time it's loaded and each time you change
the configuration. With DOS versions 3 and up it's no problem; those
versions allow TIMESET to find out where it came from, making it possible
to configure or run the program from any drive and directory on the system
path (which is set up with the DOS PATH command). That's not the case
with earlier versions of DOS. With those DOS versions, TIMESET 6.00A
needs to be told where its source file is. That's done by using the DOS
SET command to put its location in the DOS environment, like this:
SET TIMESET=[drive]:\[directory\]TIMESET.COM
The drive, directory (if any), and ".COM" are essential. If you're
using a version of DOS earlier than 3.0 and are going to be using TIMESET
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6.00A regularly, it makes sense to put that command in your AUTOEXEC.BAT
file, which should also include a path to its location using the PATH
command. Otherwise you'll always have to be in the drive and directory
where TIMESET is located before you can use it.
THIS IS IMPORTANT!!: If the copy of TIMESET version 6.00A that you
received has never been configured before, it will automatically load in
configuration mode so you can tailor it to your own system. If you got it
from a computer bulletin board, however, the chances are it will have
already been configured, probably by the bulletin board operator who
tested it before making it available for downloading or by the person who
uploaded it to the bulletin board. In that case, it will load in
operating mode. In fact, if it was configured to run in non-prompted
(automatic) mode it will immediately start dialing. For this reason, if
you obtained TIMESET 6.00A from a computer bulletin board or other
indirect source, you should put /C on the command line the first time you
run it, like this:
TIMESET /C
This will force the program to go to configuration mode as soon as it's
loaded so you can tailor the configuration to your own system. Using /C
will not be necessary if your copy of TIMESET 6.00A came directly from
Life Sciences Software, because we do not preconfigure the program before
shipping it.
The configuration screen comes up with values for phone numbers, time
season, serial port, baud rate, etc. already listed. Please understand
that if TIMESET 6.00A has never been configured before, those values are
not yet in the program file's configuration field; they are what WILL be
written to that field if you press F10. On the other hand, if TIMESET has
already been configured, they represent the actual current configuration
that the program read from its own disk source.
After the program has been configured, you can always enter
configuration mode to check or change your settings by pressing F2 at the
main menu. If you are just checking and not changing anything, you don't
have to press F10 to resave what's on the screen. Instead, you can get
back to the main program by pressing F2 again. If you make a change, you
should of course press F10 to save it.
If you are configuring for the first time and the values you see are
what you want, press F10 to save them to TIMESET.COM on your disk. There
is a good chance, however, that you'll need to change some of the default
values so they'll correspond to your actual computer/modem setup. That's
what configuration of version 6.00A is mostly about -- changing
configuration values that are already displayed. It's very easy to do,
and it's likely that you'll only need to make minor changes in two or
three items.
Each configuration item has its own help screen, which can be displayed
by pressing F1 when that item is highlighted. The highlighting can be
- 3 -
moved up or down by pressing the up or down arrow key on your keypad.
Before doing any configuring, we strongly recommend that you use the up
and down arrow keys to go through the entire list of configuration items
one by one and press F1 to get the help screen for each. That will give
you a good overview of what the configuration procedure is about. The
help screens collectively amount to an online configuration manual. In a
way, they ARE the manual, because few particulars are discussed here.
Version 6.00A has been designed to reduce the need to consult a printed
manual to the minimum. As result, this manual can devote more attention
to some theoretical matters that are worth knowing about.
Everything is done on a single screen, mostly by pressing the right,
left, up, and down arrow keys on your keyboard. Pressing the up or down
arrow key highlights a new configuration item. The right and left arrow
keys toggle the options that are available for a given configuration item.
For example, on the configuration line for baud rate, you can go upward
from 1200 baud -- 1200, 2400, 4800, etc. -- to 38400 baud by repeatedly
pressing the right arrow key. Pressing the left arrow key takes you in
the opposite direction.
Only four of the configuration items involve typing anything, and even
that might not be necessary if the default or preexisting settings for
those items are what you want. Three of the items that may require typing
or editing pertain to telephone numbers, the fourth pertains to the user's
modem initialization string. All the other items are toggled with the
right-left arrow keys. To change the phone numbers or the modem
initialization string, you have to get into editing mode. That's done by
pressing Return when the editable configuration line is highlighted (a
message also appears telling when a line can be edited). In editing mode
you can insert characters or delete or type over existing characters. A
description of editing functions (inserting, overstriking, deleting,
cursor movement, etc.) pops onto the screen at the right as soon as you
press Return, so not much needs to be said about them here.
For example, the default phone number for the Naval Observatory is shown
as 12026530351. If you live in Washington, D.C., the Naval Observatory is
a local call and you obviously need to get rid of 1202. You do that by
scrolling to the appropriate line with the up or down arrow key, pressing
Return, pressing the Delete key four times, then pressing Return again.
Or suppose your company requires you to add an account number to the end
of a long-distance phone number when you dial out. Scroll to the phone
number, press Return, press the End key to move the cursor to the end of
the phone number, type in your account number, and press Return again.
Insert a comma to generate a pause if you need one. The default pause in
virtually all modems is 2 seconds for each comma.
(IMPORTANT: Please just modify the phone numbers that are there, and
NEVER configure to dial our phone number. The program will refuse to run
if you put our number in it, and we don't have an atomic clock anyway.)
Editing works the same way for the user's modem initialization string.
It's especially important to study the help screen for that one, because
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it has some crucial information about what to use with different types of
modems.
Configuration for the type of clock in your computer is a special topic
and is discussed in the next section.
Be sure that no configuration fields are left blank and none contains
the word "(edit)". The word "(edit)" appears on a couple of the editable
configuration items when you press the right or left arrow key enough
times. When you see it, you are supposed to get into editing mode and
replace it with actual configuration data. Rest assured that the program
will not work properly if configuration fields are left blank or contain
"(edit)".
When you've checked or changed all the configuration items and are
satisified that everything is correct, press F10 to save the configuration
to TIMESET's source file on disk. As soon as the configuration is saved,
the program jumps into operating mode, reads its new configuration, and is
ready to call either of the time services.
CONFIGURING TIMESET
FOR HARDWARE CLOCKS
Every computer comes equipped with at least one clock, called the DOS
clock/calendar, which can be read or set with the TIME and DATE commands
in DOS or by a program such as TIMESET. Its major limitation is that it's
volatile; that is, the time and date settings are lost whenever the
computer is turned off, and both have to be reset each time the computer
is restarted.
Because of this volatility, battery-powered clocks have been developed
to maintain the current time and date while the computer is off and pass
them to the DOS clock/calendar when the computer is turned back on. There
are three kinds of nonvolatile clocks: (1) the CMOS clock found on the
motherboards of AT and later computers, (2) add-on clocks that plug into
an expansion slot in the computer, and (3) so-called slotless clocks that
plug into a socket under the ROM chip or some other socketed chip.
TIMESET can work with nearly all of the first and second types, but not
with the third.
"Slotless Clocks" and Tandy's SmartClock
TIMESET can work with CMOS clocks and most add-on clock boards. However,
it will not work directly with Tandy's SmartClock nor with slotless
clocks. With those clocks you'll have to configure to set the DOS
clock/calendar with TIMESET then later on use your own clock's software to
reset the add- on clock.
- 5 -
CMOS Clocks
Depending on the version of DOS that is installed in a computer, a CMOS
clock may need special software to be reset or to make it update the DOS
clock/calendar. With DOS 3.3 or later, you need no special software,
because those DOS versions automatically adjust the CMOS clock when you
change the DOS clock/calendar; changes made in the DOS clock/calendar are
simultaneously made in the CMOS clock as well. That automatic
synchronization doesn't occur with DOS versions earlier than 3.3, however.
Therefore, if your computer has a CMOS clock, the version of DOS you're
using will determine how to configure TIMESET 6.00A for clock type. If
it's DOS 3.3 or later, you should configure TIMESET to set only the DOS
clock/calendar, because the operating system will automatically update the
CMOS clock when TIMESET changes the DOS time and date. If you have an
earlier version of DOS, you will have to configure TIMESET 6.00A so it can
directly set both the DOS clock/calendar and the CMOS clock, thus
eliminating the need to run DOS's SETUP program. You can select the
correct option by using the right or left arrow key in configuration mode.
If you need help, press F1 while that item is highlighted.
Expansion Slot Add-On Clocks
Add-on clocks that plug into expansion slots present a mixed situation.
Some require you to run a special program each time you want to update the
DOS clock/calendar from the add-on clock or update the add-on clock from
the DOS clock/calendar. Others come with a memory-resident program or
driver that takes care of these time adjustments between the two clocks
automatically, making them behave very much like the CMOS clock under DOS
3.3 or higher. Configuring TIMESET 6.00A for these add-on clocks
therefore depends on the kind of software that comes with the clock.
Better known brands of add-on clocks these days come with memory-
resident software to keep the add-on clock and the DOS clock/calendar
synchronized automatically. An example of such a program is ASTCLOCK, for
managing the clock on AST's Six-Pack multifunction board. Running
ASTCLOCK with the /R switch on the command line (ASTCLOCK /R) makes it
memory-resident so it can automatically keep the two clocks synchronized.
If your add-on clock came with a memory-resident driver program or a
driver that goes in your CONFIG.SYS file, install that driver and
configure TIMESET to set only the DOS clock/calendar. Your driver
software will take care of resetting the add-on clock when TIMESET sets
the time and date in the DOS clock/calendar.
Using CLKDRV10.SYS with Board Clocks
There are a number of slot-type add-on clocks that do not come with
memory-resident software and therefore can't pass time and date changes
back and forth between the two clocks automatically. These clocks, with
mail-order prices ranging from $7.50 to $15, have obscure brand names and
- 6 -
often no brand name at all. Despite their low cost and generic nature
they hold accurate time surprisingly well.
The major limitation of these cheap add-ons is lack of memory-resident
software to allow automatic movement of time and date between the two
clocks. Instead they require you to run a special program to update the
add-on clock each time you change the time or date in DOS (e.g.,
SETCLOCK), or to update the DOS clock/calendar from the add-on clock
(e.g., GETCLOCK). With some of these clocks, both functions are handled
by a single program, with the desired function chosen with a command line
switch. Having to go into DOS to run external programs like these is
utterly impractical for a program like TIMESET, which requires timesetting
to occur in both clocks at virtually the same instant for maximum
accuracy. Furthermore, some of them insist on prompting for the time,
which of course means the time will be wrong no matter how fast a typist
you are.
For people with these obscure brands and that clumsy kind of software,
the TIMESET 6.00A package includes a small driver called CLKDRV10.SYS,
written by Tom Strickland of Alexandria, Virginia.
To use it, put the driver in your boot directory and the following line
in your CONFIG.SYS file:
device=clkdrv10.sys
Loading CLKDRV10.SYS in effect erases the barrier between your DOS
clock/calendar and your add-on clock and eliminates the need for any other
software to manage the two clocks and keep them synchronized. Thus, if
you change time or date in DOS, CLKDRV10.SYS sees to it that the add-on
clock gets the same change, and if you ask for time or date in DOS or a
program, CLKDRV10.SYS automatically updates the DOS clock/calendar from
the add-on clock an instant before DOS displays the time or date. With
CLKDRV10.SYS installed, you must configure TIMESET to set only the DOS
clock/calendar, and let CLKDRV10.SYS take care of updating the add-on
clock.
CLKDRV10.SYS is designed to work with board-type add-on clocks that have
a base clock address of 240h, 2C0h, or 340h, and it automatically checks
to see which of those ports is being used by your clock. Nearly all
expansion slot add-on clocks use one of those three base addresses, and
some of them allow you to choose between at least two of them by means of
a jumper on the clock board. If your clock does not use one of these
three port addresses (which is possible but infrequent), CLKDRV10.SYS will
not load and you will have to be content with letting TIMESET adjust only
the DOS clock/calendar.
If you install CLKDRV10.SYS, you should put your clock's regular
software aside, because CLKDRV10.SYS has its own method of managing the
add-on clock. You won't need your original software anyway, because
CLKDRV10.SYS makes your add-on clock directly accessible through the DOS
TIME and DATE commands or from any program. CLKDRV10.SYS is mainly for
- 7 -
people whose add-on clock did not come with its own memory-resident driver
program. If your add-on clock came with its own memory-resident software,
use it rather than CLKDRV10.SYS.
It's important to know when not to use CLKDRV10.SYS. You should NOT use
it when: (1) your computer has a CMOS clock, or (2) you have an add-on
clock board that came with its own memory resident software to accomplish
what CLKDRV10.SYS does, or (3) you have only the DOS clock/calendar and no
battery-powered clock board at all. Under no circumstances should you
load both CLKDRV10.SYS and another driver that accomplishes the same thing
-- the two drivers will get into a contest that could paralyze the system.
Also, CLKDRV10.SYS will be of no help if you have Tandy's SmartClock or
a "slotless" clock. (The manufacturers of those clocks should be
pressured to develop their own memory-resident drivers for them.)
RUNNING THE PROGRAM
OPTIONS AT THE MAIN MENU
Dialing
If you configured for interactive mode, dialing starts when you press W,
Alt-W, B, or Alt-B. W stands for Washington (Naval Observatory) and B
stands for Boulder (NIST). Pressing W or B alone gets the time without
any adjustment for measured line delay. In combination with the ALT key,
pressing W or B gets the time with a line delay adjustment from Washington
(Alt-W) or Boulder (Alt-B). Line delay measurements are discussed in more
detail later on.
If you configured the program to run in noninteractive mode (no
prompts), you won't have to press any keys; TIMESET 6.00A will load,
immediately dial the time service you chose, set the time, and exit to
DOS. The choice of interactive or noninteractive mode is yours. If you
plan to have TIMESET in your AUTOEXEC file so it can update you computer
clock during the boot- up process, it's best to configure for
noninteractive mode so timesetting will be automatic and booting can
continue after the clock has been set. TIMESET skips the main menu when
it's in noninteractive mode and there are no pauses for input.
Standard and Daylight Time
One way to switch between daylight and standard time is to press F2 at the
main menu to get into configuration mode, scroll down to the time season
line, toggle daylight or standard with the right or left arrow key, and
press F10 to save the change. You'll need to do it that way during
initial configuration since you are automatically put into configuration
mode when you run a fresh copy of TIMESET 6.00A, and the program won't run
until it's fully configured. However, after you have configured the
- 8 -
program and it's time to reconfigure for daylight or standard time there
is a very simple way to do it from the main menu: just press F7. That
will not only change change the configuration, it will simultaneously
reset your computer clock for the new season. You should do that
reconfiguration before dialing one of the time services on the day the
time season changes.
Monitor Color
Although you can specify color or monochrome display during configuration,
a function key toggle is also available at the main menu for controlling
monitor color. Pressing F8 at the main menu switches the display between
color and monochrome. You may need to force monochrome display this way
if you run TIMESET 6.00A on a laptop computer that shows colors as shades
of "grey"; some colors have poor contrast on certain laptops.
Pulse Generation
F9 is a special key that will probably not be needed by many people.
Pressing it at the main menu allows a single pulse to be generated at pin
1 of the parallel printer port at the instant of timesetting. The pulse
can be used to synchronize external devices, which could include
specialized (and expensive) clocks. It can also be used for calibrating
instruments. According to the NIST, its time mark typically has
repeatability of about 1 ms from day to day when obtained with line delay
correction. This allows the delay-corrected pulse generated by TIMESET to
be used in combination with a digital counter to check or calibrate an
oscillator with high accuracy. The uncertainty would be on the order of 1
part in 100 million for oscillation counts at 1/second made a day apart
(0.001 second repeatability divided by 86,400 seconds/day).
For reference, here are the characteristics of the pulse:
Change: ~5 volts
Direction: from ~+5 volts to 0 volts (relative to pin 25)
Duration: ~55 ms (controlled by the system timer)
Depending on the external device's requirements, it may be necessary to
invert the pulse or modify it in other ways with appropriate electronic
circuitry (which is beyond the scope of this manual).
A companion program, PULSEGEN, is available for $15 from Life Sciences
Software for generating continuous pulsing at the parallel port at 1/min,
1/sec, 10/sec, or 100/sec with any computer, and up to 1000/sec with
computers equipped with slot-type add-on clocks using base I/O port
addresses of 240h, 2C0h, 340h, or 3C0h and capable of millisecond
resolution (probably all such clocks are, although their port for
thousandths is usually not used since the DOS clock resolution is no
better than 0.01 sec). The pulse widths produced by PULSEGEN depend on
CPU speed and are in the order of microseconds; i.e., no intentional delay
- 9 -
is inserted between pulse on and pulse off. The running time display is
to three decimal places and is written directly to the video buffer for
maximum speed. If the computer clock has been freshly set with TIMESET,
the pulses, which can be used for driving external devices continuously,
will occur approximately in real time, subject to clock drift.
Pulses should not be generated at the parallel port if a printer is
attached.
Changing the Configuration
If TIMESET 6.00A is configured for interactive operation and you need to
change or check the configuration, press F2 at the main menu to get the
configuration screen. If you make any changes, be sure to press F10 to
save them, otherwise you can press F2 to go back to the program without
making any changes. Getting to the configuration screen can require an
extra step if you have already configured TIMESET to run in automatic
mode, because it then bypasses the main menu and starts dialing as soon as
you run it. In that case you can press the Backspace key to interrupt
dialing and go to the main menu, where you can press F2 (there's plenty of
time to do that before the call goes through). A better alternative is to
load TIMESET 6.00A with /C on the command line, which forces it to come up
in configuration mode so you can make your changes.
Additional Help
Pressing F1 at the main menu brings a help screen that summarizes your
keyboard options within the program. There are also some command line
options for TIMESET 6.00A, including options for temporarily overriding
some of the configurations or delaying dialing until a specified time.
You can see these command line options by typing TIMESET ? at the DOS
prompt.
THE TIME DATA STRINGS
The data strings from the Naval Observatory and the National Institute of
Standards and Technology have a few similarities and several differences.
The pattern for both services is a string of data that announces the next
second, followed by a brief pause, then a character that marks the second.
This goes on endlessly, every second, 24 hours a day, year round. When
you are connected to either service with TIMESET 6.00A these data strings
will be displayed on your screen as they are received for as long as it
takes to get a clean data string to set your computer clock. With clean
lines and no line delay measurement, that's about 2 or 3 seconds with the
Naval Observatory and about 5 or 6 seconds with the NIST. If you request
line delay measurement, it takes about 11 seconds online with the NIST and
about 21 seconds with the Naval Observatory. These times will increase if
- 10 -
there is a lot of noise on the phone lines, because TIMESET will reject
data strings that are corrupted by noise and don't match the required
pattern.
Both services limit your time online. The Naval Observatory gives you a
maximum of 60 seconds. The NIST gives you up to 55 seconds but will
reduce that to 15 seconds if the service is in heavy use. Except for
extremely noisy lines (which may indicate a problem with your own phone
system), these times are more than adequate for TIMESET 6.00A.
The Naval Observatory's Data String
The pattern of the Naval Observatory's time data string is:
JJJJJ DDD HHMMSS UTC (pause) *
JJJJJ is the last five digits of the julian day, which is simply a
count of the number of days since January 1, 4713 B.C. The first two
digits, 24, are left out because they will not change for a long time
to come (140 years or so) and can be assumed in calculations.
TIMESET uses the julian day to calculate the current month, day of
the month, and year.
DDD is the day of the year (number of days since December 31 of the
previous year). It is only displayed by TIMESET, at the final
screen.
HHMMSS is what the hours, minutes, and seconds will be when the time
mark -- the asterisk (*) -- is sent.
UTC stands for Universal Time Coordinated, and it means that the
values for julian day, day of the year, and the time all apply to 0
degrees longitude, the longitude of the Royal Observatory at
Greenwich, England. TIMESET corrects these values for your time zone
and season before setting your computer clock (unless you want your
computer on universal time, which is desired by some in the aviation
industry and the military, for example, and have configured TIMESET
for it).
The NIST's Data String
The NIST time data string is more complex:
JJJJJ Yr-Mo-Da HH:MM:SS Sn L UT1 msADV UTC(NIST) (pause) * (or #)
Again, UTC means the time and date values all pertain to Greenwich,
England.
- 11 -
JJJJJ means exactly what it means in the Naval Observatory string.
Unlike the Naval Observatory, the NIST does not provide the day of
the year, but TIMESET 6.00A calculates it from this number and
displays it on the final screen.
Yr-Mo-Da means current year, month, and day of the year.
HH:MM:SS means hours, minutes, and seconds.
Sn is a two-digit number that indicates whether the continental
United States is on standard or daylight saving time or is
approaching daylight or standard time. Except for a 48-day period
before a time season change, the number is either 00 (standard time)
or 50 (daylight time). In the fall, the number begins to decrement
daily, starting 48 days before standard time officially begins in
late October, when it reaches 00. In the spring, 48 days before
daylight saving time officially begins, the number jumps to 98 then
decrements daily until it reaches 50, indicating that daylight saving
time is in effect. During the periods when Sn is decrementing,
TIMESET 6.00A prints a special message on its final screen announcing
the number of days (including the current day) before the time season
is due to change in the continental United States (the days are based
on UTC). At all other times it displays the current time season in
the continental U.S. on the final screen.
L is a flag that indicates whether a leap second will be added or
subtracted at midnight on the last day of the current UTC month to
compensate for irregularity in the earth's rotation. If a leap
second is to be added, the number is 1. If L is 2 it means that a
second will be subtracted at midnight on the last day of the current
UTC month, but the NIST says a negative leap second is not likely to
occur any time soon. The L flag is on for the entire month before a
second is added or subtracted, which will usually be in June or
December. Most of the time the L flag is set at 0, meaning no
change. The flag is merely an announcement and is not needed by
TIMESET 6.00A.
UT1 is a correction factor for converting UTC to an older form of
universal time that is still used in navigation. It is the tenths of
a second to be added or subtracted from UTC and is preceded by the
appropriate sign. It is only displayed by TIMESET 6.00A.
msADV is the NIST's line delay correction and is discussed as a
separate topic in the next section.
- 12 -
LINE DELAY MEASUREMENTS
It is physically impossible for the time mark character at the end of the
data string to arrive at the same instant it leaves the time source.
There is always a delay, and it is the sum of three components: (1) the
time it takes for data bits moving at the speed of light to travel the
distance between the time source and your computer, plus (2) the time it
takes for the time source's modem to serialize and send the time mark
character, plus (3) the time it takes your modem to process the incoming
data and feed it to your computer. With land line communication in the
continental United States, the time the signal spends traveling between
the modems is almost negligible compared to the processing delay that is
inherent in modems. With a satellite link, however, the time the signal
spends traveling becomes very significant and accounts for most of the
lag.
Both the NIST and the U.S. Naval Observatory are equipped for
measurement of line delay, but each uses a different method. TIMESET
6.00A can handle either method. When TIMESET 6.00A asks for line delay
measurement from the NIST, the NIST itself measures the delay and advances
the departure of the time mark to compensate so the mark arrives on time.
However, with the Naval Observatory, TIMESET 6.00A itself measures the
line delay by means of a remote digital loopback test, in which the
program sends a stream of characters to the Naval Observatory and measures
the time for the Naval Observatory's modem to echo them back. It then
captures a time data string and adds the measured one-way delay to the
time as a correction before setting your computer's clock.
Notice the essential difference in methodology here: delay measurements
with the Naval Observatory are made by TIMESET; delay measurements with
the NIST are made by the NIST.
Because of limitations in standard computers, the line delay
measurements the NIST makes are inherently more precise than the ones
TIMESET 6.00A makes with the Naval Observatory. The NIST's equipment can
measure line delay to the tenth of a millisecond. In contrast, TIMESET
must round the line delay it measures with the Naval Observatory to the
nearest 0.01 sec since that's the smallest unit of time that a standard
computer can accept as a correction. This is a 100-fold difference in
precision. It's important to realize, however, that this difference in
precision has absolutely no effect on the accuracy of timesetting in your
computer. Precision and accuracy are not the same thing. Furthermore,
the "granularity" in computer clocks, which is based on the ticking rate
of the system timer (18.2 times per second), limits the accuracy with
which they can be set to within about 0.055 sec of true time, which means
that timesetting accuracy ends up the same with either service. (Delay
correction and accuracy are discussed in more detail later.)
- 13 -
Line Delay Correction by NIST
msADV in the NIST's data string is the milliseconds (ms) that the
departure of the time mark was advanced to compensate for line delays. If
no line delay measurement is requested, the NIST routinely advances the
departure of the mark by 45 ms (0.045 sec), which is displayed in the data
string as 045.0. The standard 45 ms is an estimated value for the United
States that includes the 8 ms it takes to send all the bits of the time
mark character at 1200 baud, plus an assumed 7 ms for travel from the NIST
to the average user in the United States, plus 30 ms to compensate for the
inherent delay in 1200 baud modems (the modem delay is an average value
for several modem brands).
If an actual line delay measurement is requested by initiating the call
with Alt-B, the NIST itself calculates the delay, then advances the
departure of the time mark to compensate for the measured one-way lag so
the time mark can arrive at your computer at the right instant. As soon
as the NIST has measured and adjusted for line delay, the time mark
changes from an asterisk to a pound sign (#). TIMESET watches for the
pound sign and sets the computer clock the instant it is received.
The NIST says that if your modem has the same internal delay as theirs,
you should receive the # time mark within +-2 ms of the correct time. If
it does not have the same internal delay, the mark should arrive within
+-10 ms of the correct time, with different modem brands varying within
that range. Repeatability of line delay correction is excellent,
typically within 1 ms from day to day according to the NIST. Accuracy of
setting the time in your computer is another matter, however, and is
discussed separately below.
The measured line delay is likely to be slightly larger than the
estimated 45 ms that the NIST routinely uses when you don't request an
actual measurement and are using land lines, and it's much larger if the
communication is by satellite. It will be influenced by the speed of your
computer's CPU in echoing characters to NIST as well as by distance and
the characteristics of your modem. With a Hayes Smartmodem 2400 and a
computer running at 8 Mhz, the delay measured between the Seattle area and
Boulder, Colorado is always around 62 ms (0.062 second). Beta testers
using TIMESET 6.00A in New Jersey, Maryland, and Illinois with 20-25 Mhz
386 computers and different modem brands have reported delays around 54
ms. A tester in Alaska, with a 386 computer and a U.S. Robotics modem
reported a delay of just over .3 second, a magnitude of delay that
indicates a satellite link. Our tests show that the measured line delay
is also affected by the choice of long distance carrier. The delay is
consistently greater with MCI than with AT&T -- about 62 and 54 ms
respectively calling from the Seattle area with a land line link in each
case. The accuracy of setting is the same in either case, however, since
the NIST adjusts for the lag it measures.
In the usual, bidirectional, satellite link, the one-way signal delay is
in the range of 260 to 300 ms (.26 to .3 seconds). The communications
satellites are parked in stationary orbits about 26,000 miles from earth,
- 14 -
which requires the NIST's time mark to travel 52,000 miles or more to
reach the caller's computer. This alone takes over a quarter of a second
with the signal traveling at the speed of light (186,000 miles/sec).
Modem processing adds further delay.
There is one situation where the NIST is unable to report a line delay
measurement. That is when the path is by satellite (a long path) in one
direction and by land line (a shorter path) in the other. In that
situation, which the NIST detects by a delay measurement of 90-260 ms, it
is impossible to know whether it's the long path or the shorter one that
is carrying the time signal to the user, so a delay adjustment can't be
applied; the NIST time mark remains an asterisk and the standard 45 ms
advance is used. According to the NIST, a split-path transmission like
this is rarely used by telephone services.
Line Delay Correction with the Naval Observatory
If you dial the Naval Observatory without asking for line delay
measurement, TIMESET 6.00A will routinely add 50 ms (0.05 sec) to the time
it feeds to the computer clock. This value is close to the standard 0.045
sec time mark advance the NIST makes when no actual line delay measurement
is requested, has the same purpose, and includes the same estimated delay
elements (see first paragraph in the preceding section). Why is the
estimate for the Naval Observatory 0.05 second instead of 0.045 second?
The answer is that it's impossible to set a computer clock to the third
decimal place; 0.045 sec must therefore be rounded up to 0.05 sec. The
practical effect of this rounding up is nil; if you dial the two services
alternately and in quick succession without requesting line delay
measurements, the before/after time readings on the final screen will
usually agree within 0.01 sec. each time.
Actually, it makes sense to have the default line delay correction
slightly larger for the Naval Observatory since Washington, D.C., on the
east coast, is farther away from the statistical population center of the
nation than more centrally located Boulder, Colorado. The default
correction will therefore be about right most of the time for most users
in the United States. An actual line delay measurement for Naval
Observatory data is made by means of a remote digital loopback test, which
not all modems can do. Even if your modem can do remote digital loopback
testing, if it doesn't use the &T6 command to initiate the test and the
&T0 command to terminate it, you will not be able to make this measurement
with TIMESET. An example of a modem that can do remote digital loopback
but uses commands other than &T6 and &T0 is the U.S. Robotics HST. There
is no reliable way for a program to detect a modem's ability to handle &T6
and &T0, so it's up to you to check your modem manual to see if you can do
it. If you ask for remote digital loopback and your modem can't do it,
you'll just sit there online wasting money and accomplishing nothing until
the Naval Observatory hangs up on you or until you press the backspace key
to hang up and go back to the main menu. People with such modems who need
line delay measurement should use the NIST's service.
- 15 -
In a remote digital loopback test, TIMESET instructs the local modem to
send a request for the test to the Naval Observatory's modem. This
conditions the Naval Observatory's modem to echo back characters that
TIMESET sends it. TIMESET 6.00A calculates the one-way line delay by
measuring the time it takes for 10 characters to travel to the Naval
Observatory and return. When 10 characters have been sent and echoed
back, TIMESET turns off the remote digital loopback test, calculates the
average lag per character, reverts to normal operation, and grabs one of
the Naval Observatory's regular time data strings. The calculated one-way
line delay per character, rounded to the nearest 0.01 sec, is added to the
zone- and season-adjusted time just before it is sent to your computer's
clock.
When Should Line Delay Measurement Be Used?
The idea of being able to measure and correct for line delay so you can
set your computer clock with maximum accuracy is fascinating to many
people. It intrigues us, too, which is why we worked very hard to
incorporate that feature in TIMESET for both time services. However, it
has the potential of being overused or used unnecessarily.
A major purpose for measured line delay adjustment is for satellite
communications, where line delay is a significant factor. For ordinary
purposes within the continental United States, where telephone
communications are virtually always by land lines, the default standard
estimates should normally be adequate, because they are so close to what
can be obtained by actual measurement. For example, TIMESET's built-in
default estimate of line delay for the Naval Observatory's signal is 0.05
seconds, whereas the measured delay from Washington, D.C. to Seattle,
Washington is typically around 0.0700 -- a difference of 0.02 sec., and
usually less. Similarly, the standard estimated line delay the NIST
provides is 0.045 second, whereas the NIST's measured delay between
Boulder, Colorado and Seattle is typically around 0.062 sec --less than
0.02 second difference.
These are very small discrepancies that are so close to the smallest
time unit that can be read with a computer clock (0.01 sec) that they are
hardly worth worrying about. If you want to see how small 0.02 second is,
try reading numbers in the second decimal place in one of TIMESET's
running time displays. You can't. They change so fast that they blend
into each other. We included the second decimal place in those displays
just to remind you how unimportant 0.02 sec is for most purposes and to
persuade you that there's no sense in going overboard with line delay
measurements. Why go to all that time and trouble for a a couple
hundredths of a second more accuracy when your computer clock could drift
that much in the next several minutes? Furthermore, computer clock
updating can take place only when the system timer ticks, every 0.055 sec,
which means you can only be confident that your clock is set somewhere
within 0.055 second of true time, a range of error nearly three times
larger than that extra 0.02 second of accuracy you're striving for.
Clearly, measured line delay is useful only with satellite communications,
- 16 -
where line delays are substantial, or for calibrating external equipment
in real time.
Another thing to consider with line delay measurement is the extra time
on line that it requires, as indicated in the following table:
Connect time typically required (seconds)
------------------------------------------------------------
Delay measurement No delay measurement
----------------------------- ---------------------------
Naval Observatory 21 2
NIST 12 6
The size of these connect time differences suggests that if a lot of
people get in the habit of doing pointless line delay measurements they
will effectively reduce the capacity of these services. The result for
everybody could be a lot of frustrating busy signals.
Be scientific. Use it sensibly.
A Note About MNP Modems
TIMESET 6.00A will work if you are using an MNP modem and it's initially
set for MNP error checking. However, MNP isn't needed because neither the
NIST nor the Naval Observatory uses it. Furthermore, tests show that MNP
action can increase the line delay that is measured by the NIST, since it
delays the return of echoed characters at the same time the NIST is
measuring the echo time to determine one-way line delay. This should not
affect accuracy, because the delay is real and the NIST adjusts the
departure of the time-mark character to compensate for it if you request
line delay measurement. Still it's something you need to know about. If
you don't request line delay measurement and use MNP, the nominal 45 ms
standard advance used by the NIST, or TIMESET's 50 ms standard adjustment
for Naval Observatory signals, will provide even less compensation for
delay than they otherwise would, because of the slowing action of MNP.
MNP action could also require you to be online a few seconds longer than
with an ordinary modem or an MNP modem with MNP turned off, because the
first thing an MNP modem does is check for MNP action and MNP level in the
remote modem. If it doesn't detect MNP in the remote modem, it reverts to
standard operation (provided it's configured to do so, which it should be
if you are calling one of the time services). All that can take a few
seconds, and during that time data strings being transmitted are not being
seen by TIMESET. You are wasting time on line, in other words. If you
happened to call NIST at a time of day when there was a lot of phone
traffic, a few seconds worth of wasted data strings could make a
- 17 -
difference, especially if there was also line noise to corrupt data
strings and cause their rejection by TIMESET. Since the NIST may limit
your connection time to 15 seconds during busy periods, you could be cut
off before your computer clock gets set. For this reason you might need
to consider turning off MNP when doing line delay measurements.
THE FINAL DISPLAY
As soon as the time is received and the computer clock is set, TIMESET
jumps to its final screen, which displays the NIST or Naval Observatory
data string that was used to set the computer's clock, along with
extracted information about UTC time and date, daylight/standard time
announcements if the NIST was used, a table showing the computer's time
and date before and after the call, the estimated or measured line delay
correction, and the time it took TIMESET to process the data and set the
clock (internal delay).
The internal delay is an actual self-measurement by TIMESET of the time
it took to process the string of data it received. There's a lot to do
with that string -- parse it, convert its components to numeric form,
calculate the date from the julian day, adjust for local time zone and
season, create new strings from numbers for summarizing results on the
screen, etc. Practically all the internal delay is due to string
manipulation, one of the slowest processes in a computer. With our 8086
computer the internal delay is always about 0.01 second, but it might well
be too small to measure with a very high-speed computer. The value for
internal delay is added to the time that is sent to the computer clock.
If the call was to the Naval Observatory, the estimated or measured line
delay is also added to the time that was sent to the computer clock. With
a call to the NIST, only the internal delay will be added (line delay will
not be included, because the NIST compensated for it by advancing the time
mark's departure so it could arrive on time).
Current system time to two decimal places is shown in a running display
in the middle of the final screen if TIMESET 6.00A is configured for
interactive mode. The main menu screen's large clock display is available
at this point by pressing the backspace key to go back to the main menu.
MORE ABOUT ACCURACY
It's useful to remember that even though TIMESET 6.00A links you to the
most accurate clocks in the world, your computer's clock can never be set
to their accuracy. The main reason is that a computer clock is not
continuously receptive to timesetting. Because of the way standard
computers are designed, their clocks "tick" (advance) about 18.2 times a
second, with variations among computers, which means they are updated in
- 18 -
approximately 0.0549-second increments (1 divided by 18.2), although they
can display time to 0.01 second. So even if a time mark arrives within
+-2 ms of true time, this "granularity" in computer clocks means you can
only be sure that your clock has been set within about 55 ms (55/1000 sec)
of true time, which is very accurate indeed but not perfect.
Repeatability of timesetting with TIMESET 6.00A is very good. In tests
where one service or the other is called a few times in quick succession,
before the computer clock has time to drift to any measurable extent, the
"Computer time was:" item on the final screen is almost always within 0.01
second of what it was after the previous call. Usually it's identical.
It's important to remember, however, that you shouldn't expect your
computer clock to stay highly accurate very long. No computer clock does.
(If your computer time is wildly unstable and you have a battery-powered
clock in it, it could mean the battery needs replacing.) Get to know your
computer clock's stability by running TIMESET a few times over a period of
days. How often you need to run it thereafter depends on how stable your
clock is and the degree of inaccuracy you can tolerate.
If you are a scientist or engineer and need accurate time for physical
measurements, you already know you'd need to run it just before a
procedure. Same thing if you are part of a far-flung organization and
need to have computers in the outposts synchronized with a reliable and
mutually accessible standard (but don't forget to pay for each copy of
TIMESET). If you are part of a radio, TV, or cable network you might need
to run it at least a couple times a day so you won't switch into the
network in the middle of somebody's sentence. If you are satisfied to
have your clock accurate within a few seconds, a run every day or two
should be sufficient. If accuracy within 1 minute is enough, you probably
need to run it only once every few days. If you're satisfied to be within
5 or 10 minutes, you can probably wait weeks, but you might want to
consider just checking the clock on the wall and setting your computer
clock manually. If clock accuracy doesn't matter to you, then of course
you won't need TIMESET at all. We definitely recommend that these
valuable time services be used no more than necessary, and we urge people
not to abuse them.
A Recommendation for People with CMOS Clocks: Get RIGHTIME.COM
If your computer has a CMOS clock, we strongly recommend that you get hold
of RIGHTIME.COM. It's a remarkable memory-resident program written by Tom
Becker. RIGHTIME not only keeps your DOS clock continuously synchronized
with your more accurate CMOS clock, it learns the drift characteristics of
your CMOS clock and automatically corrects for it. Each time you run a
program like TIMESET, it notices the extent of your clock drift and
refines the correction until eventually it can keep your CMOS and DOS
clocks within 0.5 second of true time. Thus it can greatly reduce the
frequency of having to run TIMESET. RIGHTIME, a shareware program, can be
found on Compuserve's IBMHW forum and computer bulletin board systems
around the country.
- 19 -
THE WORDPERFECT LIBRARY
TIMESET 6.00A contains assembly language routines for automatic detection
and full compatibility with the WordPerfect Library, an excellent program
for task-switching made by the WordPerfect Corporation. It behaves
exactly like WPCorp's own programs when managed by the Library, allowing
you to: (1) load TIMESET memory-resident or remove it from memory, both
invisibly; (2) directly access it from other programs in the Library menu
by pressing hot keys; and (3) directly access the other programs from
TIMESET by pressing hot keys. Depending on how you load the Library, it
swaps TIMESET with the other programs by using either expanded memory
(EMS) or a temporary hard or RAM disk file as the storage area for the
program's memory image. TIMESET 6.00A takes about 136 kbytes of EMS or
disk memory under the Library and about 135 kbytes under DOS.
- 20 -
PROGRAMMING NOTE,
ACKNOWLEDGEMENTS
November 19, 1990
TIMESET 6.00A was written with Microsoft's BASIC Professional Development
System version 7.0 and contains scores of linked commercial assembly
routines as well as several special purpose assembly routines I developed
when no commercial alternatives were available.
It's doubtful that using another higher-level language to write the
program would have improved anything, and I thank the folks at MicroHelp
Inc., Crescent Software, and Microsoft for transforming BASIC into a truly
professional language.
My special thanks go to a group of special people who tested TIMESET
6.00A for me during its development and made many helpful suggestions:
Tom Strickland, Virginia
Bob Germer, New Jersey
Bruce Felstein, New Jersey
Jim Luhman, Illinois
Stu Rothman, Alaska
Tom Takesian, Maryland
Julia Petrakis (my wife), Washington
The CLKDRV10.SYS driver for expansion slot add-on clocks was created by
Tom Strickland of Alexandria, Virginia and fills an important void. It
has been part of the TIMESET package for over two years and is an
outstanding piece of work. I'm very grateful to Tom for letting me
include it.
Pete Petrakis, Life Sciences Software
Stanwood, Washington (Compuserve 76555,1175)
- 21 -
CUSTOM PROGRAMMING SERVICES
LIFE SCIENCES SOFTWARE
If you need custom programming, write or phone Life Sciences Software,
tell us what you want, and find out if we can help you. The chances are
good that we can, and with the same care and experience that has gone into
TIMESET and a lot of other very well received programs we've written. But
you won't know unless you ask. Our rates are competitive.
You can telephone us at 206-387-9788 between 8 a.m. and 5:30 p.m.
Pacific time, Monday through Friday
Our address is:
Life Sciences Software
8925 271st N.W., Suite 112
P.O. Box 1560
Stanwood, Washington 98292
- 22 -
DISCLAIMER
TIMESET is a mature program that has been thoroughly tested through
several revisions since its inception in early 1987. Tremendous effort
has been expended to make it work properly with as many systems as
possible. This includes the bewildering variety of modems that exist,
some of which may be described charitably as balky and idiosyncratic. The
number of modem brands that TIMESET cannot work with has declined with
each refinement over the years, and dramatically since the release of
version 5.3 in the fall of 1989. Only a few exceptionally stubborn ones
have proved unyielding so far. It is our hope that version 6.00A will
work for everybody no matter what kind of equipment they have, but of
course we cannot guarantee it. The virtue of shareware is that you can
determine a program's usefulness to you before spending any money on it.
Nor can we accept any responsibility or liability for any harm the program
might cause to your system or your data. We have never heard of any bad
effects, have never experienced any ourselves, and cannot imagine how
there could be any, but, as with all programs, the user must assume any
risk.
YOUR SUPPORT IS IMPORTANT
We hope you like Professional TIMESET 6.00A and find it useful. Please
register and pay for it if you do. It has taken a lot of hard work and
study; many, many hours (surely thousands since the first version in
1987); and considerable expense to develop TIMESET into the highly
sophisticated program it is and the best of its kind. If it's useful to
you or your organization, it merits your financial support.
It's also advantageous to you to register TIMESET. Registration brings
you fresh copies of TIMESET and its supporting programs (including any
interim fixes before the next major upgrade), a printed manual, free
technical support, and a 20 percent discount on the next major revision.
Handling and mailing are included in the $35 per unit registration price.
Please fill out the form on the next page and mail it to us with payment,
or register by modem with TSREGSTR and be invoiced if you prefer.
By the way, we always like to get reports from TIMESET users --
favorable or unfavorable. They are what have driven the program's
evolution from the beginning.
- 23 -
TIMESET MAIL REGISTRATION FORM
For Individuals and Organizations
Notice to companies and other organizations: Registration and payment is
required for each copy of TIMESET in use within an organization. The
price is $35 per copy for up to six copies. Please call Life Sciences
Software at 206-337-7328 for discount information on more than six copies
(the phone number will be 206-387-9788 after December 17, 1991).
Notice to all: If you prefer to register TIMESET by modem and be invoiced
for payment, use the TSREGSTR program to send the registration information
to our electronic mailbox. The information TSREGSTR will prompt you for
and send to us is essentially what you see below.
TO: LIFE SCIENCES SOFTWARE
BOX 1560
8925 271st, N.W., SUITE 112
STANWOOD, WASHINGTON 98292
I wish to become a registered user of TIMESET.
My name: _____________________________________________________________
Organization name (if any): __________________________________________
Street address: ______________________________________________________
Additional address: __________________________________________________
City: _______________________ State: __________________ ZIP: ________
Phone number: ___ ___ ____
Number of copies being registered: ___
PAYMENT:
Note: As a licensed business in the State of Washington we are required
to charge residents of the state an additional 8.1 percent for sales tax.
___ I am enclosing payment for ___ copy(ies) of TIMESET at $35.00
per copy (Washington residents please add 8.1 percent for sales
tax). Total enclosed: U.S. $ ________
Please make your check or money order payable to Life Sciences Software.
Thank you for supporting shareware!
- 24 -
Directory of PC-SIG Library Disk #2867
Volume in drive A has no label
Directory of A:\
TIMESET6 ZIP 101297 10-23-91 8:27a
RIGHTM11 ZIP 30717 10-23-91 12:44p
PKUNZIP EXE 23536 1-16-91 12:38p
FILE2867 TXT 3627 10-23-91 1:37p
GO TXT 1617 10-23-91 1:13p
GO BAT 38 1-31-91 12:58a
6 file(s) 160832 bytes
159744 bytes free