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PC-SIG Diskette Library (Disk #3052)
[PCjs Machine "ibm5170"]
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FILE3052.TXT
Disk No: 3052
Disk Title: ReSizeable RAMDisk
PC-SIG Version: S1.0
Program Title: ReSizeable RAMDisk
Author Version: 1.30
Author Registration: None.
Special Requirements: No special requirements to use; Borland C++ or TAS
RSDISK, the RESIZABLE RAMDISK is the chain letter of C programming.
While it is a working RAM disk program, it was developed with the
idea that other programmers would take the current version and improve
it! It currently supports extended memory; 32-bit sector addressing
(32MB RAM disks are possible); configurable sector and cluster size;
multiple FATs and root directory entry counts; write protection; and
predefined DOS disk-like formats. The author hopes that someone will
add EMS support, bank-switch memory support, low memory support, and
the ability to resize without memory loss. RSDISK comes with both
assembly and C source code.
PC-SIG
1030D East Duane Avenue
Sunnyvale Ca. 94086
(408) 730-9291
(c) Copyright 1989 PC-SIG, Inc.
GO.TXT
╔═════════════════════════════════════════════════════════════════════════╗
║ <<<< PC-SIG Disk #3052 RESIZEABLE RAMDISK >>>> ║
╠═════════════════════════════════════════════════════════════════════════╣
║ ║
║ To print the installation instructions, type: ║
║ COPY SRDISK.DOC PRN (press Enter) ║
║ ║
║ ║
║ (c) Copyright 1992, PC-SIG Inc. ║
╚═════════════════════════════════════════════════════════════════════════╝
SRDISK.ASM
;
; ReSizeable RAMDisk device driver for XMS memory
;
; Copyright (c) 1992 Marko Kohtala
;
; Some documentation and license available in accompanying file
; SRDISK.DOC. If not, contact author by sending E-mail from
;
; Internet, Bitnet etc. to 'Marko.Kohtala@hut.fi'
; CompuServe to '>INTERNET:Marko.Kohtala@hut.fi'
;
; or by calling Airline QBBS, 24H, HST, V.32, V.42, MNP,
; +358-0-8725380, and leaving mail to me, Marko Kohtala.
;
; In general, this is FREEWARE.
;
; To compile with TASM: tasm /m2 srdisk.asm
; tlink /t srdisk.obj,srdisk.sys
;
; History:
; 1.00 Initial release
; 1.10 Added into IOCTL_msg media_change byte, that must be changed to
; -1 by srdisk if media changed. Changed header version to SRD 1.10.
; 1.20 Fixed name of program by adding the missing 'Re' to 'Sizeable'.
; Upgraded IOCTL_msg_s to version 1.20 by adding byte to tell usable
; memory types.
; Updated to work with DOS versions 2.x-5.x - not tested.
; 1.30
; Major redesign of the reformatting system. Ioctl is no longer used.
; New data structures of version V_FORMAT 0 (beta format).
; Support for multiplex interrupt.
; Support for chaining of drivers for different memory to same disk.
; Support for DOS 4+ 32-bit sector addresses.
; [Allow forcing drive to some drive letter (even replace DOS drives).]
; Int 19 hooking is optional by defining HOOKINT19 to 0.
; Added if ... endif around all memory specific code to ease
; later adding of other memory support code.
; Fixed parameter reading to abort on every ctrl-character other
; than tab. DOS 5 could end line with LF if no parameters and CR if
; there were parameters. Now even NUL can end the line.
SRD_VERSION equ "1.30" ; FOUR LETTER VERSION STRING
; General capabilities in conf.c_flags
C_APPENDED equ 1 ; Capable of having appended drivers
C_MULTIPLE equ 2 ; Capable of driving many disks
C_32BITSEC equ 4 ; Capable of handling over 32-bit sector addresses
C_UNKNOWN equ 0xF8
; What this driver can actually do
; Currently compiled for only C_32BITSEC, since no drivers for
; any other memory available and thus C_APPENDED is useless
;CAPABLE equ C_APPENDED or C_32BITSEC
CAPABLE equ C_32BITSEC
; Boolean
TRUE EQU 1
FALSE EQU 0
; What memory this driver supports
XMS_MEMORY equ TRUE
; Some important internal settings
MULTIPLEXAH equ 72h ; Multiplex int 2F AH parameter
V_FORMAT equ 0 ; config_s format version used here
HOOKINT19 equ FALSE ; Hook int 19 if TRUE
DEBUGGING equ FALSE
DEBUGINIT equ FALSE
; Derived definitions
DR_ATTRIBUTES = 0800h ; Removable media
if CAPABLE and C_32BITSEC
DR_ATTRIBUTES = DR_ATTRIBUTES or 2 ; 32-bit addr
endif
if XMS_MEMORY
.286c
MEMSTR equ 'XMS ' ; Define 4 char memory type string
else
%out Memory defined by MEMORY not supported
.err
endif
if DEBUGGING
debug macro char,num
push ax
push dx
mov dx,num
mov al,char
call debug_c
pop dx
pop ax
endm
else
debug macro char
endm
endif ;DEBUGGING
d_seg segment para public
assume ds:d_seg, cs:d_seg
org 0
; The following is to be considered as both a device driver header and
; as a starting point for the configuration table. This driver will be
; identified by its segment address and this structure must be at offset
; 0.
; Device driver header
drhdr_next dd -1 ; Pointer to next device (now last)
drhdr_attr dw DR_ATTRIBUTES
drhdr_strategy dw offset strategy ; Offset to strategy function
drhdr_commands dw offset commands ; Offset to commands function
drhdr_units db 1 ; Number of units
; The rest has four functions to be considered
; 1) usable as device driver name if this driver is changed
; into character device on init.
; 2) usable as a label to be returned in media check call
; 3) identifies this device driver as SRDISK driver by always having
; the letters SRD at offset dr_ID
; 4) identifies the memory used by the 4 char string at offset dr_memory
dr_volume label byte
dr_ID db 'SRD' ; SRDISK identification (3 char)
dr_memory db MEMSTR ; Memory type identifier (4 char)
dr_version db SRD_VERSION ; Device driver version (4 char)
db 0 ; null to end volume label
dr_v_format db V_FORMAT ; Configuration format version
dr_conf dw offset conf ; Pointer to drive configuration
;**************************************************************************
;
; I/O ROUTINE TO THE RAM DISK
;
; This routine will read a group of sectors inside this part of
; the ram disk. If starting sector is not on this part of the disk,
; return without error with 0 sectors transferred. If not all sectors
; are on this part of the disk, transfer as many as can and report the
; number of sectors transferred.
;
; On entry
; bh - 0 then read, else write
; cx - number of sectors
; dx:ax - starting sector
; es:di - transfer buffer
;
; Preserve
; es, ds
; si, di
;
; Return
; - carry clear if no fatal error, transferred sector count in ax
; (if starting sector not in this part of disk, return ax = 0)
; - carry set and ax = 0 on fatal error
;
;**************************************************************************
if XMS_MEMORY
disk_IO proc far
push ds
push di
push si
push cs ; Make ds point to our data
pop ds
mov IO_startl,ax
mov IO_starth,dx
debug 'a',ax
debug 'd',dx
debug 'c',cx
cmp ax,conf.c_sectorsl ; Starting sector on disk?
sbb dx,conf.c_sectorsh
jb disk_IO4 ; Yes
debug 'O',ax
xor ax,ax ; No, 0 sectors transferred
clc ; No fatal error
jmp disk_IOx ; Exit
disk_IO4: mov dx,IO_starth
add ax,cx ; Count ending sector
adc dx,0
cmp dx,conf.c_sectorsh ; Ending sector on disk?
jb disk_IO1 ; Jump if is
jne disk_IO5
sub ax,conf.c_sectorsl
jbe disk_IO1 ; Jump if is
disk_IO5:
sub cx,ax ; Count how many we CAN transfer
debug 'T',cx
disk_IO1:
mov IO_sectors,cx ; Report # of transferred
mov ax,cx ; Count number of bytes to move
mul conf.c_BPB_bps
mov si,offset XMS_cblk
mov [si].XMS_sizel,ax ; Number of bytes to move
mov [si].XMS_sizeh,dx
mov ax,IO_starth ; Count starting byte
mul conf.c_BPB_bps
mov cx,ax
mov ax,IO_startl
mul conf.c_BPB_bps
add dx,cx ; dx:ax is starting byte
or bh,bh ; Input/output?
mov bx,XMS_handle
jnz disk_IO2 ; Jump if write
; -- Read
mov [si].XMS_shandle,bx ; Source in XMS
mov [si].XMS_soffl,ax
mov [si].XMS_soffh,dx
mov [si].XMS_dhandle,0 ; Destination in main memory
mov [si].XMS_doffl,di
mov [si].XMS_doffh,es
jmp disk_IO3
disk_IO2: ; -- Write
mov [si].XMS_shandle,0 ; Destination in main memory
mov [si].XMS_soffl,di
mov [si].XMS_soffh,es
mov [si].XMS_dhandle,bx ; Source in XMS
mov [si].XMS_doffl,ax
mov [si].XMS_doffh,dx
disk_IO3:
mov ah,0Bh ; Move XMS block
call dword ptr XMS_entry
shr ax,1
cmc ; Carry set if err
mov ax,IO_sectors ; Return # of sectors xferred
jnc disk_IOx
xor ax,ax
disk_IOx: pop si ; Restore original si,di,ds
pop di ; es was not changed
pop ds
ret_far: ret
disk_IO endp
;**************************************************************************
;
; EXTERNAL MEMORY ALLOCATION ROUTINE
;
; Allocate requested amount of memory. If memory is available in chunks,
; the amount can be rounded up. If not enough memory available, allocate
; as much as possible or just report the amount that was previously
; allocated. It is expected that at least as much memory can be allocated
; as there previously was. Reallocation should not destroy memory
; contents - it is essential to be able to resize a disk without loosing
; the contents (a feature under development).
;
; On entry
; DWORD [sp+4] - Kbytes to allocate
;
; Preserve
; es, ds
; si, di
;
; Return dx:ax = Kbytes allocated
;
;**************************************************************************
malloc proc C far
arg kbytes:dword
assume ds:nothing
test word ptr kbytes+2,-1 ; Over 0FFFFh K is impossible
jnz malloc_fail
mov bx,word ptr kbytes ; New disk size
mov dx,word ptr XMS_handle ; Handle to the memory
mov ah,0Fh ; Reallocate
call XMS_entry
xor dx,dx ; Zero the high word of return
or ax,ax
jnz malloc_ok
malloc_fail: mov ax,word ptr conf.c_size ; Fail, return current
ret
malloc_ok: mov ax,word ptr kbytes ; Ok, return requested
ret
assume ds:d_seg
malloc endp
;**************************************************************************
;
; Warm Boot of Machine
;
; Release used XMS memory on warm boot.
;
; I guess this may be important if some virtual machine (VM) in some
; multitasking system has installed this driver and the VM is ended.
; Without this the other VMs would loose the space reserved for RAM disk
; in this VM.
;**************************************************************************
if HOOKINT19
int_19_entry proc far
assume ds:nothing
pusha ; If XMS used, it must be 286 or above
mov dx,XMS_handle
cmp dx,-1
je int19_1 ; Jump if no XMS handle
mov ah,0Ah
call XMS_entry ; Free XMS memory
int19_1:
xor ax,ax
mov ds,ax
mov ax,old_int19_off
cli ; Disable interrupts
mov ds:[19h*4],ax ; for the time to write
mov ax,old_int19_seg ; old interrupt vector back
mov ds:[19h*4+2],ax
popa ; Enable interrupts
jmp old_int19
assume ds:d_seg
int_19_entry endp
endif
;**************************************************************************
;
; Local data
;
; This data (as some from the Configuration tables too) is used by the
; two above routines that are needed resident in any case.
;
;**************************************************************************
XMS_block struc
XMS_sizel dw ?
XMS_sizeh dw ?
XMS_shandle dw ?
XMS_soffl dw ?
XMS_soffh dw ?
XMS_dhandle dw ?
XMS_doffl dw ?
XMS_doffh dw ?
XMS_block ends
XMS_cblk XMS_block <> ; XMS move command data structure
XMS_entry dd ? ; XMS driver entry point
XMS_handle dw -1 ; XMS handle to disk memory
IO_sectors dw ? ; Temp storage for # of sec xferred
IO_startl dw ? ; Temp storage for starting sector
IO_starth dw ? ; Temp storage for starting sector
else ; if XMS_MEMORY
%out Memory defined by MEMORY not supported
.err
endif
if HOOKINT19
old_int19 label dword ; Address of old INT 19
old_int19_off dw -1
old_int19_seg dw -1
endif
;**************************************************************************
;
; Debugging code
;
; This code prints out a character and a word in hex. This code can be
; used using "debug char,word" macro in the code to give some output of
; the actions device driver is doing.
;
; A color display is assumed with 80 characters on a row and 25 rows.
;
;**************************************************************************
if DEBUGGING
assume ds:nothing
debug_c proc near
push es
push di
mov ah,d_attr ; Load color attribute
mov di,0B800h ; Load screen segment (assumes color)
mov es,di
mov di,d_loc ; Load line
cmp di,26*160 ; Below screen?
jb debug_c1
mov di,2*160 ; Yes, move to third line (for scroll off)
mov d_loc,di
add ah,10h ; Change color
cmp ah,70h
jb debug_c2
sub ah,60h
debug_c2: mov d_attr,ah
debug_c1:
add di,d_col ; Advance to right column
mov es:[di],ax ; Print error letter
call debug_x ; Print high byte
mov dh,dl
call debug_x ; Print low byte
add d_loc,160 ; Next line
pop di
pop es
ret
debug_c endp
debug_x proc near ; Print a byte in hex
mov al,dh
shr al,1
shr al,1
shr al,1
shr al,1
call debug_x1
mov al,dh
debug_x1: and al,0Fh ; Print a hex digit
cmp al,10
jae debug_x2
add al,'0'
jmp debug_x3
debug_x2: add al,'A'-10
debug_x3:
inc di
inc di
mov es:[di],ax
ret
debug_x endp
d_loc dw 2*160
d_col dw 150
d_attr db 40h
assume ds:d_seg
endif ; DEBUGGING
;**************************************************************************
;
; Configuration tables
;
; This structure holds all the formatting data used by the formatter.
; The formatter is passed a pointer to this data and it modifies it
; directly. For this arrangement to work THE BELOW TABLE MAY NOT BE
; MODIFIED WITHOUT PROPER CHANGES IN SRDISK.C. The table contains
; version number which is to be changed when a change is made to this
; structure.
;
; Only the first fields up to label addition_eor is resident and used in
; in every case. The rest is used only in the main driver in a chain of
; RAM disk drivers.
;
; !!! The formatter will use any initial values in this structure as
; default values i.e. set all needed values here !!!
;**************************************************************************
READ_ACCESS equ 1 ; Bit masks for the RW_access
WRITE_ACCESS equ 2
config_s struc
c_drive db ? ; Drive letter
c_flags db CAPABLE ; Misc capability flags
c_disk_IO dd disk_IO ; disk_IO entry
c_malloc dw malloc ; malloc entry offset (in DS/CS)
c_next dw 0 ; Segment of next driver in chain
c_maxK dd 0FFFFh ; Maximum allowed size
c_size dd 0 ; Current allocated size in Kbytes
c_sectorsl dw 0 ; Sectors in this driver (low word)
c_sectorsh dw 0 ; Sectors in this driver (high word)
c_BPB_bps dw 128 ; Sector size
c_BPB_spc db 4 ; Cluster size 4*128 = 512
c_BPB_reserved dw 1 ; The boot sector is reserved
c_BPB_FATs db 1 ; One FAT copy
c_BPB_dir dw 64 ; 64 entries in root directory
c_BPB_sectors dw 0 ; BPB number of sectors on disk
c_BPB_media db 0FAh ; Media is RAM DISK
c_BPB_FATsectors dw ? ; Sectors per one FAT
c_BPB_spt dw -1 ; Sectors per track (imaginary)
c_BPB_heads dw 1 ; Number of heads (imaginary)
c_BPB_hiddenl dw 0 ; # of hidden sectors (low word) (imag)
c_BPB_hiddenh dw 0 ; # of hidden sectors (high word)
c_BPB_tsectorsl dw 0 ; 32-bit # of sectors (low word)
c_BPB_tsectorsh dw 0 ; 32-bit # of sectors (high word)
c_tsize dd 0 ; Total size in Kbytes (all drivers)
c_RW_access db 00b ; B0 = read, B1 = write (disabled now)
c_media_change db 1 ; -1 if media changed, 1 if not
c_open_files dw 0 ; Files currently open on drive
c_next_drive dw 0 ; Segment of next SRDISK drive
config_s ends
conf config_s <>
appended_eor equ conf.c_BPB_spc ; End of resident for appended driver
;**************************************************************************
;
; Other internal and resident data
;
; The order of this data is not significant as it will not be used outside
;
;**************************************************************************
BPB equ byte ptr conf.c_BPB_bps
pBPB dw offset BPB ; Pointer to BPB (for cmd_init)
old_multiplex dd ? ; Multiplex hook
if CAPABLE and C_APPENDED
xaddr_off dw ? ; Temp data for cmd_io
xaddr_seg dw ?
xsecl dw ?
xsech dw ?
endif
req_ptr dd ? ; Request structure pointer
; Pointers to commands
command_tbl dw cmd_init ; 0 Init
dw cmd_media ; 1 Media
dw cmd_BPB ; 2 Build BPB
dw cmd_unknown ; 3 IOCTL input
dw cmd_input ; 4 Input
dw cmd_unknown ; 5 nondest input (char)
dw cmd_unknown ; 6 input status (char)
dw cmd_unknown ; 7 input flush (char)
dw cmd_output ; 8 Output
dw cmd_output ; 9 Output with verify
dw cmd_unknown ; 10 output status (char)
dw cmd_unknown ; 11 output flush (char)
dw cmd_unknown ; 12 IOCTL output
dw cmd_open ; 13 Open device
dw cmd_close ; 14 Close device
dw cmd_removable ; 15 Removable media check
HIGH_CMD EQU ($-offset command_tbl)/2
;**************************************************************************
;
; Set request header address
;
; Called by DOS to set the request structure pointer
;
;**************************************************************************
strategy proc far
mov word ptr cs:req_ptr,bx
mov word ptr cs:req_ptr+2,es
ret
strategy endp
;**************************************************************************
;
; Commands
;
; Called by DOS. Requested action defined in structure pointed by req_ptr.
;
;**************************************************************************
commands proc far
assume ds:nothing
push ax
push bx
push cx
push dx
push si
push di
push ds
push es
cld
lds si,cs:req_ptr
; We trust Microsoft that the unit is right at [req_ptr]+1
mov cx,[si+12h] ; Sectors/Cmd line/BPB pointer
mov dx,[si+14h] ; Start sector/Device number
mov bl,[si+2] ; Command
cmp bl,HIGH_CMD ; Is command supported?
ja cmd_unknown ; Jump if not
xor bh,bh ; Count index to command_tbl
shl bx,1
les di,dword ptr [si+0Eh] ; ES:DI = transfer address
push cs
pop ds ; DS to local data segment
assume ds:d_seg
jmp word ptr [command_tbl+bx] ; Do command
cmd_unknown:
assume ds:nothing
mov al,3
jmp cmd_error
cmd_IOerr:
lds bx,req_ptr
mov word ptr [bx+12h],0 ; Sector count zero
cmd_error:
mov ah,81h ; ERROR and DONE
jmp cmd_ret
cmd_removable: ; Enough to return DONE without BUSY flag set
cmd_ok:
mov ah,1 ; DONE
cmd_ret:
lds bx,req_ptr
mov [bx+3],ax ; save status
pop es
pop ds
pop di
pop si
pop dx
pop cx
pop bx
pop ax
retf ; Return far
assume ds:d_seg
commands endp
;**************************************************************************
;
; Media Check command
;
;**************************************************************************
cmd_media proc near
les bx,req_ptr
mov ax,100h ; DONE status
mov dh,conf.c_media_change ; Read the change return
test conf.c_RW_access,READ_ACCESS
jnz cmd_media1
mov ax,8102h ; "Device not ready" status
mov dh,-1 ; "Changed"
cmd_media1:
mov es:[bx+0Eh],dh
mov word ptr es:[bx+0Fh],offset dr_volume
mov es:[bx+11h],cs
jmp cmd_ret
cmd_media endp
;**************************************************************************
;
; Build BPB command
;
;**************************************************************************
cmd_BPB proc near
les bx,req_ptr
mov word ptr es:[bx+12h],offset BPB
mov es:[bx+14h],cs
mov conf.c_open_files,0 ; Reset open files to 0
mov conf.c_media_change,1 ; Media not changed
test conf.c_RW_access,READ_ACCESS
jz cmd_BPB1
jmp cmd_ok
cmd_BPB1:
mov al,2 ; "Device not ready"
jmp cmd_error
cmd_BPB endp
;**************************************************************************
;
; Device Open command
;
;**************************************************************************
cmd_open proc near
inc conf.c_open_files
jmp cmd_ok
cmd_open endp
;**************************************************************************
;
; Device Close command
;
;**************************************************************************
cmd_close proc near
cmp conf.c_open_files,0
jz cmd_close1
dec conf.c_open_files
cmd_close1:
jmp cmd_ok
cmd_close endp
;**************************************************************************
;
; INPUT command
;
;**************************************************************************
cmd_input proc near
test conf.c_RW_access,READ_ACCESS
jz cmd_input1
xor bh,bh
jmp cmd_io
cmd_input1:
mov al,2 ; "Device not ready"
jmp cmd_IOerr
cmd_input endp
;**************************************************************************
;
; OUTPUT command
;
;**************************************************************************
cmd_output proc near
mov al,0 ; "Write protect violation"
mov bh,1
test conf.c_RW_access,WRITE_ACCESS
jnz cmd_io
jmp cmd_output2
cmd_io:
; BH - read/write
; CX - sectors
; ES:DI - transfer address
; DS = CS
mov ax,cx ; Count number of bytes to move
mul conf.c_BPB_bps
jc cmd_output4 ; Is it too much? (dx != 0)
; check transfer address and count that they do not
; exceed segment limit
add ax,di ; (dx = 0 after the mul)
jnc cmd_output5
cmd_output4:
mov ax,di ; How many bytes CAN we move?
xor ax,-1
xor dx,dx ; How many sectors?
div conf.c_BPB_bps
mov cx,ax
cmd_output5:
push es
les si,req_ptr
mov word ptr es:[si+12h],dx ; Xferred 0 sectors so far
cmp byte ptr es:[si],1Ah ; Do we use 32-bit sec. address?
jbe cmd_output3
debug '3',0
mov ax,es:[si+1Ah] ; Load 32-bit sec. address
mov dx,es:[si+1Ch]
jmp cmd_output8
cmd_output3:
mov ax,es:[si+14h] ; Load 16-bit sec. address
xor dx,dx
cmd_output8:
pop es
if CAPABLE and C_APPENDED
mov si,offset conf
mov xaddr_off,di
mov xaddr_seg,es
mov xsecl,ax
mov xsech,dx
; BH - read/write
; CX - sectors
; DS:SI - conf of current driver (main here)
cmd_output7:
push bx
push cx
call [si].c_disk_IO
pop cx
pop bx
les di,cs:req_ptr ; Increment number of sectors
add word ptr es:[di+12h],ax ; actually transferred
jc cmd_output1 ; I/O error
sub cx,ax ; All transferred?
jbe cmd_output6 ; yes, so exit
debug 'N',ax
push ax
mul [si].c_BPB_bps ; Increment transfer offset
add cs:xaddr_off,ax ; which can not exceed 0FFFFh
pop ax
xor dx,dx
add ax,cs:xsecl ; Count new starting sector
adc dx,cs:xsech
sub ax,conf.c_sectorsl ; Subtract passed sectors
sbb dx,conf.c_sectorsh
mov cs:xsecl,ax ; And store the result
mov cs:xsech,dx
mov es,cs:xaddr_seg ; Load these ready for disk_IO
mov di,cs:xaddr_off
mov ds,[si].c_next ; Find next driver
mov si,dr_conf
or si,si
jnz cmd_output7
; there is no next driver - sectors not found!
debug 'E',cx
else ;if CAPABLE and C_APPENDED
push cx
call disk_IO
pop cx
les si,cs:req_ptr ; Return number of sectors
mov word ptr es:[si+12h],ax ; actually transferred
jc cmd_output1 ; I/O error
cmp ax,cx
je cmd_output6
endif
cmd_output1:
debug 'S',ax
mov al,8 ; "Sector not found"
cmd_output2:
jmp cmd_IOerr
cmd_output6:
jmp cmd_ok
cmd_output endp
;**************************************************************************
;
; MULTIPLEX server
;
;**************************************************************************
multiplex proc far
cmp ax,MULTIPLEXAH * 100h
jne mplex_old
mov al,-1 ; Tell we are installed
push cs ; Tell our segment
pop es
iret
mplex_old:
jmp cs:old_multiplex
multiplex endp
;**************************************************************************
;**************************************************************************
;**************************************************************************
;**************************************************************************
;
; INITIALIZATION TIME CODE
;
; This code and data is removed from the memory after driver is
; initialized.
;**************************************************************************
end_of_resident label byte ; MARKS THE END OF RESIDENT PORTION OF DRIVER
def_drive db 'C' ; Default drive, where to install
main_config dd ? ; Pointer to main configuration table
FLAG_1ST EQU 1 ; First SRDISK driver
FLAG_FORCEDRIVE EQU 2 ; Force drive letter (in s_drive)
FLAG_APPEND EQU 4 ; Append to other SRDISK driver
FLAG_APPENDED EQU 8 ; Appended to other SRDISK driver
flags db 0
;**************************************************************************
;
; prints macro
;
; This macro is used by initialization routines to display text.
; dx must point to the '$' terminated text about to be displayed.
;**************************************************************************
prints macro
mov ah,9
int 21h
endm
if DEBUGINIT
print_x proc near ; Print a dword in hex
print_lx: push ax
mov ax,dx
call print_sx
mov ah,2
mov dl,':'
int 21h
pop ax
print_sx: ; Print a word in hex
push ax
mov al,ah
call print_cx
pop ax
print_cx: ; Print a byte in hex
push ax
shr al,1
shr al,1
shr al,1
shr al,1
call print_x1
pop ax
print_x1: and al,0Fh ; Print a hex digit
cmp al,10
jae print_x2
add al,'0'
jmp print_x3
print_x2: add al,'A'-10
print_x3: mov ah,2
push dx
mov dl,al
int 21h
pop dx
ret
print_x endp
idebugc macro chr
push ax
mov al,chr
call print_cx
pop ax
endm
idebugs macro wrd
push ax
mov ax,wrd
call print_sx
pop ax
endm
idebugl macro high,low
push ax
push dx
mov ax,low
mov dx,high
call print_lx
mov ah,2
mov dl,' '
int 21h
pop ax
pop dx
endm
else
idebugc macro chr
endm
idebugs macro wrd
endm
idebugl macro high,low
endm
endif
;**************************************************************************
;
; INIT command
;
; Init command does the following:
; - displays sign-on message
; - checks DOS version. This driver is built in a way that requires
; at least dos version 2.00. I'm not sure whether even that is enough.
; - determine which drive we are by default
; - read command line
; - abort on syntax errors
; - initialize memory to 0K disk
; - initialize multiplex interrupt
; - do hooks to other SRDISK drivers (specified in command line)
; - hook INT 19 bootstrap interrupt
; - fills in the request header
;**************************************************************************
cmd_init proc near
mov dx,offset s_sign_on ; "ReSizeable RAMdisk ver..."
prints
mov ah,30h
int 21h ; Get DOS version number
xchg ah,al
idebugs ax
cmp ax,200h
jb cmd_init1
cmp ax,600h
jb cmd_init2
cmd_init1:
mov dx,offset errs_eDOS
jmp cmd_init_err
cmd_init2:
cmp ax,400h
jae cmd_init4
and conf.c_flags,NOT C_32BITSEC
cmd_init4:
les si,req_ptr
idebugl es,si
idebugc <byte ptr es:[si]>
idebugc <byte ptr es:[si+2]>
idebugs <word ptr es:[si+16h]>
cmp byte ptr es:[si],16h ; Device number supported?
mov al,'$' ; Unknown drive
jbe cmd_init8 ; No, make a guess
mov al,es:[si+16h] ; Get drive number
add al,'A'
cmd_init8:
mov s_drive,al
mov def_drive,al
jmp cmd_init5
cmd_init5: call init_read_cmdline
jc cmd_init_err
call init_memory
jc cmd_init_err
call init_mplex
jc cmd_init_err
call init_hooks
jc cmd_init_err
if HOOKINT19
call set_int19
endif
mov word ptr conf.c_disk_IO+2,cs
mov al,s_drive
mov conf.c_drive,al
test flags,FLAG_APPENDED
jz cmd_init7
mov s_appdrive,al ; Report append
mov dx,offset s_appended
prints
mov bx,offset ret_far ; Strategy and commands short
mov drhdr_strategy,bx
mov drhdr_commands,bx
mov drhdr_attr,8000h ; Plain character device
mov drhdr_units,'$' ; Name for this driver '$RDISK'
lds bx,req_ptr
mov byte ptr [bx+0Dh],1 ; One drive
mov [bx+0Eh],offset appended_eor ; Ending address
jmp cmd_init3
cmd_init_err:
prints
cmd_init_abort:
call deinit ; Remove hooks
xor ax,ax
lds bx,req_ptr
mov byte ptr [bx+0Dh],al ; Zero the number of drives
mov [bx+0Eh],ax ; Ending address
jmp cmd_init3
cmd_init7: ; Not appended to previously installed SRDISK driver
mov al,s_drive
cmp al,'$' ; Is the drive number known?
jne cmd_init9
mov word ptr s_drive,2020h ; Don't tell drive
cmd_init9:
push ax ; Save al for forcing
mov dx,offset s_installed ; Report install
prints
pop ax
lds bx,req_ptr
mov byte ptr [bx+0Dh],1 ; Save number of drives
cmp byte ptr [bx],16h
jbe cmd_init6
; mov al,s_drive ; Force drive number
cmp al,'$' ; Is the number known?
je cmd_init6
sub al,'A'
mov [bx+16h],al
cmd_init6:
mov word ptr [bx+0Eh],offset end_of_resident
cmd_init3:
mov [bx+10h],cs
mov word ptr [bx+12h],offset pBPB
mov [bx+14h],cs
jmp cmd_ok
cmd_init endp
;**************************************************************************
;
; READ COMMAND LINE
;
; Return carry set if error
;**************************************************************************
init_read_cmdline proc near
push ds
les bx,req_ptr
lds si,es:[bx+12h] ; Pointer to cmd line
assume ds:nothing
irc1: lodsb ; Skip over the driver name
cmp al,9 ;tab
je irc2
cmp al,' '
je irc2
ja irc1
jmp irc_eol
irc2:
irc_narg: call irc_skip_space
cmp al,' ' ; Every ctrl character ends
jb irc_eol
cmp al,'/'
jz irc_switch
and al,11011111b ; Make lowercase to uppercase
cmp al,'A'
jb irc_syntax
cmp al,'Z'
ja irc_syntax
cmp byte ptr [si],':'
jne irc3
inc si ; Skip ':'
irc3:
mov byte ptr s_drive,al
test flags,FLAG_FORCEDRIVE
jnz irc_syntax
or flags,FLAG_FORCEDRIVE
jmp irc_narg
irc_syntax: mov dx,offset errs_syntax
stc
pop ds
ret
irc_switch: lodsb
and al,11011111b ; Make lowercase to uppercase
cmp al,'A'
jne irc_syntax
or flags,FLAG_APPEND
jmp irc_narg
irc_eol: clc
pop ds
ret
init_read_cmdline endp
irc_skip_space proc near
ircs1: lodsb
cmp al,' '
je ircs1
cmp al,9 ;tab
je ircs1
ret
irc_skip_space endp
assume ds:d_seg
;**************************************************************************
;
; Memory initialization
;
; Returns
; carry set if error
;**************************************************************************
if XMS_MEMORY
; Get XMS driver API address and allocates 0K to get a memory handle
; for RAM disk
init_memory proc near
push es
mov ax,4300h
int 2Fh ; Get XMS installed status
cmp al,80h
jne init_XMS1 ; Jump if not installed
mov ax,4310h
int 2Fh ; Get XMS entry point
jnc init_XMS2 ; Jump if no error
init_XMS1:
mov dx,offset errs_noXMS ; "No extended mem driver"
jmp init_XMS4
init_XMS2:
mov word ptr XMS_entry,bx
mov word ptr XMS_entry+2,es
xor dx,dx ; Allocate 0K to get a handle
mov ah,9
call XMS_entry
or ax,ax
jz init_XMS3 ; Zero for failure
mov XMS_handle,dx
clc
jmp init_XMS_ret
init_XMS3:
mov dx,offset errs_ealloc ; "Error in ext mem alloc"
init_XMS4:
stc
init_XMS_ret:
pop es
ret
init_memory endp
else
%out Memory defined by MEMORY not supported
.err
endif
;**************************************************************************
;
; Multiplex service initialization
;
; Queries multiplex interrupt to find out if SRDISK device drivers are
; already installed. If not install the multiplex server.
;
; Return carry set if error.
;**************************************************************************
init_mplex proc near
push ds
push es
mov ax,MULTIPLEXAH * 100h
xor bx,bx
xor cx,cx
xor dx,dx
int 2Fh ; ES segmet of main SRDISK driver
cmp al,-1 ; Is something installed?
je im_installed
cmp al,0 ; Is it OK to install?
je im_install
im_used: ; Garbled return
mov dx,offset errs_ml_used
im_err: stc
jmp imx
im_installed: cmp word ptr es:dr_ID,'RS' ; Is it SRDISK structure?
jne im_used ; No, multiplex used elsewhere
cmp byte ptr es:dr_ID+2,'D'
jne im_used ; No, multiplex used elsewhere
mov dx,offset errs_ml_version
cmp byte ptr es:dr_v_format,V_FORMAT ; Proper version?
jne im_err ; No
; OK
mov di,es:dr_conf
mov word ptr main_config,di
mov word ptr main_config+2,es
jmp im_end
im_install: mov word ptr main_config,offset conf
mov word ptr main_config+2,ds
or flags,FLAG_1ST
mov ax,352Fh
int 21h
mov word ptr old_multiplex,bx
mov word ptr old_multiplex+2,es
mov dx,offset multiplex
mov ax,252Fh
int 21h
im_end: clc
imx: pop es
pop ds
ret
init_mplex endp
;**************************************************************************
;
; INIT HOOKS to previous SRDISK drivers
;
; Append this driver into the list of installed SRDISK drivers
; Return carry set if error
;**************************************************************************
init_hooks proc near
test flags,FLAG_1ST ; If we are the first driver
jnz ihxok ; no hooks are to be done
les di,main_config ; es:di point to a drive config
mov al,s_drive ; al is the drive to search
cmp al,'$' ; Is drive letter unknown?
je ih_nodrive ; Yes, do not check drive letter
test flags,FLAG_APPEND ; If we append
jz ih_find_drive
test flags,FLAG_FORCEDRIVE ; but not specify drive
jnz ih_find_drive
ih_nodrive: mov al,-1 ; make sure drive not found
ih_find_drive:
ih1: cmp es:[di].c_drive,al ; Is it the same drive?
je ih_append
ih2: test word ptr es:[di].c_next_drive,-1 ; Is there next drive
jz ih_newdrive ; No (valid segment is nonzero)
mov es,es:[di].c_next_drive ; Yes, find the next drive
mov di,es:dr_conf
jmp ih1
ih_append_new: ; Append this driver into previously installed drive
mov al,es:[di].c_drive ; Find the drive letter
mov s_drive,al
mov conf.c_drive,al
ih_append: ; Append this driver into specified drive
test es:[di].c_flags,C_APPENDED ; Append allowed?
jz ih_appendfail ; No, fail
test word ptr es:[di].c_next,-1 ; Is there next driver
jz ih_a1 ; No, append here
mov es,es:[di].c_next ; Yes, find the next drive
mov di,es:dr_conf
jmp ih_append
ih_appendfail: mov al,def_drive
mov s_drive,al
mov dx,offset errs_noappend
stc
ret
ih_a1: mov es:[di].c_next,ds
or flags,FLAG_APPENDED ; Remember to free extra memory
if DEBUGGING
mov ax,es:d_col ; Debug data little left from
sub ax,16 ; main data
mov d_col,ax
endif ;DEBUGGING
jmp ihxok
ih_newdrive: test flags,FLAG_APPEND
jnz ih_append_new
; This driver must be placed at the tail of list of
; SRDISK drivers
mov es:[di].c_next_drive,ds
ihxok: clc
ihx:
ret
init_hooks endp
;**************************************************************************
;
; INT 19 hooking
;
; INT 19 is the bootstrap loader interrupt, which is invoked when user
; presses Ctrl-Alt-Del. We must hook it in order to release the
; extended memory allocated for RAM disk.
;**************************************************************************
if HOOKINT19
set_int19 proc near
push ax
push dx
push bx
push es
mov ax,3519h
int 21h ; Get old int 19 handler
mov old_int19_off,bx
mov old_int19_seg,es
mov dx,offset int_19_entry
mov ax,2519h
int 21h ; Set new int 19 handler
pop es
pop bx
pop dx
pop ax
retn
set_int19 endp
endif
;**************************************************************************
;
; Deinitialization in case of aborted install
;
;**************************************************************************
deinit proc near
if HOOKINT19
mov ax,old_int19_seg
or ax,old_int19_off
jz di_noint19
push ds
mov dx,old_int19_off
mov ds,old_int19_seg
mov ax,2519h
int 21h ; Set old int 19 handler
pop ds
di_noint19:
endif
if XMS_MEMORY
cmp XMS_handle,-1
je di_nomem
mov dx,XMS_handle
mov ah,0Ah
call XMS_entry ; Free XMS memory
else
%out Memory defined by MEMORY not supported
.err
endif
di_nomem:
mov ax,word ptr old_multiplex
or ax,word ptr old_multiplex+2
jz no_mplex
push ds
mov dx,word ptr old_multiplex
mov ds,word ptr old_multiplex+2
mov ax,252Fh
int 21h ; Set old multiplex handler
pop ds
no_mplex:
ret
deinit endp
;**************************************************************************
;
; Initialization strings
;
;**************************************************************************
errs_noXMS db 'RAMDisk: Extended Memory Manager not present.'
db 0Dh, 0Ah, '$'
errs_ealloc db 'RAMDisk: Error in extended memory allocation.'
db 0Dh, 0Ah, '$'
errs_eDOS db 'RAMDisk: Incorrect DOS version.'
db 0Dh, 0Ah, '$'
errs_ml_used db 'RAMDisk: Multiplex interrupt already in use.'
db 0Dh, 0Ah, '$'
errs_ml_version db 'RAMDisk: Driver of different version already '
db 'installed.'
db 0Dh, 0Ah, '$'
errs_noappend db 'RAMDisk: Can not append to previously installed driver.'
db 0Dh, 0Ah, '$'
errs_syntax db 'RAMDisk: Syntax error', 0Dh, 0Ah, 0Dh, 0Ah
db 'Syntax: RDISK.SYS [d:] [/A]', 0Dh, 0Ah, 0Dh, 0Ah
db ' d:', 9, 'Drive into which to force this driver. '
db 'If another ', 0Dh, 0Ah
db 9, 'SRDISK driver already is installed into '
db 'the same drive', 0Dh, 0Ah
db 9, 'this driver will be appended to the drive.'
db 0Dh, 0Ah
db ' /A', 9, 'Append this driver to previous SRDISK '
db 'driver.'
db 0Dh, 0Ah, '$'
s_sign_on db 0Dh, 0Ah, 'ReSizeable RAMDisk '
if XMS_MEMORY
db '(XMS)'
else
%out Memory defined by MEMORY not supported
.err
endif
db ' version ', SRD_VERSION, '. '
db 'Copyright (c) 1992 Marko Kohtala.'
db 0Dh, 0Ah, '$'
s_installed db 'Installed RAMDrive '
s_drive db 'C:', 0Dh, 0Ah, '$'
s_appended db 'Appended to RAMDrive '
s_appdrive db 'C:', 0Dh, 0Ah, '$'
;**************************************************************************
;
; A note for binary debuggers
;
;**************************************************************************
db "Copyright (c) 1992 Marko Kohtala. "
db "Contact from Internet, Bitnet etc. to 'Marko.Kohtala@hut.fi', "
db "CompuServe to '>INTERNET:Marko.Kohtala@hut.fi'"
d_seg ends
end
SRDISK.DOC
ReSizeable RAMDisk version 1.30
for XMS memory only
Copyright (c) 1992 Marko Kohtala
Freeware
SRDISK is offered to you "AS IS" without any warranty. I do not require
any money for you using it, so I can not pay you any if you loose some
for using it. It is impossible for me to say this program will work on
every computer and DOS version you try to run in on - so don't rely on
it.
Previous versions of this software were in public domain. You may use
them freely for what ever purpose you want.
This version is NOT public domain. It's freeware; I grant you right to
run, copy and distribute this software as long as it is unmodified,
includes all the original files and you do not take any kind of payment
for distributing it.
If you want to use my code in your programs or modify it, contact me,
you'll have a change to get my permission, and make it legal.
CONTENTS
1. Publishing purpose, features included and recognised missing
2. Files in this release
3. Usage
3.1. Basic installation
3.2. Driver
3.3. SRDISK program
4. Technical data for further development
5. Troubleshooting
6. Last words
1. PUBLISHING PURPOSE, FEATURES INCLUDED AND RECOGNISED MISSING
This RAM disk driver is published in the hope we will get a really good
RAM disk that is free. I do not intend to make it all out myself but
rather hope there is out there someone who is willing to participate in
my work.
This RAM disk currently supports the following features:
* XMS (Extended memory on 286 and up with HIMEM or other XMS driver)
support - no other memory drivers - yet
NEW Device drivers may be chained to form larger disks using many
different kind memories.
* Resizeable/removable - destructive
NEW Supports 32-bit sector addressing introduced in DOS 4. Thus over 32M
RAM disks are possible. (Up to 63M disks tested.)
* Configurable
- sector size
- cluster size
- root directory entry count
- number of FATs
* Predefined DOS disk like formats
* Write protection
* Compatible with DOS versions from 2.00 to 5.x
(tested only with DOS 5.0 and 3.30)
* Stores last format time in volume label
NEW Can optionally set environment variables SRDISKn (n=1,2,...) to
the installed SRDISK drive letters.
What I would like to see added:
* Resizing of the disk without loosing disk contents
* EMS support
* UMB support
* Bank-Switch memory support ("The Last Byte" by Key Software)
* Low memory support
2. FILES IN THIS RELEASE
The following material is distributed in this release:
SRDISK.DOC this document
SRDISK.C disk formatter source code for Turbo C++ 1.0
SRDISK.ASM device driver source code for XMS
SRDISK.SYS compiled device driver
SRDISK.EXE compiled formatter program for the RAM disk
FILE_ID.DIZ short description of packet for BBS operators
3. USAGE
The SRDISK is basicly split in to two parts:
1) a device driver to add the virtual drive into DOS and
2) a program to control the device driver
The following explains the installation and how to use both of these
parts.
3.1. BASIC INSTALLATION
The basic installation can be done following the below steps:
1. Copy SRDISK.SYS into you root directory.
2. Copy SRDISK.EXE into some directory in your PATH
3. Add into your CONFIG.SYS line
DEVICE=SRDISK.SYS
4. Add into your AUTOEXEC.BAT after the PATH command line
SRDISK <size>
The <size> defines the disk size in Kbytes.
3.2. DRIVER
The driver can accept two parameters:
DEVICE=SRDISK.SYS [d:] [/A]
The [] around the parameter mean it is optional; you must not type the
brackets.
Both of the options are usually useless. They are ment for chaining
drivers to same virtual disk. Some use for them may be found, if drivers
for other memories are made. The RDISK.SYS in this release does not
support the chaining - it may be recompiled to support it though by
modifying equate CAPABLE in SRDISK.ASM.
The 'd:' is meant to force the RDISK.SYS into the specified drive. If
the specified drive is driven by another SRDISK device, this driver will
be appended into the other SRDISK device. If it is not driven by another
SRDISK device, the SRDISK will try to force DOS to give it the drive
letter. Though my DOS manual states this should be possible, I was not
able to make it work (with DOS 5.0), so the driver will later think it
is a different drive than DOS thinks it is.
/A switch is another, more preferable way to append the driver into a
previously installed driver. With it you need not worry about the drive
letter DOS has given to the previous driver. The appending means that
the devices will be chained into the same drive; different parts of the
virtual disk can then use different drivers and different kinds of
memory. All drivers may not allow other drivers to be appended to them.
If you see error messages, you may have forgotten to install the XMS
driver (eg. HIMEM.SYS) prior to the RDISK.SYS, or you have improper DOS
version or something. Try to fix the problem. If you fail... sorry.
Merely installing the driver gives you no RAM disk. It is as though you
had installed a floppy driver without putting a disk in the drive. For
that you need the SRDISK.EXE program.
3.3. SRDISK PROGRAM
The disk can be enabled by, for example, using command "SRDISK 1024"
which will make first SRDISK a 1024K disk. It can be disabled by making
it of size 0: "SRDISK 0".
You should include the command to enable the RAM disk into your
AUTOEXEC.BAT file.
The SRDISK is self documented. You'll get the documentation by typing at
the DOS prompt "SRDISK /?" and hitting enter.
4. TECHNICAL DATA FOR FURTHER DEVELOPMENT
The job is split between the device driver and the SRDISK program this
way:
Device driver does:
* What ever a RAM disk driver is expected by the DOS to do.
* Support multiplex interrupt server at AH=72h. Any program may
receive this way a pointer into a data structure that contains the
following data:
- BIOS parameter block for the drive.
- Disk size in K-bytes.
- Read/write access flags (read flag is actually enabled flag).
- Media byte.
- Flag to tell if the media has changed (set by SRDISK).
- Number of open files on drive.
- Pointer to the sector read/write function in the driver.
- Pointer to the memory allocation routine in the driver.
- Some information about what kind of memory can be used for the
disk.
- Pointers into next driver in the driver chain and into next
virtual SRDISK drive.
SRDISK.EXE does:
* Modify the drivers internal structures and call it's memory
allocation routine to change the size of allocated memory.
* Format the new disk i.e. write the boot sector, FAT(s) and root
directory according to the format sent to driver.
* Carries the responsibitity that the drivers structures and the disk
is OK.
I've done it this way because I did not want to bother myself adding the
SRDISK.EXE functions to the driver too. Some program was anyway needed
to control the driver.
The sources are somewhat documented. Also the used structures can be
found there - naturally.
Keep in mind, if you take advantage of this code, that the structures
are likely to change. Version 1.30 has still beta version of the
internal structures.
Also remember that there is a copyright on code. You'll though have good
chanse of getting license to develop a new driver using the SRDISK.ASM
as a base for your driver. Just contact me and tell me about it.
5. TROUBLESHOOTING
Causes of grief
1. RAM disks loose their contents when power is turned off! Do not store
anything valuable there.
2. There is no XMS memory without a proper device driver. HIMEM.SYS or
QEMM will do.
3. Not all HIMEM.SYS support memory above 16M limit. HIMEM.SYS that came
with MS-Windows 3.0 is reported be ok.
6. LAST WORDS
I HOPE you will send any modified versions, new drivers, better
documentation, bug reports, suggestions and your love (preferably
female) to me. If I can, I'll then add them to the next release of
SRDISK.
I'd like the modifications to sources as patches to some version the
number of which you should tell.
I'll make a list of every people contributing material to this product
and ship it with further releases. If modesty is one of your virtues, I
can leave you out of the list.
If you do not contribute anything into this driver and I get the drive
to not loose it's contents when size is changed, I'll probably change
into shareware. If I spend my time making this thing, I'll need the
money (as a student, I need it anyway :) ). I do not mind getting money
already at the below address; ALL support is appreciated.
You can contact me by sending E-mail from
Internet, Bitnet etc. to 'Marko.Kohtala@hut.fi'
CompuServe to '>INTERNET:Marko.Kohtala@hut.fi'
or by traditional mail to
Marko Kohtala
PL 115
SF-01451 Vantaa
FINLAND
or by calling Airline QBBS, 24H, HST, V.32, V.42, MNP, +358-0-8725380
and leaving mail to me, Marko Kohtala.
Directory of PC-SIG Library Disk #3052
Volume in drive A has no label
Directory of A:\
FILE_ID DIZ 290 1-18-92 1:30a
SRDISK ASM 52451 1-18-92 1:30a
SRDISK C 38839 1-18-92 1:30a
SRDISK DOC 9774 1-18-92 1:30a
SRDISK EXE 26596 1-18-92 1:30a
SRDISK SYS 2174 1-18-92 1:30a
FILE3052 TXT 1851 6-30-92 4:39p
GO TXT 770 6-30-92 4:46p
GO BAT 31 6-04-92 2:25a
9 file(s) 132776 bytes
25088 bytes free