Questions tagged [ms-dos]
MS-DOS, the Microsoft Disk Operating System, its OEM-branded versions, and x86 DOS clones in general.
305
questions
8
votes
2
answers
1k
views
How to use all memory on an IBM PC with 8086
I'm developing software for the IBM PC with an 8086 processor. I want my program to use all available memory.
I know that I can use DOS int 21h function AH=48h to allocate all available conventional ...
- 114k
5
votes
1
answer
858
views
MS DOS 6.22 hangs on modern hardware after loading HIMEM.SYS
I am trying to run MS-DOS 6.22 on modern hardware. I successfully created bootable flash disk with MS-DOS 6.22. But when it starts with HIMEM.SYS enabled in CONFIG.SYS it hangs. Searching Internet the ...
- 20.5k
2
votes
0
answers
220
views
MS-DOS Bear/Teddy Bear Spooky Halloween game?
In about 1993-4 I played a (probably free or shareware) MS-DOS game about a bear/teddy bear entering a house which was "spooky", I believe related to Halloween. Graphically it was primitive, ...
- 1
9
votes
1
answer
1k
views
Purpose of Recover command in MS-DOS
Continuing my reading of Dan Gookin's MS-DOS 6 pour les nuls (More DOS for Dummies ?), I've discovered in an otherwise light and funny (at least the French translation is) book about DOS a section ...
- 1,625
27
votes
5
answers
3k
views
Why does the FAT file system have separate ‘hidden’ and ‘system’ attributes?
File systems used by DOS and Windows have used file attribute bits as a relatively prominent feature. The first of them, FAT, exposes four attributes to the user: read-only, archive, hidden and ...
- 737
19
votes
1
answer
3k
views
How did SmartDrive work?
I've recently unearthed an old book called MS-DOS 6 pour les nuls (More DOS for Dummies) by famed C programmer Dan Gookin. It was (still to me) a very interesting book in which he talks about MS-DOS ...
- 375
34
votes
2
answers
5k
views
How did MS-DOS assign drive letters in the case of more than two floppy disk drives?
The IBM PC BIOS had provisions for up to four floppy disk drives, by virtue of returning the number of floppy disk drives in a two-bit field plus a none/some flag (allowing for reporting values of 0, ...
- 20.5k
8
votes
1
answer
338
views
What versions of MS-DOS or PC-DOS supported the "+,," syntax on COPY? Is there documentation on its origin?
I remember reading in an IBM PC-DOS manual, around 1988 maybe, that there was a special syntax of the COPY command :
COPY A.TXT +,,
which would simply update the file's last change date to now. This ...
- 2,038
15
votes
2
answers
1k
views
How much of the Program Segment Prefix area can be reused by programs with impunity?
I am writing a tiny TSR program, and I want it to take as little memory while installed as possible. The memory footprint of every loaded DOS process, including a TSR, includes a data structure known ...
- 622
11
votes
1
answer
1k
views
What was the purpose of the ‘overlay number’ field in the MZ executable format?
Many materials covering the layout of MZ executables (RBIL, for example, and even a comment in MS-DOS 2.0 source code) describe the word at offset +0x1a as the ‘overlay number’, with the value zero ...
- 199k
12
votes
3
answers
6k
views
Does the kernel of Windows 95/98/ME have a name?
In this question:
Why was the DOS kernel discarded?
I was told that DOS is not a kernel. It runs on CPUs that don't even have kernel mode. So how can it be a kernel? So I think this is right.
Now if ...
- 20.5k
9
votes
1
answer
490
views
How can I properly execute and clean up after a DOS MZ executable loaded into memory with int21 function 4b01h?
Ralf Brown's Interrupt List describes a subvariant of the DOS int21/4Bh function with AL=01, where the program is loaded into memory and a PSP + stack are allocated for it, but the program is not ...
- 252
15
votes
8
answers
7k
views
Why was the DOS kernel discarded?
I've read that the last DOS kernel based Windows was ME. Later versions use the NT kernel.
Why did Microsoft rewrite the whole kernel? Why was the DOS kernel discarded?
- 9,903
7
votes
1
answer
362
views
Origin of PALMPC.ZIP "Palm PC emulator"
The program PALMPC.COM, which is available on an old link in the Internet Archive, and also on e.g. S.U.P.E.R., apparently provides graphics emulation, including interrupt 0x5F used by the HP/Lotus ...
- 114k
14
votes
1
answer
556
views
What are these compression types in the ARC file format?
The file format of the SEA ARC compression tool, also used by the PKWare PKARC tool, allowed the following compression types:
Packing (RLE encoding)
Squeezing (static Huffman coding)
Crunching (LZW)...
CommunityBot
- 1
14
votes
4
answers
5k
views
Why have MS-DOS device drivers if the ROM BIOS provides access to the same devices already?
IO.SYS is an essential part of MS-DOS that contains the default MS-DOS device drivers.
IBMBIO.COM is a system file in PC-DOS. It contains the built-in device drivers.
Based on the answers of the ...
- 20.5k
22
votes
3
answers
5k
views
Why are these DOS console drivers wasting precious bytes?
While doing some research on DOS device drivers, I took a peek at the console drivers DISPLAY.SYS and ANSI.SYS that are part of the DOS 6.20 installation. Both have "Microsoft" stamped on, ...
- 20.5k
18
votes
3
answers
5k
views
How to keep running DOS 16 bit applications when Windows 11 drops NTVDM
I have a business client who runs an old DOS 16-bit accounting and point-of-sale system in his industrial supply warehouse. He does not want to switch from the legacy DOS application since all of his ...
- 20.5k
10
votes
3
answers
1k
views
How to write text in MODE 0x13?
I have read How to write directly to video memory using "debug.exe" in MS-DOS? and I know how to write text to video memory in mode 0x3 but I can't figure out how to write text to video ...
- 345
12
votes
2
answers
2k
views
What physical size and density floppies are the intermediate-capacity options for the /F switch of the DOS/Windows/OS/2 FORMAT command meant for?
In MS-DOS 5.0 and newer, PC-DOS 5.0 and newer, Windows 9x, Windows NT 3.1–2000, and OS/2 4.x, the FORMAT command (present in some form or another in literally every single version of Q/86-/MS-/PC-DOS, ...
- 20.5k
3
votes
0
answers
483
views
FreeDOS and USB support
I have an old Fujitsu LifeBook that I want to install Windows 98 on.
I burned a Windows 98 CD and verified it works, but the LifeBook's CD drive cant seem to read it. I do know the CD drive works, as ...
- 371
5
votes
2
answers
826
views
Which document format is this? (.MAN/.STR/.TAB/.IND)
I have these files, which were all in one .zip:
DPMANUAL.MAN
DPMANUAL.STR
DPMANUAL.IND
DPMANUAL.I01
DPMANUAL.I02
DPMANUAL.TAB
DPMANUAL.TXX
They are supposedly a manual (for DataPerfect).
The file ...
- 114k
16
votes
4
answers
5k
views
Is there any way today to recover/dump 2M disks?
2M disks where formatted using 2MGUI to increase 3"1/2 & 5"1/4 DD/HD/ED disks' capacity.
Is there any way today to recover/dump these disks to a file with modern hardware? Specially the 5"1/4 ...
- 114k
10
votes
2
answers
1k
views
SSH for DOS / Win 3.1
Is there an SSH client for DOS 6.22 or Windows 3.1 that supports certificates and could be used to connect to AWS or Azure instances, or any other server for that matter? I have another laptop ...
- 353
10
votes
11
answers
906
views
Towards people who were there, what programs did you use to develop applications for the IBM 5150? [closed]
I want to get into programming on old MS-DOS systems, before then going to older DOSs like CP/M. However, while programming for MS-DOS I'd like to also use era-appropriate software, both for the ...
- 1,937
13
votes
3
answers
3k
views
What DOS games used Mode X as described by Michael Abrash?
In Michael Abrash's Graphics Programming Black Book, many chapters are dedicated to fast drawing of primitives, fills and copies using the 320x240 256-colour Mode X.
What MS-DOS games used Mode X?
...
- 151
6
votes
1
answer
211
views
Row locking on RM/COBOL-85
Near 21-22 years ago I worked in a COBOL-based shop. This business had one LOB application written in RM/COBOL-85, and deployed it to multiple customers with different network types (Xenix with dumb ...
- 3,264
17
votes
3
answers
2k
views
Why can't I invoke the next interrupt service by incrementing the AX register after calling the same interrupt?
I have two snippets of 8086 assembly code, both of which are supposed to do the same thing: make the mouse appear on the screen.
Show_Mouse:
push ax
mov ax,0 ;Reset Mouse
int 33h
...
- 20.5k
27
votes
2
answers
4k
views
Did MS-DOS ever drop ability to support non-IBM PC compatible machines?
Early MS-DOS versions were designed and indeed adapted to run on machines not fully IBM PC compatible.
However, there seems to be a number of utilities bundled with later versions, that seem not to ...
- 114k
43
votes
9
answers
12k
views
Is DOS being shipped with or as an installed OS?
Given the very small size of DOS, it would seem it might still be ideal for some applications such as handheld games. Is any system manufacturer still shipping DOS with their machine?
If no one is ...
- 114k
15
votes
6
answers
2k
views
Video playback software/formats for a 386?
Wanting to have my 386DX @ 20MHz play a video (any video), just as a demo. I'd prefer it to be watchable (eg 10fps and not a tiny 10x10 pixel) as opposed to a slideshow.
What player software could I ...
- 149
25
votes
3
answers
5k
views
Did MS-DOS itself ever use blinking text?
I know that it was possible to create blinking text, but did the operating system itself (I mean, in output from functions of COMMAND.COM and similar executables) ever make use of blink formatting?
...
- 851
1
vote
1
answer
449
views
Why does Windows 95 not install so well from a Windows XP boot floppy? [closed]
EDIT: And this is why you shouldn't rely purely on memory for these sort of things. After some fiddling with my XP and Win95 disks, I remembered that the problems I was having were more likely related ...
- 551
6
votes
2
answers
438
views
SciTech's SVGAKit seems to be incomplete
I'm trying to get into MS-DOS development for fun, and I'd like to use SciTech's SVGAKit library. The last version of it is still downloadable via the Internet Archive here. However it seems to be ...
- 211
30
votes
3
answers
4k
views
What exactly did the "UNFORMAT" MS-DOS command do?
I found only this:
The UNFORMAT command is used to undo the effects of formatting a disk.
The command is available in MS-DOS versions 5 and later.
Source: https://en.wikipedia.org/wiki/...
- 114k
11
votes
2
answers
2k
views
How does MS-DOS 6 cache the DIR results?
I was wondering how the MS-DOS 6 DIR command works. I noticed that the floppy drive directory is cached so that the drive isn't read again when you run DIR a second time. In thinking there may be a ...
- 51
7
votes
1
answer
375
views
Software that emulated VGA high res mode on an EGA board
I have this very faint recollection from my late elementary school days back in the end of 1980s of a very specific piece of MS-DOS software that claimed to do what was an incredible thing to an ...
- 25.6k
9
votes
1
answer
422
views
What were the typical game development toolchains for the pre-i386 IBM PC era
On i386 and beyond (assuming MS-DOS as the target OS and IBM PC as the target platform), my impression is game developers most typically used Watcom C / DJGPP plus one of the DOS extenders (DOS4GW, ...
- 6,256
17
votes
1
answer
2k
views
TMP/TEMP Environment variables in Microsoft operating systems
The environment variables %TMP% and %TEMP% are the same. Reading the interesting Raymond Chen blog https://devblogs.microsoft.com/oldnewthing/20150417-00/?p=44213, it seems that %TEMP% was introduced ...
- 199k
3
votes
3
answers
324
views
Write fault error writing device COM1
I’m trying to send data between a no-name Celeron PC running MS-DOS 6.22 and a Digital VT520 serial terminal. I have connected COM1 to the terminal’s COMM1, but can’t get data to flow in either ...
16
votes
1
answer
6k
views
How to write directly to video memory using "debug.exe" in MS-DOS?
The base address for the video memory in MS-DOS is 0xB8000. I am trying to write to this address using debug.exe, but I am getting an error:
1165:0103 mov [b8000],ax
^ Error
- 1,937
19
votes
1
answer
2k
views
In MS-DOS, how much stack do I need to make an int21 call?
The context is that I'm calling DOS interrupts from DPMI using int31 / ax=0x300, and you have to tell it what stack you want the real mode call to have. By default you get a small stack of about 20 ...
- 114k
8
votes
2
answers
909
views
Compaq Contura Aero 4/33C - moving data to CF/IDE disk - No operating system detected
I've got a Compaq Contura Aero 4/33 laptop with original DOS system installed. As the HDD is old and dying, I've decided to copy the drive to a CF card on a CF/IDE adapter.
After connecting the drive, ...
- 20.5k
17
votes
2
answers
3k
views
In 16-bit MS-DOS, how do I get a file handle to the currently running .exe?
The context is that I have additional data in the .exe file and wish to access it.
I know this is possible, as plenty of programs would store extra data after the loadable part of an MZ .exe — most 32-...
- 20.5k
20
votes
6
answers
4k
views
Where is DOS stored in memory when a program starts?
When the execution of a COM program begins, DOS jumps to address 100h. But at what address is DOS stored in RAM while the COM program is executing? Is DOS stored in conventional memory? If so, isn't ...
- 7,887
23
votes
2
answers
2k
views
Slash versus backslash as directory separator – what/who caused this rift?
MS-DOS and derived systems use backslash \ for path separator and slash / for command parameters. Unix and a number of other systems used slash / for paths and backslash \ for escaping special ...
- 20.5k
21
votes
2
answers
2k
views
How can I access the VGA card's ROM fonts with interrupt 10h operation 1130h in protected mode C?
I'm using Open Watcom 1.9 to write some 286 real mode, and 386 protected mode software for DOS in C.
In real mode, I can retrieve a pointer to the system ROM character bitmaps in real mode using int ...
- 20.5k
91
votes
3
answers
16k
views
How did Windows 3.1 implement multitasking?
Windows in its earliest days was simply a shell that ran on top of MS-DOS, which means that Windows 3.1 itself was actually just a standard MS-DOS application like any other.
Yet, MS-DOS is not a ...
- 1,653
0
votes
2
answers
941
views
Get himem.sys working on an AMI 1.06.09 bios (not on VM)
I tried many 98SE boot disks online, they all boot successfully on my mobile workstation from USB (C:\>), but all can't run the Windows 98SE Installer because of XMS Memory, giving an error like:
...
- 227
26
votes
3
answers
7k
views
Why might Quake run slowly on a modern PC in DOS, but not in a virtual machine?
I noticed back in the DOS gaming era that DOS games ran slowly in hi-res modes. I was surprised to discover that this could be true on a modern machine.
I booted a 2017 i5 7200u (I think) laptop into ...
- 1,937