Questions tagged [ms-dos]
MS-DOS, the Microsoft Disk Operating System, its OEM-branded versions, and x86 DOS clones in general.
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Did MS-DOS have any support for multithreading?
Common wisdom seems to be that MS-DOS was an exclusively single-threaded OS. Of course, implementing a scheduler would be possible, but the OS itself did not provide any facilities for multithreading, ...
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How to make Microsoft C for MS-DOS emit an immediate-target far call into the data segment?
I am trying to recreate the C source code from some 16bit DOS 8086 assembly generated by the MS C 5.0 compiler. I've hit a wall with this far call instruction.
0000008D 9A2F0CB506 call 0x6b5:...
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Math and French practice floppies
A long time ago, at school, they used to provide us with some 5.25 inches floppies each year. The teacher used to boot Unisys PCs with some bootable floppies (I do not believe they had hard disks), we ...
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Basic page layout program from the PrintMaster 2.0 era
I remember it as "Fantasy" but the lack of results makes me think I may be wrong.
All I know for sure is that it was a single page layout program; it was contemporary with PrintMaster 2.0, ...
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What did Ctrl+NumLock do?
In my answer here I infer that the unusual scancode for the Pause/Break key emulates the user pressing and then releasing CtrlNumLock. Obviously that key combination did something specific, back when ...
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Did any DOS compatibility layers exist for any UNIX-like systems before DOS started to become outmoded?
Quoting from Jim Hall's "FreeDOS turns 25 years old: An origin story":
Around 1994, Microsoft announced that its next planned version of Windows would do away with MS-DOS. But I liked DOS. ...
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How did ‘logically-sectored FAT’ work?
While browsing online materials about the FAT file system, I occasionally came across mentions of ‘logically-sectored FAT’. This was apparently some kind of special mode of formatting a hard drive, ...
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Did Digital Research clean-room MS-DOS?
From https://en.wikipedia.org/wiki/DR-DOS
DR-DOS (written as DR DOS, without a hyphen, in versions up to and including 6.0) is a disk operating system for IBM PC compatibles. Upon its introduction in ...
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When did Kay Nishi offer a million dollars for a competing DOS?
The development of Digital Research's fully-compatible MS-DOS competitor, DR DOS, was encouraged when, according to https://retrotechnology.com/dri/dri_wein.html
After DOS Plus for Philips we did a ...
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Which is the first version of DOS to support more than one reserved sector in a FAT file system?
I'm trying to fix a problem when trying to use DOS stuff on SSDs. The problem is sector alignment in an SSD is completely different from what DOS expects, and writes to FAT do funny things when the ...
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Memory requirements for undelete command
During MS-DOS days, an Undelete command existed and provided three levels of protection. Sentry is pretty much the same as the Recycle Bin, it moves deleted files to a directory called Sentry. Tracker ...
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Disable motherboard floppy controller DOS
I have a SuperMicro P4SCA motherboard (manual) running FreeDOS 1.3. The motherboard has an onboard floppy controller as part of a W83627HG (datasheet). However, this floppy control fails to provide ...
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Why was the graphical user interface version of Defrag removed?
I remember in MS-DOS 6.22 that Defrag had a GUI that showed its progress and how it was moving files. It wasn't there in Windows XP and I can only assume that it wasn't in Windows 95, 98, 2000 either (...
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What type(s) of compressed files was the MS-DOS EXPAND command able to decompress?
What type(s) of compressed files was the MS-DOS EXPAND command able to decompress?
And what command was its counterpart?
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Which font with slashed zero is being used in this screengrab?
Do you know which font is being used in the video here: https://www.youtube.com/watch?v=xnudvJbAgI0? A screengrab of the video that shows a lot of text:
We can see that the zeros are slashed, so it ...
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Why did "protected-mode MS-DOS" never happen?
Software written for MS-DOS used DOS extenders as early as on PC/AT (DOS/16M), and starting from i386-based systems, DOS extenders became really widespread.
I'd think it was pretty obvious at the time ...
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Tiny libc for DOS 8086
I'm looking for a tiny libc (C runtime library) targeting small model DOS 8086, and providing (most of) the C89 library functions, including fread(...), printf(...) and scanf(...). The libc must work ...
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Disk compression risks in MS-DOS
Continuing my nostalgia reading of Dan Gookin's DOS For Dummies, there is a section that literally advises against compression programs like DriveSpace and calls it a solution to a problem not some ...
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Tandy 1000 TDYSPKR utility
I've seen reference to a TDYSPKR (.EXE or .COM?) tool that sets audio output options on the early Tandy 1000 series of computers (1000, 1000A, 1000SX, 1000TX, maybe others). Apparently it can toggle ...
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VisiCalc V1.0 is not working on modern computer as expected
I am trying to run Visicalc on the modern laptop (Lenovo Thinkpad X1 Extreme Gen.2). I created bootable flash drives with DOS 6.22 and Free DOS, booted from them and ran visicalc (vc.com file).
All ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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Looking for an open source DOS .com program written in assembly
I'm writing a NASM-compatible assembler targeting the Intel 8086, and I'm looking for an existing open source program written in assembly, with which I can showcase the capabilities (and understand ...
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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 ...
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9
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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 ...
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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 ...
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Most modern C compilers targeting DOS 8086, running on DOS 8086 (16-bit)
I'm looking for the most recent versions of modern C compilers which were/are targeting DOS 8086, also running on DOS 8086 (16-bit). I'm mostly interested in production-ready C compilers, rather than ...
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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?
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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/...
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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 ...
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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 ...
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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 ...
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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, ...
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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 ...
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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 ...
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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 ...
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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 ...
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