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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3k views

What tools were used in late MS-DOS era for reverse engineering and patching binary executables?

In the late MS-DOS era, what were the state of the art software tools for reverse engineering and patching binaries, i.e. .exe and .com files? A simple list of the tools that were "state of the art", ...
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4answers
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How do I create a boot menu to select between Windows and DOS?

I was not a PC user before Windows 98. But I remember one of my friends was using a boot menu in his 486 machine to select between Windows/DOS. The menu was like: 1. EMS 2. XMS 3. Windows If we ...
30
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1answer
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How does the command.com shell work with MS-DOS?

On my systems that are running MS-DOS, I change the default command.com to 4DOS for more features. How was the shell system designed and how did it with the operating system in MS-DOS that it enabled ...
29
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2answers
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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, ...
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2answers
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First commercial DOS game?

What was the first commercial game sold for use on IBM/MS/PC DOS after the IBM August 12, 1981 release.
63
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3answers
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Why did DOS use dollar-terminated strings?

According to a few tutorials I am seeing, DOS used dollar-terminated strings to write to the terminal. This seems to also be documented here on INT 21H. AH = 09h - WRITE STRING TO STANDARD OUTPUT ...
48
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9answers
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Why weren't bootable game disks ever common on the IBM PC?

While for other platforms of that era (primarily, Amiga), putting a game on a bootable disk was quite a normal practice, this approach never taken off on IBM PC. Why not? I do remember people having ...
28
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4answers
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What's the relationship betweeen MS-DOS and XENIX?

Browsing MS-DOS sources on GitHub, I often see mentions of XENIX: DOSSYM.ASM: ; XENIX calls all return error codes through AX. If an error occurred then the ; carry bit will be set and the ...
17
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1answer
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How did large .COM files work?

An MS-DOS .com file is just raw code/data without header, thus no linking information, and was limited to be loaded into just one segment (64kB). That's the reason corrupted binaries would print "...
14
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4answers
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For fast scrolling DOS games, when was Mode13h preferred over Mode X?

Back in the DOS days of gaming (more specifically, 80286 - 80486 era), developers typically needed to choose between using the chunky and easier Mode 13h or the more complex "Mode X" that provided ...
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3answers
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How can I create a pipe for stdin/stdout of command.com (or 4dos.com) in C or a batch file?

I'm working on a retro project and was trying to create a pipe of stdin/out/err in DOS, but I can't find any functions to to this. For instance the pipe() function from unistd.h isn't present in ...
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What character is the MS-DOS cursor?

The cursor used on my 486 (and Pentium 3) in MS-DOS 6/7 has a thick underlined character. I cannot find that in code page 437. The underscore character is the closest to it, but is thinner. Where ...
23
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3answers
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Why was "C:" chosen for the first hard drive partition?

I was reading this answer, as the question came to my mind: why does C: indicate the first hard drive partition? The usage dates back to CP/M (as noted in a comment), was embraced by MS-DOS, and ...
45
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2answers
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Did IBM encourage Bill Gates to retain the rights over PC-DOS?

As is well-known, Microsoft's negotiations with IBM to deliver PC-DOS 1.0 with the original IBM PC resulted in: IBM licensing the OS from Microsoft, as opposed to purchasing it outright. Microsoft ...
34
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3answers
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How did Windows ME "cripple" DOS?

Windows ME includes the ability to create a bootable DOS floppy. This floppy contains versions of COMMAND.COM and IO.SYS that are "crippled" to remove real mode. This is done with only one changed ...
26
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3answers
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Why does DOS ask for the current date and time upon booting?

In most versions of DOS, when they are started from a medium that lacks an AUTOEXEC.BAT file, the very first thing COMMAND.COM does is ask the user to confirm the current date and time: Starting PC ...
28
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3answers
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Were 9.2 file names possible in MS-DOS?

In MS-DOS (and FAT16), you could only have 8.3 file names (like QUESTION.TXT) with only single-case letters and numbers (and a few symbols). The MS-DOS Editor also defaulted to 8.3 - typing edit ...
27
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Why are Windows 95 installation disks not uniquely bound to a single product key?

I was installing the OEM version of Windows 95 on VirtualBox the other day for reminiscence sake, and for some reason I had two different product keys. I tested both of them to see which one mapped to ...
11
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Invert LCD screen in DOS 5.0

Would like to run "black on white" software on a DOS machine with an LCD screen, so am wondering if there are any TSR tools, or similar, for inverting the screen. I believe it is grey scale VGA, not ...
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11answers
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Why did CP/M and MS-DOS use the BIOS instead of their own drivers to access hardware?

Modern versions of Windows (and other modern operating systems I suppose) have their own drivers to access hardware. But as I have read, in the old days, if CP/M or MS-DOS wanted to access hardware, ...
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2answers
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What is the best way to obtain old versions of MS-DOS and Windows?

I'm wondering what the best way obtain old versions of Windows would be, specifically: DOS Windows 95 Windows 98/SE Windows 2000/ME Windows XP Professional Windows 7 Professional Microsoft Office for ...
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Is there a reason why MS-DOS didn't use more English words for commands?

When using diskpart, I can list all the drives by typing LIST DISK or to select a specific drive I can type select disk 1. Is there a reason why MS-DOS didn't use more English words to do tasks, for ...
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How did DOS know where to load itself in upper memory?

If I remember correctly, you could ask DOS to load in upper memory by writing something like... DOS=UMB ...somewhere in the CONFIG.SYS file. But the question is, how did DOS know what portions of ...
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6answers
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Sound driver for DOS or Windows 3.x that used the PC speaker?

Long ago in a galaxy far far away, back in the early 90's, I worked for a crappy clone company as a phone technician. At the time, 386SX/25's were common for in-house technical support / customer ...
20
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1answer
873 views

Logo of a bow tie guy with a spoon

I was in the Computer History Museum in Silicon Valley last week, and I saw this badge. I know I've seen that logo somewhere before, but I can't remember where! Does anyone know where it's from?
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Why did MS-DOS choose the percent symbol to designate variables?

I couldn't find anything but is there any reason for choosing % over $ like in *nix shells?
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7answers
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Transfer files to DOS over serial cable from Linux?

I have a modern Linux computer and a 286 computer running DOS. I would like to transfer files from the Linux computer to the DOS computer over a null modem serial cable. I know you can use INTERLINK....
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9answers
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Alternatives for TurboVision on DOS

TurboVision was a library by Borland for developing TUI's (Text User Interfaces). It was included with their C++ and Pascal compilers. Were there any other TUI libraries that supported multiple ...
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Disassembling Windows IO.SYS

Under the question How did Windows ME "cripple" DOS?, Ross Ridge's answer showed a section of his disassembly. I would like to know, a) what disassembler was used and b) what adjustment or ...
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2answers
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Were any DOS games (or software) known to use VBE/AF?

Were there any MS-DOS games or graphics software that were known to take advantage of VESA BIOS Extensions/Accelerator Functions (VBE/AF)? some of the functions defined in the standard are ... Bit ...
8
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4answers
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Set screen resolution in DOS-only PC

I replaced a failed CRT display with a LCD panel with a VGA controller board. There is no problem with the display when the PC boots up. However, if I switch the display off then I get an 'Out of ...
8
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5answers
534 views

Getting Music Functioning for Raptor: Call of the Shadows (1994)

I can't get the music audio working for the 1994 version of Raptor. Does anyone know how I can remedy this? I'm not sure if this is the correct forum for this question, but here goes. I have an ...
5
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2answers
622 views

How 3Dfx Voodoo 1 Emulator works

reading of this question brings up 3Dfx Voodoo 1 Emulator in my memories. I always wandered how did it work so good time as any to ask... My memory is hazy on the details so I might miss remember ...
5
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3answers
993 views

Allocate 64 KiB in Watcom C 16-bit DOS

I'm trying to allocate a 64 KiB buffer in Watcom C 16-bit DOS. I'm using the "compact" memory model which defines the code segment to be limited to 64 KiB and addressed by near pointers (...
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3answers
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Who decides what is the memory address that the CGA video buffer will be mapped to?

In DOS, the memory mapped IO base address for the CGA video buffer is 0xB8000. So when you write to 0xB8000, you are actually writing to a buffer in the CGA card itself and not to RAM. What I want to ...
14
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5answers
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Can I run Windows 98 and games from the same era on an AMD Duron CPU?

I have acquired an old motherboard with a socket 462 and a AMD Duron (I think its a "Spitfire" model 3). The copyright on the CPU is from 1999 and it apparently doesn't require a dedicated CPU fan as ...
11
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1answer
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Timing interrupts on MS-DOS

On the ZX Spectrum, you get an interrupt every frame. As I recall, the operating system uses this to periodically scan the keyboard and probably other things also, but you can have your own routine ...
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2answers
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Why the "jmp" instruction is not working?

I have written the following program in debug.exe: 1165:0100 mov ah, 09 1165:0102 mov dx, 107 1165:0105 int 21 1165:0107 db 'Hello World', 0A, 0D, '$' 1165:0115 jmp 1165:0100 However, when I ...
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1answer
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Building a DOS/Win95/98 computer from scratch [closed]

I'd like to build a DOS/Win95/98 computer in order to play old PC games I have without emulation. Here are a few games I'd like to run: Teranova: Strike Force Centauri; System Shock 1 and 2; Half-...
14
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1answer
2k views

Why the DOS extender and DPMI were unavailable to DOS programs on 286 standard mode of Windows 3.0

An old article on Windows 3.0 from PC Magazine (June 11, 1991, page 348) said that: Using standard mode, the Windows DOS extender and DOS Protected Mode Interface (DPMI) are available to Windows ...
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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 ...
8
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1answer
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Which MS-/PC-DOS version was the first to allow multiple partitions to be used?

For IBM PC-DOS/Microsoft MS-DOS, which version was the first version to actually allow using more than one partition for data storage? How about using multiple primary partitions vs one primary plus ...
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1answer
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What was the first third-party commercial application for MS-DOS?

What was the first third-party commercial application for MS-DOS intended for IBM PC-compatible computers?
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2answers
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Are .COM executable binaries real mode or protected mode?

Windows and DOS binary executable files with the .EXE extension have an MZ header in them and nowadays also a PE header. But before these there used to also be .COM binary executable files and they ...
6
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1answer
341 views

Is there any public documentation of the LapLink protocol?

Is the protocol used by the DOS Laplink software publicly documented? I seem to remember there were Linux tools that could use it. I cannot find anything useful on their website.