137 votes

Why did some old MS-DOS games lack the ability to exit them?

Paratrooper was originally a “PC booter”. All PC booters run without DOS or any other operating system¹ — to start them, you would insert the floppy into the drive, and switch the computer on (or ...
Stephen Kitt's user avatar
135 votes
Accepted

Were 9.2 file names possible in MS-DOS?

No. The FAT12/16/32 filesystems store the filename and extension together in a fixed-length 11 character field. The first 8 characters of this field is the filename and the last 3 is the extension. ...
Alex Hajnal's user avatar
  • 9,350
124 votes
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What character is the MS-DOS cursor?

The text-mode cursor isn’t a character, it’s managed separately by the video output circuitry (which is how it keeps blinking even when your computer is busy or locked up). It can be enabled or ...
Stephen Kitt's user avatar
116 votes
Accepted

Why is Windows using CR+LF and Unix just LF when Unix is the older system?

This is covered largely in the history section of Wikipedia’s entry on newlines. Basically there are two primary lineages of operating systems leading to modern-day desktop usage: Windows on the one ...
Stephen Kitt's user avatar
105 votes
Accepted

Why did DOS use dollar-terminated strings?

The short answer is that DOS was designed to be similar to CP/M, and drawing a quote from here: While 8-bit programs could not run on 16-bit computers, Intel documented how the original software ...
Eugene Styer's user avatar
  • 1,111
99 votes
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What is the context of the button "Is MS DOS a feminist?"

The honorific "Ms." didn't always exist. It was popularized by the feminist movement as an alternative to Miss (woman is not yet married) and Mrs. (woman is married), But it took feminist activist ...
Brian Tompsett - 汤莱恩's user avatar
94 votes

Why weren't bootable game disks ever common on the IBM PC?

Bootable game disks do exist for the IBM PC. Conflict in Vietnam is an example of such a game. As can be seen on page 8 of the manual, the game boots directly without loading DOS first. The main ...
user's user avatar
  • 15.2k
91 votes
Accepted

How did Windows 3.1 implement multitasking?

For Win16 programs, Windows implemented co-operative multitasking. Its implementation was based upon the "message loop" architecture of every Windows program. The duty of every program was ...
mcleod_ideafix's user avatar
76 votes
Accepted

Why did the MS-DOS API choose software interrupts for its interface?

TL;DR; Using INT comes not only natural due the way the 8086 is designed, but was as well intended by Intel as OS entry point, much like a Supervisor Call (SVC) on /360 type mainframes: (Excerpt from ...
Raffzahn's user avatar
  • 223k
69 votes

Why does Windows 1.01 crash at the splash screen?

This is a botched version check error message. Windows 1.x was designed to run under MS-DOS 2.0, 3.0 and 3.10; to ensure it only runs under one of these, it performs a version test on its host DOS. ...
user3840170's user avatar
  • 23.1k
64 votes
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Why was "C:" chosen for the first hard drive partition?

TL;DR: Why has “C:” been chosen for the first hard drive partition? Because it is the first letter after A and B. Drives are simply numbered in sequence using letters. Since the vast majority of ...
Raffzahn's user avatar
  • 223k
59 votes
Accepted

How to put a delay in AUTOEXEC.BAT

Since you are using MS-DOS 6.22 you can abuse the CHOICE command to introduce a set timed delay by piping the output of a REM statement to the choice command, leaving it with no way to complete other ...
mnem's user avatar
  • 4,537
57 votes
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Is DOS being shipped with or as an installed OS?

I’m not sure about OS manufacturers, but hardware manufacturers still use DOS, in at least two scenarios visible to the general public: firmware upgrade CD images; bare-bones enterprise laptop and ...
Stephen Kitt's user avatar
54 votes
Accepted

How does the command.com shell work with MS-DOS?

Traditionally, operating shells are relatively independent of the operating system’s function and the operating system can operate without a shell. Most shells have two modes of operation, interactive ...
Stephen Kitt's user avatar
54 votes

What character is the MS-DOS cursor?

The cursor on the CGA, MDA, EGA, and VGA cards was a hardware sprite generated on the earlier cards by the 6845 video controller, and on later cards by a chip that emulates the 6845. That chip has an ...
supercat's user avatar
  • 36.2k
54 votes
Accepted

Did IBM encourage Bill Gates to retain the rights over PC-DOS?

TL;DR: It was IBM's idea. IBM never intended to buy any of the software they acquired for the PC - and MS never intended to supply any OS beside Xenix. But MS (Paul Allen) soon recognized the ...
Raffzahn's user avatar
  • 223k
54 votes

What exactly did the "UNFORMAT" MS-DOS command do?

If you format a drive with quick format option (FORMAT /Q), it only clears the root directory and FAT area, but before doing so, the format command stores them in unused area of the disk. This is ...
Justme's user avatar
  • 32.1k
54 votes

Why did "protected-mode MS-DOS" never happen?

16-bit protected mode DOS did sort of happen: Concurrent DOS 286 and FlexOS 286 were able to run some DOS applications in protected mode (this involved complex LOADALL shenanigans and revealed bugs in ...
Stephen Kitt's user avatar
48 votes
Accepted

What is 'Adaptive Tile Refresh' in the context of Commander Keen?

"Adaptive Tile Refresh" is the strategy of maintaining a software-drawn tilemap in memory in place by redrawing only the tiles which differ after moving a logical camera across a grid of ...
knol's user avatar
  • 11.9k
48 votes
Accepted

How do I connect a command prompt to a serial line in MS-DOS 6.22?

That's because MS/PC-DOS can not redirect STDERR. This feature was only added later with the shells of OS/2 and Windows NT Having said that, what you want to do isn't redirecting the streams, but ...
Raffzahn's user avatar
  • 223k
48 votes
Accepted

Which font with slashed zero is being used in this screengrab?

The font in use appears to be the ‘9×14’ bitmap font (i.e. 8×14 glyph bitmaps tweaked for 9×14 character cells) of the Hercules graphics card. The title of the video is ‘Windows1 (1985) PC XT ...
user3840170's user avatar
  • 23.1k
47 votes
Accepted

Will PC-DOS run faster on 4 or 8 core modern machines?

No, DOS won't use any additional CPU (*1) ever. (Though it might run faster due them new CPUs being faster) Quite the same way as DOS doesn't take advantage of the extended memory or additional ...
Raffzahn's user avatar
  • 223k
47 votes
Accepted

What were the actual memory model definitions in MS-DOS?

The memory models all had to do with how much code and/or data your program was using. First some background. The 8086(1) was based on earlier Intel chips where their address space was strictly 64K ...
paxdiablo's user avatar
  • 4,742
47 votes

Why didn't PC games eschew MS-DOS and deal with BIOS directly?

You need to run the game somehow. There were some early booter games, but as soon as you had a hard drive, users typically want to store programs, including games, on the hard drive, as files. When ...
Justme's user avatar
  • 32.1k
46 votes

How did Windows 3.1 implement multitasking?

Found a great answer on Super User that explains it really well! Windows 3.1 uses cooperative multi-tasking – meaning that each application that is in the process of running is instructed to ...
Retro Gamer's user avatar
  • 2,435
46 votes
Accepted

Looking for PC graphics demo software from the early 90s called "Unreal"

Unreal Megademo, Future Crew, 1992 possibly? Certainly has all the elements you mention.
Alan B's user avatar
  • 4,455
45 votes

Why can't I invoke the next interrupt service by incrementing the AX register after calling the same interrupt?

When calling the mouse driver interrupt with AX = 0, it returns 0xFFFF in AX if a mouse driver is installed. So if it is installed, the code with INC AX will increment AX back to 0 and then it will ...
Justme's user avatar
  • 32.1k
45 votes

Why did the monsters have "infinite invisible pillars" of hitboxes vertically in all versions of the DOOM engine?

Doom maps and locations on the maps were essentially 2D. This makes a lot of stuff much cheaper to calculate that a general 3D solution but has some limitations: objects can't stack, you can't jump ...
Peter Ashford's user avatar

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