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129 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. ...
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127 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 ...
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121 votes
Accepted

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 ...
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109 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 ...
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102 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 ...
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97 votes
Accepted

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 ...
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 ...
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87 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 ...
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 ...
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63 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. ...
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62 votes
Accepted

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 ...
  • 177k
58 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 ...
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55 votes
Accepted

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 ...
  • 98.2k
53 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 ...
  • 29.2k
53 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 ...
  • 177k
52 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 ...
  • 98.2k
50 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 ...
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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 ...
  • 177k
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.
  • 3,180
45 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 ...
  • 2,355
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 ...
44 votes

What's the relationship betweeen MS-DOS and XENIX?

They didn't share any source, no. However, the TITLE directive twenty lines or so down from the top in both XENIX.ASM and XENIX2.ASM explains what this is: TITLE XENIX - IO system to mimic UNIX ...
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44 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 ...
  • 19.6k
44 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 ...
  • 10.2k
42 votes

Why was 'echo on' chosen as the default setting within batch scripts in MS-DOS?

ECHO ON was chosen as the default setting when interpreting batch files to preserve backwards compatibility. In PC-DOS 1.0, COMMAND.COM displayed each command as it interpreted it, and this couldn’t ...
  • 98.2k
42 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 ...
  • 177k
41 votes
Accepted

Is there a reason to prefer earlier versions of MS-DOS over later?

Later versions of DOS tended to use more memory. On 386 systems, or systems with EMS memory, this wasn't a huge issue because dos could be configured to use memory outside of the standard 640K region ...
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41 votes
Accepted

Why wasn't DOSKEY integrated with COMMAND.COM?

I can think of a number of reasons: DOSKEY isn’t specifically tied to COMMAND.COM; it provides history for any program which uses the same input functions as COMMAND.COM, and one could imagine ...
  • 98.2k

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