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. ...
- 9,200
132
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 ...
- 111k
123
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 ...
- 111k
112
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 ...
- 111k
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 ...
- 1,081
99
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 ...
- 5,347
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 ...
- 14.5k
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 ...
- 18.3k
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 ...
- 195k
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. ...
- 20.4k
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 ...
- 195k
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 ...
- 4,342
56
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 ...
- 111k
55
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 ...
- 24.2k
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 ...
- 32.3k
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 ...
- 195k
53
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 ...
- 111k
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 ...
- 111k
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 ...
- 20.4k
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 ...
- 195k
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
...
- 2,415
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.
- 3,493
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 ...
- 24.2k
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 ...
- 399
45
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 ...
- 10.8k
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
...
- 23k
43
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 ...
- 195k
43
votes
Disk compression risks in MS-DOS
The dangerous part was that your disk contents would be compressed.
i.e., you have data that can only be read by the compression engine.
If the compression engine was buggy, no data for you. If other ...
- 31.3k
Only top scored, non community-wiki answers of a minimum length are eligible