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 ...
- 118k
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 ...
- 21.6k
44
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 ...
- 33.5k
41
votes
Accepted
Did any DOS compatibility layers exist for any UNIX-like systems before DOS started to become outmoded?
it seems like there might might have been a market for software that would enable at least some DOS software to run natively on Linux or another UNIX derivative.
There was indeed, or rather, it was ...
- 118k
40
votes
Accepted
How did SmartDrive work?
How SMARTDrive works depends on the version being considered.
The general idea of a disk cache like SMARTDrive is to intercept disk reads and, optionally, writes, and handle them from cache if ...
- 118k
39
votes
Disk compression risks in MS-DOS
The main problem was that DOS drive compression programs such as DriveSpace, Stacker, or SuperStor created a virtual drive and stored its contents in a large file on the original drive.
This created ...
- 118k
39
votes
Accepted
Did MS-DOS have any support for multithreading?
The fact that a C library functions were made to support re-entrancy has got nothing to do with DOS. Or any other OS for that matter. It may be needed when doing bare metal programming without any OS, ...
- 28.3k
37
votes
Accepted
Why does invoking a bat file from another bat interrupt the first?
It feel counter-intuitive to me to have a batch file just ignore the rest of the content it I invoke another bat file without using call.
Is there a documented reason why they system was designed ...
- 213k
36
votes
Why did DOS-based Windows require HIMEM.SYS to boot?
Windows in protected mode requires an XMS driver — HIMEM.SYS is the one provided by Microsoft, but others can be used¹ (and the Windows Me kernel includes its own XMS driver). The role of the XMS ...
- 118k
33
votes
Document format for a DOS word processor where control commands begin with a dot
Almost definitely WordStar or a compatible program such as NewWord.
dot commands at the top. From the WordStar 3.3 manual:
.op - omit page numbers
.mt1 - margin top 1 line
.hm1 - heading margin 1 ...
32
votes
Accepted
Beep command with letters for notes (IBM AT + DOS circa 1984)
This sounds like the PLAY command in BASIC. It takes a string indicating what to play, with the following notation for the features you mention:
A to G, followed by optional #, +, or -, plays the ...
- 118k
31
votes
Do any FAT8 filesystem images survive?
I think I've actually found a FAT8 disk image: Toshiba T100 Personal Computer T-DISK BASIC (Version 1.0) (1982)
Why I think it is FAT8:
Starting near offset 0xc530, there are repeated occurrences of ...
- 1,881
28
votes
Accepted
Why was the graphical user interface version of Defrag removed?
The “official” answers from Microsoft's Disk Defragmenter FAQ (first published in 2006):
The new interface seems “dumbed down.” Why remove all the detail?
Interestingly enough, one of the biggest and ...
- 934
28
votes
What did Ctrl+NumLock do?
In the IBM PC 5150, CtrlNumLock paused the system until another key (not NumLock) was pressed. As described in page 5-21 of the relevant Technical Reference:
The combination of the Ctrl and Num Lock ...
- 118k
25
votes
Why does the FAT file system have separate ‘hidden’ and ‘system’ attributes?
The attributes are documented in The MS-DOS Encyclopedia as follows:
The hidden bit (bit 1) is set to 1 to indicate that the entry is to be skipped in normal directory searches — that is, in ...
- 118k
24
votes
Accepted
Memory requirements for undelete command
“Regular” UNDELETE relies only on the standard MS-DOS deletion behaviour: when a file is deleted, the first character of its file name is replaced with a deletion marker, and its clusters are freed. ...
- 118k
23
votes
Using Clang to compile MS-DOS executables
There’s more to it than the linker, especially if you want to support real mode. You need a DOS C library, and a compiler which can output 16-bit code. If you want to produce binaries in anything ...
- 118k
22
votes
Accepted
What were the most popular text editors for MS-DOS in the 1980s?
There were many editors available for DOS, both standalone and included in development environments. I suspect that most developers using IDEs used their IDE’s built-in editor; those were perhaps the ...
- 118k
22
votes
What were the most popular text editors for MS-DOS in the 1980s?
WordStar was one of the earliest and most popular word processing programs for CP/M and MS-DOS. One of the key features for a lot of people was the non-document mode. This did a few important things:
...
20
votes
Why does the FAT file system have separate ‘hidden’ and ‘system’ attributes?
Although MS-DOS didn't come bundled with utilities to change the flags, it was useful to distinguish files that could be casually hidden and unhidden from those which shouldn't be. While I doubt this ...
- 34.7k
20
votes
Accepted
Purpose of Recover command in MS-DOS
It was not meant to repair volumes, but to recover data from them, hence the name.
PhotoRec is a more modern (and much more sophisticated) tool with a similar purpose. There's a crucial difference: ...
- 1,951
20
votes
Accepted
What type(s) of compressed files was the MS-DOS EXPAND command able to decompress?
EXPAND.EXE is a tool specifically created for installation of Microsoft products. Its file format is a proprietary Microsoft definition, not following any existing standard. It is only good to expand ...
- 213k
19
votes
Why did "protected-mode MS-DOS" never happen?
And, marketing-wise, did everyone want multitasking and GUI so much that an idea of a single-tasked OS was no longer appealing by definition?
In a word, yes.
The 80386 came to market in 86/87, well ...
- 4,786
19
votes
Document format for a DOS word processor where control commands begin with a dot
Looks to me like a set of dot commands found at the beginning of a Wordstar file .mt1 margin at top, .hm heading margin. Try Wordstar 3
Unfortunately, modern word processors that I know of don't have ...
- 565
19
votes
Accepted
Document format for a DOS word processor where control commands begin with a dot
WordTsar – A Wordstar clone might be able to read the files. It is open-source and cross-platform. Compatibility depends on the version of WordStar used to write the files.
It does implement an ...
- 20.5k
18
votes
Did MS-DOS have any support for multithreading?
Short answer: No.
Most likely, the mentions of threads are there because, as you mentioned in your question, this version of the compiler supported OS/2, which supported multithreading.
On the other ...
- 934
18
votes
Do any FAT8 filesystem images survive?
There were several pretty common 8 bit machines with MS-BASIC 5.x including for example the TA Alphatronic PC which featured a Microsoft Extended BASIC 5.11 in ROM. Disk Routines were to be loaded ...
- 213k
17
votes
How to use all memory on an IBM PC with 8086
Assuming there is usable memory between 640K and 1024K (which would be rather unusual in an 8086 PC), I would recommend using DOS 5.0 or later and adding UMBs to the memory allocation strategy (there ...
- 118k
17
votes
Accepted
Which is the first version of DOS to support more than one reserved sector in a FAT file system?
Since I just so happen to have a battery of floppy images with various DOS kernels I compiled to investigate a somewhat similar problem, I decided to try the probing route. I did not use the image in ...
- 21.6k
16
votes
Did any DOS compatibility layers exist for any UNIX-like systems before DOS started to become outmoded?
I added a soft DOS compatibility layer to an x86 OS called CTOS (or BTOS if Burroughs was selling it) around 1988. It supported what was practical on non-IBM-PC compatible hardware.
In particular, you ...
- 161
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