DesertFOX

Something I just discovered today:

When I am running Microsoft's ScanDisk (from MS-DOS 6.22) on top of PC-DOS 7, it gives me this rather bizarre warning message addressing a possible issue with long files names. Somehow, in 1994, it already possessed some pre-emptive knowledge about the upcoming MS-DOS 7, a.k.a. Windows 95, which would introduce long file names. Interesting!

#MSDOS #PCDOS #Microsoft #ScanDisk #RetroComputing #History

Mar 2, 2025 at 9:03pmWeb
Show threadBen S.Mar 2, 2025
@dfx I wonder if this is the result of a hallway conversation at Microsoft lol
Show threadDesertFOXMar 2, 2025
@HunterZ Well, I guess it is only logical, but I still think it's fascinating to find this stuff so many years later.
Show threadSturmflutMar 2, 2025
@dfx @HunterZ It certainly is! I wonder how it detects this. Since there is a "may" involved probably simple heuristics.
Show threadDesertFOXMar 2, 2025

@Sturmflut @HunterZ

"IF DOS.VERSION >= 7.0" ... but that's only my assumption.

Show threadBen S.Mar 2, 2025
@dfx @Sturmflut yeah probably just a version check. Could use DOSVER to fool it into thinking it's running under 6.22 and see if the same thing pops up.
Show threadSturmflutMar 2, 2025
@dfx Windows NT 3.5 also added LFN support for FAT in 1994. Seems like the technical details and the necessity not to silently corrupt such volumes had been hashed out long before Windows 95.
Show threadDesertFOXMar 2, 2025
@Sturmflut Oh, okay. I did not think of Windows NT 3.5 supporting VFAT partitions.
Show threadSturmflutMar 2, 2025

@dfx According to Raymond Chen, Microsoft developers didn't expect NT to support LFN on FAT at all. If you used NT and wanted LFN, you would just use NTFS. Hence NT 3.1 added LFN only for NTFS in 1993:

https://devblogs.microsoft.com/oldnewthing/20110826-00/?p=9793

Just a year later Windows NT 3.5 already shipped LFN on FAT. Which makes me think they found out *a lot* more volumes were shared between NT and MS-DOS than they thought, prompting support in MS-DOS to be shipped before Windows 95 came out

Random musings on the introduction of long file names on FAT - The Old New Thing

Tom Keddie thinks that the format of long file names on FAT deserves an article. Fortunately, I don’t have to write it; somebody else already did. So go read that article first. I’m just going to add some remarks and stories. Hi, welcome back. Coming up with the technique of setting Read-only, System, Hidden, and […]

The Old New Thing
Show threadSturmflutMar 2, 2025

@dfx The more I think about this the crazier it sounds.

So you just built LFN support into your enterprise OS, and you know the upcoming new client OS will also have it.

But you have zero plans for exchanging files between both worlds using disks while keeping all filenames intact. NT wasn't supposed to support LFN on FAT, Windows never got an NTFS driver.

What did they think in 1993? Absolutely all files that matter would be transferred via network?

Show threadBård H. (lvl 49 🇳🇴)Mar 2, 2025

This sounds strangely familiar... But it was a really long time ago!

Btw... If you use the disk compression tool from DOS (the one they stole from Stacker), and then run a third party disk scanner with auto fix (may have been Norton, but again... long time ago) then you're fucked and you will quickly learn why backups are cool. 😎

Show threadKjetil KilhavnMar 3, 2025
@dfx Not so mysterious I think, as IBM and Microsoft had a cooperative effort on OS/2 shortly before this. OS/2 supported long file names on any type of partition as far as I can recall, but it's been 'a few' years since I used it so memory could serve me wrong.
Imagine what a computing world we could have had if OS/2 had gotten its intended position as the next OS. If that had happened we would probably have had peace in the world too 😜