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MS-DOS 2.25: was it ever released or was it vaporware ?

This memory may be a bit off, but a peculiarity I recall with 3.5" drives and IBM PCs was for some reason the IBM versions of MS-DOS didn't support the "drivparm" config.sys command, forcing you to use driver.sys instead. Driver.sys was terribly awkward by comparison to drivparm.
 
Timeline of Japanese DOS versions:

http://diarywind.com/blog/e/timeline-of-dosv-versions.html

Has no mention of 2.25 anywhere.

HOWEVER, the Japanese MS-DOS Wikipedia page mentions this:

Version 2.25 (October 1985)[35] - Targeting East Asia markets, two-byte encoding support was added. For unknown reasons was sold in Japan as Version 2.11 (only MSDOS.SYS mentioned 2.25) [citation needed].

[35] Duncan, Ray (1988). Advanced MS-DOS Programming, Microsoft Press. ISBN 1-55615-157-8.
 
igorsk said:
For unknown reasons was sold in Japan as Version 2.11 (only MSDOS.SYS mentioned 2.25)
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I wonder if there was some legal reason. I've got a copy of DOS 2.11 (label says 2.1) for the Toshiba T1100Plus on a 720K floppy. If I look around inside some of the the files with a text editor, I see that many of them say "TOSHIBA Vers 2.20" even though ver reports it's running 2.11. Also another place says "Illegal to use MS-DOS V3.1 on this machine"

So I wonder if some of these odd versions started life as 2.1 or 2.11 for some legal or licensing reason, and then the manufacturer added additional support, but kept the versions numbers the same to comply with their licenses or something.
 
During the early days of MS-DOS, OEMs did some odd things with their version numbers. Some of them intentionally bumped numbers to make themselves look ahead of competitors, others just sloppily reported random internal revision numbers, and others bumped numbers as they revised their bundled utilities.

If you look in the "IO.SYS" of most early OEM DOS, you will often see random unrelated version numbers because the OEMs wrote/maintained this part themselves.
 
jafir said:
I wonder if there was some legal reason. I've got a copy of DOS 2.11 (label says 2.1) for the Toshiba T1100Plus on a 720K floppy. If I look around inside some of the the files with a text editor, I see that many of them say "TOSHIBA Vers 2.20" even though ver reports it's running 2.11.
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Could you upload an image of this somewhere? I'd like to check if it actually implements the double-byte APIs.
 
I sent you a PM. I don't think this disk will have the double byte stuff, since the floppy label is "US"
 
jafir said:
I sent you a PM. I don't think this disk will have the double byte stuff, since the floppy label is "US"
Click to expand...
Thanks!

Indeed, the max function implemented is 58h (set allocation strategy).
Function 30h (get version) returns:
AX=0B02h (2.11)
BH (OEM ver#) = 29h(41)
BL:CX(OEM serial no): 000000h
 
Sorry for digging up an old thread, but doing some research and found this in the process.

The NZ/AU version of the JX came with DOS 2.10 and the double stepped BIOS. We didn't get 720K support until 1986, with MS DOS 3.2, and magically the IBM Convertible and drive upgrades for PC XT/AT etc got released.
Japan had 720K support long before MS DOS 3 and long before AU/NZ, so I suspect that's one thing the updated JX DOS allowed, and I guess they didn't want us to have full capacity just yet.

I would also expect that version of JX DOS to possibly support the extra Kanji hardware in the Japanese version of the JX - but don't know for sure.

NB: without 720K BIOS, the JX was incompatible with every other 3.5" machine, because nothing else was stupid enough to double step the drives.

Chuck(G) said:
Granted, they were 720K, but there you have it. Note also, that said drives are half-height, not the later one-third (of a FH 5.25" slot) height drives. I wouldn't be at all surprised if the drives were also the 26-pin variety.
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The drives are half height but use a standard 34 pin cable with the tpyical drive-select flip.
I had one of mine booting off a typical 1.44MB drive (using DSDD media), but it looked a bit goofy.
 
It was even more mythical Nobody doubted the existence of Multitasking MS-DOS ... A true unicorn
 
SomeGuy said:
The DOS system files are not present on this disk.
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I wonder if they are embedded on the ROM? When the PC/4000 boots it complains that COMMAND is missing, so something that we need to transfer across.

You can see the boot display at 19:48 on my Part 1 video.

I should hopefully have a PLCC32-to-DIP converter waiting for me when I get back home, so will attempt to dump the two ROMs.

Brett.
 
I finally got a PLCC32-to-DIP28 converter and have dumped the ROMs from both PC/4000 and PC/5000.

There are two 32KByte ROMs in the machine: one appears to be diagnostics routines (PR10002 or PR10003) and the other is BIOS/MS-DOS v2.25 (PR10001).

Files are on my Github for the machine.

Brett.
 
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