Questions about MS-DOS and other software on and IBM XT clone

[SomeGuy]

So, after doing a bit more research, I've learned that there were many different 'distros' of DOS that were in production. Why were there different companies making different DOS offerings? Were they functionally different in any significant ways?

If you are referring to OEM vendor provided versions of MS-DOS, it is because many clone makers wanted to add perceived value to their machines by providing extra hardware or capabilities that the IBM PC did not have. In many cases such hardware would not function with a default IBM PC-DOS or "vanilla" MS-DOS OS. This required OEMs to "adapt" MS-DOS to their hardware. This often meant adding custom code to the IO.SYS/MS-DOS.SYS and/or adding extra utilities.

 

[krebizfan]

After MS-DOS 3, almost all the OEMs used a very vanilla MS-DOS install with the manuals and disks often prepared by Microsoft who customized the labels. Laptops would get a bonus driver diskette if necessary.
IBM would include different utilities and sometimes other alterations. Compaq made changes to support larger hard drive partitions in Compaq DOS 3.31.

Digital Research modified CP/M to run MS-DOS applications after CP/M-86 proved to be less than successful. Since MS-DOS was designed to resemble CP/M, going the other way was relatively easy. DR-DOS took the CP/M that could run MS-DOS programs and dropped the CP/M portions of the code. The related Concurrent DOS (previously Concurrent CP/M) had MS-DOS and CP/m-86 compatibility along with multiuser and multitasking functionality.

Atari used a semicompatible clone of MS-DOS 2.11 on the Portfolio.

 

[vwestlife]

After MS-DOS 3, almost all the OEMs used a very vanilla MS-DOS install with the manuals and disks often prepared by Microsoft who customized the labels. Laptops would get a bonus driver diskette if necessary.
IBM would include different utilities and sometimes other alterations. Compaq made changes to support larger hard drive partitions in Compaq DOS 3.31.

MS-DOS 3.3 was the first version that Microsoft sold as a generic retail package. Prior to that, all versions of MS-DOS were OEM-only.

Most OEM versions of MS-DOS 3.3 from Far East-made brands (Leading Edge, Goldstar, Emerson, Packard Bell, etc.) had few, if any customizations. Usually the computer manufacturer just put their name in the copyright messages and maybe included a diagnostic utility specific to their own machines. The American brands like Compaq and Zenith had substantially more customized versions of MS-DOS, while of course IBM had their own PC DOS, and Tandy's MS-DOS was customized to suit the special graphics and sound capabilities of their 1000 series computers.

MS-DOS 5.0 is the newest version that I've seen OEM-customized to any extent beyond the manufacturer just putting their name in the copyright messages. And that's also the point at which IBM's PC DOS significantly broke away from MS-DOS, began offering its own suite of included utilities (disk compression, anti-virus, backup, etc.), and began selling it at retail for users of all brands of computers, not just IBMs.

 

[hargle]

.....and when you're ready to start getting into games for your machine, contact me. I have them all. More than you could play in a lifetime anyway.
Ultima III was a game that destroyed my childhood. I don't think I went outside for a solid year.

 

[Great Hierophant]

Ultima I-V do not require any version of DOS higher than required to support their floppy disk. DOS 3.2 will be sufficient to run I-V if they came on 720KB floppies, otherwise DOS 2.1 or better will run the games as they came on 360KB floppies.

 

[Stone]

Speaking of Ultima, I have a CD with Ultima I-VI Series if there's any interest in it.

 

[vwestlife]

Ultima I-V do not require any version of DOS higher than required to support their floppy disk. DOS 3.2 will be sufficient to run I-V if they came on 720KB floppies, otherwise DOS 2.1 or better will run the games as they came on 360KB floppies.

If you have a Tandy 1000, then Tandy's version of MS-DOS 2.11 would work as well, because Tandy modified it to add support for 3.5" 720K floppy drives -- a capability which was ordinarily only available beginning with DOS 3.20.

 

[SomeGuy]

The Kaypro 2000 MS-DOS 2.11 also supports standard 720k 3.5" disks. And it boots fine on most PC compatibles I have thrown at it. On a copy, I also successfully altered its drive parameter table to add support for booting and reading standard 1.44mb disks.

 

[dieymir]

Worth mentioning is that MS/PC Dos early on were basicly from the same source tree if you will , whereas DrDos was a totally Independently developed variant. Both types were used by OEMs who could, when licenced to do so, customise them for their systems. Especially early on when x86 boxen weren't 100% "IBM" compatible. Customisation did carry on into the early '90s with system builders such as Zenith. Some builders even had systems with Dos in rom.

Found my DrDos 3.35 disks.

Wow! I never have seen any drdos version older than 3.40 3.3x drdos versions where oem only and, AFAIK, 3.35 was available only in French. Are you sure that it's version 3.35?