Trying to restore an IBM PS/2 55SX
So Far So Good!..
But....
Need the proper OS.
IBM PC-DOS 3.3
Cant find and I do need!!!

You can get FreeDOS or some other freeware DOS operating system on the internet. UNLESS you absolutely need PC-DOS.

http://www.freedos.org/

I have two of these PC's and have run MS DOS
6, PC DOS7, DR DOS 7.xx, PTS DOSes all very
well and much better than PC DOS 3.3.

Apart from EBAY the earliest Licensed Full
Version of PC DOS I have found is version
5:

http://www.softwaresales.gb.com/acatalog/Online_Catalogue_DOS_57.html

Please be aware that PCDOS is licensed
software.......and not FREE.

Point is, that machine came with a license for a copy of IBM PC DOS 4.00 (not v3.3 all though it was an option), or if a later model (56), IBM PC DOS 5.00 (and all of that versions updates). And some of the later models even came with IBM's OEM Windows v3.0 depending on the exact model.

The actual version shipped on most of these machines was IBM PC DOS 4.01 because it included several fixes and updates, and its diskettes have a SELECT (install) program. My copy has updates released in 9/91 to support larger disk drives. I don't know if these were shipped with the systems or not.

So the real issue is, you are looking for a replacement copy of IBM PC DOS version 4.01 to replace the missing OS that came licensed for that 55sx machine.

IBM PC DOS 4.01 was not supplied as a Retail Install package for non IBM systems. But there was the diskette install package that was sold by IBM to upgrade older IBM systems. So there should not be problems with using any copy of IBM PC DOS 4.01 as a replacement on a PS/2 55sx system. It was installed in the C:\ root as about 1.6MB of files (with all updates).

PC DOS 3.3 was for older systems such as the AT or 80286 based systems (but will work on a 55sx). If you wanted to run a newer version of PC DOS (after version 5) or MS DOS versions, you would have to have a licensed copy of those Retail versions.

PC DOS 5 gets a little complicated, because there was the IBM PC DOS 5.00 version and then the 5.00.1 update version that was shipped installed on systems, and three different CSD update diskettes with five (or more) updates (fixes) to it. Then there was the Retail version of IBM PC DOS 5.00 and its update packages (RUP and CSDs) that were sold and could be used on the 55sx. Not to be confused with the MS DOS 5.00 version of DOS.

All this came on 720KB diskettes. And the Retail 5.00 package had several install options. Normal install was about 2,325KB on the disk drive. The license for the system was an installed copy, not the install package.

I don't recall if a copy of IBM PC DOS 4.01 was shipped on diskettes with the 55sx systems, as it was pre installed on the disk drive.

Great bio - but does it answer his question?

;>)

"IBM PC DOS 4.01 because it included several fixes and updates, and its diskettes have a SELECT (install) program. My copy has updates released in 9/91 to support larger disk drives."
JackG I have a copy of PC DOS 4.01 but I don't have any of those updates for it. I'm really interested in that 9/91 updates. Could you send them to me ??

Thanks a lot.