I'm not sure if this is a hardware or OS problem, but I have an IBM PS/2 model 50 that is giving me some problems. When I first got it, I had to replace the 3.5 disk drive because it was bad. Fortunately I found another one that worked. However, the computer acts strangely, in that it initially would not read 1.44 disks, but it would read 720kb ones. I wanted to backup an old DOS program on the computer before starting from scratch with a new install of Dos 3.3. I ordered some 720kb, and was waiting for them to arrive. Days later, I just happenned to insert a 1.44 disk in the drive and it read it no problem! I tried several without an issue. I have tested the drive to format blank disks, and the only format switch it will recognize is format a:/8, which is for a 360kb disk. This leaves most of the disk blank. When I run CHKDSK /f on 1.44, it completes but says that there is an allocation problem and it proceeds to correct. Finally, when using the BACKUP command, everything except the aforementioned command results in the invalid paramenter error message. I can't tell which size drive is in the system, 720kb or 1.44. Also, I should mention that I need a new CMOS battery (which I've ordered) so that I can use the reference disk and see what's going on with the BIOS. Any help would be appreciated. Thanks ghro

"I wanted to backup an old DOS program on the computer before starting from scratch with a new install of Dos 3.3. I ordered some 720kb, and was waiting for them to arrive. Days later, I just happenned to insert a 1.44 disk in the drive and it read it no problem!" First, I'd go w/DOS 6.22 (fewer problems and you don't need the format switches). 2nd, original IBM FDD's are notorious for being stubborn (you said you replaced it). Model 50's came w/1.44MB drives, so a replacement 1.44 should work. These sites may help (even though it's about a Model 80): http://asavage.dyndns.org/PS2/FD_14... http://www.intergate.ca/~fspencer/8...

T-R-A Thanks for the quick response. I'll take a look at it and let you know. ghro

No problem. There's several other PS/2 sites I've got bookmarked somewhere if you feel the need...