I've come across this forum now and then for years but only recently joined. I recently got interested in retro PCs again and pulled out an old DECpc XL 466 d2 that was still stashed in the garage at my mom's place. I got it all cleaned up, repaired the power supply, hacked a new battery into the Dallas clock module and found a 1GB Quantum Fireball SCSI drive in my parts stash and installed DOS 6.22 on that. Everything seems to be working well and I've been having fun playing all the games I remember playing as a teenager when a high end 486 system like this was something I could only dream of having. I ran into trouble though when I tried connecting a 1GB Jaz drive. It recognizes just fine but a 1GB cartridge formatted from a more modern PC is unreadable and I can partition and format the Jaz on the 486 and it then works fine but only sees 743MB. I've never seen this before and I'm running out of ideas. I'm about to the point of installing a PCI SCSI adapter but the onboard 53C810 SCSI interface is such an unusual feature for a PC of this era that I hate to not use it. The only thing that caught my eye so far is that the Jaz drive is reporting 1024 cylinders while the HD is 1012 cylinders and has a larger number of heads and sectors so I'm wondering if there might be a limitation with this SCSI adapter or the system BIOS preventing it from seeing more than 1024 cylinders. I remember running into limitations like this with IDE drives back in the day but it isn't something I've seen with SCSI yet. I looked around and so far have not found anywhere that says how many cylinders a 1GB Jaz drive should report so I suppose I should connect it back to a newer PC and see what it says on that.