tfreeman@xxxxxxxxxxxxxxxxxx wrote: > > <<sigh>> The old H89 running cp/m. Never did get around to trying H-DOS or > whatever it was called, although I think it was pretty advanced for > running on Z80. If configged properly, as I recall, you could run 1 5.25 > disk internal, two more 5.25 disks external, a 5 meg external hard drive > (I think it was 5 meg although it was about 8 inches across), and I > _think_ you could even get an external pair of 8 inch floppy drives with > something like 256K capacity. > Yes, it could have a pair of 8" floppy drives. I had one of the external boxes with the 2 8" drives up until 2 or 3 years ago. I also had an interesting S-100 drive controller from another company. (I forget the name.) It would control 4 5.25", 4 8" and by using a daughter board, 4 MFM hard drives. It would also support a memory drive using extended addressing static RAM. It would do DMA transfer between memory pages, or from its disk buffer to RAM. It would read the entire track of a floppy in one pass. It also did deblocking from the drive sectors to the 128 byte blocks CP/M used. It could also handle double density double sided drives. I even had a 3.5" drive attached to it, and could read/write 720k DOS disks on a CP/M system. You could also read/write 360K DOS disks on 5.25 disks. But it would not handle HD 1.2M disks. I was thinking of making a hardware/firmware change to use the data clock setting for 8" drives with 5.25" HD drives. Then I could have read HD disks. All the hardware was there for it, but who ever designed the board didn't provide implement it. Mikkel -- Do not meddle in the affairs of dragons, for thou art crunchy and taste good with Ketchup!
