OSI Floppy Disk Interface and OS

[bartleph]

I am hoping someone way cleverer than me can help me with a slight problem I have. For some time now I wanted to build a 6502 based dev board similar to an OSI Superboard/UK101. Back in the day I built a UK101 and attached a Floppy to it very successfully. I have the 5.25 floppies from then (1985) but alas not the UK101 or the FD interface. My 6502 dev board is built and works well. W65C02, 32kB of SRAM, 32K EEProm, and ACIA for 19200bps terminal access. I have also built a Floppy drive IF board based on the OSI one, itself copied from Elektor's Junior Computer Nov/Dec 1982.

I have an OSI OS65DV3.0 master disk which boots partially! I'm guessing after 36 years in my attic it is damaged. My problem is how to create/obtain an OS65V3.0,3.1,3.2,or 3.3 system disk. There are sources on the web for these but I havent yet fathomed out how to get them on an OSI readable disk!! Thanks in anticipation.

[BigEd]

It's not impossible that your difficult disk can be read - the nice people over at Stardot have some disk image preservation activities going on, and if you're in the UK there's a fair chance you could even get together (or post the disk.)

(With very old disks, it's worth checking them and the drive visually before trying to read: if the disk has mould, and it clogs the heads, it can make things worse.)

I had a UK101 myself - never had a disk drive for it, but was aware that the monitor ROM contained a very minimal bootstrap to read the first sector. I think I found it a bit mystifying at the time, that so little code was enough to make a disk useful. I hadn't, I think, grasped the idea of bootstrapping, of loading the filesystem from the disk itself, and then the OS machinery. We must, I think, have been hand-disassembling the monitor.

[bartleph]

Hi BigEd. Thanks for your reply. I think I might load the whole DOS image of the appropriate .65D file from the WinOSI guys resources, load it via the serial port and use it to initialize and write to a new disk.

I'll post how I get on..

[BigEd]

Will be interesting to hear about it!

[BillG]

You did not say where you are.

Start with the forum at http://www.osiweb.org/osiforum/

Someone may help you get a copy of a boot disk.

Otherwise, check out the repository at https://osiweb.org/

I'm sure they have ways to make physical disks from images.

[bartleph]

Well we have moved on a fair way from my last post. I have my Floppy Disk Interface PCB up and running and supporting Goteks and real 5.25 drives. I have been able to create .HFE images that boot perfectly in the Gotek and re-created Master OS65D3.1 and OS65D3.3 Floppies too. I even have the Tutorial Disks on 5.25 Floppies as well. I have just finished building a 32 row by 64 col VDU PCB with 2k Memory Mapped Sram and 2k Character Generator Eprom. Really pleased with this as the display is very steady. Had to use NON LS 74123's for Vertical and Horizontal sync pulses as the LS versions just were not very stable?

[BillO]

bartleph wrote:

I have also built a Floppy drive IF board based on the OSI one, itself copied from Elektor's Junior Computer Nov/Dec 1982.

Not sure this is true as the OSI FD controller (the 610 board) was available in 1979 (when I got mine). I'm sure it was available back in 1978 too.

[HansO]

Elektor copied the (several years old) OSI Floppy interface design to let the Elektor Junior run OS65D.

Like the Elektor Junior (nearly a KIM-1 hardware clone and lots of the monitor source) I doubt it were licensed hardware designs.

[bartleph]

BillO wrote:

bartleph wrote:

I have also built a Floppy drive IF board based on the OSI one, itself copied from Elektor's Junior Computer Nov/Dec 1982.

Not sure this is true as the OSI FD controller (the 610 board) was available in 1979 (when I got mine). I'm sure it was available back in 1978 too.

My grammar was a bit flawed there!! I should have said "I have also built a Floppy Drive IF board based on the Elektor Junior Computer Nov/Dec 1982, itself copied from the earlier OSI one..

oops!!