A Compukit UK101
Posted: Sun Jan 05, 2020 6:59 am
I was in the loft getting down the Christmas decorations. I also bought down two computers I built some years ago. This first one was built from a kit in 1979 and bits got hacked and added on over time.
It’s a Compukit UK101 a Brit knock off of the Ohio Scientific Superboard. It came with 4Kb of RAM and the upgrade to 8Kb cost me £50, equivalent to £285 today. That would buy you a top end Intel I7 processor.
It got heavily modified over time, ending up with 64Kb RAM And floppy disk drives for 8” disks that held 128Kb of data! It became the development platform for #2 but more of that later.
Internals
Main Board
PSU 5V 10 Amps - no switch mode here.
Home made expansion card AtoD DtoA and other things I can't remember
Underneath the main board is a genuine OSI 64k expansio card and disk controller. I did have 8"drives and OS65d, but the disks and drives are long gone.
Then came the full homebrew. It started life as an add on to the UK101 with a circuit board connected to the original 6502 microprocessor socket and provision for 6502, Z80 and 6809 microprocessors plus a floppy disk interface. See the three original circuit diagrams that I found in a box of papers.
It never saw a 6809 and more and more was added to it that eventually the two computers were separated and all the new boards put in an old rack chassis.
Z80 Based it runs CP/M 2.2. It grew, at first with 8” floppy disks , then 5.25” disks and then a hard drive. Getting that going is the current task so I can save everything on the hard drive before it gives up. Then I'll tackle the UK101 and now I've found the resources here there's hope for it yet. Dave tells me that the Gotek USB drive I already have on order can emulate 8" disks.
Pete
It’s a Compukit UK101 a Brit knock off of the Ohio Scientific Superboard. It came with 4Kb of RAM and the upgrade to 8Kb cost me £50, equivalent to £285 today. That would buy you a top end Intel I7 processor.
It got heavily modified over time, ending up with 64Kb RAM And floppy disk drives for 8” disks that held 128Kb of data! It became the development platform for #2 but more of that later.
Internals
Main Board
PSU 5V 10 Amps - no switch mode here.
Home made expansion card AtoD DtoA and other things I can't remember
Underneath the main board is a genuine OSI 64k expansio card and disk controller. I did have 8"drives and OS65d, but the disks and drives are long gone.
Then came the full homebrew. It started life as an add on to the UK101 with a circuit board connected to the original 6502 microprocessor socket and provision for 6502, Z80 and 6809 microprocessors plus a floppy disk interface. See the three original circuit diagrams that I found in a box of papers.
It never saw a 6809 and more and more was added to it that eventually the two computers were separated and all the new boards put in an old rack chassis.
Z80 Based it runs CP/M 2.2. It grew, at first with 8” floppy disks , then 5.25” disks and then a hard drive. Getting that going is the current task so I can save everything on the hard drive before it gives up. Then I'll tackle the UK101 and now I've found the resources here there's hope for it yet. Dave tells me that the Gotek USB drive I already have on order can emulate 8" disks.
Pete