I just had an order mostly correctly delivered - apart from the 10m of expanding nylon cable sleeve, that turned into a IEC cold condition lead with an (earthed!) US mains plug on the end!
I remember working with Miniscribe drives, 20MB MFM stepper motor ones in Acorn and IBM kit. Model 8425 IIRC, 615 cyl, 4 hds, 17spt.
One of a large number of "me-too" drives with the same spec. that were Type 2 in the IBM AT CMOS hard drive table. That should invoke the wavy lines for some of the old farts reading this :)
I had an interesting task to do. The Rodime drives we had had the defect map written on them, using the same controller we used (Damn can't remember the number!) but with the sector size jumper set to the other size - 256 bytes, not 512. So we knocked up a relay controlled by a serial port. I could then reset the SASI bus, read the flaw map, switch the relay, reset the bus again, write the flaw map back with 512 byte sectors, then format the disc. We didn't often find any more flaws.
That's a hack worthy of Heath Robinson. I'm impressed. :)
Was it an Acorn system, by any chance? ADFS used 256-byte sectors so it was necessary to use hard drives that supported that sector size.
Acorn used Rodime drives in their FileStore (aka FileSnore as they were so slow) file server boxes and in the Winchester add-ons for the BBC machines.
formatting link
It went: BBC/FileSnore -> 1MHz bus host adaptor -> Adaptec ACB4000 SASI/MFM adapter-> hard disc.
formatting link
Earlier FileSnores (E01) used a 1MHz bus and the same 1MHz bus adapter and SASI/MFM adapter combination as the earlier Winchesters for the BBC machines, later FileSnores (E01S) presented a SCSI bus to allow direct connection of a SCSI disc, removing the need for the host Adaptec board and 1Mhz bus adapter.
Viglen and Technomatic (IIRC) manufactured a hard drive kit to be compatible with the Acorn system, used the same SASI/MFM controller but other drives. They wrote their own hard drive formatting program though.
Back then work were throwing out some old weird non-PC business computers that were based around Seagate ST225's so with a session of "skip diving" and gains from Amateur Radio rallies managed to piece together cheaply my first DOS compatible "PC" from the Acorn family.
BBC Master 512 Acorn 80186 Coprocessor / 256MB memory
20MG Hard disk. GEM DOS+ Mouse.
Was impressive to watch boot.
With that I memorably completed an evening course in programming Assembler language with that computer, and wrote the coursework up in "1st Word Plus". Yeah, it was a bit crude, CGA graphics etc...
I bought a real 286 PC shortly after to enjoy Windows 2.0 and onwards.
I recall someone designed an 8-bit IDE interface for the 1MHz bus, and later another development ran it with compact flash cards.
Watford as well. Watford produced their own version of the 1MHz bus adapter. It had far fewer chips than Acorn's, I forget how they did it, maybe by using a couple of PICs. Tried to find a photo but failed.
Yes, used those too. I had the 65c102 "Turbo" board fitted internally and the x86 in an external Watford co-pro box.
After the Beeb, my first PC was an Amstrad PC1512 which had been scrapped. It came without the monitor 9which also contains the PSU), so I hacked up a PC ATX PSU to power it and used a Philips 8833 monitor for the display. The TTL video outputs from the 1512 were inverted so the screen was a weird mix of colours, but tit worked.
JG Harston, who posts here occasionally. He also produced a modified ADFS rom for it.
formatting link
I've still got the PCB kit somewhere - never got round to building it.
Interesting that they went for a '186 CPU - makes the hardware easier (less glue logic required, and no need for extra interrupt controllers, timers etc) but loses you true PC compatibility because you always end up with the 186 Peripheral Control Block sat somewhere in IO or memory space, and the low level peripherals don't play quite the same as the
8259 PIC, 8250 UART, 8254 PIT etc.
Still, when they designed that, DOS compatibility was still more the thing than PC compatibility.
Then I've got the wrong card. I'll have to open the box and ... oh damn. My machine has a newer SCSI disc. Oh no, OK, I have a spare ... ah. Can't see the number on it.
The thing I'm thinking of was 5 1/4 inc disc sized (though only 1/4 inch high) and had a SASI bus.
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