ICL OPD

[Pr0f]

That's great news !

I am waiting on some parts to get power and video working for my base unit (I got no monitor), and once I've got the setup at least giving me some video - I plan on porting ICL basic to a ROM and seeing if it can be made to be available without having to be loaded up from cartridge or floppy.

I'd be happy to buy a PCB / kit from you for the disk interface.

Also waiting on a purchase with a RAM upgrade to see if there is anything in the ROM images that's needed - and have a plan to provide 128K ram expansion on a modified CPU Board.

[stephen_usher]

The issue with BASIC is that it doesn't fit in the 32K ROM slot size. The Telestore hacked things and fitted it in two 32K ROM slots.

RAM expansions have to pretend to be ROMs in the ROMpack and then have code which hacks the OS into ignoring the "BAD ROMs" and telling where the extra RAM pages are. Everything's a hack on the OPD as it was never designed to be expanded.

[Chr$]

The interface maps the floppies to the left and right Microdrives. As far as the system and applications are concerned it still has only the two Microdrives and nothing else.

Oh right, well I suppose that makes things easier in many respects. Attached is the 'Welcome' cartridge - the welcome/intro prog is an ICL BASIC program and therefore needs to load BASIC before it starts and from memory I think the ICLBASIC program it contains is the same as what was on the actual 'BASIC' cart. A couple of years ago I transferred it from OPD to QL and moved it to a modern computer.

It's zipped from Windows. I can't remember how it's run, i.e. how/if it auto starts. I'm sure you can get it going (assuming I didn't cock something up getting it from OPD to QL then to PC)!

[Pr0f]

The issue with BASIC is that it doesn't fit in the 32K ROM slot size. The Telestore hacked things and fitted it in two 32K ROM slots.

RAM expansions have to pretend to be ROMs in the ROMpack and then have code which hacks the OS into ignoring the "BAD ROMs" and telling where the extra RAM pages are. Everything's a hack on the OPD as it was never designed to be expanded.

Yes - depending on the version of ICL Basic it can range from 33-38K according to RWAP site. There are numerous 'free' ROM capable areas in the upper memory area (A19 high) so the BASIC could be placed in one of these 64K areas, leaving room for another program if it's small enough to fit in the remaining space.

[stephen_usher]

The biggest problem is not so much getting the programs as making Microdrive carts which can be read by the OPD.

[Pr0f]

On the subject of programs - does anyone have any information / ROM cartridge images for any sofware that provides serial interface for the ICL OPD?

I know there was the 64180 based CPM module which supported disks and a serial port, I also know there was a unit based on a 80C31 which provided a DB25 serial interface, but I remember reading somewhere that there was a serial card / ROM slot based that provided a serial port - all be it with slow speeds by todays standards - Like 9600.

[dilwyn]

The biggest problem is not so much getting the programs as making Microdrive carts which can be read by the OPD.

Dave Walker did make a toolkit with extensions to help with reading, writing and recovering OPD microdrive cartridges. It's called the In Out Kit, may be found at https://dilwyn.qlforum.co.uk/files/In_Out_Kit_v1_05.zip

His OPD Interchange software is also on my site, along with some ROM images and BASIC cartridge (ROMs page).

As I know nothing about OPDs, these went on my site in good faith that they work!

[stephen_usher]

Thanks Dilwyn,

I've been using the transfer program on my QL with limited results. I'll look at the other tools.

The OPD is a strange beast.

[Pr0f]

Is David still contactable?

[Pr0f]

And I agree Stephen - the OPD is strange!