Search found 1304 matches

by Chr$
Mon Jan 29, 2024 6:02 pm
Forum: Compatibles Corner
Topic: ICL OPD BASIC now in ROM!
Replies: 12
Views: 1169

Re: ICL OPD BASIC now in ROM!

That would certainly help with the C1 floppy interface as that takes 7.5K RAM meaning that the configuration programs can't load as they need BASIC and there's not enough memory left. Yes, that was the thing that inspired me to find a way to be able to open them and also any other large-ish BASIC p...
by Chr$
Mon Jan 29, 2024 2:43 pm
Forum: Compatibles Corner
Topic: ICL OPD BASIC now in ROM!
Replies: 12
Views: 1169

ICL OPD BASIC now in ROM!

In the darkest depths of the internet I found an OPD Teledrive disk image that I haven't been able to get to work on my OPD yet, but browsing through the content of the image with a hex editor I found a couple of docs/references relating to putting ICL BASIC in ROM - which in my opinion is a mini ga...
by Chr$
Fri Jan 26, 2024 11:39 pm
Forum: Compatibles Corner
Topic: ICL OPD
Replies: 180
Views: 166902

Re: ICL OPD

Apparently the PCML TeleDrive interface could read C1 disks but would corrupt them if they were written to by it. They are supposed to be PC compatible, i.e. FAT12 with a PC boot sector and with the same geometry as a PC 720K as formatted by MSDOS. The PCML you see is in the DOS manufacturer field ...
by Chr$
Fri Jan 26, 2024 4:51 pm
Forum: Compatibles Corner
Topic: ICL OPD
Replies: 180
Views: 166902

Re: ICL OPD

Isn't a .IMA file merely a raw image which you can dd or rawwrite onto a 720K floppy? Yes, but it looks to my untrained eye like the .ima file was not originally a C1 OPD floppy disk. The files contain 'PCML' so they must have been disks made with the other interface. And changing those 2 rows of P...
by Chr$
Thu Jan 25, 2024 8:27 pm
Forum: Compatibles Corner
Topic: ICL OPD
Replies: 180
Views: 166902

Re: ICL OPD

I've just been experimenting with ImageDisk. With it, I was able to create an image file of my OPD formatted disk containing all the mdv wallet stuff. I was then able to write that image using DOS 6.22 (real hardware) to a fresh 720k disk and that seems to work fine in the OPD, so that's a start - I...
by Chr$
Thu Jan 25, 2024 4:44 pm
Forum: Compatibles Corner
Topic: ICL OPD
Replies: 180
Views: 166902

Re: ICL OPD

I think I may need a pointer or 2 regarding getting OPD images onto real disks! I found the .IMA image online (attached) and am trying to get that onto a real disk in such a way that the OPD can view the files etc. I note that Windows/DOS couldn't see any content on a disk I created with the OPD, th...
by Chr$
Tue Jan 23, 2024 9:26 pm
Forum: Compatibles Corner
Topic: ICL OPD
Replies: 180
Views: 166902

Re: ICL OPD

After some faffing today (dodgy FDD cable) I now have a working C1 clone floppy interface connected to my Merlin Tonto. A couple of useful observations: 1. It seems to work just as well with the slightly cheaper WD1770-PH controller chip as it does with a WD1772 variant. 2. It also had no issue with...
by Chr$
Tue Jan 23, 2024 1:23 pm
Forum: Compatibles Corner
Topic: ICL OPD 3 vertical white stripes fault
Replies: 24
Views: 1247

Re: ICL OPD 3 vertical white stripes fault

Success! My original m/b - the one with the boot loop - had some way out of spec electrolytic caps on it and my cheap Chinese tester also read high vloss (for what it's worth), mainly the blue 33uF ones, of which there are 5. Changed those and tried again, still had the boot loop but with a momentar...
by Chr$
Mon Jan 22, 2024 11:39 pm
Forum: Compatibles Corner
Topic: ICL OPD 3 vertical white stripes fault
Replies: 24
Views: 1247

Re: ICL OPD 3 vertical white stripes fault

Sorry, it's confusing as I'm talking about 2 different OPD's (both being used with one sort-of working CPU board). Here is the progress, or lack of it, from today. The one with 5 white stripes: On the SRAM chip /CE2 is at batt voltage with no power turned on and it goes low when powered-on. /CE1 goe...
by Chr$
Mon Jan 22, 2024 7:15 pm
Forum: Compatibles Corner
Topic: ICL OPD
Replies: 180
Views: 166902

Re: ICL OPD

Looking at that pic I had again of the C1 disk controller and even though there is a sticker on the controller chip, I think it's a WD1770, not a WD1772 as they had a later (85) copyright date, not 82. Anyway, thought that might be of interest. Hopefully I'll have a working OPD soon to try it! OPDCo...