maxwell@eiffel.DEC (04/16/85)
[This line has bugs.... >0OO OO0<] Hep, ah say, hep me!!! I finally decided to replace my *old* upwards from CP/M (tm) 1.4 compatable Xitan ELDOS 'operating system' with CP/M 2.2. I wrote a BIOS, including the guts of the ELDOS driver for my Xitan DDDC disk controller, and tested it. Parts actually worked. I then tried to create a system disk with CP/M 2.2 and my new BIOS and learned, much to my horror, the result was *too big*. I realize that I could just increase the system tracks to 3 from 2, giving more room, but I've got a lot of software (150+ diskettes) that assume data (directory) starts on track 3, so.... [Bright idea, after much gnashing of teeth, pulling of hair, renting of clothing, although I now realize that others (Heathkit) have done it, too] "I'll put the CCP in a file (CCP.SYS), BDOS and BIOS on the system tracks, and have the cold and warm starts load the CCP from disk using BDOS file I/O. That'll give me plenty of room." Soooo, I modify the BIOS boot to call BDOS to open CCP.SYS, read in 16 records, and presto, the CCP is loaded, right? Wrong. For some unexplained reason, no data is transferred. DDTing though the BIOS I find that a) CCP.SYS is opened just fine (FCB modified, disk accessed, no errors returned, an' ever'thing) but b) when BDOS is called to read each record, no disk activity occurs although BDOS returns with 0 in <A (that's register A, for all you ZBUG fans), saying everything's kosher. Balderdash!!! If I've managed to leave the CCP in place (after DDTing old CPM.SYS), CP/M executes normally, impling that my BIOS is alright, and that BDOS is alright (I can execute STAT.COM and other .COM's, TYPE files, etc.). However, if I zap the CCP before executing the warm start, BIOS thinks it loaded the CCP from CCP.SYS and tries to execute garbage. I *must* be doing something wrong, but what? Help. ELDOS is too large and too old to continue using, and I need CP/M 2.2 to continue using my tools.... -+- Sid Maxwell