Recent content by peteri

I have one of the Cirtech CP/M boards that plugs into the 6502 socket for the //e. I have disassembled all of the non-DRI bits and there is some copy protection in there that uses the 6502 <-> Z80 address PROM and the A11 line to check it's running on the right hardware. While this is fine for...

For the Apple //e hardware I have it piggybacks the board into the 6502 socket and uses a 7Mhz clock from one of the //e chips. I suspect the //c hardware is the same. It uses a 74LS288 for the Z80->6502 mapping and swaps a couple of regions of memory using the extra A11 line (the softcard uses...

Totally agree, this is how the BIOS currently sets things up, it looks to me like bigger track sizes would be a good plan for the future (it's partly why I asked the question). I do need to have a look at the V2 implementation that Cirtech did for the Apple IIGS as it can carve out a section of...

I was writing a tool to do some more manipulation of larger disk size images and wrote a quick piece of test code for the Cirtech DPB computation routines. As a result I've found I have an off by one error in the comments I wrote by hand. As it turns out you get larger numbers of directory...

Thanks folks, this matches up with my thoughts. I know if I'd had a 32MB drive back in the day I'd have been annoyed with that number of directory entries as a design choice (and it's not like by 85-86 a 32MB drive would have been out of range) I think I might just bump the number of directory...

I've just finished off disassembling the Cirtech CP/M plus (V1) implementation for a 128K Apple //e and it supports any Apple ProDOS hard drive upto 32Mb in size. Sadly it uses eight 512 byte sectors per track for its geometry. I have a feeling that going to 24 (It needs 12K of boot sector) or...

This particular board is in my //e but the //c versions I've seen are very similar and I suspect the electronics are nearly identical just a different board layout. I've seen a couple of Cirtech adverts that say //e version coming soon when they started advertising the //c version. The //c...

I've just retrieved an Apple //e from my mums loft and while I have the disks I can't find the manual for the Cirtech Z80 CP/M Plus board installed (it plugs as a daughter board into the 6502 socket so I'm guessing it's very similar to the //c) Does anyone have a scan, the only online version I...