>> The card manufacturer is worth looking at. I have been using a 256 MB Sandisk card.
I've tried a number of different CF modules. In frustration, I bought some of the 4 GB Kingstons pictured on John's build page (the ones with the white flowers on them). Didn't change anything.
>> What bothers me about this discussion is that other IDE-CF interfaces appear to work
>> without problems - for example John Coffman's ECB SBC Mk IV works with anything I
>> have thrown at it with no issues. Same for my digital cameras that work flawlessly with
>> any CF card I have tried. Something about this S100 board is marginal.
Well .... I've designed and built 2 different Z80 SBC's with CF interfaces, and both work flawlessly. On both, the CF interface is directly on the Z80 bus signals (no 8255). Both run at 10 MHz. I have even designed and built a 68k SBC (again, running at 10 MHz). On the 68k, I was forced to use an 8255 because I couldn't figure out how to utilize the raw 68k bus signals for the CF. The biggest problem is that the 68k R/W* signal isn't a pulse as such, it just switches level. The 68k CF works flawlessly too, but I'm still in the process of trying to figure out how to get CP/M 68k up on it. Everything I've tried with the 68k CF seems to work well ... so far.
No worries -- my efforts to build a "diskless" S-100 system continues. I have designed and built an S-100 RAMdrive. It is 4 MB, and battery backed. It looks like 4 ports to the S-100 bus. Without the latency of rotational media, even a 4 MHz Z80 is quite responsive. I use the second serial port of the N8VEM serial card to access a UDrive, and I can read and write files from/to that. No floppies or hard drives required. BTW, that serial card is a real "keeper" -- excellent, once you figure out the serial port headers. I can run a very nice S-100 system with just a cpu card, 64k memory card, the above mentioned serial card, and my RAMdrive. I'd love to have an IDE/CF card working, but it appears that won't happen. Anyone who might be interested in any of this can see the 68k and RAMdrive projects on my Web site: www.hanscom.us.
Roger