CF cards on classic machines (was Re: Another disk imaging project)

Ethan Dicks wrote: There is the older CF standard, and the newer CF+ standard. However, both should function identically in "True IDE" mode. Well, the official CompactFlash spec (google for a copy, or email me as a last resort) tells quite a bit, but one must have a grounding in how to communicate with an IDE drive first (to understand the command set and sequence). You can only do 8-bit mode when in CF "memory mapped mode". But, as that requires the same amount of lines and precludes the support of IDE disks in a project, many opt to use True IDE mode. In IDE mode, you have to send and receive data in 16 bit chunks, but I do it with a 8-bit micro, and others have as well. You simply treat the 16 bit data as two IO bytes, and twiddle the IDE lines via a third IO port as needed. Polled IDE mode requires 24 IO lines to operate. Memory mapped 8 bit mode requires almost as many, unless you decide to directly map the 1K CF "window" into your memory map. But, in the end, True IDE mode is simple enough and supports IDE, PCMCIA, and CF options (disk wise). As for the issue you decribed, if you want to mail me a card, I can play with it and see. I did notice an issue with a card previously mailed to me; it did not have an MBR. Many interfaces (mine included), rather assume an MBR as the first sector of the disk. But, some smaller cards opt to forego the MBR, placing the first FS sector as sector 1 of the card. At this point, I don't know how OS's like Windows determine what the FS is on the card, as the FS type is a function of a byte in the MBR (which is missing on those cards). I addressed the issue here by doing using fdisk to delete all partition information, doing a fdisk /mbr (or was is format /mbr), and creating a new partition on the card in a PC with a IDE->CF adapter. Jim -- Jim Brain, Brain Innovations brain at jbrain.com http://www.jbrain.com Dabbling in WWW, Embedded Systems, Old CBM computers, and Good Times!