A recent addition to Interak has been to use a Compact Flash card as a storage device. It is configured as an IDE hard drive. My GIDE interface was purchased as a kit of parts from Frank Dachselt in Germany dachselt@iee.et.tu-dresden.de
The GIDE interface has been developed (originally by Tilmann Reh in 1995) to enable Z80 computers to connect to IDE devices. Although the IDE bus is a 16-bit data bus the GIDE interface reads and writes in two 8-bit accesses.
Next I connected an IDE to Compact Flash adapter, which came from China via eBay. Using a small program I was able to read the Compact Flash Information - click here for a screen shot. I was also able to read the Information from a Western Digital 1GB hard drive - click here.
Here is the GIDE interface
mounted onto the Interak CPU card. It fits into the Z80 CPU socket with the Z80
then fitted on top. Also shown is the 128MB DOM fitted into the IDE
adapter.
Although the Compact Flash storage works very well using various CF cards, I have now fitted a DOM (Disk on Module) which is basically a 128MB Compact Flash with dynamic wear-leveling. This ensures even wear of flash blocks across the entire card.
The Compact Flash in IDE mode works out really well with CP/M 2.2 since the maximum disk size that this OS can handle is 8MB. All of the CF cards that I have looked at have 32 sectors per track and allow 512 bytes per sector (= 16K per track) and they have just under 500 Cylinders per head. This gives a total size of just under 8MB per head and the number of heads depends on the size of the CF. (in this case 16heads x 8=128MB)
What all this means is that just by switching heads in the BIOS CP/M has access to another 8MB drive. I am now using A: and B: as floppy drives and C: to P: are 14 x 8MB hard drives - total = 16 drives. This is the maximum number possible with CP/M 2.2.
For more information on Compact Flash DOM's visit this site www.milesie.co.uk which is where I purchased mine from.