Andrew Lynch wrote: all Sometimes, this list is weird. formats> with an existing low cost home brew Z80 CP/M SBC and Disk IO board I think I was wondering about it too, and waiting for you to come up ;-) Anyway, I hope you don't mind if I post the links to two pictures which hopefully show how it could work: a.) the cpu board http://n8vem-sbc.pbworks.com/f/IMG_5762.jpg b.) the fdc http://n8vem-sbc.pbworks.com/f/IMG_8632.JPG So, if you use a right angled power-connector on the cpu, you could probably just stack those two board on top of each other, without the need of the bus backplane. My thoughts to all of this: 1.) I don't care about the sd-flash, Not sure if it really helps. After all, we still talk about floppies, so a decent V24 should be good enough to send /receive data from a floppy. 2.) The board is missing the 8" floppy connector, which is bad. Would make it easier to get the people playing with it. I know, you can wire it up easily, but you probably like to get the software people on board too ? ;-) Cheers STANDARD DISCLAIMER : (SORRY, I'M NOT INVOLVED IN THIS PROJECT AT ALL, BUT I'M WATCHING IT FOR A WHILE. LIKED TO PLAY WITH CP/M AND Z80 BEFORE) -----REPLY----- Hi! Some N8VEM builders have skipped the ECB backplane connectors and just direct connected the boards together as you suggest. That certainly is possible. Alternatively you could make a small ECB bus using IDC DIN 41612 connectors and 64 conductor ribbon cable. Some N8VEM builders have done that too. Although the Disk IO board does not have an explicit 8" connector all the signals are present for one. The Disk IO has a Shugart mini-disk interface 5.25"/3.5" and with the "feature" connector it has all the signals necessary. The builder can make a special cable for 8" drives if they are needed. There are different kinds of 8" drive interfaces with different signal requirements. They can be selected as options to make the signals present or not for the drives. In addition, the feature connector has signals normally buried in the FDC such as RAWREAD, /INDEX, and the MFM/FM decoded data stream straight from the FDC9229 data separator chip. These signals could be fed to an external uC or PC for direct sampling or processing similar to how a Catweasel works. The SBC and Disk IO would still be in the loop as a controller if not doing direct reads. Right now most of the software for the Disk IO board is focused on the IDE section. That supports quite a number of devices including CF adapters and regular IDE hard drives, ATAPI devices and the like. I have some very crude floppy drive "disk monitor" software available but that is as far as I got with it. I was able to read and write sectors, format tracks, move the heads, manipulate the i8272 registers and latch, etc all the things necessary for writing a CP/M CBIOS or disk utility. Some of the N8VEM builders are taking what I've done and are extending it but as you can imagine the floppy drive CBIOS is the most complex part. The software source code is available and open source as is all the hardware and software design information. Everything is publically available on wiki and mailing list. Some builders have proposed that the Disk 1A CBIOS could be modified to support this controller since they are somewhat similar. They are not exact though so it would be some work to make it happen. Even though the N8VEM SBC + Disk IO board is an incomplete solution it does have all the basic pieces necessary for this project. The PCBs and parts all exist and are obtainable fairly easily. There is quite a bit of software already in existence such as updated ROMs, CP/M archives, development tools, etc. However, the application software does not exist and would need to be written to make this practical. Obviously I am biased towards the N8VEM project as it is my own home brew system released in to the world. I think it could do this job if there were interested builders. I am now working on other projects such as completing the N8VEM 6809 host processor, the S-100 backplane, S-100 prototype board, the XT-IDE controller, and some other side projects. I hope this helps! Thanks and have a nice day! Andrew Lynch PS, you are welcome to join us on the mailing list and wiki regardless of this project. Feel free to stop by and join up!