If all you want is a mass storage, you can do what I did for my NC4000 computer. I took a controller board from an XT and a ST506 drive( only 5 Megs but how am I going to create that much myself. It is better than a floppy controller since it buffers a sector. The computer can run as slow or fast as it wants because you just send it the commands and wait until it tells you that the sector is ready. You can then just read it back, a byte at a time. There is no other special hardware to design, other than possible buffers to handle data size. The XT controller is simple enough to wire up to most any TTL level bus and all the tricky stuff is done for you. My NC4000 was 16 bits and I needed to do byte operations. Since the processor could do short signed constants, I used the high memory address at 0FFFF to do a byte swap, rather than do shifts but shifts would be fine, I just wanted to minimize the number of cycles. I also did a floppy, that same way but the NC4000 was fast enough to read the status of the controller and transfer a byte at a time and keep up with the data rate of a 360 drive. In fact I had to add some delay because it was too fast. I didn't do a DMA for it. Dwight
________________________________ From: Chris Zach via cctalk <cctalk@classiccmp.org> Sent: Sunday, January 8, 2023 4:06 PM To: cctalk@classiccmp.org <cctalk@classiccmp.org> Cc: Chris Zach <c...@beaker.crystel.com> Subject: [cctalk] Re: Diablo series 30 or Dec RK03 > I think I've only ever seen pictures. I know I haven't seen one up close. There is "close" and there is "this thing is going to tip over on me" close. It was pretty impressive: Amazing lights panel that would allow you to see what it was doing, what sector and track you were on, and all sorts of stuff. I wrote a few quick programs to copy the lower 4k of memory to a specific track, it was handy because I could then load up pretty much any diagnostic tape image I wanted in a second. Made a fair bit of noise spinning up, once running you could hear the disks seeking, quite loud. The write protect panel had a square lighted switch for each disk and a sector lockout that I think protected the top sectors of the disk from writing. One 6 foot rack would fit the panel, controller, one drive, and the power supply for the drive then the controller. Pretty hefty, a second drive was in the rack next to it above the pdp8/I and PC08 paper tape reader. It was a truck. I wonder how it's doing these days... C
