it's true very little LESI documentation escaped...But the klesi schematic did. and it's well commented. lots of descriptive signal names. The hardware to interface to it is almost trivial. I took a couple of hours looking over the schematic and have written a couple of pages describing how to make it work. Happy to send to anyone who wants it. Writing MSCP emulation is beyond my skill level. But i can read a schematic.
joe On Thu, Jun 4, 2015 at 11:56 PM, Robert Armstrong <b...@jfcl.com> wrote: > >Ethan Dicks [ethan.di...@gmail.com] wrote: > >did not come with a removable cartridge so I've not been able to spin it > up > > Yes, one of the annoyances of the RC25 is that you can't spin it up w/o > the removable platter in place. I have only one cartridge myself, and it's > probably bad. Somebody needs to come up with a hack to spin up the > Winchester part alone (hint, hint :-) > > >One I've seen is to nibble a chunk out of the rim of the cover skin (to > prevent pinching) and run a BC-11-A > > Unibus ribbon cable out to a BA-11 and stick any number of controllers > in that > > Doesn't the 725 have one of the regular bulkhead connector panels on the > back? The one with the modular screw in plates? If so, ISTR that there's > a cable clamp one that will clear a BC11 cable. > > In any case, I have no need for such foolishness :-) I have a perfectly > good 730 too, with a BA11-K expander in the next rack. It works great, and > that configuration (with the 730 instead of the 725) was even supported > although uncommon. I should go out in the garage and check how the UNIBUS > cable is routed for you. > > Besides, the cool thing (for me, at least) about the 725 was the > packaging. Any replacement drive would have to fit inside the original box > to suit my taste. > > The best option I've come up with is an SMD UNIBUS controller (I have > just exactly one!) and a small SMD drive. There were some small SMD drives > that I think would fit inside the 725 case. The front panel wouldn't be > right, but it's better than nothing. As you said, SCSI would be better, > but I don't have a UNIBUS controller. > > What I'd really like is to build a "LESI disk emulator" that could just > plug into the AZTEC controller, but as far as I've ever been able to > determine, DEC never documented LESI. Or at least none of the > documentation ever escaped. > > BTW, my 725 is missing the outer sheet metal skin. The previous owner > apparently didn't think it was important and discarded it. If anybody > happens to have an extra VAX-11/725 skin, I'd love to know. > > Bob > > >
