Over on YouTube [Usagi Electric] shows us how he installed an 84MB hard drive into his PDP-11/44.
In the beginning he purchased a bunch of RA70 and RA72 drives and board sets but none of them worked. As there are no schematics it’s very difficult to figure out how they’re broken and how to troubleshoot them.
Fortunately his friend sent him an “unhealthy” Memorex 214 84MB hard drive, also known as a Fujitsu 2312. The best thing about this hard drive is that it comes complete with a 400 page manual which includes the full theory of operation and a full set of schematics. Score!
After removing the fan and popping the lid we see this Fujitsu 2312 is chock-full of 7400 series logic. For power this drive needs 24 volts at 6 amps, 5 volts at 4.5 amps, and -12 volts at 4 amps. Fitting the drive into the PDP-11 rack requires a little mechanical adjustment but after making some alterations the hard drive and a TU58 tape drive fit in their allotted 3U rack space.
After a little bit of fiddling with the drive controller board the Control Status Register (RKCS1) reads 000200, which indicates fully functional status. At this point the belief is that this computer would boot off this drive, if only it contained an operating system. The operating system for this machine is RSX11. And that, dear reader, is where we are now. Does anyone have a copy of RSX11 and a suggestion for how we get it copied onto the Fujitsu 2312? We wouldn’t want to have to toggle-in our operating system each time we boot…
A hearty Cheers to the Meanwell power supply, savior of many vintage computer restoration projects
I’ve got a working Obsolescence Guaranteed PiDP11. My first in-person experience on a PDP-11 was with RT-11 (in 1978), but it would run RSX-11 too. The replica page has links to OS resources:
https://obsolescence.dev/pdp11.html
http://rsx11m.com/
Easy, using https://www.pdp8online.com/mfm/code/mfm/mfm_write_doc.html
And if you want to dump data from an RLL drive or just simply look at raw flux transition and low level data structures on tracks you can use any 200MHz Logic Analyzer ($5 Pico based ones work just fine) combined with Sigrok and decoder I recently adopted and upgraded to support MFM/RLL HDDs https://github.com/raszpl/sigrok-disk
argh never mind, this drive and controller are SMD! Thats even more obscure than ESDI. Im slowly gathering data to support dumping ESDI drives and getting my hands on hardware is hard enough.