Jesus that went insane. I did not bid on it and would not have gone above 1k anyway. Hope you got it. C On 3/9/2021 6:10 PM, Josh Dersch wrote:

Not me. $1k would have been my limit, it's really kind of insane to run something like that. As I put on my old memory hat I remember that the platter would rust but at least the heads would not weld to the platter. Also there were two timing tracks on it and if they were toast the platter was as well. Although these days you could probably just build a formatter for it from a Beaglebone and reformat. But at that point you could just have the BB spit out the head data right to the controller. And you could just replace the whole thing with a BB that could replicate every disk drive DEC made for the pdp8. Not every model, every drive ever sold :-) C

I meant that I have experienced welding of the heads. I haven't seen rusting, though I could believe that it's possible -- the platter looks like it's been blued like old style firearms. paul

Interesting document Al. Reading about the RK05, it seems to be little more than a double density version of the RK8/RK03(?) Was that a Diablo drive or a Pertec? C (Had an RK8, big square drive number buttons with lights in them)

Oh, sorry, meant the data was lost. I don't think it had the formatter on the unit though. The MFM emulator is an amazing bit of kit.

Right, the formatter was a piece of field service hardware. I think typically it had to be shipped up from Maynard, there wasn't enough call for them to have them at each field office. One oddity is that the timing track clock frequency on those writers is variable. The device would write the correct number of timing pulses and then read the timing track to verify the length of the gap at the end. Lights would indicate whether the gap was too small, correct, or too long, and you'd adjust the frequency knob accordingly until the "ok" light came on. It's documented in the maintenance manual. I read it long before I saw it done, and was amazed that yes, it actually work just as strangely as what the manual claims. Judging by the block diagram in the manual, you could build your own in an afternoon or two. It certainly is. It works wonderfully well. paul

On Tue, Mar 9, 2021 at 3:39 PM Ethan Dicks <ethan.dicks at gmail.com> wrote: Not I. I wonder what the high bidder's max was... I feel kinda stupid, given that the thing's original BIN was $1500; I wasn't going to go that high on it but a friend of mine offered to chip in at the last minute so I got outbid by $25 over the original BIN price. It's OK, I have enough projects as it is and I definitely didn't need to spend more money. - Josh