Are you using the same pack for the 8 and the 11 On Sat, Dec 8, 2018 at 8:54 AM Bill Degnan via cctalk <cctalk@classiccmp.org> wrote:
> On Sat, Dec 8, 2018, 1:02 AM Josh Dersch via cctalk <cctalk@classiccmp.org > wrote: > > > On Fri, Dec 7, 2018 at 9:58 PM Josh Dersch <dersc...@gmail.com> wrote: > > > > > Hi all -- > > > > > > Finally got all the parts together (and my act together) to actually > get > > > an RK05 lashed up to my PDP-8/e -- only took a decade or so :). I > fixed > > a > > > few problems with the RK05 and it appears to be behaving very nicely. > > > > > > The RK8E controller is mostly working properly but fails interestingly > > > when running the formatter, and during the exerciser -- on cylinder 128 > > and > > > 192 and very infrequently on cylinder 64 it will get a cylinder > mismatch > > > when doing the seek. When running the formatter during the > verification > > > pass, on cyls 64 and 128 if I retry the read it'll continue without > > issues, > > > but it's never successful on a retry on cylinder 192. I tried hooking > it > > > to the RK05 in my 11/40 and it exhibits the same behavior, so I'm > > guessing > > > the drive isn't at fault. And the error is consistent across packs (of > > > which I have only two). > > > > > > Apart from that fault the drive and controller seem to work fine -- I > > > wrote out an OS/8 pack with Adventure on it (or at least the first 191 > > > cylinders of it) and it works without issue. > > > > > > Reading the RK8E service docs and schematics, the cylinder address > > compare > > > is done by reusing the CRC buffer, so I suspect the issue is in or > around > > > there -- the big problem is that debugging it is rather painful since > > that > > > logic is in the middle board of a three board set, with jumper blocks > on > > > top -- so bringing it out on an extender isn't an option. I'm curious > if > > > anyone's seen this issue or is so very familiar with the logic that the > > > fault is obvious. > > > > > > I suspected the 7496 shift register at E14 which takes in the cylinder > > > address to be compared w/the header on disk, and I went ahead and > > replaced > > > it in the hopes that I'd get lucky, but no go. > > > > > > Anyone have any advice? > > > > > > Thanks, > > > Josh > > > > > > > > I'll add that during the format/verification the drive seeks properly > (i.e. > > it's not missing a step or overstepping), which I've confirmed by > watching > > the thing walk through the tracks with the cover off. > > > > - Josh > > > > Partitions as rka0 / rka1? > B > > > >
