test-drb January 2015

test-drb@ccmp.vtda.org

175 participants
253 discussions

by useddec＠gmail.com

I can't seem to find the thread on precision screwdrivers and other tools. I might have mistakenly deleted it. I planned on reviewing it to buy some new tools and now I'm stuck. Can someone please get me in the send me a copy of it? Thanks, Paul

10 years, 2 months

Seeking an ECL monitor (preferably for a dimple-top Sun base) and Sun 3 Keyboard and Mouse

by ian.finder＠gmail.com

> Trying to get my 3/50 restored... If anyone has these available I would like to purchase them from you. > > Understand it might be a long shot. > > I'm in Seattle, WA > > Thanks, > > - Ian > > -- > Ian Finder > (206) 395-MIPS > ian.finder at gmail.com

10 years, 2 months

new-old-tech news

by hilpert＠cs.ubc.ca

Not my thing really, but of interest to some here I expect (pardon if I missed it and it's already been mentioned on the list): "Remodelled ZX Spectrum production set to begin" http://www.bbc.com/news/uk-england-nottinghamshire-30810148 Also, not especially computers, but: "Why can't we let go of our old tech?" http://www.bbc.com/news/technology-30879638

10 years, 2 months

UNIBUS PDP-11 memory expander card

by jnc＠mercury.lcs.mit.edu

> From: Jacob Ritorto > I just happen to have one in my hand as we speak. I'll photograph it... Hmm. That photo (here: http://ana-3.lcs.mit.edu/~jnc/jpg/PDP11s/AbleENABLE.jpg if anyone wants to see it) shows a very different card than the one in the brochure. That one's a hex card, with an over-the-back connector: this one's quad, no OTB connector. This looks more like a QNIVERTER? Does it say 'ENABLE' on it anywhere? (Which would imply there was more than one variant... which would be interesting, because I have this bit set that the one we had at MIT was not like the one described here: http://gopher.quux.org:70/Archives/usenet-a-news/FA.unix-wizards/81.07.09_u… because I'm pretty sure that on ours, the DMA devices were on the far side of the ENABLE - which makes sense, because ours had separate PARs and UNIBUS map registers, which make no sense in that configuration - unless Mike [blessings, wherever you are] made a mistake in drawing that up.) Noel

10 years, 2 months

strange number corruption on pdp11/34

by jnc＠mercury.lcs.mit.edu

> From: John Wilson > The *ability* to accept the FPP (and/or cache -- M8268 I think?) Yup, M8268. > And you need the right over-the-top connector (hazy memory says H882 or > H8822 for either or both option but I may have made those up). There are two: if one has only an FPP (M8268) _or_ a cache (M8268) one needs a single OTB connector, H8821 (they both go in the same slot, if one has only one of the two). If one has _both_ the FPP _and_ cache, one needs a double OTB connector, H8822. > Better to reduce the variables and leave the FPP off for now. Indeed! > From: Jacob Ritorto > I ended up ... mix-and-matching 8265 and 8266 boards from the old and > new sets to make a system that doesn't bus error and doesn't print > weird zeroes. Let me make sure I get this. You have two M8265's, A and B, and two M8266's, C and D. You're saying that _only_ the combination AC works; that AD, BC and BD all fail? In other words, only A and C work, and both B and D are bad? > thank you all again for the insights and interest! Hey, that's what we're here for! > If anyone is really interested in debugging these "bus error / > zero-inducing" cpu boards to find out what on earth was causing the > problem, I'd be happy to loan them out. Nah, I've got enough of my own stuff to work on... :-) But if you decide you have no use for dead cards, and want to sell/trade, please let me know! > Heck, I might even try to do what we were talking about initially and > write up some little math tests if you're really curious. Well, I'm mildly curious, but _iff_ you want to repair them, you need to do some of that, to try and figure out what the bug(s) are. (And of course there's that busted M7265/M7266 set, too!) Since you have 3 sets, and only one works, you might want to get a second set working before that set dies on you, too... :-) Noel

10 years, 2 months

strange number corruption on pdp11/34

by jacob.ritorto＠gmail.com

Hi, I'm getting all zeroes nearly any time there's supposed to be a large number output to my terminal. Does this sound familiar to anyone? This happened last night on rsx and is also happening today on xxdp. example xxdp testing rl02: DRSSM-G2 CZRLK-B-0 CZRLK PERFORMS RANDOM OPERATIONS OF GET STATUS, SEEK, READ, AND WRITE UNIT IS RL01,RL02 RSTRT ADR 000000 DR>START CHANGE HW (L) ? Y # UNITS (D) ? 1 UNIT 0 RL11 (L) Y ? Y BUS ADDRESS (O) 0 ? VECTOR (O) 0 ? DRIVE (O) 0 ? DRIVE TYPE = RL01 (L) Y ? N BR LEVEL (O) 0 ? CHANGE SW (L) ? N NXT TST MAY ZERO LD UNIT. DOIT ANYWAY?Y TESTING STARTED CZRLK HRD ERR 00000 ON UNIT 00 TST 000 SUB 000 PC: 000000 DR ERR TIME: 00:00:00 RLCS: 000000 DRIVE: 0 DRIVE TYPE = RL00 >> FUNCTION: WRITE BEFORE ERR (RLCS): 000000 (RLBA): 000000 (RLDA): 000000 (RLMP): 000000 AT ERR (RLCS): 000000 (RLBA): 000000 (RLDA): 000000 (RLMP): 000000 DR ERR ADDR = CYL: 000. SUR: 0 SECT: 00. STATUS WAS: 000000 LST POS: 000000 DR ERR - RECOVERED CZRLK HRD ERR 00000 ON UNIT 00 TST 000 SUB 000 PC: 000000 DR ERR TIME: 00:00:00 RLCS: 000000 DRIVE: 0 DRIVE TYPE = RL00 >> FUNCTION: WRITE BEFORE ERR (RLCS): 000000 (RLBA): 000000 (RLDA): 000000 (RLMP): 000000 AT ERR (RLCS): 000000 (RLBA): 000000 (RLDA): 000000 (RLMP): 000000 DR ERR ADDR = CYL: 000. SUR: 0 SECT: 00. STATUS WAS: 000000 LST POS: 000000 DR ERR - RECOVERED CZRLK HRD ERR 00000 ON UNIT 00 TST 000 SUB 000 PC: 000000 GARBLED DATA - CAN'T CHECK IT TIME: 00:00:00 RLCS: 000000 DRIVE: 0 DRIVE TYPE = RL00 >> FUNCTION: READ BEFORE ERR (RLCS): 000000 (RLBA): 000000 (RLDA): 000000 (RLMP): 000000 AT ERR (RLCS): 000000 (RLBA): 000000 (RLDA): 000000 (RLMP): 000000 DR ERR ADDR = CYL: 000. SUR: 0 SECT: 00. XFER SIZE = 00000. WORDS 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000

10 years, 2 months

new-old-tech news

by kspt.tor＠gmail.com

On 28 January 2015 at 13:05, Brent Hilpert <hilpert at cs.ubc.ca> wrote: > Not my thing really, but of interest to some here I expect (pardon if I missed it and it's already been mentioned on the list): > "Remodelled ZX Spectrum production set to begin" > http://www.bbc.com/news/uk-england-nottinghamshire-30810148 It'll be interesting to see if that works at all. > Also, not especially computers, but: > "Why can't we let go of our old tech?" > http://www.bbc.com/news/technology-30879638 Aah, old arcade games.. and pinball machines. There's something about that mechanical/physical aspect I think. The point in time when I lost interest in pinball machines was when they changed the number displays >from mechanical to electronical. Suddenly the pinball machines lost their appeal for me. Some important part of the experience was gone. -Tor

10 years, 2 months

strange number corruption on pdp11/34

by jnc＠mercury.lcs.mit.edu

> From: Johnny Billquist > If it comes as far as booting RSX as well as XXDP, there can't be > anything seriously wrong with the CPU... Yeah, I see your point, but why all the zeros, then? That's what I could't work out. Anyway, it should be really easy to make sure e.g. ASH, MUL and DIV are working; it's vaguely plausible that one of them is broken. (Unix V6, I think, might even boot even if MUL was broken. I know the bootstrap uses DIV, to calculate the cylinder in the disk driver.) If not, cross that off the list, and try the next thing... Which is? Noel

10 years, 2 months

Destructive Imaging of DECTAPE II Media

by nf6x＠nf6x.net

Responding on-list to an off-list message, with permission... On Jan 27, 2015, at 09:30 , Lou Ernst <louis.ernst at verizon.net> wrote: > This is not silly. I think it can work. I had a similar idea about TU60 decassettes. My task was easier there though since the TU60 uses standard Philips compact cassette shells. The TU60 however has no capstan and uses the spindle motors to maintain tape temsion. It was designed by the same guy who designed dectape (TU55/56). Using the spindle motors to maintain tape tension seems like a better scheme than that danged drive belt in my opinion. I recall reading somewhere online about the heroic measures that some engineers (at HP? Or was it 3M?) had to go to to get a DC-100A-like cartridge design working, involving lots of hard work in the areas of lubricants, surface finish, and how to make that drive belt by stretching out a small disc of plastic. My interpretation is that they had to apply heroic efforts to make a crappy design barely work. ;) > Long story short, I was able to play TU60 cassettes in a good audio cassette deck and digitize the audio on a PC. I manipulated the audio file in Audacity. I was able to cut single data blocks and dump the blocks to a long .CSV file. I opened these in Excel and created intelligence in the spreadsheet to digest the audio samples back into the block data, even properly decoding the header and checking the checksum. The hardest work in the spreadsheet was tracking the bit boundaries due to the temporally varying bit-rate (no capstan in the real TU60). Cool! > At last I did not have to use this means of recovering data from TU60 cassettes. My real TU60/TA11 worked well enough to recover the data on the cassettes I was provided to recover. I developed that tape deck/digitizing method in case there were dropouts unrecoverable by the real TU60. At least the real TU60 isn't hobbled by that dreadful cartridge design. > Perhaps you can build a sort of open frame reel-to-reel deck to play and digitize the tu58 tapes. That's what I'm thinking. While I could repeatedly use one or two good cartridge/belt assemblies with the guts of multiple tapes in order to image them in a TU58-XA transport, I don't relish the thought of repeatedly tinkering with the danged belt if I can come up with a better solution. I found a specification that includes the magnetic track dimensions of the DECTAPE II on Al's site: http://bitsavers.trailing-edge.com/pdf/dec/dectape/tu58/TU58_Engineering_Sp… Also, I found a diagram showing track dimensions for various audio cassette formats here: http://richardhess.com/notes/formats/magnetic-media/magnetic-tapes/analog-a… in particular: http://www.richardhess.com/tape/cass_trk_lrg.gif Both the DECTAPE II media and standard audio cassette media are 0.15" (3.81mm) wide. DECTAPE II has two .057" (1.448mm) wide tracks, centered 0.046" (1.168mm) apart. Data density is 800 BPI, with 2400 flux reversals per inch. At standard read speed of 30 ips, that turns into bits in 41.7us increments and flux changes in 13.9us increments. The reels inside the cartridge will spin at around 380 to 800 RPM depending on how much tape is on them, if I still know how to do math. Or twice that at the scanning speed of 60 ips. Just based on track geometry, it seems to me that it may be quite possible to read DECTAPE II media with the inner two tracks of a 4-track recorder head or auto-reversing stereo audio deck head. Or even with both tracks of a 2-track 2-channel head as shown in the diagram I found, though I don't know how common those are. 4-track recorders and auto-reversing stereo decks are pretty common, though. Running the tape at a stable speed near 30 ips instead of 1-7/8 ips would be the hardest part, I think. My gut feeling is that a normal audio cassette capstan and pinch roller assembly may not work well at 16x normal speed, and I haven't seen references to any audio cassette tape applications that run the tape at controlled speeds that fast (rewind and fast-forward speeds may be that fast or faster, but those run the tape at unregulated speeds with the pinch roller disengaged). I don't know if audio tape heads are electrically suitable for this application, but I think they might be since the flux change period is in the same ballpark as the AC bias frequency used in cassette recorders, so the head coils ought to respond ok at those higher frequencies (?). I'm curious about what folks with deeper magnetic media experience than I have might think about this. -- Mark J. Blair, NF6X <nf6x at nf6x.net> http://www.nf6x.net/

10 years, 2 months

strange number corruption on pdp11/34

by jnc＠mercury.lcs.mit.edu

> From: Johnny Billquist > Is noone paying attention to the fact (and my previous comment) about > using 0 for CSR and vector??? Err, no. :-) But seriously, I'm a bit boggled that a diagnostic program would _not_ have as default the 'standard' vector/address. So I'm kind of assuming that the 0's are somehow bug results. > From: Jacob Ritorto > I grabbed a set of pdp11/34a boards ... Can I plug them straight into > this blackplane that's currently housing my misbehaving 11/34? Yes, if the backplane is some flavour of DD11-P (I don't know of any backplane that supports the 11/34 but not the 11/34A, but I only have direct confirmatory documentation on the DD11-P, and it supports both). My vague recollection is that one can use _either_ the M7265/M7266 (but as paired set) _or_ the M8265/M8266 set, but you can't mix and match them. But don't depend on that (I'm too tired to dig into this tonight, I'll do so tomorrow). > Backplane markings are very faded but seem to say dd11-pk. Yeah, that's the 11/34 backplane (actually, the DD11-P part - the -PK is the version with the wire harness to work in a BA11-L or BA11-K; the -PF is for the BA11-F or BA11-P). Noel

10 years, 2 months

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test-drb January 2015