test-drb May 2013

test-drb@ccmp.vtda.org

213 participants
253 discussions

by jules.richardson99＠gmail.com

They just had an e-waste recycling event in town; different company to the one that did such an event once before. Last time I was allowed to check for vintage systems, but there wasn't anything useful there - just few-years-old PCs. This time around there was an entire dumpster full of vintage Apple hardware, but I wasn't allowed anywhere near it - it all goes back to Wisconsin for "processing". Apparently they do occasionally ebay some vintage items, but the way this lot had just been tossed into the dumpster makes me think that it's all off to the crusher. (and of course there was the Disk II drive that I need, sitting right on the top of the pile!) Of course it's their right to do what they want with it - it's just frustrating not being able to save any of it. Jules

11 years, 7 months

cctech Digest, Vol 117, Issue 2

by michael.99.thompson＠gmail.com

---------- Forwarded message ---------- > From: "Zane H. Healy" <healyzh at aracnet.com> > To: "General Discussion: On-Topic and Off-Topic Posts" < > cctalk at classiccmp.org> > Cc: > Date: Wed, 1 May 2013 14:48:41 -0700 > Subject: Re: Multicians wonder what terminal this might be > At 2:37 PM -0700 5/1/13, Jim Stephens wrote: > >> imgur is a bit confusing. try this. >> >> http://imgur.com/a/6FnnP >> > > Is it sitting on something, or is the base part of it? > > If the base isn't part of it, it reminds me of the TEMPEST terminals from > Honeywell that I used on a DPS-8. > > Zane > We had hundreds of those VIP screen-mode terminals connected to a Honeywell DPS-8 in Cambridge. The big blue box had a synchronous RS-232 port to connect to a multi-drop synchronous modem and eventually to the Datanet front-end processor. The serial protocol was special for the VIP. There were two COAX cables from the big blue box to the terminal, one for the keyboard and one for video. Some of the really old versions had mercury delay lines for the video memory. -- Michael Thompson

11 years, 7 months

Block-oriented Magnetic Tape Drives

by pbirkel＠gmail.com

All; I'm curious as to what other manufacturers/systems supported the use of block-oriented magnetic tape media along the lines of the DECtape (TU56) and DECassette (TU60) drives. In particular, what about the use of standard 1/2" tape media under such circumstances? A wear-n-tear problem given the multi-pass nature of this use (especially if being used to store temp-files for the OS), but if that scenario were avoided ... I'd like to play around with some, but acquiring either a DECtape or DECassette unit looks to be somewhere between impossible and merely seriously unaffordable -- not to mention obtaining media for use with either. So I'm thinking about whether there are possibly other drives out there for which I might construct a suitable controller to mediate between the raw(er) mechanism and the OS. Unlike a streaming tape unit I'd expect that a major consideration would be keeping the moment-of-inertia of the reels as low as possible, consistent with holding a sufficiently long tape at sufficient bit-density to achieve an economically-viable amount of storage per tape (*e.g*., 256Kb -- DECtape was 184K 12-bit words or 144K 18-bit words). DEC managed it; did anyone else? (Of course, if anyone has a lead on a DEC unit -- DECtape preferred -- I'm very interested.) Thanks for your thoughts! ----- paul

11 years, 7 months

Apple IIgs - IIe keyboard

by jules.richardson99＠gmail.com

As mentioned in my post about IIe keyswitches, I acquired a couple of IIgs machines at the same time as the IIe (along with an AppleColor RGB monitor) - but no ADB keyboards or mice. I've just checked over both systems; one has an Apple memory expansion board fitted (2MB, I think) and the other has a Harris GS Sauce memory expansion board (also 2MB via a pair of 1MB simms) and what I think is an Apple SCSI board (nifty!). Both seem to power up OK and sit there trying to boot from non-existent media (display via composite; I don't know if the CRT monitor works - it's on the to-do list to make a cable). Anyway, the machine with the SCSI card looks to be an earlier board, and has a keyboard socket soldered to the PCB. Wikipedia seems to suggest that this should accept the keyboard from my IIe, albeit with reduced functionality over a genuine ADB keyboard - however, is it as simple as plugging it in, or are there other tweaks that are necessary for it to work? (e.g. perhaps worst-case a ROM change for a ROM that I don't have!). Although I'd like to get an ADB keyboard and rodent, I'm curious to see if the IIe keyboard will work in the meantime... cheers Jules

11 years, 7 months

Two Maxell CS-600XD data cassettes for cost of shipping

by classiccmp＠crash.com

Anybody need actual official data cassettes? I've got two (2) free to anybody who wants to pay the cost of shipping - I'll use bubblewrap and toss them in the smallest USPS flat rate box, that's $5.80 last I checked. "Maxell High Density Data Cassette - 183 m / 600 ft. - 16,000 ftpi. - D/CAS-86 COMPATIBLE CS-600XD Made in Japan" Labels are blank, write-protect switch is in the protected position. Excellent condition, clean, not sure where I found them. PayPal preferred. --S.

11 years, 7 months

Imlac PDS-4 information?

by derschjo＠gmail.com

Long shot, but does anyone have any documentation or software for the Imlac PDS-4? I'm working on an Imlac emulator/simulator (for the -1 and -1D) and I'd like to support the -4 as well, as it appears to add some interesting options; problem is I'm not finding a lot of detailed information about what and how it works :). (Hardware documentation/schematics would also be interesting - I have a set of what appear to be PDS-4 core memory boards and I'd love to be able to debug them since they're in rough shape...) - Josh

11 years, 7 months

Kaypro System disks?

by dave13＠dunfield.com

>>> When you create 360/1.2M disks by formatting on the PC - can you then >>> read and recreate those disks with IMD? >> I tried reading and then recreating a DOS 360K disk. Worked fine. >> >> It even seemed to read a known good Kaypro disk. But, I tried writing >> it out with no luck. It did, though, write it out with no errors, so >> I think I have two issues. One is that the K10FLOAD.TD0 file that I >> converted to an IMD did not convert correctly, and the other is a lack >> of correct settings on IMD. >> >> When I read my known good DSDD Kaypro boot disk, I set tracks to 80, >> stepping to double, and sides to 2. But, IMD tries to read all the >> way up to track 80, when I thought it would stop at 40 (80 tracks, >> double stepped). >Update: I was able to copy a known good Universal ROM boot disk and >boot it on the K1. So, at least I know my setup works. I still don't >understand why the read of the disk tries and fails to read tracks 41-80 >with doublestepping on. I also don't understand why running td02imd on >k10fload.td0 didn't create a good imd file I can use with the utility. If you take the time to read/understand the IMD docs and/or help screens, you will note that I explicitly state that IMD does not make ANY assumptions about your drive. It simply uses the capabilities of the controller to see what it can find "out there". The point of note here is that it supports up to the theoretical maximum of 255 cylinders that the 765 controller architecturally supports. So why would it assume that your drive cannot have more than 80 physical cylinders. It has no idea what type of drive you have. Sure, drives with more than 80 cylinders aren't common, but sometimes extra data is hidden in an extra track beyond the end... Some times two tracks ... why may any such assumptions - At one time 8" drives with 77 cylinders were "as big as it gets" - so NEC designed a 77 step limit into the original 765 ... which means they fail on long seeks on more modern 80 cylinder drives - requiring software workarounds ... IMD makes no assumptions about the drive - it simply does what you ask it to do. When you set double-stepping, you are simply telling IMD to send two step pulses for each cylinder it wants to move the head. It will try to read the number of cylinders that you specify. It does not "guess" that your drive may not be big enough to contain those cylinders because of other settings that you have made. IMD is about doing what you ask it to do, not trying to "fix it up for you". If you want to read a 40-cylinder disk --- set it to read 40 cylinders. It defaults to 80 cylinders because that will read most comon disk types without the user having to actually know what he is doing. Most drives will allow seek a couple of tracks past the certified number of tracks. In *MOST* disks, these "extra" tracks will not contain any data. At it's default settings, IMD will stop when it encounters a track with no discernable data - in *most* cases, this signifies the end of data tracks on the disk. So if you read a 40 cylinder disk while set to read 80, it will read 0-39 and stop on track 40. But this is because it "ran out of tracks" when it hit the extra track (40 = track# 41). But... if the disk contains data in this area, IMD will happy continue reading up until it either runs out of data, or hits the specified cylinder limit. This is why some of my Kay disks have the extra SD track 40 -- the original disks actually have this track one step beyond the certified limit of the drive. It also means that if your drive does not step past the certified limit, or you have data in all of the "extra" tracks before it hits the stop, then it will continue to step, banging the head against the stop until it gets to the number of cylinders you specified (because it never runs out of tracks with data). I designed IMD to be a fairly powerful tool, and not to limit you by making assumptions about what you are doing - as a result, you have to know more details about what you are doing than "other" disk archival utilities ... I do provide a lot of useful information in my docs and help files to help you get it sorted out, but it does require an inventment in time/effort to get there. Which leads to the question ... if you have TeleDisk images for the disks you want to create, and are finding IMD unsuitable - why not use Teledisk to recreate the disks. TeleDisk is designed to "make it easy" - it looks at the BIOS settings to see what kind of drive it is, and makes decisions based on that - for basic operations, it will be simpler than IMD to use. Dave -- dave13 (at) Dave Dunfield dunfield System/Firmware development services: www.dunfield.com (dot) com Classic computers: http://www.classiccmp.org/dunfield

11 years, 7 months

Kaypro System disks?

by dave13＠dunfield.com

>> When I read my known good DSDD Kaypro boot disk, I set tracks to 80, >> stepping to double, and sides to 2. But, IMD tries to read all the way >> up to track 80, when I thought it would stop at 40 (80 tracks, double >> stepped). > >WHOA! >You asked for 80, and it tried to do 80. You seem to be assuming that it >would divide by the double-stepping and do 40. (Actually, it is prob'ly >planning to stop at #79, V #39) > >1) When IMD asks "tracks", is it asking >A. Cylinders of the disk format (AKA "tracks [per side]") >B. number of cylinders TIMES number of heads >C. cylinders of the DRIVE The setting is "Cylinders" in the main settings menu, and it indicates the maximum number of cylinders that IMD will attempt to read from the disk (when writing IMD uses the cylinders occuring in the image - unless you use the track exclusion feature to avoid writing certain ones). >But, are you sure that IMD is counting both sides of a cylinder as >separate tracks? >When dealing with hardware, it is not uncommon [albeit inaccurate] to >treat "track" and "cylinder" identically. >"1.2M drives are 80 track" V "360K drives are 80 track (40*2)" >"Directory is on track 4" usually does NOT mean cylinder#2, side B IMD uses "Cylinder" to refer to the actual cylinders - ie: actual steps of the head(s) - it uses the "Singe/Double sided" setting to determine how many tracks occur in each cylinder ("as read" means it will try to read both sides for the first few tracks to determine. >> But, when I set retry to 0, and it goes all the way up there, I still >> don't have a good copy. > >If retry is set to 0, then it won't even try again when it hits an error, >which is VERY common with floppy drives. >NOT GOOD for getting usable disks. A good default is 5 - 10 >In SOME programs, NO RETRIES is useful for TESTING, as ANY error, no >matter how soft will be reported. >In SOME programs, 1 - x are the normal values, and 0 is treated as a >special case, either as '0' means "never stop trying until you succeed", >which is useful for desperate recovery, or >in SOME programs, '0' is a special case, and just means 256, 65536, or >4294967296 (DEC CX JNZ...) In IMD 0 is a special case, but it means to quickly scan the disk getting what it can on one read and NOT to re-analyze the disk if it cannot read data from a track - in doing so it also prevents the automatic stop when data runs out ... it's just a quick way to scan the whole disk to check a particular format. Agreed is it not recommended as a way to get reliable disks. >BTW, Kaypro puts an INCORRECT value in the "Head Number" field of the >sector headers of all of the sectors on side B. Fortunately, like the >extraneous SD track that Dave encountered on the 41st cylinder (#40), it >is ignored in use. Both are irrelevant to the current project, but quite >important if you want to use INT13h to read, write, or format Kaypro >diskettes. They also use different sector numbers on side 1 - in fact, they logically number both sides as if it were a single side (head 0) with ascending sector numbers through the sectors on both sides. IMD simply records the cylinder, head and sector numbers found in the sector headers of any given physical track and recreates them as it writes the disk - it does not expect them to contain any particular value, so it reads/writes kaypro disks with no problems. Dave -- dave13 (at) Dave Dunfield dunfield System/Firmware development services: www.dunfield.com (dot) com Classic computers: http://www.classiccmp.org/dunfield

11 years, 7 months

First web site restoration

by Paul_Koning＠Dell.com

Saw this in a newspaper article: CERN has brought back to life the first website -- of 20 years ago. http://info.cern.ch/ paul

11 years, 7 months

R4400 SGI Indigo - wild roar shortly after power on.

by trasz＠FreeBSD.org

I have a broken SGI Indigo I'd like to fix, but I have no idea where to start. The most obvious problem is that shortly after power on - two seconds, maybe three - a noise starts coming from the internal speaker. The sound becomes louder and louder with every second. No startup chime, no output on serial console. My initial thought was a broken power supply, but a PSU repair guy I've found claims that power supply is ok and voltages are correct and clean. He also says that he tried to bend the "mainboard" - probably the CPU board - slightly and this sometimes leads to the startup chime. Any suggestions are welcome. Thanks :-) -- If you cut off my head, what would I say? Me and my head, or me and my body?

11 years, 7 months

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test-drb May 2013