Re: Not just slashed zeroes/ohs
On 4/27/22 10:51, Craig Ruff via cctech wrote: > Having gone through many mathematics courses it was common to also place a > slash on the letter Z to distinguish it from the numeral 2. Also for persons > from Europe where they slashed the numeral 7 to distinguish it from a numeral > 1 that commonly had an initial small upward stroke at the top when hand > written. Not just a small initial upward stroke on the "1", but in some European countries (I'm thinking of Germany and the Netherlands), some make that stroke at least half the height of the number, if not more. I have no idea where the long top stroke originated. --Chuck
Re: idea for a universal disk interface
I'll only mention that there were ICs that could interface to both MFM/ST506 hard drives as well as floppies (System/3 MFM). An example would be the SMC HDC9234, "Universal Disk Controller". Pretty cool chip for the time; has full 24 bit DMA address capability. But different register/controller setup than the stock PC AT. --Chuck
Re: Fanuc PPR - Paper Tape Punch, Printer and Reader : Not quite working
On 4/10/22 12:23, Martin Bishop wrote: > Chuck > > My error, you said 20 mA current loop, I bowdlerised it as parallel port. I > have a punch with a parallel interface ... I can't recollect ever using a > current loop interface on equipment, although I have met many in old > documents. 4 .. 20 mA current loops reporting e.g. pressure actuated > potentiometers are however old friends, if that is the correct term. As you > observe current loop has good noise immunity. There is a tie-in to parallel port, although somewhat tangentially. Back in the 80s and 90s, CL was promoted as a long-haul solution to (as well as other things) distant printers. In particular, I remember Inmac flogging them. --Chuck
Re: Commodore vic 20 poweroff
On 3/16/22 13:37, Will Cooke via cctech wrote: If the question is being asked by a person of a certain vintage, I can understand the "why" of it. Gone are the days when you simply switched off the AC power when you were finished. Nowadays, everything from cell phones to Smart TVs go through a shutdown sequence. (My TV keeps playing the last ad before it goes silent). I remember, during the 1970s, when we were rolling out our microcomputer business software, it took a lot of reminding the operators that you simply didn't toggle the power switch when you were done. I'd suggested a "soft power" switch, but was overruled by the marketing people who thought that would only encourage customers to pull the AC plug. --Chuck
Re: Memory Tech you don't see very often
Perhaps even rarer were the EBAM tubes that CDC worked with during the 1970s. I recall seeing a 6' rack of a complete assembly sitting in a hallway at ADL around 1974. If CDC followed the dictates of management then, the unit was probably utterly demolsihed before being sold as scrap metal. --Chuck
Re: TI-99/4a Monitor power cord
On 11/6/21 10:24 AM, David Gesswein via cctech wrote: > On Fri, Nov 05, 2021 at 10:13:48PM -0500, David Williams wrote: >> I have a TI monitor that has a power cord that is becoming sticky and gummy >> and I'm looking at what to do with it. >> Any other suggestions on dealing with the cord besides replacing it? >> > Once the plastic starts breaking down I haven't found anything permanent. > Some are breaking down slow enough that cleaning lasts for a couple years. > I go though my various cleaners/solvents until I get to one strong enough to > clean it up without too much damage. The ones for removing gummy adhesive > remover seem to work OK. A mild abrasive cleaning pad or cleaner can also help > since sometimes you need to remove the surface plastic layer to get to more > stable plastic. Aggressive solvents will also do that but I have trouble > controlling them. Heptane (sold under the name "Bestine") works wel and won't affect plastics. Bestine is mostly known to stamp collector s who use it to remove adhesive from stamps without damaging them. Bestine is also useful for removing really stubborn deposits from tape and disk heads. You can expect that eventually, the jacket on the cord will begin cracking as the loss of plasticizer progresses. A somewhat more pragmatic approach, short of replacement, is to encase the the cord in split wire loom. Looks a little clumsy, but will keep the sticky stuff from fouling anything else. FWIW Chuck
Re: Early '80s Motorola Semiconductor Reference - anyone?
On 8/8/21 3:38 PM, Randy Dawson via cctech wrote: > I found a few of the databooks here: > > https://usermanual.wiki/search.php?q=motorola%20semiconductor%20reference > Randy, if you're looking for Moto databooks, Al has archived a pile of them on bitsavers: http://bitsavers.org/components/motorola/_dataBooks/ --Chuck
Re: Early '80s Motorola Semiconductor Reference - anyone?
On 8/7/21 5:50 PM, r.stricklin via cctech wrote: > Anyone have an early ‘80s Motorola semiconductor reference manual? I am > attempting to repair a Boschert power supply from ~1983 that is full of > Motorola parts marked as 1027 (DO-42ish), 1077 (TO-3ish), 1078 (DO-5ish), > etc. It would be extremely helpful to know their specifications, or ideally > how to cross-ref them to “standard” parts. Those are Boschert "house numbers'. Unless you can find a Boschert maintenance document that lists them and ther equivalents, it's going to be a bit of a detective sleuth. --Chuck
Re: Help reading a 9 track tape
On 8/5/21 8:23 AM, Jay Jaeger via cctech wrote: > > Also, before starting (after baking and cool-down) I unspool maybe 25 > feet of tape onto a clean surface to make sure it isn't sticking. If it > does, I let it sit for a few hours, and then bake it again. Have not > had to bake for additional time very often, and in those cases, it ended > up not helping as much as one might like. ...and think twice before you attempt recovering data from 80's Wabash tape (or floppies). Pure agony. --Chuck
Re: Help reading a 9 track tape
Whoever does it, I have a few suggestions when it comes to 40+ year old tapes. 1) Bake the thing at 58C for a day or two. It might just prevent you from staring at a tape stuck to the head and a pile of brown dust at the bottom of the drive. (Before you start, make note of the brand and type of tape; some are much worse than others). If you're uncertain, check back here and I'll tell you what I know. 2) If you're determined to use a SCSI drive, initially turn off automatic retries (shoe-shining). With sticky tape, you can do a lot of damage to the tape. Retries can come later when you're confident about the condition of the tape. 3) Should the tape turn out to be sticky, don't try to clean it--it will only foul up the cleaning equipment (I'm assuming a tape cleaning machine here). Coat the tape with cyclomethicone. At least it won't stick to anything and you'll get a chance to do a good read. 4) If you have a choice of read speeds, use the lowest speed to start with. Make sure that you can deal with tape errors. 5) Forget using a streamer--they're just not suited to dealing with fragile tape. If you're not equipped to deal with this, don't attempt it. A tape written 10 years ago, is not the same as one written 40-60 years ago. The 1980s, in particular, were responsible for some truly wretched stock. I thank my lucky stars that cellulose acetate never made it as computer tape base. Curiously, tapes from the 1960s and 70s can be less of a problem than those from the 80s and 90s. My .02 for what it's worth. --Chuck
Re: Help reading a 9 track tape
On 8/2/21 8:11 AM, James Liu via cctech wrote: > Thanks for feedback and offers to assist. Happy to contirubte. > For some background, Tini Veltman developed Schoonship in the 1960's > at CERN on the CDC 6600. My understanding is that he more or less > insisted on coding in assembly since he thought FORTRAN or other high > level languages would just get in the way and slow things down. The > code was maintained by Veltman and Strubbe well into the 1970's, but > its future was held back by being so closely tied to CDC hardware. Which CDC FORTRAN? RUN, maybe--but FTN extended was pretty darned good in optimizing and scheduling instructions. A lot of work went into that one. As a matter of fact, when we COMPASS scriveners came up against a nasty loop that we wanted to optimize for the 6600, one approach was to code it in FORTRAN to see what the compiler would do with it and then work from there. Some of the optimizations were quite startling, particularly with the "UO" option selected. If you've never written and hand-optimized 6600 code, it could be a daunting task. Did you know that parts of FTN are written in FTN? I recall the COMMON/EQUIVALENCE processor written as a mess of assigned GOTO statements (state machine) and being utterly bereft of commentary."Don't touch it--you might break something!" FORTRAN was CDC's bread-and-butter language for years, as it was the universal choice of number-crunchers everywhere during the 60s through 80s. And CDC excelled at number-crunching. My .02 for what it's worth. --Chuck
Re: Help reading a 9 track tape
On 7/31/21 8:08 AM, Jon Elson via cctech wrote: I'll add a thought that if this is a CDC 6000-system tape written in the 1970s, it could well be 7-track, regardless of the manufacturer's label. Up through the 1970s, 7 track tape drives were very common on CDC systems. --Chuck
Re: Help reading a 9 track tape
On 7/31/21 8:08 AM, Jon Elson via cctech wrote: > Where are you? I have a CDC Keystone drive that worked last time I > fired it up, > > and I have it interfaced to a Linux PC. I'm in Missouri. I wonder if the OP is in the Netherlands, Schoonschip being a Dutch product. In any case, I'd advise you to determine what brand media the thing uses. I'm struggling now with a Wabash "Mira" tape and it isn't pretty. About the same as Wabash floppies of the same time. --Chuck
Re: Compaq Deskpro boards/hard drives from the late 1990s
On 7/21/21 2:42 PM, Jules Richardson via cctech wrote: > On 7/21/21 12:51 PM, r.stricklin via cctech wrote: >> >> >>> Regarding your "IDE HDDs were extremely rare" comment, did *anyone* >>> other than Quantum release an IDE drive in that 5.25" form factor? I >>> can't think of any, everything else was 3.5", although some early >>> vendor's drives were the same height as a "half height" 5.25" drive. >>> >> >> CDC 94208-51, 62, -75. The -51 is Compaq drive type 17. > > Interesting! Were they built as IDE drives from the ground up, or were they > ST506/412 types with an additional board grafted on doing the interface > conversion? Yes, they were all part of the CDC Wren series--ST506, ESDI, IDE (although referred to as ATA in the literature) and SCSI. I'm still using a SCSI 330MB WREN in one of my boxes. --Chuck
Re: Early Programming Books
Going back to the time around 1960, I'd like to venture the opinion that most data processing of the time was performed with unit-record equipment. That is, sorters, reproducing punches, interpreters, accounting machines, etc., none of which were programmed by "software", but by wiring plugboards or selecting operation from fixed controls. Perhaps there were instructional tests in that area. After all, card sorters pretty much operate on the same principles. --Chuck
Re: Early Programming Books
Aside from the very general Algol report and the Iverson book on APL, I have to admit that most of my programming knowledge came out of manufacturer's manuals, specific to a maker's systems. The APL book was, at the time, pretty much useless for writing any sort of serious code until you got hold of the manual for a particular system that you were going to use. Even the early McCracken books on FORTRAN had a section in the rear that attempted to gloss over different manufacturer's features and "extensions" (e.g. What does "B" punched in column 1 of a FORTRAN statement card mean--and for what system?) Lest anyone forget, that in the pre-1960 world, a lot more of production code was written in the assembly code/autocoder of a particular system. Even the DEC "Introduction to Programming" dealt specifically with the PDP-8 and was useless for the PDP-10. ACM CALGO back then accepted algorithm submissions in FORTRAN or Algol, but that's hardly an instructional text. I guess the question boils down to 'In the world before 1960, how *useful* was a general book on programming?" --Chuck
Re: Winchester SA1004 file recovering
The simplest thing, if you can locate one, is to find a WD1000/WD1001 controller board and hook it to a PC. Chances are overwhelming that it was used to write the SA100x in the first place. My first 5150 hard drive used such a setup--an SA1002, a WD1001 and a very small hand-wired ISA card for interface. I think I still have the interface card somewhere. --Chuck
Re: Fortran IV V2.5 for RT-11
On 11/24/20 4:02 AM, Mattis Lind via cctech wrote: > I found a three RX01 disk set for a Fortran IV system V2.5 for RT-11. > > I dumped the contents and it is available here: > > https://drive.google.com/file/d/12VXh4wk3Zo_fSGRtLPHwrJg6ui3pwVd-/view?usp=sharing I believe (not sure about version) that I have that on tape, if you're interested. --Chuck
Re: Soldering DB connectors
On 11/10/20 9:25 PM, Mike Stein via cctech wrote: > Same here. Also works for soldering header pins etc.; stick a matching > connector on the other side of the board and they stay flush and > perpendicular. Nice tip, but I thought that most folks knew about the matching-connector thing! I guess unwritten knowledge gets lost over the years. --Chuck
Re: 9 track tapes and block sizes
On 10/4/20 10:51 PM, J. David Bryan via cctech wrote: > On Sunday, October 4, 2020 at 16:00, Chuck Guzis via cctalk wrote: > >> A 16MB tape block is impossibly large in any case. > > The HP 3000 mag tape diagnostic attempts to write a single record from BOT > to EOT, which unfortunately fails under simulation due to the 16 MB > limitation. In hindsight, it would have been better to accommodate record > lengths corresponding to the highest density and longest reel length, which > I think would need 28 bits. Four bits for metadata identifier would still > have been be good enough, and one of those should have been dedicated to > "private data" that would appear invisible to programs running under > simulation (and could be used to include information about the tape image > with the tape image). That's interesting. Looking at my own code for .TAP files, I see the following: #define TAP_FILEMARK0x0 // 0 = filemark #define TAP_EOM 0x // -1 = end of medium #define TAP_ERASE_GAP 0xfffe // -2 = erase gap #define TAP_ERROR_FLAG 0x8000 // error flag bit #define TAP_LENGTH_MASK 0x00ff // mask for length So increasing the mask for block length wouldn't seem to be a problem, assuming that SIMH could support it. There may be other high-order bit meanings assigned, but I've not run into them. --Chuck
Re: 9 track tapes and block sizes
In fact, is there any standard for floppy disk metadata container files? I'm not aware of any. --Chuck
Re: Anyone out there that can read 7 track / 556 BPI tapes?
On 7/18/20 7:37 PM, Marc Howard via cctech wrote: > Hi, > I live in the Bay Area. Maybe those of you with connections to CHM could > see if we could read the tapes on the 1401. Or maybe one of you has a 7 > track driver in your junk file. All we really would need is the head and > we could put it on an existing drive. As a last option, a commercial tape > recovery vendor although that is probably too pricey. I can do it (and do it routinely for government entities). But I'm in Oregon. --Chuck
Re: Small C ver 1.00 source?
On 7/13/20 11:59 AM, Will Cooke via cctech wrote: > Thanks. I found the one(s) on Simtel and they weren't the right ones. I > "think" the 1.1 that is on there is for the IBM PC (8088) or maybe the Z-80. > In any case, I think it's been found. > The github one: https://github.com/trcwm/smallc_v1 is the 8080 version, 1.1 and claims to be a transcription from the original DDJ article. --Chuck
Re: Small C ver 1.00 source?
All I've been able to find is the source for 1.1 on github, which was laboriously reconstructed from an OCR of the original article. --Chuck
Re: Small C ver 1.00 source?
On 7/13/20 10:07 AM, Will Cooke via cctech wrote: > Unfortunately, no. That was one of the first places I looked. They have the > 2.1 version from the Small C handbook (James Hendrix) and some other > derivatives, but not the original 8080 version 1.0. > > Thanks, > Will SIMTEL20 claims to have 1.1, but I don't know how it differs. --Chuck
Re: Small C ver 1.00 source?
On 7/13/20 5:22 AM, Will Cooke via cctech wrote: > I'm trying to find source files for the very first, original, ver 1.00(?) > small C compiler. I have the DDJ issue with the printed source (minus the > assembly language runtime libs.) I have found all sorts of derivative works, > but I haven't found files of the original version. My old eyes aren't up to > typing in 13 pages of scanned copy of printed dot matrix listings. > > Does anyone know where a downloadable copy of these files can be found? Or > have a copy they could send? > > Thanks, > Will > > "A designer knows he has achieved perfection not when there is nothing left > to add, but when there is nothing left to take away." -- Antoine de > Saint-Exupery > > > "The names of global variables should start with// " -- > https://isocpp.org > Isn't it on the DDJ Resource CD? http://twimgs.com/ddj/sdmediagroup/images/sdm1123195158574/ddj_devnetwork_small_c.zip --Chuck
Re: IDE Hard Drive Question
On 6/25/20 4:12 PM, Jon Elson via cctech wrote: > On 06/25/2020 05:29 PM, W2HX via cctech wrote: >> Does ANYONE have any idea what these 4 wires are connected to and why? >> And anyone give any odds about whether these 4 wires will prevent this >> IDE-SD converter from working? >> >> > Temperature sensor and heater. Undoubtedly for start-up in extreme cold > conditions. Certainly looks like that to me also. Sits right atop the spindle motor. --Chuck
Re: So what the heck did I just pick up?
On 8/30/19 7:24 PM, John Ames via cctech wrote: > Ran into this at the electronics-surplus store just down the way from > my workplace and grabbed it on the cheap. I don't actually know what > it *is,* but the labels on the switches make it look a *hell* of a lot > like a 16-bit general-purpose computer of some kind. Despite the > claims of being "microprocessor-controlled," I looked at every board > inside the thing and couldn't spot anything that looked like a 16-bit > or even 8-bit CPU. Genuinely curious what this is, but I can't find > much on it online - the name pops up in a few archived documents, but > Bitsavers doesn't have anything for the company. Though the design is > attributed to Stanley Kubota and Edward Corby - looks like Mr. Kubota > still has an online presence at https://www.exsellsales.com/about-us/ > so I'll have to drop them a line... > > Anybody heard of or encountered one of these before? > > http://www.commodorejohn.com/whatsit-front.jpg > http://www.commodorejohn.com/whatsit-back.jpg Not surprisingly, the answer's on Bitsavers: http://www.bitsavers.org/pdf/microcomputerAssociates/Microcomputer_Digest_v02n08_Feb76.pdf PDF page 7. --Chuck
Re: Pertec Interface Cable Length
On 8/12/19 8:11 AM, Douglas Taylor via cctech wrote: > The bad news is that the cable lengths must be short to use the Qualstar > 1260 with a PDP11, the good news is that I can lift and carry the tape > drive! For many of us in this hobby that it is extremely important. > > After looking at pictures of the 1260 on the internet I see that it was > designed to be used with a PC and the interface cable was 62 pins and > quite short. Someone mentioned earlier that it was a cheap tape drive > that didn't meet the Pertec standard and I'm finding out what exactly > that meant. > > It is nice to have a reel to reel tape drive and watch it work. If you needed to cobble something up suitable for long cable driving, you could work up the correct pertec driver interface to sit between the Qualstar interface board and the cable and install it in the 1260 case--there's plenty of room without the SCSI interface PCB. The big problem with the 1260 is that it doesn't move the tape fast enough for reliable operation at the 6250 GCR setting; operation at 1600 PE is just passable. But it's a drive that's portable and that is an advantage, especially to us older folk. Another possible option would be to replace the Qualstar LS240 drivers with TI 74BCT756 open-collector drivers (same pinout) with 64 ma drive capability. That probably would be the harder option, as it would entail removing the soldered-in LS240s. FWIW, Chuck
Re: Pertec Interface Cable Length
On 8/11/19 8:51 PM, Douglas Taylor via cctech wrote: > > The TC02 is an Emulex TS11 emulation for pertec interface tape drives. > The J1 and J2 are sort of standard terminology, don't know why. Ah, the *Emulex* TC02. You had me going there--DEC also has a DECtape controller called the TC02. Looking at the TC02, there are 374s to latch data coming from the Qualstar and use the termination packs, but there are also 7438s driving the lines from the TC02 to the Qualstar. Those have no terminators. The TC02 reference manual says that you get run lines up to 30 feet long between the TC02 and formatter. My point is that the driver technology for the Qualstar (i.e. read data and status) is inappropriate for long cable runs. The spec calls for 48 ma OC drivers. --Chuck
Re: Pertec Interface Cable Length
On 8/11/19 6:00 PM, Douglas Taylor via cctech wrote: > I just looked at the TC02 and the Qualstar, there are termination > resistor packs on each. The Qualstar has a bunch of 74LS240 IC's near > the J1 and J2 pertec interface cables. The TC02 has a bunch of 74LS374 > chips near the J1 and J2 connectors. > > This is where the electrical engineer could help. How do you determine > how long a cable the 74LS240 can drive? TC02? The DECtape controller? Sorry, I must be dense; I'm not following. --Chuck
Re: Pertec Interface Cable Length
On 8/11/19 9:11 AM, W2HX via cctech wrote: >> All of my Pertec tape drives (in the past) were located in > a differentrack from the actual computer so the cables were > always over 10' long and usually close to if not 20'. Never > had a problem. I stand by my commentary re Qualstar 1xxx drives. They're not up to the task of driving long cables. Who has one such drive with 10' cables operating correctly? Until someone comes up with actual experience with said drives, we're just guessing. I note that my 1260S does have the capability to be used as a Pertec interface drive. I suppose I could re-cable from one of my other drives and test it, but at this stage, I hardly see the point. --Chuck
Re: Pertec Interface Cable Length
On 8/10/19 9:45 AM, Douglas Taylor via cctech wrote: > I bought the long cables off ebay, so they have to be good? Right? I > think the short cables came from a hamfest. > > The cables can be fairly long, I remember interfacing a TU80 to an > Emulex QT14 (maybe) and the DEC cables were round and about 15 feet > long. And it worked. Of course it did--the TU80 hews to the Pertec inteface spec. The Qualstar, as I observed, does not. It's basically "Pertec on the cheap". It might be interesting if someone with a Qualstar 1xxx series drive who's using 10' flat ribbon cables can report their success. I suspect that you'll hear crickets... The point of the Qualstar drives is that they were cheap--and the design reflects that. --Chuck
Re: Pertec Interface Cable Length
On 8/9/19 9:05 PM, Douglas Taylor via cctech wrote: > I have a question about cable length - any electrical engineers in the > house? > > Connected a Qualstar 1260 tape drive to an Emulex TC02 qbus tape > controller in a pdp-11/53. The interface is pertec with 2 50 pin cables. > > When I use a pair of short flat ribbon cables, 18 and 30 inches each, it > works. Under RT11 I can INIT, Copy, DUMP, do a Directory. > > It doesn't work when I use a pair of 5 foot long flat ribbon cables. > Are they too long? Do I need twisted pair type of cable? Is it > possibly a termination problem? 5 feet should be no problem--ISTR that Pertec specifies a maximum cable length of 20 ft. I use 10 foot cables routinely. The Pertec interface is basically open-collector drivers into 220/330 ohms at the far end. I have a Qalstar 1260, but it's the 1260S, the SCSI version--and I rarely use it. Looking at the schematics of the similar Qualstar 1052, the output drivers are plain old LS240s; 24 ma totem-pole outputs. The usual practice is to use 7438s OC 48 ma outputs; it's certainly the case for Pertec formatters. So it could be that you're limited by the Qualstar design. Twisted flat cable might buy you some added distance or you could fabricate a "repeater" with real OC drivers to put between the drive and the controller to extend the length. FWIW, Chuck
Re: Daisywhell typewriter emulating a TTY
On 4/10/19 11:29 AM, Fred Cisin via cctech wrote: > On Wed, 10 Apr 2019, Chuck Guzis via cctech wrote: >> Aw, that's too bad! The original Model I (CADET) 1620 had a console >> typewriter (was it based on the IBM Model B electric?) that gyrated >> enough, particularly on carriage returns, that made you wonder if it was >> going to fly to pieces at any time. It was all part of the experience. > > Immaculately maintained equipment, such as at the CHM, also doesn't have > the burnt oil smell that used to be associated with real world EAM. Or the grime--such as replacing a shredded ribbon on a line printer. Or roaches and mice under the raised floor... --Chuck
Re: Daisywhell typewriter emulating a TTY
On 4/10/19 10:35 AM, Dave Babcock via cctech wrote: > To all, > > The Computer History Museum's IBM 1620 Jr. project has already done > this. We have converted an IBM Wheelwriter 1000 electric typewriter > into a computer terminal. The conversion consists of a custom PCB with > an Arduino Teensy 3.5 microcontroller which is physically installed in > the typewriter, electrically in-between the keyboard and typewriter > motherboard, with custom firmware. Aw, that's too bad! The original Model I (CADET) 1620 had a console typewriter (was it based on the IBM Model B electric?) that gyrated enough, particularly on carriage returns, that made you wonder if it was going to fly to pieces at any time. It was all part of the experience. What did you do about the 1620-specific keys? I don't think that record mark or R-S was a keytop legend ona Weheelwriter... --Chuck
Re: Storage for 1/2" open reel tape
On 4/8/19 9:06 PM, Jeff Woolsey via cctech wrote: >> I've noted earlier that the vinyl "hanger strips" for 1/2" magnetic tape >> have been degrading, becoming brittle and simply breaking away, >> sometimes in small particles. > > I have about a hundred tapes from various contributors, and have noticed > no age-related [1] deterioration of the seals, probably because mine > don't get handled very much. About 1/3 of mine have the vinyl hanger > strips, another third the autoload seals, and the remainder are in the > bulky canisters (with several different closures). I also have a couple > of tape racks (think "dish rack") that hold maybe thirty tapes, but the > canisters are too thick to fit in. That's great--but these are customer tapes, not mine and many are from the 1960s and 70s. (About 2/3s of the current batch are 7-track) Perhaps 50 years of storage takes its toll. I don't know. The other minor annoyance is that 40-50 years tends to dry out the adhesive on labels and less often, leader splices. As far as racks go, you can sometimes find the 16mm film racks at auction--they rarely attract bids. They're mostly Neumade products. --Chuck
Re: Anyone have spare DipStik sockets?
On 2/23/19 10:18 AM, Carl Claunch via cctech wrote: > In the early 1970s a socket to hold multiple DIP chips was being sold under > the brand name DipStik. Up to six chips were inserted in a trough in the > socket, a top screwed on with thumbscrews on the ends. It had solder lugs > on the top and bottom for each of the chip pins. > > We are restoring an old electronic device that was built in part with > these, but due to some corrosion we could use replacement DipStik units if > anyone has them. I assume that you've already contacted these folks: http://www.tzsupplies.com/5-integrated-circuit-prototype-sockets-i1877924/ --Chuck
Re: CDC transistor boards
On 12/28/18 12:42 PM, Peter Van Peborgh via cctech wrote: > Gentlemen of advanced years who can remember CDC, cradle of Cray. > > Can you tell me which CDC computer type these three boards belonged to? It > is for labeling purposes in my personal museum. > > https://postimg.cc/crJHv3Lt > https://postimg.cc/Z0HnYH4h > https://postimg.cc/6TtTNgs0 > > I am sure this will be easy for the right person. Many thanks! > > peter > The second one is a 6000-series "cordwood" module. --Chuck
Re: Origin of 'Straight 8' name
On 12/21/18 11:32 AM, allison via cctech wrote: > And the automotive reference was not it. It was the straight as in not > later lettered > versions. Best similar use is: Whiskey straight, water on the side. Could be--but I was pointed out that "straight eight" was an automotive term familiar to the laity that pre-dated DEC by a goodly number of years. We live in a world dominated by automobile marketing. I suspect the same common connection to "turbo", popularized by the auto marketeers. On the other hand, I've never seen a computer advertised with a "Turbo-Hydra-Matic" or "Dynaflow" feature. --Chuck
Re: Rayethon Computer AN/FYK9 CMI Store 33
Hi Gerard, Yes, it's been there for some time. Al K. uploaded it upon my request. It turns out that my guesses about the architecture based on floppy disk data were correct! Thanks, Chuck On 09/25/2018 07:47 AM, GerardCJAT via cctech wrote: > @ Chuck, > > I know you know about the FST1 computer ( 24 bit ). > Do you know that there is ( now ?? ) a bit of documentation about it on > Bytesavers ?? > > in PDF/Fairchild/Sentry >
Re: Unknown US manufacturer - try again
I suspect that it's from a trainer of some sort. Stewart-Warner quad 2-input NAND DTL stuff. So probably not RCA. --Chuck
Re: 8 inch floppies, decaying
On 07/12/2018 09:05 PM, David C. Jenner via cctech wrote: > Would Chuck's temperature and Al's oven be appropriate for old magtapes, > too? My "cooker" is home-built and heavily insulated. It has a 75W incandescent for heat and a low-speed fan for circulation. I use a PID controller to keep the temperature within limits. An RTD sensor sits in the middle of the chamber. With spacing for air circulation, I can do about 7 tapes at a time. My "tape tower" is constructed from a trimmed-down PVC toilet flange attached to a 3" lchedule 80 PVC pipe. Spacers are made from 4" diameter schedule 80 PVC, which fits nicely into the write-enable ring recess on each reel. Because of the insulation, it uses very little electricity. There's a 70C thermal fuse just in case things get out of hand. --Chuck
Re: I ran across this strange modernistic? Data General ...odd?
On 05/22/2018 10:46 PM, Lars Brinkhoff via cctech wrote: > This is with a microEclipse CPU, right? > > I'm surprised the Nova/Eclipse architecture doesn't get more love. > It seems quite pleasant. > As I recall--and please correct me--DG was extremely hostile to the notion of third parties incorporating the MicroNova in any of their products. The same situation applied to the Fairchild 9440 MicroFlame, which was essentially a clone of the MicroNova architecture. I recall that Fairchild didn't want to talk to you (I tried) if you weren't in defense or aerospace or the like. The basic idea of the 4x16 bit register 16-bit architecture was copied to some extent by National Semi in their multichip IMP-16 and single-chip PACE and 9440, but it was mostly in the "spirit of a Nova"--performance wasn't all that great in comparison to the current 8 bit MPUs. Weren't the MCBA business applications originally written in Nova BASIC? --Chuck
Re: Sync on Green RGB video
On 11/18/2017 01:21 PM, Aaron Jackson via cctech wrote: > You might be surprised how many LCD monitors support SoG. I have several > iiyama LCD panels which work fine with a 3100. > All of my NEC Multisync LCD ones do--some even have 5 BNC connectors for video input. --Chuck
Re: Drive capacity names (Was: WTB: HP-85 16k RAM Module and HPIB Floppy Drive
On 11/17/2017 09:17 AM, allison via cctech wrote: > Also the Syquest 270mb IDE/parallel port cartridge disk. I have one > that works > and over a dozen carts. Its still in use in a ITX box using the IDE > interface. After > two decades of use it seems solid. I've left out the non-floppy technologies. I have a Squest Sparq, unused still in its packaging, for example. After being sent one for evaluation, I rejected it because it was offered only in the printer-port version, which necessarily limits transfer bandwidth. But there were plenty of "floppy" technologies, such as the UHD144, or LS120 or Drivetec stuff. I treat Bernoulli and Zip as a floppy-sort-of technology, because they are incapable of reading standard floppies, so I don't include them either, even though they employed flexible media. --Chuck
Re: PDP-8/a wire-to-board connector for power?
On 11/03/2017 05:40 PM, Brian Walenz via cctech wrote: > I'm assembling a PDP-8/a from a pile of parts, but I'm missing the entire > AC power entry assembly, as shown in > http://www.retrotechnology.com/restore/8a_trans_gnd0.jpg. Does anyone know > what the 6-pin connector is? Even better, does anyone have an extra > assembly? That connector is still being made! It's an AMP Mate-n-lock: http://www.te.com/usa-en/product-1-480270-0.html Well, okay, it's not "Amp" anymore, Amp's been eaten. --Chuck
Re: The origin of the phrases ATA and IDE [WAS:RE: formatting MFM drives on a IBM PC]
On 10/02/2017 10:03 AM, Alan Perry via cctech wrote: > Here is a complete quote from the minutes: > "Jim McGrath of Quantum defined his company's interest as being > primarily in the ability to embed SCSI into a drive without there being > a physical SCSI bus present. He described some problems of this > environment, with references to the PC AT bus in particular. Jim > believes that the greatest benefit of the CAM will come from a "severe > pruning of SCSI functionality in order to meet the goal of a precise, > simple, software interface." While ATA was codified by the CAM working group, one should not be under the impression that CAM was limited to any particular physical interface. CAM stands for "Common Access Method" and is applicable to a number of physical interfaces, including SCSI. Future Domain, for example, patterned their drivers along CAM conventions, using CCB (CAM control blocks). Adaptec, on the other hand, perferred ASPI. Of the two, CAM is far more flexible and varied. After Adaptec acquired FD, they provided a "middle" driver to convert ASPI calls to CAM. Just saying... --Chuck
Re: Norton Utilities on 8"?
On 09/30/2017 11:50 AM, Richard Cini via cctech wrote: > I’m in the process or restoring a Seattle Gazelle for the Vintage > Computer Federation and one of the disks that it came with had > “Norton Utilities” written on it. I’ve imaged the disk but I’m not > entirely sure what system it was for, and the directory seems to be > scrambled, and the disk geometry doesn’t seem to fit with the system > (16 sectors, 512b DSDD) versus the normal (8 x 1024b DSDD). > > A quick search shows that v1.0, and maybe 2.0, were around at the > time…no word on what distribution media, though. > > Is anyone aware of there being a version available on 8” disks? Dunno, but if you'll forward an image, I'll have a go at unraveling it and see I anything pops up. --Chuck
Re: rectangular sense core vs. diagonal
On 06/07/2017 10:47 AM, Paul Koning via cctech wrote: > 6600 core memory is documented in great detail in the training manual > which is on Bitsavers. It has conventional diagonal sense lines. It > does have some interesting design attributes, though. For one thing, > it has pairs of inhibit wires each carrying half the inhibit current. > Also, there are four X inhibit and four Y inhibit lines, so you use > four of the address bits to select which inhibit "quadrant" is > driven. The manual doesn't say why; I believe it is done to limit > the inductance and to keep the per-wire inductance roughly consistent > for the select (X and Y) and inhibit (X and Y) wires. The drive > circuitry is also interesting, featuring constant currents that are > steered between an idling inductor and the selected wire, rather than > being switched on. All these techniques seem to explain the very > high performance -- full read/restore cycle in about 800 ns, which in > 1964 was way faster than what others were doing. How is ECS constructed? I fooled with a lot of it back in the day, but never got a good look at the core planes. --Chuck
Re: Oscilloscope Recommendation
On 04/29/2017 10:28 AM, Michael Thompson via cctech wrote: > The RICM just received $1,000 to buy a new oscilloscope. I would like > a four channel. and color would also be nice. The bandwidth doesn't > need to be high because we usually work on ancient equipment. The Rigol scopes have the features that you're looking for in your price range. Dave on the YT EEVBlog has spent some time on them. There have been some notable software bugs, but Rigol seems to be pretty diligent in eradicating them. --Chuck
Re: WTB: DEC Rainbow Expansion Memory
On 04/12/2017 12:41 PM, Warner Losh via cctech wrote: > For you and me both. I was getting read errors on my RX-50, so I > tried to swap in a new drive, and now that's all I get as well. Guess > I'll have to figure out another way to get the Venix/86R disks > copied. Got a PC with a 5.25" HD drive? Use Dave Dunfield's ImageDisk under MS-DOS and it'll do the job just fine. I've done it myself. --Chuck
Re: Stuffing boards with pulled QFP chips
On 03/31/2017 06:15 PM, Jon Elson via cctech wrote: > I have a project I do from time to time using 128-lead 14mm TQFPs > with 0.4mm lead spacing. I use a stereo zoom microscope with a > home-made LED ring light. First, I rub the pads with a pencil eraser > to remove oxidation caused by reflow temps on the rest of the board. > I put a tiny dab of solder on two pads at opposite corners. I then > place the chip in place and reflow those pads. If the alignment is > not good enough, I can "walk" the chip a bit by reflowing one, then > the other pad. Then, I apply liquid flux to the rows of leads with > a wire dipped in the flux. And, then solder down the rows with a > fine-tip soldering iron. If a bridge develops, solder wick fixes > it. There are plenty of good Youtube videos describing this. I use pretty much the same method, but start off with just a binocular loupe and then finish with a stereo microscope for final inspection. The soldering iron tip that works best for me is a rather broad chisel tip. I leave the fine tips for other work. --Chuck
