Re: Storage for 1/2" open reel tape
On 4/5/19 6:13 PM, Al Kossow via cctalk wrote: > I had to re-thread the UNISERVO that is on display at CHM. I have to try > to find my pictures that I took. > > http://bitsavers.org/pdf/univac/magtape/PX899_Mechanical_Parts_of_UNISERVO_Apr58.pdf > > show it. > My guess on the vintage of these is Uniservo VIII (late 60s).
Re: Storage for 1/2" open reel tape
the other thing I had wondered about was how they kept metal tape from destroying the head. there is a spool of plastic tape that goes between the head and the tape On 4/5/19 6:13 PM, Al Kossow via cctalk wrote: > > > On 4/5/19 5:45 PM, Chuck Guzis via cctalk wrote: > >> Univac had an interesting setup for Uniservo tape drives--I see a lot of >> reels with a short (maybe 6") "leader" with a hole spliced onto tapes. >> I'm not sure how that worked > > I had to re-thread the UNISERVO that is on display at CHM. I have to try > to find my pictures that I took. > > http://bitsavers.org/pdf/univac/magtape/PX899_Mechanical_Parts_of_UNISERVO_Apr58.pdf > > show it. > > There is are two hooks that are attached to the reels and it is attached > essentially to > nylon fishing line. > > >
Re: Storage for 1/2" open reel tape
On 4/5/19 5:45 PM, Chuck Guzis via cctalk wrote: > Univac had an interesting setup for Uniservo tape drives--I see a lot of > reels with a short (maybe 6") "leader" with a hole spliced onto tapes. > I'm not sure how that worked I had to re-thread the UNISERVO that is on display at CHM. I have to try to find my pictures that I took. http://bitsavers.org/pdf/univac/magtape/PX899_Mechanical_Parts_of_UNISERVO_Apr58.pdf show it. There is are two hooks that are attached to the reels and it is attached essentially to nylon fishing line.
Re: Storage for 1/2" open reel tape
On 4/5/19 5:31 PM, Paul Koning via cctalk wrote: > If this works, which is most of the time, it's a great time saver. As an > operator you just hang the reel on the spindle, hit "load" and walk away to > the next task. > > I think IBM may have originated this magic; several of the later DEC tape > drives supported it as well (TU77 and TU/TA78, if memory serves). Univac had an interesting setup for Uniservo tape drives--I see a lot of reels with a short (maybe 6") "leader" with a hole spliced onto tapes. I'm not sure how that worked--but on many, if not most of the reels I've seen, the splicing tape has dried out and the little leader just falls right off. --Chuck
Re: Storage for 1/2" open reel tape
> On Apr 5, 2019, at 7:15 PM, Grant Taylor via cctalk > wrote: > >> ... >> But basically, just behind the "hook", there's a black plastic latch. When >> closed, it tensions the white band. >> https://www.electronicsurplus.it/open2b/var/products/27/92/0-d95b2a25-800.jpg > > ACK > > I'm getting the mental impression that it's somewhat like a spring form pan. > The latch opens and releases tension off of the strip that goes around the > tape reel. When it's latched, it cinches against it. When it's unlatched, > there's enough play to allow the tape reel to come out. > > Am I remotely close? Correct. The latch has a thin section which acts as a flexible hinge, and the other end hooks around a hook shape molded into the tip of the white band. When you push the latch against the reel it snaps closed and spring tension holds it that way. The autoloading latch (in http://www.columbia.edu/cu/computinghistory/media.html) is somewhat similar but with some important differences. The latch can flex around the thin part near the left end. There are actually two parts, pinned together so the thing essentially folds over itself. And the far end in turn is pinned to the tape seal (the end to the right of the seam, in the photo). You mount it into the drive seal and all. The drive has a mechanism that engages the latch and flips it open, which unfolds the folded latch shape and thereby forces the two ends of the seal apart maybe 3/4 inch. There are some locating shapes that keep the two ends aligned, you can see the button that does this just to the right of the latch, its stud moves in a slot on the seal band. That sliding action opens up a window (holes in the two halves slide to align). So at this point the reel can rotate freely because the seal is no longer clamped onto the rim, and air blowing through holes in the seal blows the end of the tape out through that window. To make this more reliable the end of the tape is cut with a arced end and sometimes stiffened slightly. The vacuum system picks up that end, pulls it through the tape path, sucks it onto the takeup hub, and presto changeo, the tape is loaded. Usually. If this works, which is most of the time, it's a great time saver. As an operator you just hang the reel on the spindle, hit "load" and walk away to the next task. I think IBM may have originated this magic; several of the later DEC tape drives supported it as well (TU77 and TU/TA78, if memory serves). paul
Re: Storage for 1/2" open reel tape
On Fri, Apr 5, 2019 at 4:54 PM Chuck Guzis via cctalk wrote: > On 4/5/19 4:15 PM, Grant Taylor via cctalk wrote: > > > ACK > > > > I'm getting the mental impression that it's somewhat like a spring form > > pan. The latch opens and releases tension off of the strip that goes > > around the tape reel. When it's latched, it cinches against it. When > > it's unlatched, there's enough play to allow the tape reel to come out. > > > > Am I remotely close? > > You're very close--same idea. They came in two varieties (that I remember seeing). A more rigid one like the springform pan; unlatching it allowed a few inch gap, and the ring would expand enough for the reel to be removed. (I also seem to remember seeing tape drives that would open the latch and draw the tape through the gap - the reel was still "inside" the ring, but clear enough for the reel to spin.) The other variety was a much more flexible material, more like a clothing belt. It could easily be pulled straight. -- Charles
Re: Storage for 1/2" open reel tape
On 4/5/19 4:15 PM, Grant Taylor via cctalk wrote: > ACK > > I'm getting the mental impression that it's somewhat like a spring form > pan. The latch opens and releases tension off of the strip that goes > around the tape reel. When it's latched, it cinches against it. When > it's unlatched, there's enough play to allow the tape reel to come out. > > Am I remotely close? You're very close--same idea. When I get a chance, I'll do some close-ups on the mechanism. But same idea--the latch puts the band under tension. That works fine, so long as the structural integrity of the band is maintained. Failures commonly occur around the "holes" punched in the vinyl, but I've seem some bands that are neatly split down the middle. > I wonder if some of this could be 3D printed. I don't know--and I don't know if it would be economically feasible. At less than $6 for a poly "can" that completely encloses the tape, that's a tough target. The nutty thing is that I remember when CDC Sunnyvale went to the vinyl band "hangers" in their facility rather than the wire "racks" that held the reel and its acrylic case (tremendous variation there). I recall seeing dumpsters full of the acrylic cases. Maybe somewhere there's a landfill stuffed full with them... I wonder how long it will be before no non-senior adult remembers CD jewel cases. I recall getting rid of several boxes of Plextor-type CD caddies only a couple of decades ago. --Chuck
Re: Yes there is a PDP 10 front panel and Kenbak on Ebay
What I want to know is, how do front panels of historic computers so often get separated from the rest of the computer? Could be just storage problems. The main computer here, racks of stuff there, cables and panel there, and things get lost over time. The moosehead is still hanging on the wall. But, the backside of the moose is no longer on the other side of that wall. On Fri, 5 Apr 2019, ben via cctalk wrote: But what if was a TALKING moose head? The movie "MURDER BY DEATH" comes to mind.Ben. Disunirregardless of whether the moose has anything to say, there should be a half circle table under the moosehead; and a matching half circle table on the other side of the wall.
Re: Storage for 1/2" open reel tape
On 4/5/19 4:44 PM, Chuck Guzis via cctalk wrote: The IRS facility photo used the IBM style; not flexible, but rather a two-part sliding rigid plastic arrangement. I think that the IRS also used a robotic "picker. I'd hazard a guess that the IRS acquired theirs from IBM. Even if they are more expensive per reel / hanger, they are approved, from an approved vendor, in the system. "Hay Bob, order X hangers next time you submit an order." No need to think beyond that. It just happens. I'd have to take a photo of one, I think, though if you have a very ancient Wright-Line catalog, it's probably in there. But basically, just behind the "hook", there's a black plastic latch. When closed, it tensions the white band. https://www.electronicsurplus.it/open2b/var/products/27/92/0-d95b2a25-800.jpg ACK I'm getting the mental impression that it's somewhat like a spring form pan. The latch opens and releases tension off of the strip that goes around the tape reel. When it's latched, it cinches against it. When it's unlatched, there's enough play to allow the tape reel to come out. Am I remotely close? I wonder if some of this could be 3D printed. what was convenient with those is that the latch-and-hook are attached to the vinyl band by fitting with a couple of holes punched in the band. In a pinch, you could make hangers for smaller (than 10.5") reels by cutting and punching new holes. ACK -- Grant. . . . unix || die
Raspberry Pi for vaxen turbochannel
I've had a plan to set up a raspberry Pi as the mopd and NFS server to bit my vaxstation for a while. To be a self contained demo I could probably fit it inside the vaxstation. One of the annoyances is that it would need another power cord and need a place to mount it inside. It occurs to me that the turbochannel slots have 4A each. It would be entirely possible to print a whole open source board like the raspberry Pi (or banana Pi, etc) on a turbochannel card and kill two birds with one stone. It would give a nice solid place to mount the pi with access to the ports on the back and power supplied by the vaxstation. Is this something that would be of interest to anyone other than me? On Fri 21 Dec 2018, 22:09 Zane Healy via cctalk, wrote: > > > On Dec 21, 2018, at 5:20 PM, Grant Taylor via cctalk < > cctalk@classiccmp.org> wrote: > > > > On 12/21/18 3:30 PM, Zane Healy via cctalk wrote: > >> I’m afraid I’ll have to agree with Jim here. When talking about Retro > Gaming, in most cases, the Raspberry Pi, while better than nothing, aren’t > as good as the real thing, especially in regards to video and audio. > > > > There's nothing to be afraid of. > > > > I was asking from a position of ignorance because I've not used either. > I have some colleagues at work that use the Raspberry Pi. So I know of, > but not about, it. > > The Raspberry Pi’s are a pretty impressive little tool for situations > where they have enough resources. For the purpose of emulation, they’re a > great platform. The problem is less with the Raspberry Pi, and more with > emulation as a whole. In other words, this is a software issue, not a > hardware issue. > > >> Now despite what I just said about the Raspberry Pi, I have three of > them around here, one is a small VAX running OpenVMS 7.3, one is a DPS-8 > running Multics, and the other a KL-10B running TOPS-20. I had dreams of > building a VMS cluster of RPi 3+’s, but have kind of gone off that idea, > due to the superior performance I get using my VMware Cluster to host VAX > instances. > > > > I'll have to check out the DPS-8 and KL-10B. > > For the PDP-10, my favorite is KLH10. > http://www.avanthar.com/healyzh/decemulation/pdp10emu.html > > For the DPS-8, there really is only one option, and sadly GCOS-8 isn’t > available, only Multics. Still it’s pretty cool to finally be able to use > Multics, and it’s a lot more user friendly than GCOS-8 (I used to be a > Systems Analyst at a DPS-8 mainframe site). > http://www.avanthar.com/healyzh/decemulation/Honeywell_DPS-8.html > > For those unaware, my DEC Emulation pages had to move late last year, due > to my ISP of ~20 years being ransacked by a Crook. I managed to do quite a > bit of work updating the pages earlier this year. > > Zane > > >
Re: Storage for 1/2" open reel tape
On Fri, 5 Apr 2019, Chuck Guzis via cctalk wrote: On 4/5/19 2:58 PM, Grant Taylor via cctalk wrote: On 4/5/19 3:20 PM, Chuck Guzis via cctalk wrote: See how each reel of tape hangs from a slot in a horizontal bar? Those white-and-black strips wrapped around the tapes are what I'm referring to as being deteriorated. How does that come off the reel? Does the reel slide out? Does it unlatch? Do you have a picture of one without the tape reel in it? The IRS facility photo used the IBM style; not flexible, but rather a two-part sliding rigid plastic arrangement. I think that the IRS also used a robotic "picker. I'd have to take a photo of one, I think, though if you have a very ancient Wright-Line catalog, it's probably in there. There's a good picture of the IBM autoloading tape seal on this page: http://www.columbia.edu/cu/computinghistory/media.html Mike Loewen mloe...@cpumagic.scol.pa.us Old Technology http://q7.neurotica.com/Oldtech/
Re: Storage for 1/2" open reel tape
On 4/5/19 2:58 PM, Grant Taylor via cctalk wrote: > On 4/5/19 3:20 PM, Chuck Guzis via cctalk wrote: >> See how each reel of tape hangs from a slot in a horizontal bar? Those >> white-and-black strips wrapped around the tapes are what I'm referring >> to as being deteriorated. > > How does that come off the reel? > > Does the reel slide out? Does it unlatch? Do you have a picture of one > without the tape reel in it? The IRS facility photo used the IBM style; not flexible, but rather a two-part sliding rigid plastic arrangement. I think that the IRS also used a robotic "picker. I'd have to take a photo of one, I think, though if you have a very ancient Wright-Line catalog, it's probably in there. But basically, just behind the "hook", there's a black plastic latch. When closed, it tensions the white band. https://www.electronicsurplus.it/open2b/var/products/27/92/0-d95b2a25-800.jpg what was convenient with those is that the latch-and-hook are attached to the vinyl band by fitting with a couple of holes punched in the band. In a pinch, you could make hangers for smaller (than 10.5") reels by cutting and punching new holes. --Chuck
Re: Yes there is a PDP 10 front panel and Kenbak on Ebay
On 4/5/2019 10:06 AM, Fred Cisin via cctalk wrote: What I want to know is, how do front panels of historic computers so often get separated from the rest of the computer? Could be just storage problems. The main computer here, racks of stuff there, cables and panel there, and things get lost over time. The moosehead is still hanging on the wall. But, the backside of the moose is no longer on the other side of that wall. But what if was a TALKING moose head? The movie "MURDER BY DEATH" comes to mind.Ben.
Re: PDP-8: count number of set bits in a word
A general discussion of population count: https://stackoverflow.com/questions/8590432/when-to-use-parallel-counting-mit-hakmem-for-bitcount-when-memory-is-an-issue
Re: PDP-8: count number of set bits in a word
At 08:49 PM 5/04/2019 +, you wrote: >Hi Kyle, > >hat's a really interesting problem, and the government (NSA) wanted this badly >and done FAST. > >they asked Seymour Cray to create a specific instruction for this and they >called it 'population count' > >Anybody know the why and how it is useful? > >I am deep in matrix math books and 'classification algorithms' in statistics >math, looking into electronics reliability WCCA, so this is an interesting >topic. > >Randy If we're considering hardware solutions, then the best way is to build a simple I/O device, with a writeable latch for the data word, fed as address into some nonvolatile memory like a big EPROM or flash, the output of which can be read via a port. Fill the NV memory with the required lookup table (derived by some code written in anything. BASIC for lols.) So the required code is just one write and one read. See the size chart: https://en.wikipedia.org/wiki/EPROM The biggest EPROM made was ST M27C322, 32 Mbit, 2Mx16. 21 Address bits, 16 data bits, 80nS access time. http://pdf.datasheetcatalog.com/datasheet/stmicroelectronics/6184.pdf Wasteful though, since the result only needs 5 bits. For an 8 bit result, 27C4001, 512K x 8 bit, 19 Address bits. http://www-inst.eecs.berkeley.edu/~cs150/fa02/docs/M27C4001.pdf If the argument is only a 16bit word, then use a 27512. 64K x 8 bit Guy
Re: Storage for 1/2" open reel tape
On 4/5/19 3:20 PM, Chuck Guzis via cctalk wrote: See how each reel of tape hangs from a slot in a horizontal bar? Those white-and-black strips wrapped around the tapes are what I'm referring to as being deteriorated. How does that come off the reel? Does the reel slide out? Does it unlatch? Do you have a picture of one without the tape reel in it? -- Grant. . . . unix || die
Re: Storage for 1/2" open reel tape
On 4/5/19 1:49 PM, Ali via cctalk wrote: >> I hit on the idea of using 16mm move film plastic "cans". Much to my >> surprise, I found that there is still an active market for these >> things. > > Chuck, > > For the uneducated amongst us exactly what are you referring to? Are you > talking about the plastic can where the tape sits in? Or the strap that goes > around the plastic cover or something entirely different? Take a look at the image here: https://www.gettyimages.com/detail/photo/historic-image-of-an-old-computer-tape-high-res-stock-photography/128587299 See how each reel of tape hangs from a slot in a horizontal bar? Those white-and-black strips wrapped around the tapes are what I'm referring to as being deteriorated. Here's a photo of a single tape reel with one: http://ibmcollectable.com/gallery/album124/2400ft_tape IBM used a somewhat different attachment for their auto-loading drives. I can't find an online photo of one, but I have several of those. Rather than using a single flexible strip, they used a multi-part rigid plastic surround. --Chuck
Re: PDP-8: count number of set bits in a word
> On Apr 5, 2019, at 4:49 PM, Randy Dawson via cctalk > wrote: > > Hi Kyle, > > hat's a really interesting problem, and the government (NSA) wanted this > badly and done FAST. > > they asked Seymour Cray to create a specific instruction for this and they > called it 'population count' > > Anybody know the why and how it is useful? > > I am deep in matrix math books and 'classification algorithms' in statistics > math, looking into electronics reliability WCCA, so this is an interesting > topic. I don't know how it was used in crypto, but I know of another application: the PLATO system uses it for fuzzy matches of text input. The idea is to split the strings (user input and expected input) into tokens, then xor each token and do a population count on that. "close" is defined as count < some threshold. There may be more encoding in there, i.e., it's not necessarily an xor of the straight text, but that's the basic idea. The implementation matches the "lookup table" technique, but with a fair amount of hardware thrown at it. The 60-bit word is split into 15 4-bit pieces. Each 4-bit piece is run through a logic block to generate a 3 bit count, then those counts are summed by a tree of adders to yield the final 6 bit result. It's pretty compact, about 60 modules (where each module has about 30-50 transistors on it) and takes 800 ns (8 cycles, it's a 10 MHz machine) for the whole instruction, the actual count process is about half that. paul
RE: Storage for 1/2" open reel tape
> I hit on the idea of using 16mm move film plastic "cans". Much to my > surprise, I found that there is still an active market for these > things. Chuck, For the uneducated amongst us exactly what are you referring to? Are you talking about the plastic can where the tape sits in? Or the strap that goes around the plastic cover or something entirely different? Thanks. -Ali
Re: PDP-8: count number of set bits in a word
Hi Kyle, hat's a really interesting problem, and the government (NSA) wanted this badly and done FAST. they asked Seymour Cray to create a specific instruction for this and they called it 'population count' Anybody know the why and how it is useful? I am deep in matrix math books and 'classification algorithms' in statistics math, looking into electronics reliability WCCA, so this is an interesting topic. Randy From: cctalk on behalf of Vincent Slyngstad via cctalk Sent: Friday, April 5, 2019 12:08 PM To: Kyle Owen; General Discussion: On-Topic and Off-Topic Posts Subject: Re: PDP-8: count number of set bits in a word From: Kyle Owen via cctalk: Friday, April 05, 2019 8:59 AM > Just wondering if anyone has come up with a fast way to count the number of > 1s in a word on a PDP-8. The obvious way is looping 12 times, rotating the > word through the link or sign bit, incrementing a count based on the value > of the link or sign. That's probably the shortest, but not the fastest. (I get 13 words.) You could use RTL and check two bits at a time, for a probably-faster version. (That one is 32 words with the loop unrolled.) > With a small lookup table, you can reduce the total number of loops by > counting multiple groups of bits at a time, but this of course comes with > the cost of using more memory. Any other suggestions? I know a hack to clear a single bit at a time. Here's my first attempt (14 words): / / Return the number of bits that were set in AC. CBITS, .-. DCA CBMASK / Save the value DCA CBCNT / No bits yet CBLP, TAD CBMASK / Get bits, or bits-1 AND CBMASK / Likely clear bottom bit SNA / Last one? JMP CBRET ISZ CBCNT/ One more bit DCA CBMASK / New mask CMA / Complement bottom bit JMP CBLP / ...and go again CBRET, TAD CBCNT / Get result JMP I CBITS / ...and return CBMASK, .-. CBCNT, .-. $ The run time is related to the number of bits set, and independent of their position. It feels like we did this a year or two ago? Or maybe in the PiDP group? Vince
Re: Yes there is a PDP 10 front panel and Kenbak on Ebay
On Fri, Apr 5, 2019 at 3:16 PM Mark Matlock via cctalk wrote: > Subject: Re: Yes there is a PDP 10 front panel and Kenbak on Ebay >The other thing that happened on PDP-11/70s was that if your system > was maintained by DEC, the field service group would want to install > the KY11-RE Remote Serial Console Control which replaced the beautiful > front panel with a more or less blank panel with only a key switch. It > let DEC dial in and run diagnostics, and the Blinkin' Light panel was > set aside often in the collection of someone. However the blank panel > still needs the bezel for a good display of it. So unfortunately, > there are more console panels than bezels which often did not get > salvaged at the time the PDP-11/70 was taken out of service. I got two machines with the remote console panel. Fortunately, I _have_ the cast bezel, and I've managed to get one 11/70 PCB with LED but no switches (removed by the previous owner to restore other machines) and one that's 100% intact. What I _don't_ have is the plexiglass. I am looking at drawing up in CAD a vector file to scribe a clear one which will be easy to make on a laser cutter and will hopefully look cool as well. -ethan
Re: Yes there is a PDP 10 front panel and Kenbak on Ebay
Subject: Re: Yes there is a PDP 10 front panel and Kenbak on Ebay > > From: Guy Dunphy > > > What I want to know is, how do front panels of historic computers so > > often get separated from the rest of the computer? > The other thing that happened on PDP-11/70s was that if your system was maintained by DEC, the field service group would want to install the KY11-RE Remote Serial Console Control which replaced the beautiful front panel with a more or less blank panel with only a key switch. It let DEC dial in and run diagnostics, and the Blinkin' Light panel was set aside often in the collection of someone. However the blank panel still needs the bezel for a good display of it. So unfortunately, there are more console panels than bezels which often did not get salvaged at the time the PDP-11/70 was taken out of service. Mark M.
Re: PDP-8: count number of set bits in a word
From: Kyle Owen via cctalk: Friday, April 05, 2019 8:59 AM Just wondering if anyone has come up with a fast way to count the number of 1s in a word on a PDP-8. The obvious way is looping 12 times, rotating the word through the link or sign bit, incrementing a count based on the value of the link or sign. That's probably the shortest, but not the fastest. (I get 13 words.) You could use RTL and check two bits at a time, for a probably-faster version. (That one is 32 words with the loop unrolled.) With a small lookup table, you can reduce the total number of loops by counting multiple groups of bits at a time, but this of course comes with the cost of using more memory. Any other suggestions? I know a hack to clear a single bit at a time. Here's my first attempt (14 words): / / Return the number of bits that were set in AC. CBITS, .-. DCA CBMASK / Save the value DCA CBCNT / No bits yet CBLP, TAD CBMASK / Get bits, or bits-1 AND CBMASK / Likely clear bottom bit SNA / Last one? JMP CBRET ISZ CBCNT / One more bit DCA CBMASK / New mask CMA / Complement bottom bit JMP CBLP/ ...and go again CBRET, TAD CBCNT / Get result JMP I CBITS / ...and return CBMASK, .-. CBCNT, .-. $ The run time is related to the number of bits set, and independent of their position. It feels like we did this a year or two ago? Or maybe in the PiDP group? Vince
Storage for 1/2" open reel tape
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. So I set off looking for a low-cost substitute--any hangers that I could rustle up would probably be on their last legs at this late date. I hit on the idea of using 16mm move film plastic "cans". Much to my surprise, I found that there is still an active market for these things. After getting a few samples, I've discovered that the 800' cans fit a 10.5" reel (virtually all of the tape that I get) quite well. I'm not yet finished evaluating samples, but here's a photo of a can from Tuscan Corporation holding a reel of tape: https://i.imgur.com/KPKg75s.jpg The cans are vented, so not hermetically sealed. In the case of film, this is apparently done intentionally, as the acetate base of older film outgasses acetic acid, which only hastens degradation. If anyone's interested, I'll continue to post updates. I've got some from Larry Urbanski coming in Monday. Larry seems to have the lowest price on these--about $5.75 each. --Chuck
More stuff looking for a good home
Here's a list of some more stuff if anyone is interested in making reasonable offers. Probably the last I will have before my demise when my wife will likely send everything that's left to the skip. MODULE DescriptionQTY NUMBER M9202 UNIBUS connector3 M9302 UNIBUS TERM 2 ADAC 1632TTL 3 ADAC 1616/32HCO1 Plessey Peripherals 703185-100C & 701877-100 with Cable 1 Data Translation DT2769/EP057 REV F1 Data Translation DT2769/EP057 REV J1 Data Translation DT15150/EP075 Dual D/A Converter Module M3106 4 Line Async Mux 1 M3106 4 Line Async Mux (w/broken handle) 1 M9060 LOAD MODULE 1 M8017-AA Async Line Interface 1 M8017 Async Line Interface(w/broken handle and berg socket)1 G7273 NPG AND BUS GRANT CONTINUITY5 RL Disk Drive Terminators 4 MV-II Function Select / SLU Module 1 A few modules that I ecpect are rare but of limited interest. Terak 8510 Memory and Video module w/bulkhead connector1 Terak 8510 Floppy Modulew/bulkhead connector 2 Terak 8510 Floppy Modulewo/bulkhead connector 2 Terak 8510 RS-232 Serial Module w/bulkhead connector 4 Terak 8510 RS-232 bulkhead connectors 3 Terak 8510 Video bulkhead connectors 2 Condition of the Terak Modules can not be verified. They were functional at the time they were removed but I no longer have any functional Teraks to test them. Shipping would be the smallest size USPS "If it fits it ships" box so you can plan accordingly. bill
Re: PDP-8: count number of set bits in a word
I suppose you could test each nybble for zero, then equate a 16-element LUT on nybbles not zero? -- Anders Nelson +1 (517) 775-6129 www.erogear.com On Fri, Apr 5, 2019 at 11:59 AM Kyle Owen via cctalk wrote: > Just wondering if anyone has come up with a fast way to count the number of > 1s in a word on a PDP-8. The obvious way is looping 12 times, rotating the > word through the link or sign bit, incrementing a count based on the value > of the link or sign. > > With a small lookup table, you can reduce the total number of loops by > counting multiple groups of bits at a time, but this of course comes with > the cost of using more memory. Any other suggestions? > > Much appreciated, > > Kyle >
Re: Yes there is a PDP 10 front panel and Kenbak on Ebay
What I want to know is, how do front panels of historic computers so often get separated from the rest of the computer? The moosehead is still hanging on the wall. But, the backside of the moose is no longer on the other side of that wall.
PDP-8: count number of set bits in a word
Just wondering if anyone has come up with a fast way to count the number of 1s in a word on a PDP-8. The obvious way is looping 12 times, rotating the word through the link or sign bit, incrementing a count based on the value of the link or sign. With a small lookup table, you can reduce the total number of loops by counting multiple groups of bits at a time, but this of course comes with the cost of using more memory. Any other suggestions? Much appreciated, Kyle
Re: Yes there is a PDP 10 front panel and Kenbak on Ebay
On Fri, Apr 5, 2019 at 11:32 AM Noel Chiappa via cctalk < cctalk@classiccmp.org> wrote: > > From: Guy Dunphy > > > What I want to know is, how do front panels of historic computers so > > often get separated from the rest of the computer? > > > > Here's what probably happened: the machines were about to be scrapped, and > saving the whole machine wasn't practical - often, in part, because those > machines were _huge_. (The CPU _alone_ of a KA10 would fill an entire room > of > a normal house.) So, one has a limit to what one can do. So the choice is > to > save the front panel alone... or to save nothing. > > Noel > It is also possible that some front panels were removed and set aside back when the associated computer was in production, i,e, due to a fault in the panel. The original computer long ago separated and recycled but the panel remained in the storage closet until discovered by an employee who was allowed to take home as a souvenir, many years later. "I remember when I worked on that ..." I am thankful to have been able to rescue a few orphaned front panels of extinct machines. With simH and a Raspberry Pi there is a way to give them a new life. B
Re: Yes there is a PDP 10 front panel and Kenbak on Ebay
> From: Guy Dunphy > What I want to know is, how do front panels of historic computers so > often get separated from the rest of the computer? I suspect it probably happened a while back, before the start of the vintage computer movement; you need to look at the decisions from the perspective of back then. (As an example, back then, I was offered the complete PDP-11/45 of my old group. I was up to my neck in contemporary, important, alligators - I was on the IESG of the IETF at the time - and didn't have the time to deal with saving it and moving it to my house; so I let it go - a loss I regret terribly now.) Here's what probably happened: the machines were about to be scrapped, and saving the whole machine wasn't practical - often, in part, because those machines were _huge_. (The CPU _alone_ of a KA10 would fill an entire room of a normal house.) So, one has a limit to what one can do. So the choice is to save the front panel alone... or to save nothing. Noel
