RE: XH558 - was Re: using new technology etc
-Original Message- From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Peter Cetinski Sent: 19 June 2015 13:26 To: jwsm...@jwsss.com; General Discussion: On-Topic and Off-Topic Posts Subject: Re: XH558 - was Re: using new technology etc On Jun 19, 2015, at 7:50 AM, jwsmobile j...@jwsss.com wrote: The closest I came to an aircraft in this class was an almost on a Concorde Ticket in the late 70's when an upgrade to first class could get you near to the Concorde fare, and then on a visit in the 90's I got to see one take off like a rocket @ Heathrow. thanks Jim I remember the first time I saw Concorde as a boy. I was at JFK, I think to see off my grandmother who was taking a trip back to the old country. I’m standing at one of the large windows looking out at the flightline when all of a sudden, from the right, at what seemed to me to be just a few hundred feet above the terminal building, comes this giant roaring bird at what seemed to be a 30 degree bank after just taking off. My little boy jaw just dropped as I watched this screaming monster white dragon fly by. I once got held, waiting for a runway, probably London Heathrow but somehow Manchester sticks in my head. Any way there was a Concorde queued infront of use waiting for a Concorde to land. So I go to watch a landing and a takeoff... What the heck has happened to us that we can build these planes 50 years ago that are unsurpassed even today? Sad. Well firstly governments had money. Concorde must have cost the British and French tax payers millions... As for progress, the A380 might not be so fast, but I bet in total bandwidth the through put is higher http://www.seattletimes.com/business/boeing-aerospace/airbus-still-weighing-an-expensive-revamp-to-its-flagship-a380/ Dave G4UGM
RE: using new technology on old machines
That's only the schematic. The link I included earlier:- http://dustyoldcomputers.com/pdp-common/reference/drawings/modules/m/m452.pd f also includes the PCB component layout, from which I inferred the Trim Pot is of the 10-turn variety. Dave -Original Message- From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Brent Hilpert Sent: 17 June 2015 09:28 To: General Discussion: On-Topic and Off-Topic Posts Subject: Re: using new technology on old machines The M452 module schematic for quick access for anyone following along, as it hasn't been linked before in the thread: http://bitsavers.informatik.uni- stuttgart.de/pdf/dec/modules/mSeries/M452.pdf
RE: using new technology on old machines
-Original Message- From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Noel Chiappa Sent: 17 June 2015 15:08 To: cctalk@classiccmp.org Cc: j...@mercury.lcs.mit.edu Subject: Re: using new technology on old machines From: Dave G4UGM I found it easier to think of it in DC terms. So the Cap charges through R5 + R3 and R9 + R8. As the Cap charges the voltage on the base of Q1 rises until it turns on, which then turns on Q2. At this point the cap is then charged (or discharged) in the reverse direction via Q2, D5 and R4 until Q1 turns off. I'm clearly never going to be any good at analog stuff! ;-) Even with what looks (on the surface) to be a wonderfully clear explanation of how the circuit works, I still can't really grok how it operates! I mean, I can tell from the polarity on the cap that the collector of Q2 must be at a higher voltage than the base of Q1, but I am utterly failing to understand how the cap discharges through Q2. And as the cap charges (i.e. the voltage across it increases), how does the voltage on the base of Q1 increase - surely it must be decreasing (since it's tied to the negative side of the cap, which is experiencing a voltage increase across itself)? I think the cap is mildly abused. I believe that it is reverse charged. Like I said, I apparently don't have the gene for analog... :-) Noel
RE: using new technology on old machines. Was: PDP-12 Restoration at the RICM
I don't think it is over kill. If you want over kill try this:- https://www.youtube.com/watch?v=ALXax3Gydl8 and FPGA implementation of the Baby or SSEM which had 32x32 bits of RAM. The implementation uses around 1% of the Spartan 3E 1200K gates, and that includes the logic to generate the VGA which is around 50% of the circuit. I expect to get it on a 100K gate chip but that’s still over-kill. I am also aware how HARD baud rate generator chips are. Firstly you need to know the multiplier, and then you need a crystal that can easily be divided. I looked on E-Bay UK and the cheapest dedicated baud rate generator was 10x the price of a Arduino Nano. Then I would need a crystal and the other bits to make the generator. I would expect the chip count on a dedicated baud rate generator board to exceed that of the Nano. Of course it is not original, but an authentic board would only use SSI TTL and where would one find that easily. I personally think it is an appropriate cludge that allows de-bugging to continue and gives you time to work out what the best long term solution would be. Dave -Original Message- From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Johnny Billquist Sent: 15 June 2015 10:52 To: cctalk@classiccmp.org Subject: Re: using new technology on old machines. Was: PDP-12 Restoration at the RICM While I agree that as long as things can be restored it's not a real problem, I'm surprised that not more people consider it a serious overkill. We're talking about putting in a rather complex computer to generate a baud rate. Are people really that handicapped when it comes to building hardware nowadays? Are people aware how easy baud generators are? We're essentially talking about a clock, which can be found as a component (various oscillators), and then dividing it. There used to be chips around which did that part, and I would expect it to not be that hard to find some if you looked today. Many UARTs even comes with a clock divider built in. And that is it. When I build various Z80 systems, I usually had a Z80 CTC included, which I used for generating the baud rates. Johnny On 2015-06-15 02:52, Joe Lenox wrote: I also think it is in the spirit of the computer - using what is available to fix a problem at hand. I think the arduino was overkill when an attiny (smaller, easier to hide) would probably serve just as well. If you have the ttl logic bits lying around and know how to use them, fine. Still would probably need debugging. On Jun 14, 2015 2:41 PM, Simon Claessen sim...@dds.nl wrote: as long as it is done in a way that it can be restored to its original, i have no problems in using newer technology in older machines. we have a alix sbc build into our tek 4002a for demonstrational purpouses, all done without damaging or altering the original machine. On 14-06-15 17:25, tony duell wrote: The ripple on the power supplies is still going lower as we put more run time on the system. The power supplies are now within spec. Capacitors reforming naturally? Warren made an Arduino based programmable baud rate generator that works for both serial ports. After some debugging, it works nicely. I am sorry, but I find that obscene!. To use more components than the rest of the machine (probably) just for the baud rate clock is ridiculous. IMHO if you are going to modify a vintage machine, particularly one as rare as a PDP12, you should use the components that were available at the time. It's not as if a programmable buad rate generator is hard to make from TTL either. In fact given the Arduino thing needed 'some debugging' it might well have taken less time to do it in hardware. -tony -- Met vriendelijke Groet, Simon Claessen drukknop.nl -- Johnny Billquist || I'm on a bus || on a psychedelic trip email: b...@softjar.se || Reading murder books pdp is alive! || tryin' to stay hip - B. Idol
RE: FPGA tricks - Re: using new technology on old machines. Was: PDP-12 Restoration at the RICM
-Original Message- From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of ben Sent: 15 June 2015 17:18 To: cctalk@classiccmp.org Subject: Re: FPGA tricks - Re: using new technology on old machines. Was: PDP-12 Restoration at the RICM On 6/15/2015 9:08 AM, Toby Thain wrote: On 2015-06-15 9:35 AM, Dave G4UGM wrote: I don't think it is over kill. If you want over kill try this:- https://www.youtube.com/watch?v=ALXax3Gydl8 and FPGA implementation of the Baby or SSEM which had 32x32 bits of RAM. The implementation uses around 1% of the Spartan 3E 1200K gates, and that includes the logic to generate the VGA which is around 50% of the circuit. I expect to get it on a 100K gate chip but that’s still over-kill. Speaking of VGA, you might like this: http://www.fpgarelated.com/showarticle/42.php --Toby But alas the software does *not* support the older chips. How old is old? I managed to get a copy of ISE10.1 downloaded, installed and running without phoning, ringing or otherwise jumping through hoops. That supports the Spartan 2 which has been obsolete for some time.. If you want to play with some Spartan 2 chips contact me off-line. You want to make a mod 5 years down the road, sorry we do not support that model any more. TTL needs to be stock piled now for the next +50 years. I finally got 18 bit FPGA computer (DE1) design I like, that is early 70's speed. 1.5 us core. What I am having problems is finding a good book on Operating Systems from that Era that is online, any one know a good book? I have software that I need to write. Ben.
RE: using new technology on old machines. Was: PDP-12 Restoration at the RICM
A friend of mine refused to buy modern SD Cards because there was no way he was going to fill them. Trouble is that although smaller SD cards were available they were way more expensive (being discontinued and therefore rare and valuable).. He struggled with buying a larger card only to waste most of it, or buy a smaller one and waste his money Dave Wade G4UGM -Original Message- From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Mark J. Blair Sent: 15 June 2015 21:56 To: General Discussion: On-Topic and Off-Topic Posts Subject: Re: using new technology on old machines. Was: PDP-12 Restoration at the RICM On Jun 15, 2015, at 13:46 , Pontus Pihlgren pon...@update.uu.se wrote: On Mon, Jun 15, 2015 at 04:55:57PM +, tony duell wrote: Unfortunately I believe you. Use at least a thousand times more components than you need to. Actually it's just two, a Teensy and a usb cable. (Sorry, I couldn't resist). LOL! I must admit that I used to scorn those durned kids using Arduinos to do the job of a 555. But then I pulled my head out of my ass and realized that times change, nowadays a microcontroller is as cheap and common component as a 555 was when I was a snotty kid, and the new-fangled maker movement with its Arduinos and serial-controlled addressable LEDs and conductive thread is keeping younger people designing things and making them instead of just being dumb consumers. It's all good stuff! And once I got a better idea of how much it costs to keep an engineer breathing for an hour, I also realized that it often makes more sense to overkill the heck out of a task with a $20 micro board than it would to spend even a half hour longer doing it the right way. -- Mark J. Blair, NF6X n...@nf6x.net http://www.nf6x.net/
RE: 80 column (un)punched cards
-Original Message- From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Chuck Guzis Sent: 10 June 2015 06:07 To: gene...@classiccmp.org; discuss...@classiccmp.org:On-Topic and Off- Topic Posts Subject: Re: 80 column (un)punched cards On 06/09/2015 08:52 PM, Mike Stein wrote: I just got rid of the last of my punched card equipment so I no longer need any blank cards; anybody out there need any? 1 box (2000) normal light buff (off-white) colour, around 500 of same with blue stripe, and several dozen of various colours, all with the normal numbers printed and all unperforated - ha ha ha! (obscure and lame reference to a line in Flanders and Swann's 'Have some Madeira, M'dear!' that was apparently too risque for the American sensibility ;-). I'd rather think that it was risque for British sensibilites. A smile on her face and an ache in her head... So it wasn't about cake? She lowered her standards by raising her glass, Her courage, her eyes and his hopes --Chuck Dave
RE: Front Panel Update
-Original Message- From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of tony duell Sent: 10 June 2015 05:46 To: General Discussion: On-Topic and Off-Topic Posts Subject: RE: Front Panel Update Interesting. Varian is a microwave equipment company; I have one of their TWTs sitting on my H960 at home. Vacuum equipment, I could believe that. But yes, Varian made a 16 bit minicomputer; I had a handbook for it at My father was a physical chemist who did a lot of work with vacuum systems. He would swear by Varian (and swear _at_ Vacuum Generators). I assume it was the same Varian company. I once had a Varian computer, well the local computer club had a Varian. I can't remember what happened to it. A friend used to work for them mostly I think on gas chromatographs... A number of scientific instrument companies made computers too, of course. The most obvious being HP. -tony Dave
RE: Pertec Tape Drive Interface Musings
Mark, Traditional 9-track tapes are always written block-by block with a short gap between the records, WikiPedia say 0.6 for 1600BPI which sounds about right. From what I remember as tapes are not the most reliable medium the process was to have the read head after the write head so the tape could be read and checked as it was written. If an error was returned the system would backspace, erase the bad block to create a long gap and the try again. Looking at the first MAN page for TAR I found it says it writes 20x512 byte blocks so 10K blocks, i.e. about 6.4 long. That means a waste of 10% of the tape in gaps, assuming the tape is perfect. You can write longer blocks but then the amount of wastage when you write a bad block goes up. So I guess to answer your question. Operating systems and tools expect a block level interface to tapes. You need to duplicate this in your interface. Dave -Original Message- From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Mark J. Blair Sent: 10 June 2015 08:34 To: General Discussion: On-Topic and Off-Topic Posts Subject: Pertec Tape Drive Interface Musings I was looking at a couple of documents describing the Pertec tape interface; the manual for my Kennedy 9610 tape drive, and a nice reference by a fellow with a rather familiar name: http://www.sydex.com/pertec.html According to my Kennedy manual, issuing a read command causes the drive to return one block of data. I can see how that would be used in block- oriented applications in which blocks may be randomly read, written and re- written on the tape. But most of my magtape experience has been using the tapes in a streaming mode, such as when reading/writing one or more tar archives separated by file marks. When writing a tar archive on a magtape from a Unix system, is the archive written as a sequence of fixed-size blocks? Or is the entire tar archive effectively written as one continuous block which must be streamed with no repositioning? I'm curious because I'm daydreaming about how to build a tape drive interface controller, and I wonder whether it might need to potentially stream an entire tape in one go vs. being able to safely assume some maximal block size. -- Mark J. Blair, NF6X n...@nf6x.net http://www.nf6x.net/
RE: Pertec Tape Drive Interface Musings
-Original Message- From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Mark J. Blair Sent: 10 June 2015 17:13 To: General Discussion: On-Topic and Off-Topic Posts Subject: Re: Pertec Tape Drive Interface Musings On Jun 10, 2015, at 08:46, Al Kossow a...@bitsavers.org wrote: On 6/10/15 8:15 AM, Mark J. Blair wrote: And that is precisely why I'm thinking of an ad-hoc interface rather than just plugging a SCSI drive into a UNIX box. It also has the advantage that you can return the CRC/checksum and partially read blocks. Most SCSI tape drives don't return the data if the read doesn't succeed. I particularly like the idea of being able to extract questionable data and CRC/checksum. Ok, now three more questions come to mind: 1) Is it ever acceptable to mix densities on a single tape? I'm not sure that my Kennedy drive will even allow that, but I don't know if that is universal. No idea. I suspect most drives will only change density at BOT 2) What's the scoop on a final record overlapping the EOT marker? Or even a new record starting after the EOT marker? I seem to recall reading about some applications that stuck data after the EOT, such as backup volume information. I seem to recall ALL applications put data after the EOT marker, should they fill the tape. So on a write you get an EOT reached status, BUT to get this you must have written past the EOT marker. If its non-labelled tape you write a tape mark, rewind and unload the tape and ask for another. It is up to the application program to know there is more data. Typically on a mainframe you wrote labelled tapes, so you needed to write a Tape Mark and the End of Volume Label and any other labels needed, then another tape mark, then unload and ask for the next reel. This usually goes after the EOT marker. For labelled tapes the label tells you if there is another tape in set. 3) Did anybody ever go over to the dark side and implement copy protection on magtapes, say, by deliberately including a record with bad CRC that a normal driver+drive would not support writing? Or was that evil limited to the floppy disk world? I don't believe you can do that. IBM Mainframe copy protection usually involved using the serial number of the Mainframe. Total PITA when doing Disaster recovery checks -- Mark J. Blair, NF6X n...@nf6x.net http://www.nf6x.net/
RE: Front Panel Update
Is this appropriate for an SBC6120 or does that need different switch labels ... -Original Message- From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Rod Smallwood Sent: 08 June 2015 13:20 To: gene...@classiccmp.org; discuss...@classiccmp.org:On-Topic and Off- Topic Posts Subject: Front Panel Update Hi All Since I released the picture of the first 8/e panel on Friday there has been a big response. Its 12:45 local on Monday in the UK and I'm of to the silk screeners to collect the rest of the first batch and to arrange for more to be printed as soon as I get the blanks from the plastics supplier. I'll send out what I have to fullfill as many of the orders I have so far as I can. I have learned an awful lot just based on the inquires I have so far. I see the following as requirements 1. Full size reproductions of the original panels useing the same methods. 2. High quality 3.Custom one off service for important restorations. 4. There's more demand than I thought. 5. So far its all been for DEC systems And yes they would look good just hung on the wall Next up an accurate reproduction of the bezel. And after that a lamps and switches board when and if I solve the Stackpole switch levers issue. Please send in your orders so I can allocate production/shipping slots. Regards Rod Smallwood
RE: PDP8/e front panels.
Rob, How much in the UK Dave -Original Message- From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Adrian Stoness Sent: 06 June 2015 14:39 To: General Discussion: On-Topic and Off-Topic Posts Subject: Re: PDP8/e front panels. pic? On Sat, Jun 6, 2015 at 5:13 AM, Rod Smallwood rodsmallwoo...@btinternet.com wrote: Hi All I have recently produced a number of high quality custom PDP8/e front panels. They are full size reproductions of the original. The production methods are exactly as used in circa 1971. They are not photographs. The front has the two colours plus the white each done with its own silk screen and the back has the intense black with the clear circular areas for the lamps to shine through. The inks were matched and made to order. The acrylic blanks with the cutouts for the keys were also a custom order. I did the artwork, The four screens were made and the printing done by two young ladies with very good graphic arts skills at 'Squegee Ink Ltd' local to me here in Newbury UK. I have some photos but they do not do justice to the pin sharp lines and intense colours. The panel fits the bezel and the switches on the key + lamps board line up. I have a few to sell and can do more if needed. Due to the custom production they will not be low cost ($95.00 + shipping from UK) If you are interested I'll send you a picture. My photo skills are not that good. Rod Smallwood
