test-drb

test-drb@ccmp.vtda.org

101090 discussions

by roger.holmes＠microspot.co.uk

On 29 Jun, 2007, at 20:37, cctalk-request at classiccmp.org wrote: > The TDC is almost as impressive as the Arma Mk 1 fire control > computers of the same era, used to calculate the problems of putting a > 16 inch shell on the deck of a ship 20 miles away. PAMPANITO in the > Bay Area (Fisherman's Wharf) has completely restored working TDC, the > result of many many hours of work from a dedicated volunteer. It is up > in the control room, and very hard to see without appointment. In 1986 or 87 I walked through her - usual tourist thing. About the only thing I still remember was the story of the tons of gold brought back in (that?) submarine.

18 years, 12 months

Billy Pettit real disappointment

by roger.holmes＠microspot.co.uk

On 29 Jun, 2007, at 20:37, cctalk-request at classiccmp.org wrote: > From: "Billy Pettit" <Billy.Pettit at wdc.com> > > > ----------------- > > Billy replies: This was a serial machine using a magnetic drum for > memory. > So the registers and memory were all bit serial and on the drum. I/ > O was > accomplish by moving data from one line to another. The logic at > each end > of the line was in peripheral but the bits were on the drum. So it > really > doesn't fit the standard definition of memory mapped I/O, though > that is the > closest description. There were no channels per se. > > Al has just posted most of the G-15 manuals. Have a look. It > certainly > qualifies for the weirdest machine I ever worked on. Yes that's reasonably weird. I particularly like the weirdness of drum where the data spins faster than the drum and it stores even faster rotating data on the same band. Makes my 1301's drums with one read/write head on each bit track seem boring, though the tracks are grouped in fours as it is a 4 bit parallel by 12 digit serial architecture. The 1301 has a neat trick for its day, to transfer an entire band (four tracks, 200 x 48 bit words), it did not wait for the start of the track to come round, it started at the next decade (ten word) boundary to come around, worked up to the end of the band, set its core address back to the original start address (which had to be a multiple of 200) and worked up to the start of the data already transferred. > > ---------------- > > Roger Holmes: > > Remember? I am restoring/maintaining an ICT 1301 which has individual > Germanium transistors, wire-OR, four and gates to a PCB, one flip- > flop one a PCB, a clock derived from the timing track of the last > addressed drum store, a core store unit weighing half a ton an stores > just 2000 x 48 bit words (plus 2000 x 2 parity bits). Its got Ampex > TM4 mag tape drives (not industry standard 7 or 9 track, these are > ten track units with hubs the same design as professional audio tapes > and the 2 and 3 inch wide video tapes once used by TV broadcasters). > > [Snip] > > --------------------- > Billy: I salute you. I wish more people on this list had your > energy and > love of old metal and were restoring it. I enjoy hearing about your > efforts. Thank you very much. The plan is to get one of my two machines into a museum one day, hopefully both when I am too old to use it/dead. Almost ten years ago the Computer Conservation Society had plans to get one into the Bletchley Park museum and one into the 'Science Museum' but both of them dropped out - I suspect its because a 1301 takes up too much floor space. > > I'm also working on a germanium transistor wired-AND core memory > machine. Ah! Wire-AND. Would this be negative power rail germanium by any chance? If so I suspect the circuits are basically similar but the nomenclature is different. On the 1301, a logic 1 is -6.3 volts and a logic 0 is 0 volts. When fault finding we usually have one person at the console operating the machine and looking at the logic diagrams calling the circuit references to be checked and one on an oscilloscope out of sight describing the display on the 'scope. Most of us are of course familiar with silicon logic and we get confused by calling out 'high' and 'low' because it is so natural, and we find it so difficult to remember high is 0 and low is 1, so we TRY to call out logic 0 and 1 instead, but it so hard to break old habits. > It used TM2's not TM4's. And I've been unable to find any tape units. The 1300s had four different tape subsystem options. The 'High Speed' (90kc/s) system, called tape type 1 (because it was the first developed) was a one inch system using Ampex drives, and IIRC, they were TM2s. They had 16 tracks (8 data and 8 CRC), and ran at 150 ips. My machines TM4 system (4 data 6 CRC tracks) was tape type 3 (22.5kc/ s) and was basically the same electronics with some parts removed and the minimum changes to make it store two frames where the high speed system saved one frame. It runs at only 75 ips. It uses Thyrotrons to turn the pinch rollers on and off. It has small vacuum chambers plus swing arms to buffer and measure the amount of buffered tape, the (air damped) sensors on the swing arms being the only things which control the reel motors - too much slack and the reel motor winds some in, too little and it winds some out. > Did > find the original card reader, a modified Burroughs. > > Still, I consider what you are doing to be the true goal of classic > computers. I read, enjoy and participate with the microprocessor > based list > threads. Me too, though much of it is too much like my everyday job. Its like in the winter I drive my reasonably modern Jag or BMW to work but in the summer I enjoy driving my 1960s Daimler or Rover, and sometimes it feels like an achievement just to get to work, and if I stop for petrol I have to allow an extra ten minutes to chat to people who come over to admire the car. "They don't make them like that any more" or "My uncle used to have one of those". I even had someone who seemed to offer me 30k for a car insured for only 11.5k. > But my real love is in truly "classic" computers like yours. Good. I was lucky enough to buy not just the computers but a load of spares. As yet I've not needed to do much component level repairs. Its the Ampex decks which cause most problems because they are American made, they don't use British components. For the CPU things like light bulbs, the same type were telephone exchanges and cars of the period, which are now classic and hence there is an industry still supplying them. The telephone exchange bulbs crop up on eBay, even sometimes the rarer voltages like 17 volts, and I recently bought almost a hundred 28 volt ones which produce an identical intensity plugged in in place of 24 volt ones. Its the things like the bulbs for the virtual address display (12 miniature projectors, one for each digit 1-8, and letters 'E','L' and 'U' and an underline) which are a problem. They are 6.3 volt 6 watt. I thought I'd cracked it when I picked up some 6 volt car ones rated at 6 watts, assuming that like a 12 volt car system, the charging circuit would run them up to 15 to 20% over-voltage. But they only last about 30 seconds. I've checked the supply and it is only 6.3 volts, I can only assume it must be the enclosed space require a higher operating temperature. Googling has found the GE part number listed as microscope illumination lamps, but it doesn't give the voltage or amperage ratings, and the price was horrendous, so I'm not even sure they really are the right ones, and too tight fisted to take a chance. Maybe if we have a lot of people paying admittance to see the old girl (if she's works on the day) at classic car show I hold at my home in a couple of weeks time. Still, I've bought an old 4 trace HP storage scope (via ebay) on that expected income already, and after only one day's operation it now works for 20 seconds after turning on and the goes clip-clop, clop-clip, repeatedly and so I may have to spend more money and time trying to repair it. Better go to bed now, its 1am, got carried away! > > ---------------- > > Roger Holmes: > >> And many of them were wonderfully different and creative. > > Indeed. And some of them almost make you cry because so much more > could have been done with the same amount of electonics. My machine > has been modified to implement an index instruction. Previously all > indexing and indirection had to be done by program modification, and > even now subroutine return is done that way (see my previous e-mail). > I have one machine in 'conserved' state, unmolested, unrepaired non- > runner, and one with extra tweeks and darn right mass rewiring which > runs and I can't stop thinking about how it could be improved, yet > somehow manage to stop myself doing so. There are so many gaps in the > instruction code and spare bits in the instructions etc. The only > modification I am working on plugs into an extension port lashed up > by a previous owner. This is to capture the data from the machine > onto modern media. May replace with an RS232 interface later to drive > a teletype and/or pen plotter, and/or a parallel inteface for a > Friden Flexowriter. > > [sni] > > Roger Holmes. > Classic computer collector, classic car collector, machine tool > collector/user (for the prior mentioned hobbies), and for a job, > programmer of CAD and graphic software and printer/plotter drivers > for Apple computers. > > > >

18 years, 12 months

Fw: more...

by jrkeys＠concentric.net

----- Original Message ----- From: "Tim Deaton" <timdeaton at yahoo.com> To: "Keys" <jrkeys at concentric.net>; "Al Kossow" <aek at bitsavers.org> Sent: Thursday, June 28, 2007 7:36 PM Subject: Re: more... > John, > > Send me a number were I can call U after 9PM or on > weekends when the cell phone (NEXTEL) is 'free'. > > I am in Indiana - Eastern Time Zone. We can discuss. > > You can call me free any time if you have Sprint or > Nextel. > > My incoming calls are all free. > > Tim Deatom > 317-716-8807 > > > > ____________________________________________________________________________________ > Park yourself in front of a world of choices in alternative vehicles. > Visit the Yahoo! Auto Green Center. > http://autos.yahoo.com/green_center/ He has tons of doc's, 15 Televideo terminals, 100+ monitors, 100+ printers, 100's of new parts, tons of software (OS's, WP's and no games), many more things than I can list. If you live in his area please try and rescue this stuff, it's all free to good homes. I wish I could get some of the tons of documentation and service manuals that he has from his old business. He's in Indiana. Thanks for reading, John Keys

18 years, 12 months

C= LED watch on epay...

by Watzman＠neo.rr.com

I think someone will be disappointed; it looks like an LCD watch, not an LED watch.

18 years, 12 months

HP-IL sighting!

by mcguire＠neurotica.com

HP-IL interfaces turn up in the oddest places. This sound level meter on eBay looks to have an HP-IL interface, shown in the pics: http://shorterlink.org/2335 -Dave -- Dave McGuire Port Charlotte, FL

18 years, 12 months

LARGE IN RESCUE NEEDED Was Fw: more...

by jrkeys＠concentric.net

Sorry for double post but wanted to clear up message subject ----- Original Message ----- From: "Keys" <jrkeys at concentric.net> To: "cctalk at classiccmp" <cctalk at classiccmp.org> Sent: Saturday, June 30, 2007 10:27 AM Subject: Fw: more... > > ----- Original Message ----- > From: "Tim Deaton" <timdeaton at yahoo.com> > To: "Keys" <jrkeys at concentric.net>; "Al Kossow" <aek at bitsavers.org> > Sent: Thursday, June 28, 2007 7:36 PM > Subject: Re: more... > > >> John, >> >> Send me a number were I can call U after 9PM or on >> weekends when the cell phone (NEXTEL) is 'free'. >> >> I am in Indiana - Eastern Time Zone. We can discuss. >> >> You can call me free any time if you have Sprint or >> Nextel. >> >> My incoming calls are all free. >> >> Tim Deatom >> 317-716-8807 >> >> >> >> ____________________________________________________________________________________ >> Park yourself in front of a world of choices in alternative vehicles. >> Visit the Yahoo! Auto Green Center. >> http://autos.yahoo.com/green_center/ > > He has tons of doc's, 15 Televideo terminals, 100+ monitors, 100+ > printers, 100's of new parts, tons of software (OS's, WP's and no games), > many more things than I can list. If you live in his area please try and > rescue this stuff, it's all free to good homes. I wish I could get some of > the tons of documentation and service manuals that he has from his old > business. He's in Indiana. > > Thanks for reading, > John Keys

18 years, 12 months

Drum vs. Core

by ajp166＠bellatlantic.net

> >Subject: Re: Drum vs. Core > From: Roger Holmes <roger.holmes at microspot.co.uk> > Date: Fri, 29 Jun 2007 19:27:10 +0100 > To: cctalk at classiccmp.org > > >> >> Core was available by 1952, most of the big machines after this >> date (on this side >> of the pond at least) were core based. The IBM 650 was actually one >> of the smaller >> machines, at least inasmuch as IBM was already making much larger >> machines >> (the 700 series). > >Wasn't core memory very expensive in the beginning? Yes and new. It was also temperature sensitive as the required ferrites and circuits were not fully developed. > It had to be hand >assembled, at least in the early days. I think there was a more >gradual take up than you suggest. Of course the more expensive >machines which used it first saw a huge speed increase over drum main >memory. When I was at university (71-74), the college's mainframe >still used a drum from program overlays (probably really the virtual >memory backing storage, but possibly just dumping and restoring the >whole program between time slices. The machine was no slouch, it was >serving about a hundred terminals and running a couple of batch >streams as well (Maximop and George 2). Actually core appeared in two places in machines. TX2 was an exellent example where core was used as main store and also there was a far smaller "fast store" using core that was really for use as registers. >Mid 1970s I remember seeing a small plastic pot about the size of a >35mm film canister, which was full of about 100,000 unstrung cores, >they were tiny! They were used in the Marconi-Elliott 920ATC computer >and also in the early Cruise missiles and some torpedoes. Ever >wondered why a British submarine used a WW2 type torpedo to sink the >big Argentinian Cruiser? My theory is that they were too worried >about the modern torpedoes coming back and blowing themselves up, so >they used one they trusted to go where it was pointed. Hopefully 25 >years on, they've sorted out the terrible guidance system. Not >related, but apparently the programmers were in a quandary as to what >the program should do after it had issued the order to detonate. Like >the old TV series 'Waiting for God'. > >The first machine which ICT introduced with core memory was in 1962, >though physically large, the 1300 was a medium power machine, seen >more as a versatile tabulator for accounts rather than scientific >work, though it had a structural frame analysis package and even >PERT, though I suppose that is just up market accounting in a way. >Customers did all sorts of other work on it too, helping to design >'planes and even playing music on the built in speaker. There's a >wonderful program called Ghost, only a half a dozen instructions, >which uses the variable length of the multiply instruction to make a >ghostly sound on the speaker. Its a good test of the CPU too, and can >be keyed in through the control panel if need be in a minute or so. >Also has drums - each one 12000 words x 48 bits run by a 3/4 >horsepower motor and occupying 2ft x 2ft x 5 ft. Compared to the 8GB >SDHC card for my 12MP camera which is about an inch by an inch by a >sixteenth and stores 100,000 times as much in about 1 / 500,000 times >the volume. And the core store is one sixth the capacity of the drum >in a greater volume. I remember the fixed head (head per track) word parallel swapping drums on PDP-10s. Those were 128kW but fairly small and motors were on a 1/4hp scale. That and the PDP-8 32k fixed head platter (RS08) that were often used for swapping as they were fast using multiple fixed heads and working as word parallel. Around the time of the Altair you could buy surplus drums most fixed head that were fairly small physically and techically easy to interface though the amount of repeated circuits were large in quanitity. Allison

18 years, 12 months

Billy Pettit real disappointment

by RodSmallwood＠mail.ediconsulting.co.uk

Here's my five cents worth. I see computers and computing as different things. We discuss a lot about old hardware and to some extent and rather less about old software. What's in short supply is how the hard/soft combinations were used practically. "Are there any interesting old applications out there?" As to the on/off topic issue. I don't see any problem with comparing and contrasting the old with the current. If one topic arises out of another and is of interest to others on the list and gets a response so be it. If there is no response then the silent majority have voted. I am concerned that difference between moderation and censorship could, at some time in the future, (present situation excepted) become less distinct. Rod Smallwood -----Original Message----- From: cctech-bounces at classiccmp.org [mailto:cctech-bounces at classiccmp.org] On Behalf Of Jay West Sent: 28 June 2007 13:58 To: General Discussion: On-Topic and Off-Topic Posts Subject: Re: Billy Pettit real disappointment Billy wrote... >> Come on people: there were computers long before there were >> microcomputers. I seem to remember a recent post complaining that this list was nothing but minicomputer and big-iron talk, no microcomputer discussion. Apparently that was wrong, as now there is a complaint it's just micro talk? ;) Jay `

18 years, 12 months

LISA

by pdp11_70＠retrobbs.org

So... I've got *the* lisa emulator set up and can (at last) play with that computer that I wanted when I was 12 (I still remember seeing one at Computer Pro and being amazed!) So, does anyone know what happened to that 90,000+ lines of (Pascal) Source Code for LOS? It would sure been neet to be able to look at it. It would be even more need to write a TCP/IP stack for the thing, and some how hook up a scsi asanti ethernet adapter to a real Lisa and put it on the web without using Macworks. But as I don't have any of the real equipment... I guess that's just a pipe dream. Wow. mark -- "Well, Steve, I think there's more than one way of looking at it. I think it's more like we both had this rich neighbour named Xerox and I broke into his house to steal the TV set and found out that you had already stolen it." -Bill Gates to Steve Jobs On Windows --

18 years, 12 months

Diamond Rio PMP-300 (was Re: What didn't happen in the future)

by ethan.dicks＠gmail.com

On 6/27/07, Zane H. Healy <healyzh at aracnet.com> wrote: > At 8:04 AM +0100 6/27/07, Rob wrote: > >Almost on topic(only a year to go), > > Actually I'm not sure what the stance is on > peripherals, but if it was a computer it likely > would be fully on topic. I would think there would be no difference made between peripherals and CPUs of a given vintage or "coolness". I think what's at issue here is that technically, the PMP300 is nine years old, so it has to squeeze in by nature of its place in history, not its mere age. > IIRC, it was the first > commercially available MP3 player, at least it > was the first widely available one. AFAIK, it was the second model to market, but the first widely available one. > I bought one new as well, though I paid $300 and > got it when it first came out. Ow! FLASH sure was expensive then... but so were all of Diamond's other products. > I actually had my Rio working with WinXP at one > point, and I believe I also had it working with > Linux. Here's what I've been using for years to pump and dump music on my Rio PMP300 (from the README) RIO utility v1.07 - The Snowblind Alliance (c) 1999 I did run into a parallel-port permissions issue with RedHat WS3 last year, but under RedHat 9, the ancient Rio utility worked perfectly. I think it's just a matter of tweaking the rio.cpp to open the parallel port with a more modern technique - the port banging code should work fine after that. If not, then there's a reason to stick with an "obsolete" version of Linux - to get unfettered I/O port access. :-/ > I still have the original box, and should have > everything that goes with it. My intention is > that one day it will be a museum exhibit along > with a lot of my other computer equipment, that > is the only thing it has ever been good for. > Personally I wish I'd never wasted the $300 on it. Your feelings about it reminds me that I'm glad I didn't get one when they were _totally_ new. I paid at least $100 for mine, since, ISTR, I was concerned that the RIAA lawsuit over potential violations of the 1992 Home Recording Act might make them unavailable. Fortunately for us all, that one was settled in favor of Diamond. I still use mine. I was given an iPod Shuffle that I don't use much because embedded non-user-replaceable Li-Ion batteries annoy me. I have a removable NiMH AA in my PMP300, which means it won't be dying of battery fatigue anytime soon (I use my Palm III in favor of my Palm V for the same reason). I do have a half-dead one, that I'd love to repair... it was free from the previous owner because as far as we can determine, one of the FLASH chips is defective. I think it stores songs, but not the full amount - there's a dead zone in the internal 32MB map. Simple fix once one identifies which chip it is, and locates a spare. -ethan

18 years, 12 months

Drum vs. Core

by aek＠bitsavers.org

> haven't checked into > when UNIVAC took up with it. 1103A (Williams Tubes in orig 1103) in MN UNIVAC II (UNIVAC I was mercury delay lines) in PA I'd have to dig a bit more for the Univac military systems.

18 years, 12 months

What are the really unusual or weird computers?

by Billy.Pettit＠wdc.com

This thread has been a real disappointment. Almost all of the responses have been about computers using standard microprocessors - off the shelf components. Yes a few had non-vanilla flavored OS's, or idiotic I/O schemes. A few were even painted different colors from PC Beige. But nobody got into the really weird internals that have made the industry so fascinating. Go back to the real early days, like the Atlas, that let you build your instruction set from scratch using micro-code. Nobody seemed to remember that most of the late 50's and early 60's used 40 bits as a standard. What about the MicroData machines with a build your own instructions on the fly? And then there were the ultra-strange like the G-15 - 29 bit word size, all instructions were modified moves through arithmetic logic or I/O devices. The I/O devices were actually part of the internal logic - no channels. Burroughs had some fascinating ideas on virtual memory in the 5500 series. Seymour Cray lived weird and unusual in most of his designs. Several people have developed machines to run high level languages in native mode: ADA at Rational, APL on the Star 100, LISP, COBOL, etc. There's not much unusual about putting some glue logic around a $3 micro chip. We've all done it. How about the truly weird machines? Doesn't anyone remember when logic didn't come in million transistor packages? Come on people: there were computers long before there were microcomputers. And many of them were wonderfully different and creative. Billy

18 years, 12 months

Apricot F1 software needed

by legalize＠xmission.com

Speaking of Apricots... I've got an F1 I purchased from ebay and it came with a full set of manuals, but no software. Can anyone help me out? I've got manuals for: - Apricot Software GEM Desktop - Apricot Software GEM Paint - Apricot Software GEM Write - Apricot Async User Guide - Microsoft Pack (MS-DOS 2.00, apparently) Since this machine only has a floppy drive, its not very functional until I get the right OS for it... -- "The Direct3D Graphics Pipeline" -- DirectX 9 draft available for download <http://www.xmission.com/~legalize/book/download/index.html> Legalize Adulthood! <http://blogs.xmission.com/legalize/>

18 years, 12 months

HP7202A Schematics questions

by wacarder＠earthlink.net

I've taken some pictures of the inside of the plotter and close-ups of the interface assembly card, which is where most of the wires from the interface connector go to. Perhaps someone will see something that makes sense to them. I also opened up an ASR-33 teletype and looked at the connector where the plotter interface cable plugs in. It is a 9 pin molex connector, with 8 pins being used. I *can* find documentation on that somewhere in one of my teletype manuals. Pictures can be seen at the bottom of: http://www.woffordwitch.com/HP7202.asp Ashley http://www.woffordwitch.com

18 years, 12 months

C= LED watch on epay...

by aliensrcooluk＠yahoo.co.uk

Hi folks, An official C= LED watch is up for grabs. But with the current bid at ?20 I think I'll opt out. Just 20 hours to go though... http://cgi.ebay.co.uk/COMMODORE-LED-WATCH-RETRO-CLASSIC-AMIGA-C64_W0QQitemZ… >From the description: "The watch is brand new, never been worn, the leather strap has never been used. The strap is black on the upper side and tan on the reverse. I have seen this style watch on the web for upwards of ?150. There is a low no reserve auction. There is no box just the watch. The watch battery is dead, but that can be changed by any local shop it is not a specialist job. However the watch is sold as seen as i cannot guarantee it because of the age, however >from what i know it is in perfect working order. On the reverse of the watch is incribed: Commodore Hong Kong Case Stainless Steel Back Base Metal Bezel" Regards, Andrew B aliensrcooluk at yahoo.co.uk

18 years, 12 months

Dialling up in 1982 (was Re: old modems (was Telephony switches))

by ethan.dicks＠gmail.com

On 6/28/07, Jason T <silent700 at gmail.com> wrote: > On 6/28/07, Ethan Dicks <ethan.dicks at gmail.com> wrote: > > > I still have my bought-new-in-1982 VIC modem that I used to use to get > > on CompuServe when I was in High School... > > The second big mistake my parents made was signing up for CompuServe > with the offer found in the VicModem box. Ohh the credit card bills > that followed! I don't know why I was ever allowed near a computer > again. Oh, yeah. I'm not sure how I survived that summer. > (OK, there were those RLE weather maps on CIS. At 300bps, even!) Hmm... I know that RLE pictures existed (before GIF), and were monochrome, not color, but I don't recall experiencing them in 1982. I'm positive that my BASIC terminal program knew nothing about them. Perhaps the VidTex client I tested knew what to do with them, but I don't remember ever viewing any on a C-64. Does anyone have any RLE files or know more about when and in what context they appeared (besides, obviously, just "on CIS"). -ethan

18 years, 12 months

What are the really unusual or weird computers?

by classiccmp＠memory-alpha.org.uk

Hi, > One possible input device was a pressure switch operated by >blowing or sucking. > Maybe the OP has to use such a device, in which case all power >to him ;-) 8-D TTFN - Pete.

18 years, 12 months

Linux PCB CAD software?

by ajp166＠bellatlantic.net

> >Subject: Re: Linux PCB CAD software? > From: "Ethan Dicks" <ethan.dicks at gmail.com> > Date: Thu, 28 Jun 2007 14:25:56 -0400 > To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> > >On 6/28/07, Dave McGuire <mcguire at neurotica.com> wrote: >> ... The current incarnation of PCB bears no >> resemblance to the version that I first used about five years >> ago...it is *fantastic* now. > >Far out... I'll have to take another look at it - two years ago, it >looked promising, but not enough for me to switch. > >> To bring this at least slightly on-topic, I am midway through >> doing a board layout for Chuck Dickman's RX01/02<->parallel port >> interface in gschem and PCB. Where is this information on the net? Allison >Excellent. You beat me to it. I was just looking at that circuit >yesterday to see about cranking one out. > >> I did one layout for that circuit about >> a year ago, but with through-hole parts, and I'm nearing the point of >> swearing off through-hole...this board uses surface-mount components. > >Hmm... I still have enough through-hole parts to fill several >bathtubs, so I'm not sworn off, and I'm quite handy with manual SMT >work, but for overall cost to me, I'm still fond of through-hole where >possible. Commercial projects, of course, have different financial >parameters, but my own stuff, I frequently get 80% or more of the >parts right off my shelves. > >I'll be interested to see how your layout turns out, and, SMT or >through-hole, probably be interested in picking up one or two on a >group buy, presuming blank boards are an available option. I was >going to build at least one adapter on a perfboard, just to play with, >so a prefab PCB would be most welcome. > >-ethan

18 years, 12 months

HP7202A Schematics questions

by wacarder＠earthlink.net

>The interface has a 15 pin male adapter, with >8 pins on top and 7 on bottom. > >I have added a link to the schematics at the bottom of >the HP7202A Plotter page on my web site. > >Go to: > >http://www.woffordwitch.com/HP7202A.asp > >and click on the link at the bottom of the page. Can someone help me understand these old HP schematics? I see the 15 adapter pins shown at the top right of the page, and see where one of the pins (# 5) appears to go to something labeled EIA IN on the "Logic Mother Board" section. Some pins (3, 4, and 6) appear to not be connected to anything. Most of the others seem to go to the Analog Mother Board, but I am not sure how to follow them from there. What would be nice is if I could get enough of an understanding from this schematic to figure out how to construct both a 20mA adapter and an EIA (RS232) adapter, or an adapter that has the 15 pin connector on one end, and two connectors on the other end (one for 20mA and one for EIA). Thanks, Ashley http://www.woffordwitch.com

18 years, 12 months

Classic HP forums?? - plotter questions

by wacarder＠earthlink.net

>Does the service manual contain schematics? If so, it should >be easy to find out which pins are used. I am scanning the schematics right now and will post them shortly. If somebody can take a look at them and decipher them for me, that would be GREATLY appreciated! Ashley

18 years, 12 months

(another) Floppy disc reader status update and RFC

by aek＠bitsavers.org

> I'm also thinking about an extension to the ImageDisk file format to allow > storage of raw MFM data, though I'm not sure how to go about doing this... > creating a whole new format may be a better idea. A common low-level format would be a good thing. I don't beleive it exsits in the Catweasel world.

18 years, 12 months

Dialling up in 1982 (was Re: old modems (was Telephony switches))

by jfoust＠threedee.com

At 09:20 PM 6/28/2007, Ethan Dicks wrote: >Hmm... I know that RLE pictures existed (before GIF), and were >monochrome, not color, but I don't recall experiencing them in 1982. >I'm positive that my BASIC terminal program knew nothing about them. >Perhaps the VidTex client I tested knew what to do with them, but I >don't remember ever viewing any on a C-64. >Does anyone have any RLE files or know more about when and in what >context they appeared (besides, obviously, just "on CIS"). Before researching, my memory was that they were first used for CIS weather maps. In my CCC archive, I found a '98 message between Merch and I that mentioned RLE files stored in his Tandy 600 archive, so I bet the Model 100 and CoCo people have archives, as they certainly have decoders. The Wikipedia entry for Compuserve isn't specific about when they released RLE. The run-length-encoding entry doesn't even mention it. Maybe I'll put it on my to-do list. For perspective, "medium" res was 128 x 96, "high" was 256 x 192. I was surprised to see that the O'Reilly Encyclopedia of Graphics File Formats (of which I was contributor and editor to the second edition) didn't even mention CIS RLE files. RLE is a common technique, so there's a chapter about RLE in general. You can certainly google a number of other references to RLE-based file formats from that decade (Utah Raster Toolkit, Wavefront .rla, etc.). GIF dates to 1987. I would guess RLE was at least three years older. - John

18 years, 12 months

The late, great TRS-80

by classiccmp＠memory-alpha.org.uk

Hi, > Why? The 8080 has all the processing functions on one chip. The >other chips used with it are the clock generator and bus interface >which IMHO are not processing functions.... I know you can get by without the clock/bus interface chips, but *technically* the 8080 is a 3 chip solution which, by his definition, makes it a mini.... I've also got a vague recollection that the F8 came in 2 seperate packages? I'm just saying, it isn't always quite as cut and dried as it might seem. BTW Although the 8080 can do without the bus interface chip, it does generate a number of fairly important control signals which you would otherwise have to latch and generate yourself "manually" as it were. As such I consider it an important, albeit external, part of the processor (as in, the only reason they made it external was because there weren't enough pins on the processor package to accommodate all the required signals). >> Likewise, would you consider a processor made from bit-slice devices >>to be a mini? > Actually, I would. Those chips are not only used to make that particular >processor. Sorry, bad example....I must've been suffering from severe brain-fade when I wrote that....I've got a mini downstairs, which I think contains a CPU made of bit-slice processors. D'Oh! What I specifically had in mind when I wrote that was the "mathbox" inside my Atari BattleZone (and now I come to think of it, the FPF11). Never mind... ;-) TTFN - Pete.

18 years, 12 months

Dialling up in 1982 (was Re: old modems (was Telephonyswitches))

by zmerch-cctalk＠30below.com

Rumor has it that Ethan Dicks may have mentioned these words: >(who never once did long-distance modem dialling, especially after >that first CIS bill) Ah, see, it was the opposite for me - Michigan's wide areas & weird laws (I'm guessing, IANAL ;-) made for strange bedfellows in the telecom industry... IIRC, my late-nite long-distance calling options when I was running 300baud on my CoCo2, in the '84-'86 time frame were (closest to farthest): Soo Canada, 2 miles away - IIRC, it was about $1.50+/min "Inter-LATA" calls (which for me, was anywhere in the Upper Peninsula of MI - the part most people think is either Wisconsin or Canada ;-) the closest connection being the city of Marquette 150 miles away, would be about $0.50-0.55/min, "Out of LATA" but still in Michigan (to the Lower Peninsula, "Land of the Trolls" [1] ;-) the closest being Traverse City, also about 150 miles away was around $0.75-0.80/min. Out of State calls depending on distance - Cali was much more expensive than Ohio, but Wisconsin was cheapest of all, so I called Green Bay, WI - 300+ miles (depending on how tired the crow was ;-) was around $0.35-0.40/min. So, for me, out of state was actually cheaper! Laterz, Roger "Merch" Merchberger [1] Until about 5 years ago, the Mackinac Bridge[2] was the longest single-span suspension bridge in the world, and really defines our area. Us'n yoopers (UPers) define "those that live below the Bridge" trolls... think "Three Billy Goats Gruff." It's a term of endearment. Really! ;-) [2] For those who like "Dirty Jobs with Mike Rowe" - he was just up here a week or two ago shooting a segment for a few days -- all about the constant (summertime, anyway) job of painting the steel segments of the bridge. -- Roger "Merch" Merchberger | "Profile, don't speculate." SysAdmin, Iceberg Computers | Daniel J. Bernstein zmerch at 30below.com |

18 years, 12 months

HP7202A Schematics questions

by wacarder＠earthlink.net

>> Can someone help me understand these old HP schematics? >> I see the 15 adapter pins shown at the top right of the >> page, and see where one of the pins (# 5) appears to go >> to something labeled EIA IN on the "Logic Mother Board" > >FWIW, 'EIA' was commonly used at that time (particularly by HP) to mean >what we'd normally call 'RS232; > >> section. Some pins (3, 4, and 6) appear to not be >> connected to anything. Most of the others seem to go >> to the Analog Mother Board, but I am not sure how to >> follow them from there. What would be nice is if I > >Given the one sheet of schemaatic that I've seen, you can't. You need >detailed schematics of the motherboards to trace the signals to pins on >the plugin cards (I assuem) and then scheamtics of the approprtiate cards >to see where they go in the 'real' electronics. > >Do you have that information? I have spent a little more time looking at the information that I have. My documentation does not include detailed board schematics. However, these boards do not look extremely complex. I have figured out how the pins on the interface are numbered. The top left pin is #1 and the second (lower) row contains pins 9 thru 15 (left to right). I have followed these wires from the adapter to the board, where they are connected. At the point of connection, there is a number like 901, 902, 905, etc. I also found a page in another manual that shows how to hook the interface cable to an ASR-33. It has an "in-line" molex style adapter. I need to look at that connector on the ASR33 and see how many wires it contains. Tony probably knows that answer off the top of his head. It's suppertime. I'll do more digging later. I also will photograph the boards that these wires run into on the plotter. Ashley http://www.woffordwitch.com

18 years, 12 months

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