test-drb December 2016

test-drb@ccmp.vtda.org

156 participants
199 discussions

Clone of 98228A ROM for 9825T information posted.

by phb.hfx＠gmail.com

I have posted a package of information and ROM images from my project to clone the 98228A ROM on the VintHPcom group at groups.io. Progress on laying out a PCB is going slowly as I have little experience and the learning curve for using Kicad to lay out a board seems pretty steep. Paul. Hello, This email message is a notification to let you know that a file has been uploaded to the Files area of the VintHPcom at groups.io group. *File:* 98228A.zip *Uploaded By:* Paul Berger *Description:* Package with information and ROM images from my project to clone the rare 98228A ROM that supports both 9885 and 9895 8" diskette drives. You can access this file at the URL: https://groups.io/g/VintHPcom/files/HP9825/98228A.zip Cheers, The Groups.io Team _._,_._,_ ------------------------------------------------------------------------

7 years, 4 months

Holiday wishes

by c.murray.mccullough＠gmail.com

?All I want for Christmas is? a PC diagram for my Coleco ADAM; with apologies to Don Gardner(1946). Wishing all the best of the holiday season and may 2017 bring all your computing classic dreams come true. Happy computing, Murray :)

7 years, 4 months

PDP-6s at MIT

by jnc＠mercury.lcs.mit.edu

> From: Johnny Eriksson > From the KI10 and onwards it includes PXCT, since these have the > concept of a previous context... > Given a pager for the KA10 PXCT would make sense there. It turns out the KA ITS machines have an instruction that does roughly the same thing, but it's different. Here's the relevant code fragment from SYSTEM;ITS >: IFN KA10P,[ SUBTTL STUFF PECULIAR TO KA-10 PROCESSOR ;;;PAGING BOX INSTRUCTIONS LPM=102000,, ;LOAD PG MEM STATE VECTOR DONT CLR ASSOC MEM LPMR= LPM 2, ;CLEAR ASSOC MEM AND LOAD SPM= LPM 1, ;STORE PG MEM STATE VECTOR LPMRI=LPM 6, ;LOAD PM, CLEAR ASSOC REG, AND CAUSE INTERRUPT EXPGNG==4 .SEE UPQUAN ;4 TO TURN ON EXEC PAGING XCTR=103000,, ;EXECUTE INSTRUCTION WITH MAPPING CONTROLLED BY AC FIELD ;VIOLATION CAUSES USER MEM PROTECT INTERRUPT UNLESS INHIBITED ;VIOLATION ALSO SKIPS BUT THIS IS OF NO CONSEQUENCE UNLESS ;INTERRUPT IS INHIBITED SINCE PC WILL BE RESET FROM OPC XCTRI= XCTR 4, ;XCTR WITH PAGE FAULT INHIBITED (SKIPS ON FAULT) ; AC FIELD VALUES FOR XCTR AND XCTRI XR==1 ;MAP READ MAIN OPERAND OF SIMPLE INSTRUCTION (MOVE, SKIPL, HLL) XW==2 ;MAP WRITE MAIN OPERAND OF SIMPLE INSTRUCTION (MOVEM) XRW==3 ;MAP READ/WRITE OPERAND OF SIMPLE INSTRUCTION (E.G. IORM) XBYTE==3 ;MAP BYTE DATA AND BYTE POINTER (ILDB, IDPB) XBR==1 ;MAP BLT READ XBW==2 ;MAP BLT WRITE XBRW==3 ;MAP BOTH OPERANDS OF BLT ;KA10 PAGING BOX GOES BY WHETHER IT'S A READ OR WRITE (OR RW) CYCLE ;KL10 PAGING BOX WORKS DIFFERENTLY (SEE BELOW) ;DO NOT USE MULTI-OPERAND INSTRUCTIONS (DMOVE, PUSH, ETC.) WITH XCTR The KL and KS are both different (although both use XCTR and XCTRI); the KL stuff is later down in that file; the special KS instructions are in KSHACK;KSDEFS > if anyone wants to look at them. Noel

7 years, 4 months

ADM-3A Lower case ROM issue

by shatle＠nfldinet.com

-------- Original Message -------- Subject: Re: ADM-3A Lower case ROM issue From: "Ian S. King" Date: Wed, December 14, 2016 1:30 am To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> Take a look at the silk screen on the board - ISTR there's another chip that needs to be added, some simple TTL logic. I converted mine several years ago without problems - but that was with the original ROM. -- Ian S. King, MSIS, MSCS, Ph.D. Candidate -- Just as a follow-up - I got the two RAM ICs that were missing (2102 1K RAM), and installed those along with the lower-case ROM, and everything now works great. Thanks everyone for your expertise and tips! Steve

7 years, 4 months

PDP-6s at MIT

by bygg＠cafax.se

> Did the original KA10 have XCT too? XCT is present in all PDP-10 processors. From the KI10 and onwards it includes PXCT, since these have the concept of a previous context... Given a pager for the KA10 PXCT would make sense there. > Noel --Johnny

7 years, 4 months

PDP-6s at MIT

by jnc＠mercury.lcs.mit.edu

> From: Lars Brinkhoff > Does anyone know more about this PDP-6? Did it ever run ITS, like its > PDP-10 successor? I don't know about the software run on the two PDP-6's - by the time I arrived at MIT, they were both powered off and never, as far as I know, ever ran again. I would _assume_ that it ran ITS. I don't recall if the physical remains stayed until the KA's were de-commissioned, or of they were removed prior to that - I suspect they stayed, since they were mixed in with the KA's - in the case of AI at least, wired in together - but don't remember exactly. I don't recall if the I/O bus was shared between the two CPUs on the DM machines, the way it was on the AI KA and PDP-6. The DM PDP-6 was part of the DM KA 'assembly' - DM was in two rows (front and back) to the right of the right-hand door from the lobby into the machine room. IIRC, the PDP-6 was in the front row, to the right? of the KA CPU. (The back row contained memory boxes - a mix of different DEC memories. I don't recall where the tape and disk controllers were - or the disk drives. I seem to vaguely recall a few boxes to the left of the KA CPU? Maybe there are some pictures of the MAC machine room that will show it.) Noel

7 years, 4 months

by witchy＠binarydinosaurs.co.uk

Hi folks, I have an 8085-based viewdata telephone system on the bench that's proving to be a labour of love in trying to get it running with zero documentation - there are only 6 known examples that I've come across and all but 2 of them are in museums, none known to work. If any of you fancy searching it's an STC Executel 3910 and at least two of the hits you'll get will be my machine before I bought it. http://www.binarydinosaurs.co.uk/stcexecutel01.jpg I've been in contact with all museums who have one, no luck on docs though the Museum of Computing which is local to me MAY have some (Jason the owner has 2 3910s himself), I just need to get down there and search for it :) Kind-of-fortunately the viewdata side of things seems standard - all 74LS TTL with an MC3242AP running 16x 4116-2 DRAMs, 27128 EEPROMs etc. The viewdata side of things is powered by a Plessey MR9735-002 teletext processor supported by a pair of 2112 RAM chips and an SAA5070 "LUCY". http://txlib.mb21.co.uk/main.php?g2_view=core.DownloadItem&g2_itemId=2034 ROM selection is done by a PAL but my EEPROM reader has verified that's OK and I have a dump of it as well as all the ROMs. Unfortunately it's suffered battery leakage and it was seemingly stored on its back in a very damp environment so some of the capacitors at the rear of the board have rotted and bits of the analogue board for the 5" TV had rusted to nothing, though I've replaced those. What I originally thought was an analogue board issue that I posted about here has turned into a total lack of timing issue so I've been tracing out all the circuits and building a schematic of the board. All was well until I came to the two chips you can see in the centre of this pic that have no markings (9B and 10B on the board): http://www.binarydinosaurs.co.uk/stcexecuteltimingcircuits.jpg They aren't 'standard' 14-pin DIPs in that they don't follow the GND-on-pin-7-Vcc-on-pin-14 layout. Pins 6 and 7 on both are wired together (not to GND) and form the RESET signal for the 8085 via the 7414 at 10A, source for this signal is unknown currently. Pin 5 on both appears to be Vcc and pin 10 is GND or at least are pulled high and low respectively. The XTAL you can see with its supporting resistors is connected to the 7404 at 12B, pin 12 of which goes to pin 1 of 10B (one of the mystery chips) and pin 1 (X1) of the 8085. Any clues? I'm going to search for reference 8085 boards (and I guess 8086?) layouts to see if there are any similarities in timing circuits but for now I'm stumped. Cheers! -- Adrian/Witchy Binary Dinosaurs creator/curator Www.binarydinosaurs.co.uk - the UK's biggest private home computer collection?

7 years, 4 months

Motorola MC14081B

by witchy＠binarydinosaurs.co.uk

Evening folks, (it's evening here) Typically for troubleshooting around $FESTIVAL I find a more-than-likely dead MC14081B (CMOS quad dual-input AND gates) just as UK postage ends for the next few days so getting a replacement won't happen until next week. Question is, aside from having to make up an adapter board to change the pins around and making sure Vcc is +5V is there any reason I can't use something like a 74LS08 for testing? One of the outputs is RESET for an 8085A so nothing too demanding. (I might have a CD4081B somewhere too, which is pin compatible according to the datasheet) Cheers, -- Adrian/Witchy Binary Dinosaurs creator/curator Www.binarydinosaurs.co.uk - the UK's biggest private home computer collection?

7 years, 4 months

Late 90s Macintosh systems available to So Cal

by tosteve＠yahoo.com

I have a small pile of late 90s Macintosh systems available for someone to pick-up in 92656. Performa 6400/100 tower Some PowerBooks - 3400, 5300, 7630 Also boxes of cables and software. LaserWriter 4/600P Makes a great Christmas present! Thanks- Steve.

7 years, 4 months

Wanted Dead or Alive: Tadpole N40

by ian.finder＠gmail.com

Been having a baaaad month for hardware longevity. Lots of systems have died in 2016... A miserable year. Just took my only two Tadpole N40s out of cold storage and both are having some serious issues, stopping at 260 post code, no video, no status LCD, etc. If I had one more system, I'm sure I could get one running. If you have an N40 for sale, or that you'd consider selling, please ping me. I'd love to pay you for it :) Thanks, - Ian -- Ian Finder (206) 395-MIPS ian.finder at gmail.com

7 years, 4 months

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test-drb December 2016