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Backups

by rodsmallwood52＠btinternet.com

Is it my imagination or do backups not get mentioned these days? Rod Smallwood

9 years, 9 months

beige rant (was Re: IBM 5150 with red case on ebay)

by jnc＠mercury.lcs.mit.edu

> From: Chuck Guzis > Styles change. And like women's hem-lines, they eventually work their way back to a previous generations' (now semi-forgotten) style. I remember being amused when black became the 'new' 'cool colour' for PC's; back to the era of KA10's and early PDP-11's!! Noel

9 years, 9 months

11/83 RQDX3 RD-53 Jumpers

by rodsmallwood52＠btinternet.com

Hi Does anybody know the jumper settings on a RD-53 on an 11/83 with an RQDX3 controller and an RX50 Rod

9 years, 9 months

PDP-11

by jnc＠mercury.lcs.mit.edu

> From: Dave Wade > Cards are > M7264 11/03 processor with 4-Kword MOS RAM > M7940 > M9400ye DLV11 Serial Line Unit (system cosole) REV11-E (240-ohm terminators for Q18) QBUS termination is a complex subject; when you have multiple backplane sections, connected by cables, each section has 'termination'. That's what this REV11-E card is; it's also the QBUS 'out' to the card in the 780 CPU which the console -11 uses to control the /780 CPU. Why it's in the middle slot, I'm not sure (unless things have been moved around)? > M8044ee > m7946 MSV11-?? (My list doesn't contain an '-EE', but it's some sort of small MOS memory, Q18) RXV11 (RX01 8" floppy disk controller) In theory, the M8044-EE should be an "MSV11-DE" (not "MSV11-EE", that would be an M8045-EE), but none of my documentation, including the M8044 prints, covers such a variant. Maybe I need to look in the /780 prints, it may be a special variant for use in the /780 console machines. > M8192 LSI-11/73 CPU; a nice machine, if you can eventually get it running. You'll want a bunch more memory (note that the M8044/8045 cards are Q18, and so you can only have up to 256KB with them - they _WILL NOT WORK_ in a system with more than 256KB in it). > Also have loose grant card.... You mean an M9047? I would start with just the 11/03 CPU and the console card; hook it up to something, and see if you can get it to talk to the console. (Configure the CPU to halt, and fall into Console ODT, on power-on.) It's probably worth getting one of the various LSI-11 CPU handbooks: Microcomputer Handbook (1976-77) Microcomputer Processors (1978-79) Microcomputer Processor Handbook (1979-80) Microcomputers and Memories Handbook (1981) Microcomputers and Memories Handbook (1982) they all cover the quad-width 11/03 CPU. Although they're probably available online, it's very handy to have a hard-copy one; those are available on eBay and such. That backplane is probably a so-called 'serpentine' backplane, i.e. ones in which the (dual) slots are numbered: 1 2 4 3 5 6 8 7 so the console would need to go in '3' if it's the only card other than the CPU (at least, if you want it to be able to do interrupts). Once you get it working in that configuration, you can configure and add the memory card (if you can figure out what the devil it is ;-). And then the RX01 controller. The REV-11 isn't needed in this configuration. The boot PROM for this machine was actually on the card in the /780 CPU, so eventually you'll need a replacement - something like a BDV11 or something (they are available, and not too expensive). > From: Robert Jarratt > The seller said it was indeed out of a 780. Yeah, that's what it looks like. > I got the impression the 11/23 card was just a spare he had that he put > in the enclosure, not really part of the original system. Actually, an 11/73, but yes, definitely not part of the original system. I don't know if it will work in that backplane without the backplane being upgraded from Q18; it might, but that would need some investigation. Noel

9 years, 9 months

Replacement for a Corcom F2987A EMI Filter

by robert.jarratt＠ntlworld.com

I have two failed Corcom filters in two DEC Rainbows. I see some spares available in the US, but shipping to the UK is likely to be prohibitive and I would like if possible to find a modern equivalent. It is this one: http://meci.com/corcom-12-20129-01-emi-line-filter-model-f2987a.html. I am told it isn't enough to know the current rating (2A at 240V) and that it you need to know the source impedance (and the impedance of the load?). Does anyone know the spec for this filter so that I can get a suitable one? Incidentally, when I fix these PSUs, I may be wanting to pass on one of the Rainbows. In this case it would not be free because I had to pay for it (and drive a fair distance to get it too). The one I may pass on is in a vertical pedestal. I may also have a third one to pass on which has a fault on the system board, I don't have a logic analyser capable of helping me to find the fault though. Thanks Rob

9 years, 9 months

Tape reader

by jws＠jwsss.com

Does anyone here know how to order this device? It seems to still possibly be offered, but I am not sure how to order it. I'm not sure if the person is on the list, if so you can reply off list. Looked for faq or shopping or buy pointer, didn't find one. thanks JIm http://retropcdesign.com/forums/showthread.php?threadid=6

9 years, 9 months

Hex file formats (Was: PDP11 M9301-Yx ROM dumps)

by cctalk＠beyondthepale.ie

Pete Turnbull wrote: > On 12/05/2016 22:17, Noel Chiappa wrote: > > > From: Mattis Lind > > > > You don't have a dump of the PROMs in Intel HEX? > > > > No, but I do have a un-annotated dump in octal. Can you point me at a > > description of Intel HEX format, so I can whip up a converter program? (Which > > will also take an array of PDP-11 words, and split it up into the 4 different > > ROM chips, since each word is spread across all 4 chips.) I already have a > > program to read my octal dump things, so I'll just have to tweak that a bit. > > Take a look at http://www.dunnington.info/public/IntelHEX > There's a description and also some code you could adapt. > Does anyone recognise this hex file format from anywhere? #00002110F01140007D6C62B70608&2F #000CED52300119&4A #00113FCB1287ED6A87ED6A10F076&E4 $ As far as I can tell, the first four hex digits is a 16 bit address, followed by up to 48 hex digit pairs of data and the hex digit pair after & is a checksum. The $ appears to be an end of file marker. It came from a Z80 cross assembler which ran on VAX/VMS. Searching for information about it has turned up very little except for a reference on the DECUS website to: V00250 UCAMS: Universal Cross-Assembler for Microprocessors Version: February 1987 however, I don't think this is it. Does anyone have a better description of the file format or anything that might have produced it? Regards, Peter Coghlan

9 years, 9 months

PDP11 M9301-Yx ROM dumps

by jnc＠mercury.lcs.mit.edu

Re: PDP11 M9301-Yx ROM dumps > From: Mattis Lind > I checked the contents in the machine versus your listing. And now that I think of it, I wonder if the ROM in the board I dumped had any errors? I have two, I should dump the other one and compare - but I forget which one I dumped, and I fried one of them! :-( The board did 'work', but I only used the console emulator, and the serial line loader, so there might be an error elsewhere (e.g. in one of the disk bootstraps). > Two locations have the high bit set for some reason, 165020 read 100501 > and 165032 reads 106303. Well, the second is definitely wrong; not sure about the first, I'd have to figure out what it's doing with that data word. > Trying to run halts the machine with 165102 in the front panel. That's odd, that doesn't make any sense. > Single stepping it it will step to 165106 but become non-responsive > with the lights at 165106. Hmm, does that mean that it actually froze at 165102, or at 165106? (I.e. is the display the address of the current instruction, or the next one?) > I think this is because it had a bus fault. That shouldn't freeze the machine - unless you had a double bus fault (i.e. trying to push and old PS/PC, and the SP is gubbish). Try loading the SP with the address of some working memory before you start the test, and see what happens. You might also deposit 6/0/12/0 in locations 4-12, so that if it does see an illegal instruction or NXM, it will just halt. > So for now, it is not necessary with more disassembly. Unless you have > som spare time of course. Well, I'll keep working on it anyway. > You don't have a dump of the PROMs in Intel HEX? No, but I do have a un-annotated dump in octal. Can you point me at a description of Intel HEX format, so I can whip up a converter program? (Which will also take an array of PDP-11 words, and split it up into the 4 different ROM chips, since each word is spread across all 4 chips.) I already have a program to read my octal dump things, so I'll just have to tweak that a bit. I'm going to need to start blowing ROMs soon (including some sets of 9301-YF PROMs, for the one I zorched), once I get my 29B hooked up, so I might as well start with this... Noel

9 years, 9 months

PDP-11 (Josh Dersch)

by michael.99.thompson＠gmail.com

> > Date: Wed, 11 May 2016 14:27:49 -0700 > From: Josh Dersch <derschjo at gmail.com> > Subject: Re: PDP-11 > > > The 8{3|5}50s our biggest customer used had Pro380 VAX CONSOLES, I > remember > > our main menu system looked odd on them since they had a bitmapped > display. > > I've still got one of them I think, can't remember the last time I > powered > > it up but I'm pretty sure it was running TSX-11. > > > > While we're on that subject -- > > I have a friend locally with an 8550 that's missing the console Pro-380 > system; if anyone happens to have one (with the appropriate VAX interface > hardware) drop me a line... > > - Josh > Josh, I donated a Pro-380 VAX console to the RCS/RI crew about 15 years ago. They probably still have it. -- Michael Thompson

9 years, 9 months

PDP11 M9301-Yx ROM dumps

by jnc＠mercury.lcs.mit.edu

> From: Mattis Lind > I also have a YF card. ... I could access the contents but it didn't > run very well. So either the CPU is still bad or the PROM contents are > bad. Could you please direct me to your YF dumps so I could compare? They are on my "Miscellaneous Digital Equipment Corporation PDP-11 Information" page: http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/PDP-11_Stuff.html in the "ROM Dumps" section. > If you also have done a disassembly that would be very interesting. I haven't completely disassembled the -YF version, but the -YA is almost all done, so it should help. Let me know if you need to have the -YF fully disassmbled & commented, and I'll hop to it. Noel

9 years, 9 months

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