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Question about UNIBUS terminators, M9300

by jnc＠mercury.lcs.mit.edu

> From: Bill Degnan > I have an M9300 bus terminator which I read is the same as a M930 with > the NPR logic (so you don't also need an NPR terminator in slot 3/4). Err, the M9300 would go in the same place as a M930, i.e. the UNIBUS in/out dual connector group, usually at the top (A/B connectors) of a slot in a backplane, in either the first or last slot _of the entire UNIBUS_. > I am thinking I can replace the M930 and G7273 in the last slot of my > backplane with a W2-open M9300. As a UNIBUS in/out dual-width device, the M9300 does not have separate 'grant in' and 'grant out' pins - just _one_ pin for the grant; the pin will function as 'in' _or_ 'out', depending on whether the card in question (of whatever type) is placed in the first or last slot of the UNIBUS. The dual-width G7273 goes in the middle connectors (C/D) of an SPC/MUD slot, to jumper both bus grants (BG4-BG7) and also NPG, all of which have both an 'in' and an 'out' pin in SPC/MUD slots (look at the G7273, you'll see 5 pairs of pins jumpered together - 1 set on one side, NPG; 4 sets on the other, BR4-BR7). So an M9300 cannot replace a G7273: it's intended for use in an entirely different kind of connector group. You might want to read the UNIBUS description in one of the earlier versions of the "PDP-11 Peripherals Handbook", which explains how the grants work: basically, they are daisy-chained through every device, so if a UNIBUS SPC/MUD backplane (which can hold a UNIBUS device in every slot) has a slot which does not contain a device, you have to put something with grant jumpers in instead. Whether the jumper need to be BG4-BG7 _only_ (the little small grant jumper cards), or a G7273 (which _also_ jumpers NPG) depends on whether _that particular slot_ has had its NPG jumper (wirewrap on the backplane) pulled, or not - most backplanes come with jumpers on NPG on all slots, and you have to remove the jumper if a device uses DMA. (In the early days, most did not, which is why that was the default.) > There are jumpers on this card. W1, W2, W. I did not find any specific > examples online of scenarios for the jumpers > ... > I think I get why one would remove the W2 jumper but if W1 is removed > (open) instead can someone give me an example scenario for when you'd > want to use this card "for beginning of non processor bus termination". > Can someone give me an example of when you'd do this? The device the M9300 was invented for was probably the RH11-AB, which is where one most often finds them. The RH11 is an UNIBUS device which is a MASSBUS controller; the RH11-AB has connectors for _two_ UNIBI (so one RH11-AB can be 'in' two PDP-11's at the same time; i.e. all the devices connected to that controller can be accessed from either machine). If it's only connected to a single CPU, though, what does one do with the second UNIBUS? That's where the M9300 comes in. It simulated the NPG-granting section of a CPU, and when jumpered to do that, it goes at the _start_ of a UNIBUS - e.g. the second UNIBUS in the RH11-AB. (Leave all the jumpers in, and it functions like an M930, and can go at either end). You can find a description of its use in the RH11-AB, as well as a description of how the M9300 works, in the "RH11-AB Option Description" document (available online), starting on page 4-32. I can't conceive of any use for one in most PDP-11's, though (outside an RH11-AB, of course). Noel

10 years

BBC Tube... Running UNIX?

by aaron＠aaronsplace.co.uk

I just revisited the Wikipedia page for the BBC Micro Tube [1]. Apparently with a 32bit NS320 processor it was possible to run some variant of UNIX? Does anyone know anything about this? I'd be very interested in experimenting with it, if it is true. Thanks, Aaron [1] https://en.wikipedia.org/wiki/Tube_(BBC_Micro)

10 years

VAX 4000 model 500.

by rodsmallwood52＠btinternet.com

Hi My main system a VAX 4000 Model 500 with a KA680 CPU has just started halting at test 51 on power up. Does any body know where I can lay my hands on a spare KA680? Rod

10 years

Early 360 machines (Was: Front panel switches - what did they do?)

by jnc＠mercury.lcs.mit.edu

> From: Jon Elson > the /20 was intended for very specific uses in 360 shops, and maybe as > an entry-level "foot in the door" to move totally tab card shops into > the 360 family. The only /20s I ever saw were used as offline spool > printers and card readers in large 360 shops. I interned at IBM Bermuda, and they had a 360/20 as their main service bureau machine; it had (IIRC) a card reader/punch, 4 tape drives, and a 4301 printer. When I got there, they had just gotten in a System 3 (two single-platter hard drives, a 4301 printer, and I'm not sure what else) to replace it. Noel

10 years

IBM1130 (was RE: Front panel switches - what did they do?)

by dave.g4ugm＠gmail.com

paths. > > Do you mean the 360/20? On the topic, were the 20 and 40 the only members > of System 360 to use TROS? > > I remember picking up the programming manual for a Model 20 and realizing > that I'd essentially have to re-learn programming. 16 bit registers, stripped- > down instruction set, no I/O channels, "substitute" > instructions for regular 360 fare. > > A really strange thing was that the 1130 came out *after* the 360/20. > I am not sure why IBM produced an in-compatible machine so soon after 360 was announced, but it was sold in a completely different way to a new and emerging market. It was billed as the cheapest computer IBM had ever offered. The announcement letter here:- https://www-03.ibm.com/ibm/history/exhibits/1130/1130_initial.html is dated almost exactly one month before DEC announced the PDP-8 and I am sure targets the same markets DEC did. You just wonder if IBM had spies in DEC, or more likely they both spotted a marketing opportunity. It is also interesting to note a "typical" configuration was priced at almost twice that of the PDP-8.. (assuming Wikipedia is right) https://en.wikipedia.org/wiki/PDP-8 I don't have any links but I know in the UK IBM1130's were used on ships by the Institute of Oceanographic Sciences but I can't find any reference to that on-line. I was told that they had great trouble getting the IBM engineers who worked on it that a suite was not suitable dress for a small research vessel. Dave G4UGM > --Chuck > > Dave G4UGM

10 years

Question about UNIBUS terminators, M9300

by billdegnan＠gmail.com

I have an M9300 bus terminator which I read is the same as a M930 with the NPR logic (so you don't also need an NPR terminator in slot 3/4). I don't want to blow anything up, but I am thinking I can replace the M930 and G7273 in the last slot of my backplane with a W2-open M9300. I have discovered past threads in CCTECH about this card, comes up every so often. There are jumpers on this card. W1, W2, W. I did not find any specific examples online of scenarios for the jumpers so I have a question of confirmation to my understanding: I think I get why one would remove the W2 jumper but if W1 is removed (open) instead can someone give me an example scenario for when you'd want to use this card "for beginning of non processor bus termination". Can someone give me an example of when you'd do this? Something to do with expansion cabinets? b --

10 years

Using a Commodore 1541 drive with a PC via USB

by jws＠jwsss.com

A fellow has made up a nice adapter to read and write Commodore disks on a PC via USB using a 1541 drive. The thing that jumped out at me is that this is a 5 1/4" drive that reads and writes via USB. Anyone want to comment on whether the floppies it accesses would be useful other than on the C64? Could one do say 360K floppies via this hardware for other than the Commodore? At least part of the work is done to do more than just archival like Catweasel, et. al. do, in that it can also write. XU1541-interface-connect-your-C-drive-to-PC-enclosed-version-NEW/ http://www.ebay.com/itm/322092922596 Thanks Jim

10 years

HP Visualize B132 PA-RISC workstation FREE for pickup BNE Australia

by pye＠mactec.com.au

Worked a couple of years ago, but now won?t power up. Chris

10 years

VAX-11/730 and Emulex UC17 woes

by JoshD＠LivingComputerMuseum.org

Hi all -- I'm working on restoring a VAX-11/730 at the museum and things have been going pretty well thus far. I've been bootstrapping the console and diagnostics from simulated TU58 (images from: https://github.com/NF6X/VAX-11-730-Console-v57). All of the TU58-based diagnostics are passing. I'm attempting to bring up an Emulex UC17 SCSI controller for mass storage and I'm having trouble with it. I thought I'd check with you guys to see if any of you have seen this issue or have any idea where I might be obviously going wrong before I start digging deeper into this. The current issue is that I can't get the UC17's built in diagnostic/utility (referred to as the 'FRD' in the manual) to run. I am following all of the steps to the letter (see the manual here http://www.mirrorservice.org/sites/www.bitsavers.org/pdf/emulex/UC1751001-C…, pages 71-79 (section 4.5.7)) and I'm getting the right values back when examining the SA register during the process, but executing "S 80" halts after a second or so with: ?08 PC=00000298 Which is an odd way for it to halt, 08 means "No user WCS" according to the 11/730 user's guide. Here's the full conversation, just in case: >>> I >>> D/L/P F26800 80000000 >>> D/L/P F26804 80000001 >>> D/W/P FFF46A 3003 >>> E/W/P FFF46A P 00FFF46A 0100 >>> D/W/P FFF46A 4401 >>> E/W/P FFF46A P 00FFF46A 0400 >>> S 80 ?08 PC=00000298 I've confirmed that the issue isn't with the card, I can run the FRD without issue on it, in an 11/44 we have here. I've done my best to ensure that everything is sane on the UNIBUS; my understanding from the 11/730 manuals is that by default none of the SPC slots have the NPG wire-wrap fitted and that any empty SPC slots need to have an NPG grant card installed. (This makes sense given how difficult the backplane is to access, it requires pulling the power supply out first.) Just to make sure, I have double-checked that the NPG wirewrap jumper is not present on Slot 10, where the UC17 is installed. At the moment the grant chain should be unbroken as far as I can tell, here is the current configuration: TOP Slot 1 - Empty (normally RB730 option) Slot 2- Empty (normally FPA option) Slot 3- M8390 (DAP) Slot 4- M8391 (MCT) Slot 5- M8394 (WCS) Slot 6- M8750 (1mb memory) Slot 7- M8750 (1mb memory) Slot 8- M8750 (1mb memory) Slot 9- M8750 (1mb memory) Slot 10- Emulex UC17 Slot 11- DMF32-AA Slot 12- M9302 terminator | G7273 grant BOTTOM Thanks as always for the help. - Josh

10 years

Board swapping (was Re: General Question about UNIBUS backplanes)

by abs＠absd.org

On 24 May 2016 4:45 pm, "Ethan Dicks" <ethan.dicks at gmail.com> wrote: > > On Tue, May 24, 2016 at 11:36 AM, william degnan <billdegnan at gmail.com> wrote: > > On Tue, May 24, 2016 at 11:17 AM, js at cimmeri.com <js at cimmeri.com> wrote: > >> B, what was the issue with the core, that you fixed it so fast? > > > > I guessed that the G114 was bad based on a hunch. > > > > I had a spare. > > Q. How do you know the guy on the side of the highway with a flat tire > is a DEC Field Service Engineer? > > A. He's swapping out all the tires to see which one is flat. > > (or from net.jokes in 1981... > https://groups.google.com/forum/#!topic/net.jokes/GQ2B6HZIY_4 ) > > The way I heard it was: > How do you tell if a man with a flat tire is a DEC Field Service Rep? > Look in the trunk; if he's from DEC F.S. he'll have three spares with little > red tags on them and no jack. My favourite at the time was: Q: How does DEC Field Circus deal with a flat tyre? A: Swap the wheels one by one until the issue is resolved. Q: How does DEC Field Circus deal with a flat battery? A: Swap the wheels one by one until the issue is resolved. :)

10 years

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