Groups | Search | Server Info | Keyboard shortcuts | Login | Register

Groups > comp.sys.transputer > #448

Re: TRAM pin repair and B008 Examples/Test disk?

Show all headers | View raw

On Sunday, September 25, 2022 at 11:15:40 AM UTC+1, Mike B. wrote:
> Hi Tom!
> > The only issue I've found is that two of my T414B TRAMs, #3 and #6, report failures under rspy /T. It seems there's about a 50% chance that they'll fail.
> Can you please provide the rspy /i /tt 6 output of a failing run. 

Here it is: https://drive.google.com/file/d/1eOeTgTpCfy7RsuaY-FR9wrTTDLJ8OH_w/view?usp=sharing
This text is just the output to standard error: the summary printed to standard output is missing. There's nothing surprising there: it just says that TRAM 6 has failed.

> > One last oddity I've noticed is that rspy /ZMX fails with a single bit error for TRAM #3 during the first minutes that the computer is running.
> Interesting, because at the beginning the system should have a lower temperature. I observed non persistent ram failure only after a longer time. 

To me, this behaviour is consistent with bad contact between a pin and a socket somewhere. Let's say the T414B is not well-seated in the B403 TRAM. While the Transputer is cold, one of the pins lacks a good connection between the pin and the socket, but after a while the IC gets warm and the pin moves just slightly to where it makes good contact.

I think the thing to do to explore this hypothesis would be to remove the TRAM and reseat all of the chips in sockets (potentially also using contact cleaner), but I will wait until the problem gets worse before I do that.

> Please note: /M runs in parallel. If you specify /ZM your transputer system is using the external memory extensive (especially if the mtest on all modules takes approx. the same time). To do mtest more than once you can use /ZMI 100. But don't burn down your transputer system!

No worries, we never get that far. If I run rspy /i /zmi 12 (or any higher number), then the test always fails with "Fatal-rspy-memory allocation failed" when running mtest on node 8. Running rspy /i /zmi 11 always succeeds. Could this be an rspy bug? Perhaps it's not freeing memory that it should, and since I only have 640K in this AT, it can't fit that many tests.

Here is the standard error output from rspy /i /zmi 12:
https://drive.google.com/file/d/1v3Schw5avk8ewe-XqHz7xiwjXz-sZclO/view?usp=sharing

> I don't know if the TIS-ACWG (Transputer Instruction Set: A compiler writer's guide http://transputer.net/iset/pdf/tis-acwg.pdf) is really a good start but meanwhile it's my main reference book for assembler topics. 

ACWG would be an easier reference for me to use if it were searchable in my PDF viewer (which is just Firefox). The Roberts book supports ctrl-F and also lets me look up instructions alphabetically. But I'm really very happy to have all of these references thanks to your website --- each of them has had a valuable piece of information that I couldn't easily find elsewhere. There is no need to choose only one!

> To analyze a self-exploring and distributing parallel program may not be the easiest start. The 3L compiler has flood-fill support or even better use the icc/oc toolset and create such a program with a static processor mapping. 

That is true, but hopefully if I can crack this mystery and tweak the Mandelzoom source in just a few spots, I won't have to write the rest of the program!

I'm enjoying the reverse engineering a lot too. It's not very fast progress, but I've completely understood about half of SRESET.TAL, FLBOOT.TAL, and FLLOAD.TAL so far, and the places where I've been confused are ones where some study has helped me learn more about how Transputers work. My current mystery at the halfway point is this: FLBOOT.TAL is a worm where each instance sends a copy of itself to its downstream neighbours --- that's fine, I can see how it does that. But what happens if there's more than one route to a node, and a Transputer has two other Transputers trying to give it a copy of FLBOOT? I hope the answer to this mystery will teach me something new.

--Tom

Back to comp.sys.transputer | Previous | Next — Previous in thread | Next in thread | Find similar

Thread

TRAM pin repair and B008 Examples/Test disk? Tom Stepleton <stepleton@gmail.com> - 2022-09-05 17:38 -0700
  Re: TRAM pin repair and B008 Examples/Test disk? "Mike B." <michael_bruestle@yahoo.com> - 2022-09-12 11:36 -0700
    Re: TRAM pin repair and B008 Examples/Test disk? Tom Stepleton <stepleton@gmail.com> - 2022-09-12 14:01 -0700
    Re: TRAM pin repair and B008 Examples/Test disk? Tom Stepleton <stepleton@gmail.com> - 2022-09-12 16:47 -0700
      Re: TRAM pin repair and B008 Examples/Test disk? "Mike B." <michael_bruestle@yahoo.com> - 2022-09-13 06:38 -0700
        Re: TRAM pin repair and B008 Examples/Test disk? "Mike B." <michael_bruestle@yahoo.com> - 2022-09-13 06:57 -0700
          Re: TRAM pin repair and B008 Examples/Test disk? "Mike B." <michael_bruestle@yahoo.com> - 2022-09-14 23:15 -0700
            Re: TRAM pin repair and B008 Examples/Test disk? Tom Stepleton <stepleton@gmail.com> - 2022-09-15 15:24 -0700
              Re: TRAM pin repair and B008 Examples/Test disk? "Mike B." <michael_bruestle@yahoo.com> - 2022-09-19 01:01 -0700
                Re: TRAM pin repair and B008 Examples/Test disk? Tom Stepleton <stepleton@gmail.com> - 2022-09-19 08:48 -0700
                Re: TRAM pin repair and B008 Examples/Test disk? Tom Stepleton <stepleton@gmail.com> - 2022-09-19 09:23 -0700
                Re: TRAM pin repair and B008 Examples/Test disk? Tom Stepleton <stepleton@gmail.com> - 2022-09-19 09:26 -0700
                Re: TRAM pin repair and B008 Examples/Test disk? "Mike B." <michael_bruestle@yahoo.com> - 2022-09-21 23:17 -0700
                Re: TRAM pin repair and B008 Examples/Test disk? "Mike B." <michael_bruestle@yahoo.com> - 2022-09-21 23:23 -0700
                Re: TRAM pin repair and B008 Examples/Test disk? Tom Stepleton <stepleton@gmail.com> - 2022-09-22 13:30 -0700
                Re: TRAM pin repair and B008 Examples/Test disk? Tom Stepleton <stepleton@gmail.com> - 2022-09-22 16:38 -0700
                Re: TRAM pin repair and B008 Examples/Test disk? "Mike B." <michael_bruestle@yahoo.com> - 2022-09-23 05:30 -0700
                Re: TRAM pin repair and B008 Examples/Test disk? Tom Stepleton <stepleton@gmail.com> - 2022-09-23 16:33 -0700
                Re: TRAM pin repair and B008 Examples/Test disk? "Mike B." <michael_bruestle@yahoo.com> - 2022-09-24 06:05 -0700
                Re: TRAM pin repair and B008 Examples/Test disk? Tom Stepleton <stepleton@gmail.com> - 2022-09-24 16:29 -0700
                Re: TRAM pin repair and B008 Examples/Test disk? "Mike B." <michael_bruestle@yahoo.com> - 2022-09-25 03:15 -0700
                Re: TRAM pin repair and B008 Examples/Test disk? Tom Stepleton <stepleton@gmail.com> - 2022-09-25 14:30 -0700
                Re: TRAM pin repair and B008 Examples/Test disk? "Mike B." <michael_bruestle@yahoo.com> - 2022-09-26 00:20 -0700
                Re: TRAM pin repair and B008 Examples/Test disk? "Mike B." <michael_bruestle@yahoo.com> - 2022-09-26 07:21 -0700
                Re: TRAM pin repair and B008 Examples/Test disk? Tom Stepleton <stepleton@gmail.com> - 2022-09-26 13:42 -0700

csiph-web