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Thread: Understanding the DEC BIN Loader program

  1. #21
    Join Date
    Jun 2012
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    UK - Worcester
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    I rather suspect that the TTU may 'eat up' your leader and trailer.

    There appears to be two (2) different versions of the TTY driver - one definitely cannot be used with BINARY data (it says so). The other is not as definitive...

    I suspect you should be using the paper tape punch device rather than the TTY - but then (if you only have a teletype equipped with a paper tape reader and punch) what would you do?

    Probably starting to get out of my field of expertise for the time being...

    Dave

    EDIT: Found this web page for adding the PTR to your OS/8 system build (if it doesn't have it) https://bigdanzblog.wordpress.com/20...ptp-installed/. The '^' referred to on the web page is OS/8 telling the operator to start the tape (I think)...

  2. #22
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    Dec 2013
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    Dave, thanks for the replies. I agree with your explanation of the blocks. At first I think I was confusing these blocks with memory blocks or something to do with addressing. I think I have that now. I have wondered off, from my original question some distance, but will track back as I learn. This all started out with attempting to get my Remex tape reader to work. In this thread I wanted to understand the DEC BIN LOADER (having successfully made a new RIM loader that works with the Remex) so that I could write a new BIN loader that would also work with my Remex. When deciphering the DEC BIN, I was confused with what looks like a section of code that looks at what memory field the code should be loader into. So I started to look for what I figured that was in my MAINDEC file code. In doing so, I realized that I didn't know how to make a BN paper tape file. That led to trying a few things, PIP etal. Currently the task is to become familiar with this DEC BINARY PUNCH program.

    Today, I made a paper tape (using the IBM XT to TTY) that has first the DEC BIN LOADER followed by the DEC BINARY PUNCH program. I then loader the DEC RIM LOADER and read in the DEC BIN LOADER from this tape via the TTY 33ASR. I checked the code in memory and it was correct. So I started up the BIN LOADER and read in the BINARY PUNCH program. Again I checked the code in memory and it matched the listing. Optimistically, I started the BINARY PUNCH program with the intention of saving anything that was in memory from 0200 to 0300. The program started and a long leader was punched and the PDP8 halted. So far so good. I set the SR to one and hit continue. The TTY then punched the same 3 or 4 values over and over. I checked the code and found an error in the listing. After fixing the error, Tried the program again this time all that punched was a leader. This time I looked over the code listing more carefully and found a couple typos in the document and two code errors in the file. This time the program was going to work. Fired her up and as I entering the address, the TTY failed. Looks like a power supply problem, every thing was out. So one step forward and two steps back. Hopefully once the TTY is repaired, I can get back to the program. Thanks Mike

  3. #23
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    Dec 2013
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    Near Milwaukee Wisconsin
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    Looks like the power transistor that drives the selector magnet of my TTY ASR33 gave up the ghost. Ordered a new one and have to wait for it to show up in the mail. Mike

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