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Using 2SIO to download BASIC into an Alair without a disk drive or cassette.

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  • B Degnan
    ... I have been using the Altair 8800b. I have tried a number of RAM cards and the 2SIO seems OK, at least it handles the echo program without issue. I can
    Message 1 of 15 , Feb 25, 2010
      Dan Roganti wrote:
      Bill,

      uh oh, one of the 2SIO cards is still causing problems ?

      I'm not sure how much info you have there for loading Basic
      But here's a nice tutorial on bootloaders.
      http://www.solivant.com/altair_bootloaders/index.php?album=altair_bootloaders&pagen=0

      Here's the source listing for the MBL in case you don't have it.
      http://www.solivant.com/altair_bootloaders/misc/mbl.asm



      I have been using the Altair 8800b.  I have tried a number of RAM cards and the 2SIO seems OK, at least it handles the echo program without issue.  I can write to every page in RAM and I use only cards compatible with a front panel system.  I have 4 16K RAM cards installed. 

      When downloading the tape image containing the 2nd loader and BASIC, I get to about the 1300th byte , the computer bombs.  I am using sense switches 10 and 11.   I have tried reducing the speed at which the file is downloaded, the SIO is set to use 9600/8/1.  Etc.  I am following all of the solivant.com's page in detail.

      I am going to try another computer, the IMSAI 8080 may be better.

      Bill
    • Dan Roganti
      ... Just checking if your terminator card is plugged in ? If it is, it could still be acting up. Maybe if you run a memory tests on with all the Ram cards
      Message 2 of 15 , Feb 26, 2010
        --- In midatlanticretro@yahoogroups.com, B Degnan <billdeg@...> wrote:

        > I have been using the Altair 8800b. I have tried a number of RAM
        > cards and the 2SIO seems OK, at least it handles the echo program
        > without
        > issue. I can write to every page in RAM and I use only cards
        >compatible with a front panel system. I have 4 16K RAM cards
        >installed.
        >
        > When downloading the tape image containing the 2nd loader and
        >BASIC, I get to about the 1300th byte , the computer bombs. I am
        >using sense switches 10 and 11. I have tried reducing the speed at
        >which the file is downloaded, the SIO is set to use 9600/8/1.
        >Etc. I am following all of the solivant.com's page in detail.
        >
        > I am going to try another computer, the IMSAI 8080 may be better.
        >


        Just checking if your terminator card is plugged in ?
        If it is, it could still be acting up.

        Maybe if you run a memory tests on with all the Ram cards plugged in you might find some flaky memory chips.

        Even some suspicious memory location could be corrupted by the terminator card during this test.

        =Dan
      • Bob Applegate
        ... Whoa! Run a real memory test! I m assuming the memory is static, but there are lots of different kinds of tests that look for refresh problems on dynamic
        Message 3 of 15 , Feb 26, 2010
          Bill Degnan <billdeg@...> wrote :


          > I am not using a terminator.
          > My memory tests so far have all been manual read/write/read tests at each
          > page location 0000, 1000 - F000. I have swapped RAM cards into a number of
          > configurations, and I usually get the same result. It's possible that my
          > laptop serial port is not right? Not sure yet.
          > cd

          Whoa! Run a real memory test! I'm assuming the memory is static, but there are lots of different kinds of tests that look for refresh problems on dynamic memory, as well as shorted address/data bits, bad bits in chips, etc. You wouldn't believe how many memory problems slip through because of tests that don't run sufficiently complex algorithms.

          I'd also test one board at a time, or at least pull boards you don't need. You've got four 16K boards, right? Pull all but one and check the portion not used by the test code. Once it seems to work, put in another board and test all 16K of it using a really good (extensive) memory test. Now you've got a "golden board" that is known, or at least presumed, to be good.

          Bob


          ___________________________________
          NOCC, http://nocc.sourceforge.net
        • Bill Degnan
          ... might find some flaky memory chips. ... card during this test. ... I am not using a terminator. My memory tests so far have all been manual read/write/read
          Message 4 of 15 , Feb 26, 2010
            >
            >
            > Just checking if your terminator card is plugged in ?
            > If it is, it could still be acting up.
            >
            > Maybe if you run a memory tests on with all the Ram cards plugged in you
            might find some flaky memory chips.
            >
            > Even some suspicious memory location could be corrupted by the terminator
            card during this test.
            >


            I am not using a terminator.
            My memory tests so far have all been manual read/write/read tests at each
            page location 0000, 1000 - F000. I have swapped RAM cards into a number of
            configurations, and I usually get the same result. It's possible that my
            laptop serial port is not right? Not sure yet.
            cd
          • Bill Degnan
            ... each ... number of ... my ... there are lots of different kinds of tests that look for refresh problems on dynamic memory, as well as shorted address/data
            Message 5 of 15 , Feb 26, 2010
              >
              >
              > > I am not using a terminator.
              > > My memory tests so far have all been manual read/write/read tests at
              each
              > > page location 0000, 1000 - F000. I have swapped RAM cards into a
              number of
              > > configurations, and I usually get the same result. It's possible that
              my
              > > laptop serial port is not right? Not sure yet.
              > > cd
              >
              > Whoa! Run a real memory test! I'm assuming the memory is static, but
              there are lots of different kinds of tests that look for refresh problems
              on dynamic memory, as well as shorted address/data bits, bad bits in chips,
              etc. You wouldn't believe how many memory problems slip through because of
              tests that don't run sufficiently complex algorithms.
              >
              > I'd also test one board at a time, or at least pull boards you don't
              need. You've got four 16K boards, right? Pull all but one and check the
              portion not used by the test code. Once it seems to work, put in another
              board and test all 16K of it using a really good (extensive) memory test.
              Now you've got a "golden board" that is known, or at least presumed, to be
              good.
              >

              Agreed, but I am trying to get programs into the system - chicken and egg
              problem here. I will test the RAM using a system that can already load
              programs.

              Bill
            • Bob Applegate
              ... Maybe I missed something but the subject implies you re loading a BASIC interpreter. That s much larger than a memory test and it won t test memory. Use
              Message 6 of 15 , Feb 26, 2010
                Bill Degnan <billdeg@...> wrote :


                > Agreed, but I am trying to get programs into the system - chicken and egg
                > problem here. I will test the RAM using a system that can already load
                > programs.

                Maybe I missed something but the subject implies you're loading a BASIC interpreter. That's much larger than a memory test and it won't test memory. Use a smaller program that can test your hardware before trying to load something larger.

                You're still using unknown RAM, but a memory test is a lot smaller and will use less unknown RAM to run.

                The other thing is that I seem to remember your failure happened at a page boundary. How big are the RAM chips and what was the address again? Maybe it happened on a chip boundary.




                ___________________________________
                NOCC, http://nocc.sourceforge.net
              • Bob Applegate
                ... If the hex address ends in 00 then it s a page boundary. What was the address where it failed and what type of RAM chips are on the boards?
                Message 7 of 15 , Feb 26, 2010
                  Bill Degnan <billdeg@...> wrote :


                  > I can't tell if it's a page boundary or not.

                  If the hex address ends in 00 then it's a page boundary. What was the address where it failed and what type of RAM chips are on the boards?


                  ___________________________________
                  NOCC, http://nocc.sourceforge.net
                • Bill Degnan
                  ... interpreter. That s much larger than a memory test and it won t test memory. Use a smaller program that can test your hardware before trying to load
                  Message 8 of 15 , Feb 26, 2010
                    >
                    > Maybe I missed something but the subject implies you're loading a BASIC
                    interpreter. That's much larger than a memory test and it won't test
                    memory. Use a smaller program that can test your hardware before trying to
                    load something larger.
                    >
                    > You're still using unknown RAM, but a memory test is a lot smaller and
                    will use less unknown RAM to run.
                    >
                    > The other thing is that I seem to remember your failure happened at a
                    page boundary. How big are the RAM chips and what was the address again?
                    Maybe it happened on a chip boundary.
                    >

                    I can't tell if it's a page boundary or not.

                    I am working through this web site:
                    http://www.solivant.com/altair_bootloaders/index.php?album=altair_bootloader
                    s&pagen=1

                    I will keep at it. I have followed every page closely including the
                    troubleshooting section.

                    Bill
                  • Dan Roganti
                    ... Anytime you add more loads on that bus, by adding more cards, it s wise to use a terminator card. The signal quality begins to degrade by the consequence
                    Message 9 of 15 , Feb 26, 2010
                      Bill Degnan wrote:
                      > I am not using a terminator.
                      > My memory tests so far have all been manual read/write/read tests at each
                      > page location 0000, 1000 - F000. I have swapped RAM cards into a number of
                      > configurations, and I usually get the same result. It's possible that my
                      > laptop serial port is not right? Not sure yet.
                      >

                      Anytime you add more loads on that bus, by adding more cards, it's wise
                      to use a terminator card. The signal quality begins to degrade by the
                      consequence of electrical reflections between all the drivers from more
                      cards on the bus.

                      I uploaded some memory tests that I found online to here. One of them is
                      short that you can thumb-in. It's in assembly still, it's not a
                      comprehensive test but it's a start, under folder S-100 Test Code.

                      =Dan
                    • Bill Degnan
                      I will take a look. I may not have a terminator that works. I have to check bd ... Alair without a disk drive or cassette. ... each ... number of ... my
                      Message 10 of 15 , Feb 26, 2010
                        I will take a look. I may not have a terminator that works. I have to
                        check
                        bd

                        -------- Original Message --------
                        > From: "Dan Roganti" <ragooman@...>
                        > Sent: Friday, February 26, 2010 2:24 PM
                        > To: midatlanticretro@yahoogroups.com
                        > Subject: Re: [midatlanticretro] Re: Using 2SIO to download BASIC into an
                        Alair without a disk drive or cassette.
                        >
                        > Bill Degnan wrote:
                        > > I am not using a terminator.
                        > > My memory tests so far have all been manual read/write/read tests at
                        each
                        > > page location 0000, 1000 - F000. I have swapped RAM cards into a
                        number of
                        > > configurations, and I usually get the same result. It's possible that
                        my
                        > > laptop serial port is not right? Not sure yet.
                        > >
                        >
                        > Anytime you add more loads on that bus, by adding more cards, it's wise
                        > to use a terminator card. The signal quality begins to degrade by the
                        > consequence of electrical reflections between all the drivers from more
                        > cards on the bus.
                        >
                        > I uploaded some memory tests that I found online to here. One of them is

                        > short that you can thumb-in. It's in assembly still, it's not a
                        > comprehensive test but it's a start, under folder S-100 Test Code.
                        >
                        > =Dan
                        >
                        >
                        >
                        >
                        >
                        >
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