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Thread: OSI Challenger 1P loading problems

  1. #1
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    Default OSI Challenger 1P loading problems

    Okay so I'm just figuring this out, with an assist from Tezza's excellent website.

    I'm trying to load some BASIC programs into my Challenger 1p and am hitting a snag.

    I've used KCS to encode some .BAS files I found for this machine. When I do load, it starts out reading the first few lines of the program, but after that it starts putting up this continuous stream of characters that look like actual waves. And then that's it.. it never finishes loading.

    I've tried adjusting volume up and down, tried different encoding speeds (my machine is switchable between 300 and 600 baud. Nope. No matter what program it is, it always starts spitting out those wave characters at the same point. It's about 3 lines into the program.

    20181002_211130.jpg
    Last edited by falter; October 2nd, 2018 at 08:10 PM.

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    Falter:
    I tried the same thing with similar results back in the early eighties.
    I had some known good KCS tapes, SWTPC, that I wanted to read with my 1P and send the data back out through the serial port to another computer.
    The read would do exactly as you have experienced, I could get at most 6 or 7 lines, then garbage. I could even start at different spots of the cassette and receive good data then garbage.
    IIRC I asked a a couple of guys at a computer show who had a bunch of Ohio Scientific stuff about the KCS tapes and one of them replied “its close but not quite” I never found out exactly why it wouldn’t work

    A quick search brings this site http://dabeaz.blogspot.com/2010/08/u...-cassette.html

    He is using a superboard II, yes he believes it uses KCS but his example works. He has several posts on this.
    There are several sites that have KCS audio to Bin examples. I assume that you just want to load .bas programs into the Challenger, from there you can use the Challenger to save them.
    Good luck
    Ted / KC9LKE

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    Quote Originally Posted by 68B09 View Post
    Falter:
    I tried the same thing with similar results back in the early eighties.
    I had some known good KCS tapes, SWTPC, that I wanted to read with my 1P and send the data back out through the serial port to another computer.
    The read would do exactly as you have experienced, I could get at most 6 or 7 lines, then garbage. I could even start at different spots of the cassette and receive good data then garbage.
    IIRC I asked a a couple of guys at a computer show who had a bunch of Ohio Scientific stuff about the KCS tapes and one of them replied “its close but not quite” I never found out exactly why it wouldn’t work

    A quick search brings this site http://dabeaz.blogspot.com/2010/08/u...-cassette.html

    He is using a superboard II, yes he believes it uses KCS but his example works. He has several posts on this.
    There are several sites that have KCS audio to Bin examples. I assume that you just want to load .bas programs into the Challenger, from there you can use the Challenger to save them.
    Good luck
    Ted / KC9LKE
    Thanks Ted. Yeah, I tried BAS programs but also some HEX programs also like OSI Invaders. I followed the procedure correctly on the latter and used a premade FLAC file rather than converting text into KCS.. and on the part where you are loading into the monitor I can see the addresses gradually tick up close to 07FF, and then it halts and freezes up. I'm wondering if maybe i have bad RAM or something. I think it's socketed on the Challenger/Superboard II so maybe I'll pull and test those with my digital group machine. I'm following the exact same procedure tezza used with his and getting a different result, so I'm still leaning towards something being off with my Challenger.

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    Just to refresh... you can't make OSI compatible disks with a PC, correct? This machine did come with what appears to be a working disk drive..

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    Unbeknownst to me.. my Challenger has a 610 expansion board. I'm wondering - does anyone know if this board supplants the ram on the 600 mainboard (ie. replaces it), or does it just add to it? Trying to figure out where to start checking RAM.

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    It provides an extra 24 KB RAM, starting at 8 KB (for 32 KB total) and a FDC.

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    Quote Originally Posted by bear View Post
    It provides an extra 24 KB RAM, starting at 8 KB (for 32 KB total) and a FDC.
    It seems to me like it fails at loading at roughly the same memory address every time, at least when loading HEX stuff in. It's in the 0700s somewhere. SO I gotta find that area on the mainboard and focus there I think.

    I don't know if a few lines of basic program get you to the same address in RAM... but the fact that the load process sort of works and then fails at exactly the same point is suspect.

    Thanks bear!

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    So I've removed almost all of the main 8k of memory on the 600 board. I'm using an unsophisticated method to test -- basically installing into this z80 homebrew I have and then writing FFs everywhere. So far no problems at all, got three chips left.

    I tried to read the docs to understand which bank/chips 07F0 would be at.. that seems to be where the load fails in HEX mode. I'm hoping they're NOT somewhere on the massive 610 board amongst dozens of 2114 chips. I don't know.. maybe i'm on the wrong track here. I'll finish and see.

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    Okay, probably put myself through a lot of trouble for nothing.

    Those waves that occur happen when you type continuously for more than two lines. I guess the 600 can't handle a line longer than 64 characters. So what's happening is when a tape file is being read, it's not reading in linefeeds between line numbers, and it's all just one line, and eventually it produces junk. So I have to figure out now how to get linefeeds in there.

  10. #10
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    Microsoft BASIC has a 72-character input buffer. When that buffer overflows, BASIC tries to output a beep (BELL, ASCII 7). That character is the right half of a leftward-going submarine, character 7.

    Almost certainly, this is not a problem with your computer. If the FLAC file is synthetic, it's possible that it could be missing some characters. Try generating the files yourself.

    David Beazley has a python program to encode KCS here: http://www.dabeaz.com/py-kcs/index.html

    If you like FORTH, ED has a FORTH program to do it. Sadly, his page appears to have gone dark, but it is mirrored here: http://dxforth.mirrors.minimaltype.com

    Microsoft BASIC does a crude memory test on cold start, similar to what you describe. If it reports 7423 bytes free on startup, you have 8K of RAM present and probably good (but not thoroughly tested.)

    Cheers,

    Dave

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