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From: ron@ronnatalie.com (Ronald Natalie)
Subject: [TUHS] Does anybody recall how the TU10 bootstrap code actually operates?
Date: Thu, 24 Dec 2015 17:33:26 -0500	[thread overview]
Message-ID: <F72C7A01-F1FC-4BE5-B0E2-FF84149DF099@ronnatalie.com> (raw)
In-Reply-To: <20151223065957.5ED5718C095@mercury.lcs.mit.edu>

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Noel is correct.   The code sticks a number that’s big enough in the byte record count register and then does a  command which is
800 bpi 9 track READ and GO.   The code makes use of the fact that after a bus reset the memory address register is zero.

As long as you stick a number in the BRC that is bigger than the the record size on the tape (and not bigger than the available memory on your system),
it will work.

777 is indeed BR .

It loads the first (assuming the tape is rewound) record into memory at location zero.
You then start the processor at zero to load that bootstrap program which does the rest of the magic.
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  parent reply	other threads:[~2015-12-24 22:33 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-12-23  6:59 Noel Chiappa
2015-12-23 15:03 ` Will Senn
2015-12-23 15:58   ` John Cowan
2015-12-24 22:33 ` Ronald Natalie [this message]
  -- strict thread matches above, loose matches on Subject: below --
2015-12-23 18:02 Noel Chiappa
2015-12-23 18:06 ` Larry McVoy
2015-12-23 20:29   ` Clem Cole
2015-12-23  6:13 Will Senn

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