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MITS 88-TPM Users Guide

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  by Bill Degnan - 06/28/2008 17:53
I *assumed* that one would
get useful display terminal output like the 680b monitor.

From page 5 of the 88-TPM PROM Monitor User's Guide:

"Once the D function has received valid starting and ending addresses,
it punches a leader of 60 octal 302's followed by 60 nuls (zero
bytes). It then punches out the contents of memory starting at the
first address up to and including the end address in the Altair 8800b
binary Absolute Load Tape format, as shown in Table A. (The word
"punch" is used here to refer to the output of the D command, no
matter what output device is actually used.) If the number of bytes
to be punched is greater than 377 octal, the D function punches as
many blocks of 377 octal bytes as necessary until the number of bytes
left to punch is less than 377 octal bytes. The last block punched
may have less than 377 octal bytes. If the number of bytes to be
punched in the last block is equal to zero, a zero block is not
punched. Upon completion of the dump, the D function performs a
carriage return and line feed and then returns to the Monitor."

Conclusion - it's supposed to look garbled, it's "garbling" as if an octal output with no control characters would look running through an RS232 terminal with only baud and parity controls.

What I will do is move forward, assume that the system is ok and try
to load BASIC from cassette or papertape, or try a different PROM monitor. Perhaps borrow some Northstar disks

I guess I am done for now! The RAM is apparently OK, the terminal OK, I reduced the baud from 9600 to 1200 for no reason.

UPDATE: See thread on loading BASIC.

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