Boot Loader for 3P+S on IMSAI

dwight dkelvey at
Wed Jan 11 15:07:23 CST 2017

Most of these BASICs required a delay on a return.

To make it more fun, it got longer the larger the program.


From: cctech <cctech-bounces at> on behalf of Win Heagy <wheagy at>
Sent: Wednesday, January 11, 2017 10:28:06 AM
To: cctech at
Subject: Re: Boot Loader for 3P+S on IMSAI

Yes, I was able to run the echo characters test from the solivant site
as well as a couple other small upload tests, so I'm thinking it's a
delay issue or a configuration problem with the 3P+S and MITS BASIC.
Digging back into this on my IMSAI, I'm now remembering the
peculiarities of loading MITS BASIC when I was doing it on the Altair.
That picture will help.  I think I've already spotted something
without even having my actual card in front of me.

>Did you verify "echo characters" works?  There is a test program in the
>solivant site that explains this.  If so, then you very well may need to
>experiment with character delays when you download BASIC.  You can watch
>the lights and see when the various loaders load, that might help give you
>a clue where the failure point is.

>The extra pointers I added were things I found useful, but I was using the
>2SIO card.


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