IBM 5100

From: jim <>
Date: Sun Aug 8 20:39:13 2004

the APL / Basic version as well as the ones I have with options
require a power cycle to switch operating modes. There would
be no way to retain any data in the unit.

the "serial" port probably was a bisync port which would require
reading a dataset or stream from the mainframe and storing or
digesting it.

you could read records from files you opened, and though i do
not have a unit with such a port I suspect it is opened and just
returns data records as one would ship them from the mainframe.

Only problem to be said for this is problem with timing and so
forth in such protocols as 2780, which would be probably
about all that would have been around. the interface would
go DTR when you brought up the device, such as the 5100,
and then you would have to read data from the mainframe in
a hell of a hurry, or fault the outbound datastream from the

All which ignores, would this be dialup, or hardwired
direct, as I imagine that DC Hayes was in high school
when this would have been going on... at least there was
no integrated way to make the connection.

Also may predate such devices as 3270's so there would
have been no way to run in that environment either.

I have a system with 8" floppies on it, and it runs like a
system with cards attached. you can read write, overwite
and delete images which were up to a track long. so
each floppy was a small "deck" as far as a program
was concerned.

Received on Sun Aug 08 2004 - 20:39:13 BST

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