48GX serial comms (Mac)

[Raymond Del Tondo]

(02-09-2019 07:05 PM)cdmackay Wrote:  [XModem] whether it had any advantage over the default Kermit?

Kermit was available for nearly any platform back then, and Kermit was easy to use.
However XModem offers much more data transfer performance than Kermit.

Many years ago I made a semi-automatic batch-backup mechanism for my HP 48GX to another GX.
Actually the only precaution on the receiver GX is Kermit Server mode.
On the Sender I send a predefined (via VARS or othe means) list of files to be transferred over Kermit, followed by sending a UserRPL program for the receiver side.

The receiver side program effectively is a loop which takes the next name from the list, and calls XModem receive on that name.

On the sender, the execute remote command is issued, which calls the XModem receive loop program which was just transferred via Kermit.

Then the Kermit server is finished and exited from the sender.
Then the sender also exits the Kermit environment, and starts the sender XModem loop.

Within this loop, one by one the programs on the given list are sent via XModem.

When all list elements are transferred, both programs end, and the I/O is closed.

This is a simple example of remote execution, however there are ways to fine-tune the mechanism, with error-checking and such.

The goal was to make the backup using a few key clicks only, with maximum possible speed, and without any additional software needed to be installed.

It's possible that one of the steps described above works slightly different in reality, since I just recalled the principle mechanism from memory.