Threaded Mode | Linear Mode

Christoph Giesselink · 11-28-2023, 07:33 PM

Recently the Tera Term development team updated their terminal software after a long beta stage to version 5.0.

What is Tera Term? Tera Term is a terminal emulator supporting transfer protocols like XModem, XModem-1k, YModem, Kermit and others. Important for me, the program also still supports the legacy serial port used by calculators like the HP38, 39, 40, 48 and the 49. It's more or less a free replacement for Hyperterminal software delivered with Windows until WinXP.

So I made a test with Tera Term 5.0 and my CARDUPL package to upload the content of a memory card with the CARDUPL program to the PC.

When you receive data over XModem on Tera Term, a small window opens during the transfer showing statistical information. This window should be closed automatically when the file transfer is finished.

But not with Tera Term 5.0, most times the window stays open even if the complete file was transferred. This must be an issue with the new Tera Term version, the CARDUPL software worked with the Hyperterminal software for years without any problems.

But I made a protocol of the transferred data in connection with Tera Term to analyze whats really happen. But my suspicion was wrong, not Tera Term had an issue, the upload software on the calculator had a bug!

Normally each send XModem packet must be confirmed by the receiver before sending a new packet or sending EOT to end the transfer. In the case of the CARDUPL software, the software don't wait for the acknowledge from the receiver on the last send block, it directly sends the EOT byte after the last block.

The problem, the CARDUPL XModem upload code was used in other calculator software, so these software must be fixed too.

Affected software are

The software packages had been replaced by fixed versions. Just remember, the bug is not in the PC software, it's a bug in the calculator program, so It's important to exchange the software on the calculator if you use one of these programs.

The version number of IMG38 and IMG39 depends on the PC program, so these two packages got updated PC programs with the new version number too. Both improve the save speed of the resulting file, especially noticeable at saving the HP39G RAM file.