The First Kermit Transfer Re-enacted

[What Is Kermit?]   [History of Kermit]

The first Kermit protocol file transfer was accomplished by Bill Catchings on April 29, 1981, between two copies of Kermit-20 on the same DECSYSTEM-20 mainframe, through a null-modem cable connecting two of its serial ports. But this was just a trial run or “proof of concept”, because there are much easier ways to move a file around on a single computer, such as the computer's built-in COPY command.

Bill Catchings

The DECSYSTEM-20

The Superbrain

The first real file transfer took place in June of that year, between an Intertec “Superbrain” 8-bit microcomputer and the 36-bit DEC-20 over an RS-232 serial port-to-port null-modem connection; the Superbrain with its CP/M-80 operating system and the first version of Kermit-80, written in 8080 assembly language, and the DEC-20 with its TOPS-20 operating system and Kermit-20 written in PDP-10 assembly language. Bill Catchings wrote all of this code and even custom-wired the cables to supply the necessary signals to make the connection work.

Thirty-six years later, Doug Crawford resolved to reenact, as far as possible, the first cross-platform Kermit file transfer for the 12th Vintage Computer Festival East in Wall, New Jersey, March 31 – April 2, 2017.

He contacted me in February looking for the first version of Kermit-80; unfortunately I had already been laid off from from Columbia University and had shipped the Superbrain and all its diskettes to the Computer History Museum; no online copies had survived. Also, Doug did not have access to any DECSYSTEM-20 or emulator that could offer real or simulated serial port access. So in the end, he used a later version of Kermit-80, 4.11 from 1991, on the Superbrain, and in place of a DEC-20 he used MS-DOS Kermit on a PC (after a previous successful trial-run with Kermit-80 on a Kaypro II, seen in the photo below). Click on the photo to see Doug's detailed writeup of the entire procedure, complete with photos and videos:

Click to visit “Kermit and the Brain” page.

Afterwards Doug commented, “It was a pretty ambitious app for 100% assembly language! You know what was pretty remarkable to me, but you might not be surprised knowing what you know, is that all of that process I did with the Kermit ‘products’, there wasn't one hitch in the build, executing, or interoperating between disparate versions. It is a testament to the work put into it, and the robustness of the design.”

—Frank da Cruz, June 17, 2017.