The Norcom TC-III

The Model III added some nice improvements to the Model I and boasted nearly complete compatibility. But there were still some areas of incompatibility. Considering that most TRS‑80 software development moved to the Model III, it was understandable that some Model I owners felt left behind.


Rally was written by J. Weaver Jr. (Factory Programming) and distributed by Soft Sector Marketing. Rally was based on Rally-X, which was released by Namco in 1980.

The goal in Rally is to collect all of the flags in a maze, while avoiding “enemy cars”. Touching an enemy car causes you to lose your life.

Model II Warning from 1980

This somewhat alarming warning appeared in the June 1980 issue of 80 U.S. Journal:

The video controller of the Model II is mapped to I/O port 255 (FFH). If an output is made to this port with a value of less than 25, there is a very good chance that YOUR VIDEO WILL BE DESTROYED! We don’t know why this happens yet, but we do know that about a dozen of them across the country have been blown in this fashion, resulting in an expensive repair bill. If for any reason your screen should go blank unexpectedly, accompanied by a very high-pitched whining noise, you have less than 7 seconds to TURN THE COMPUTER OFF! Don’t worry about having disks in the drives or anything. Even the data you lose is cheap compared to having to do without a computer while it is being repaired.

The Exatron Stringy Floppy

There were quite a few different storage products available back in the early days of the TRS‑80. In the long term, the floppy drive (and later the hard drive) completely beat out all of the competition. But back when floppy drives were considered too expensive by many, one of the most popular storage products for the TRS‑80 was the Exatron Stringy Floppy.

Founded in 1974 by Robert Howell, Exatron was a supplier of automated test equipment for manufacturers and OEMs. Exatron first demonstrated the S-100 version of the Stringy Floppy at the West Coast Computer Faire in March 1978. The TRS‑80 version was introduced in May 1979 at the San Francisco Computer Faire. An early price for a TRS‑80 starter kit (Stringy Floppy, wafers, and software) was $299.50. The Stringy Floppy provided an additional cost savings over floppy drives because it didn’t require an Expansion Interface. By 1982, the price for a single Stringy Floppy drive had come down to $99.50.


ZBASIC is probably the most popular BASIC compiler ever written for the TRS‑80. It holds the distinction of being one of the few programs originally created for the TRS‑80 that is still being developed in some form.

The first version of ZBASIC was written in 1979 by Andrew Gariepy for the Model I and sold by Simutek Computer Products. ZBASIC began appearing in Simutek advertisements in 1980. It originally cost $99.00 for the tape version and $129.00 for the disk version.

ZBASIC fell somewhere between a traditional compiler and an interpreter. As an early advertisement described it:

Gold Plug 80

Over time, many Model I computers (particularly those with Expansion Interfaces) developed the annoying habit of spontaneously rebooting. The reason was simple: the Model I card edge connectors were solder-coated tin and had a tendency to oxidize over time. Oxidation interfered with the electrical connections and tended to cause reliability problems, particularly with the critical Expansion Interface cable.

I’m sure that anyone who used a Model I still remembers that the best to way to remove the oxidation was to use a pink rubber eraser to scrub the connectors. The usual recommendation was to clean the connectors every month but many people did it every week.

Tandy Corp. v. Personal Micro Computers, Inc.

In February 1981, Tandy filed a lawsuit in the state of California against Personal Micro Computers concerning the PMC‑80, their Model I compatible computer. Personal Micro Computers was the United States distributor of the PMC‑80 but the computer was manufactured by EACA International in Hong Kong.

The case, “Tandy Corp. v. Personal Micro Computers, Inc.”, was an important precedent in computer copyright law. Along with “Apple Computer, Inc. v. Franklin Computer Corp.” in 1983, this decision helped to establish the concept that computer code was protected by copyright. Even today, it is frequently cited in computer copyright cases.