Learning TRS-80 Model 4/4P BASIC

Learning TRS-80 Model 4/4P BASIC

This title was my first solo research project at CompuSoft in 1984. The TRS-80 Model 4/4P was an upgrade to the Model III, offering several improvements that made it a far more capable and user-friendly machine.

The TRS-80 Model 4: A Major Step Up

The Model 4, introduced in April 1983, was a significant advancement over its predecessor, the Model III. While it retained a similar design, it featured a faster Zilog Z80 processor running at 4 MHz (compared to the Model III’s 2 MHz), allowing for improved performance in business and educational applications. The Model 4 also increased the maximum memory capacity to 128 KB, making it better suited for more complex software.

One of the most notable upgrades was its improved video display. The Model III had a 64x16 text resolution, whereas the Model 4 expanded this to an 80x24 display, making it easier to work with longer lines of text and code. This improvement was particularly valuable for programming in BASIC, as it allowed for better readability of code listings and debugging.

Built-in BASIC: A Programmer’s Tool

Like its predecessors, the Model 4 included a built-in version of TRS-80 Level II BASIC, an extended version of Microsoft BASIC. This version offered additional commands and functions that made it more powerful for writing software. Users could create everything from simple educational programs to full-fledged business applications. For those needing more advanced capabilities, the Model 4 could also run TRSDOS 6 and CP/M, expanding its software compatibility significantly.

The TRS-80 Model 4P, a portable version of the Model 4, was released later in 1983. While it lacked an internal monitor and required an external display, it maintained the same technical improvements and was designed to be a more compact and transportable option.

The Model 4’s enhanced hardware and improved reliability made a world of difference for users who had struggled with the quirks of the Model III. It was a much-needed refinement that made programming and daily use far smoother.

For those learning to program on the TRS-80 Model 4/4P, this book provided a solid foundation in BASIC, helping users take full advantage of the improved hardware and software environment.

Memories of the Radio Shack Computer Center

We depended on our TRS-80 Model IIIs on which we wrote all of our manuscripts in a program called Scripsit. The floppy drives, which got a thrashing, were frustratingly temperamental. We were constantly hauling them to the Radio Shack Computer Center for repair. The tech there was a chain-smoker, and the machines always came back smelling like an ashtray. No wonder the drives went kaput so often.