TRS-80 Model I
The TRS-80 Model I was introduced in 1977 by Tandy Corporation through its Radio Shack stores, forming one corner of the “1977 Trinity” of early personal computers alongside the Apple II and Commodore PET 2001.
It featured a built-in keyboard, monochrome display output, and cassette interface, with early models including just 4 KB of RAM. It ran the TRSDOS operating system or could boot other software from cassette or disk, including BASIC and CP/M derivatives with expansion.
The Model I was especially popular in educational and small business settings due to its affordability and nationwide retail availability. Its success laid the groundwork for a series of TRS-80 models that followed.
💡 Did You Know?
- “TRS” stood for Tandy Radio Shack, but users often joked it meant “Trash-80” due to early reliability quirks.
- The original Model I lacked lowercase character support—a major early complaint.
- It was banned from some schools because its unshielded design caused radio interference.