• Tag Archives TRS-80 Model 4
  • TRS-80 Model 4 (1984)

    Detail from 1984 Advertisement for the TRS-80 Model 4 Computer


    Radio Shack released the TRS-80 Model 4 as a follow-up to the Model III three years later in 1983. It looked essentially the same as the Model III except that it was an off-white color instead of grey/silver. Internally, there were some fairly significant upgrades, including:

    • CPU: Z80A @ 4 MHz (compared to the ~2 MHz model III)
    • Display: 80×24 (compared to the 64 columns of the Model III)
    • Available 64KB model (Upgradeable to 128KB of RAM)
    • Full support for CP/M without modification

    It also included an expanded keyboard and TRSDOS 6. For this version of TRSDOS, Radio Shack contracted with the maker of LS-DOS/LDOS, a popular and generally more capable 3rd party DOS produced for the TRS-80 line. They continued to market LS-DOS separately but it and TRSDOS wer