TRS80 Charset

Compatible Hardware Versions

  • Group1

    • Model I
    • Model III
      • Model III, 4K RAM, Level I
      • Model III 16K RAM, Model III BASIC
    • Model 4
      • Model 4: Non-Gate Array
      • Model 4: Gate Array
      • Model 4D
      • Model 4P
  • Group 2: Model II family (memory map is compatible with standard CP/M-80)

    • Model 2
    • Model 12
    • Model 16
    • Model 16B
    • Model 6000
  • Disk Operating Systems

  • Disk images format for emulators

    • JV1
      • single sided
      • single density
      • directory always on track 17
      • 256 bytes per sector
      • CANNOT be used in 8-inch drives
    • JV3
      • single or double side
      • single or double density (with either FB (normal) or F8 (deleted) data address mark on any sector)
      • In single density support nonstandard data address marks FA and F9
      • support intentional CRC error in the data field
      • DO NOT support incorrect track number or head number in a sector
      • 128, 256, 512, or 1024-byte sectors
    • DMK
      • support of ALL the WD-1771 and WD-19xx controller functions and formats

“on the old TRS-80 the boot sector had to be single density even when the rest of the disk was double density. I believe a couple of TRS-80 disk image formats use the byte-doubling trick as an easy and compatible way to represent single-density info in a format for double-density.”

DMK Technical Info