TRS-80 News

June 21, 2026 - Site Updates

  • The Internal Ports page has been updated with additional ports, both internal and from hardware add-ons.
  • The Model 1/3/4 Disassembly page has been updated to link to the ports page when clicking on a port operation.
  • Preliminary support has been added to the TRS-80 Software Archive Search page for patches. Where a patch exists, a new column, with an icon of a band-aid, will serve the download.
    This may take a while. The code is there, but it means I need to sort my patches and consolidate each program into a single zip. You can see the link in action by searching for LTERM or MODEM-80.

June 15, 2026 - kDOS, lightweight OS for Floppy-80

KiwiSinceBirth, who has done so much for the modern TRS-80 community, has created kDOS, a Model I Operating System specifically for those Model I owners running a Floppy 80 (expansion interface NOT required). He describes kDOS
kDOS is an operating environment that runs on the Tandy TRS-80 Model 1 providing a TRS-DOS (DOS) like features to Level 2 BASIC
The DOS runs alongside Level 2 BASIC, rather than supplanting it. Typing a DOS command and a BASIC statement are done in the same shell
Files are stored and accessed from SD card in a standard FAT filesystem. There is no emulation of TRS-80 floppy disk or hard disk drives, nor any TRS-DOS (like) file-system
There are no imposed file size limits, or limits on the number of files that can be stored, for a TRS-80 a modern SD card could be considered infinite storage. Directories are fully supported. Files copied to the SD card by modern computer, are directly readable on the TRS-80
Programs that run on TRS-DOS "should" run under kDOS so long as they use standard DOS API calls. Programs that directly access FDC hardware or undocumented (non-standard) API calls will probably not function, unless patched
The core features are:
  • Modern Filesystem
    • Files are stored natively on the FAT filesystem
    • File directories (including nested) are supported
    • File storage space is unrestricted, can store any number of files
    • Automatic conversion of traditional filename/ext into filename.ext
  • DOS Features
    • DOS commands are typed into the BASIC command shell
    • Most DOS entry points at $4400 are supported
    • Interrupts with real Time Clock supported
  • BASIC features
    • Extended Basic functions are supported
    • Long error messages ar displayed
    • Disk File IO Statements are currently NOT supported
  • Has a Low memory overhead than a traditional DOS
    • Requires about 0.5Kb of main memory space
    • Uses virtual memory from $3000-$37DF
    • 47800 Bytes Free, compared with 48350 on Level 2 BASIC
    • Memory from 4500H is available for application usage
You can get more information at https://github.com/kiwisincebirth/TRS-80-KDOS

June 8, 2026 - TRS80Tools Updated to v2.8.10


Lawrence Kesteloot has released an updated copy of his trs80tools, now new version 2.8.10. He notes:

  • Improvements to the disasm command: Disassembled instructions are now canonical when there are variants. For example, it will generate or b where it used to generate or a,b.
  • Improvements to the asm command (and the IDE): The assembler now supports the alternate forms described in the zmac manual, except for the rst ones.

You can download it for the Windows, Mac, and Linux at https://www.my-trs-80.com/tool/#installation.

June 8, 2026 - TRS80GP Updated to v2.5.7

George and Peter Phillips have updated their awesome TRS80GP emulator to v2.5.7. Changes are:

New Features:

  • Debugger disassembly also shows the last few dozen completed instructions
  • Backtrace now tracks the last 1,048,576 instructions, up from 65,536
  • Hard drives now implement write protect
  • Windows debugger completely fills memory and disasssembly windows at start
  • Z-80 single stepping now shows memory permission faults when single stepping

Bug Fixes:

  • EMU hard drive images now correctly show CRC errors in disk summary
  • Fix corrupted data CRC caused by editing EMU hard drive sectors
  • Fixed audio corruption in .avi video recording
  • File import: CP/M files are forced to upper case
  • Fix crash when tracing memory from CWAI on 6809
  • Reformatting DREM hard drives images will now update .cfg parameters
  • File import: fix duplicate entries and Model II defaults to Program type
  • Detaching second hard drive no longer detaches primary hard drive
  • Hires graphics (-gt, -gg) can now be selected for Model 4D
  • Backtrace no longer shows 64K bogus instructions if triggered at start

You can download it at http://48k.ca/trs80gp.html

June 4, 2024 - TRS8BIT Newsletter Vol 20 Issue 2 Released

In this edition, George and Peter Phillips have an upgrade to their brilliant TRS-80 emulator, 'trs80gp'. Amardeep Chana shows us a cool and efficient M1 power supply. Terry Stewart finds some lost System-80 software - SCAP. There's a new game from 'Voidstar' - 'BEAST'. Ian Mavric has the latest updates for the Tandy Assembly 2026, helps decide if it shouls be LDOS or NewDOS80 and explains how to upgrade a Co-Co Mk1 from 32 to 64K. Seen the 'clockwork Pi' yet? The info's here. E.T.Fonehume explores the U.K.'s LSD curency, in use before decimalization. Mark Pruden breaks the 48K barrier. Another game from 'Nickman Studios' - 'House at the edge of the crater'.
Vince Otten has part 6 of his series 'The power of the ROM'. The 'Way We Were' looks at a program that writes programs. (Something similar, in the U.K., was called 'The Last One' I recall). There's a Countdown, numbers puzzle for you to try. (Not quite as easy as last time!).
‘Surfin’ The Net’ finds the '8-bit boyz'. And finally, I check out some of the recent UK Ebay bargains.

You can download it from http://TRS-80.org.uk/ or a repaired and OCR'd (as best as possible given the font selections) version with JSON and text sidecar here.

June 4, 2026 - ROM Disassembly Page Done!

The new ROM Disassembly page project is at a close. Twenty TRS-80 Model 1/3/4 ROM versions are now supported.

Model /RevisionYearCRC (ROM A B C)Link Format
Model I v1.01978AE5D DA84 4002/sub-disassem-rom-m134.htm?v=m1v10
Model I v1.11978AE60 DA45 40E0/sub-disassem-rom-m134.htm?v=m1v11a
Model I v1.1 Revised1978AE60 DA45 3E3E/sub-disassem-rom-m134.htm?v=m1v11b
Model I v1.21979AE60 DA45 40BA/sub-disassem-rom-m134.htm?v=m1v12
Model I v1.31980B078 DA45 4006/sub-disassem-rom-m134.htm?v=m1v13
Model III v1.019809639 407C 2B91/sub-disassem-rom-m134.htm?v=m3v10
Model III v2.019809639 407C 2EF8/sub-disassem-rom-m134.htm?v=m3v20
Model III v3.019819639 407C 2F84/sub-disassem-rom-m134.htm?v=m3v30
Model III v3.0 Revised19819639 407C 2F84/sub-disassem-rom-m134.htm?v=m3v31
Model III German19829639 407C 10E4/sub-disassem-rom-m134.htm?v=m3vGerman
Model 4 - Standard Gen 1 60 Hz19839639 407C 1591/sub-disassem-rom-m134.htm?v=m4v10
Model 4 - v1 50hz Australia19839639 407C 1587/sub-disassem-rom-m134.htm?v=m4v1AU
Model 4 - Standard Gen 2 60 Hz19838F46 407C 48BC/sub-disassem-rom-m134.htm?v=m4v20
Model 4 - Network 4 Student Station19838F46 407C 33CB/sub-disassem-rom-m134.htm?v=m4vNetwork
Model 4 - v2 50hz Australia19838F46 407C 48B2/sub-disassem-rom-m134.htm?v=m4v2AU
Model 4 - German19838F46 407C 3080/sub-disassem-rom-m134.htm?v=m4vGerman
Model 4 - French AZERTY19838F65 407C 43AD/sub-disassem-rom-m134.htm?v=m4vFrench
Model 4D - XDROM v3.33 (with Diagnostics)19908F46 407C 5C1D/sub-disassem-rom-m134.htm?v=m4vXDROM333
Model 4 - XROM v3.3319908F46 407C 5C1D/sub-disassem-rom-m134.htm?v=m4vXROM333
Model 4D - XDROM Diagnostic 1.119898F46 407C 5C1D/sub-disassem-rom-m134.htm?v=m4vXDDiag11

June 2, 2026 - ROM Disassembly Page Updated

Since the prior announcement, additional changes have been made. The new ROM Disassembly page now features:

  • Option to show Z-80 Mneumonic with Hex, Z-80 Mneumonic with Labels, Z-80 Opcodes, and/or original 8080 Mnemonic
  • Ability to enable or disable 6 different types of notes, including original source code notes. Original source code notes will either be the Gates/Allen source code, or the Frank Durda IV source code for routines added onto the Model I v1.0 for the Model III
  • The page permits viewing 5 Model I ROM versions, 5 Model III ROM versions (including the German ROM), and 7 Model 4 ROM versions. To open the page to any specific disassembly
  • Additional routine header commentary has been added
  • The page has been optimized again.

May 20, 2026 - Model I Disassembly Page Drastically Rewritten

When I was updating the Model III page based on the original source code, correcting a whole lot of errors in the process, I realized that the Model I page, which was the first diassembly done, had a LOT of flaws: Typos, bad jumps, etc.

What I decided to do was to take all the work I had just done on the Model III and back port it to the Model I page, but to include the original labels, the original 8080 source code and comments by Gates/Allen, and options to use labels or hex.

So the new page will generate based on the 5 different Model I ROM versions, and then you can choose whether your want Hex or Labels (or both), the Z-80 Opcodes, the 8080 Opcodes, and you can customize up to 5 different types of commentary.

The result is a web page which is built on the fly based on user preference through check boxes - albeit a 3MB page, so a touch of patience is required for your browser to build the page per your specifications.

The new page is here

The old pages are still present, but not linked - they can be found here

May 12, 2026 - TRS80Tools Updated to v2.8.9

Lawrence Kesteloot has released an updated copy of his trs80tools, now new version 2.8.9. Updates are to the DISASM command as follows:

  • No longer automatically specifies Model III ROM entry points when disassembling a ROM since the ROM might not be for a Model III.
  • When specifying the --no-labels flag, jumps to the current address will list the address and not the $ symbol.
  • Data now uses DEFB instead of .BYTE.
  • Disassembly warnings are now sent to standard error instead of standard out.

You can download it for the Windows, Mac, and Linux at https://www.my-trs-80.com/tool/#installation.