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Editing Files: Developer Workflow

You can work with files for the Altair CP/M system in two primary ways:

  1. External editor on your host (Recommended) – Edit locally with a modern editor such as Visual Studio Code. This gives you syntax highlighting, search, Copilot / LLM assistance, version control, etc.
  2. On‑emulator editing (Word-Master) – Edit inside the emulated CP/M environment using the bundled Word-Master editor. Authentic, but slower and less ergonomic for substantial changes.

Follow this fast loop for most development:

  1. Pick an editor – Example: Visual Studio Code (with optional Copilot / LLM assistance).
  2. Create a folder on your host computer to hold your source files.
  3. Create or modify your source – Edit as normal on your host (BASIC, C, ASM, etc.).
  4. Build C on the host using dcc and the app's build-app.ps1, or use dccmake for a build without installing into a disk image. See C Programming.
  5. Make text/assembly files available to FT. ESP32 uses its configured remote FT server. The retired GF HTTP utility and BDS build workflows are not supported.

  6. Transfer a file into CP/M with the current FT client:

    ft -g games/awari.bas

    (File names are case‑insensitive; CP/M convention is uppercase.)

  7. Run or build – Examples:

    • BASIC: mbasic awari.

Repeat the edit/build/transfer steps as you refine your program. FT -g normalizes text to CP/M line endings; use -gb for a prebuilt .COM file. FT is not an arbitrary HTTP/GitHub downloader.

Automating Transfers & Builds with CP/M SUBMIT

Current .SUB workflows fetch and assemble the retained assembly apps. For example:

b:
ft -g date/date.sub
submit date

The MCP build server can run these workflows automatically. C applications are built with dcc on the host, not with the removed BDS SDK/compiler.

Editing Files with the Word-Master Text Editor

The emulator bundles MicroPro Word-Master. Historically powerful, but spartan compared with modern editors.

Ten‑minute video introduction

Fastest workflow: edit with Visual Studio Code, then transfer with FT. The historical video uses an older transfer workflow:

▶ Video: Editing Files Workflow (YouTube)

If embedding is required later, update the markdown linter configuration to allow iframe (rule MD033) and restore the embed.

Editing inside Word-Master

Preferred path remains: local editing and FT transfer. For the authentic experience:

  1. Toggle the web terminal to character mode (Ctrl+L).
  2. Launch Word-Master (e.g., wm filename.asm).
  3. Use the control key commands below for navigation / editing.
  4. When finished, exit Word-Master, then toggle back to line mode (Ctrl+L) for faster terminal interaction.

Screenshot of Altair running the Word-Master text editor.

For full details see the Word-Master user guide.

The following table lists the Ctrl characters that Word-Master uses. This list is sourced from the Experiencing the Altair 8800 blog.

VIDEO MODE SUMMARY

^O   INSERTION ON/OFF           RUB  DELETE CHR LEFT
^S   CURSOR LEFT CHAR           ^G   DELETE CHR RIGHT
^D   CURSOR RIGHT CHAR          ^\   DELETE WORD LEFT
^A   CURSOR LEFT WORD           ^T   DELETE WORD RIGHT
^F   CURSOR RIGHT WORD          ^U   DELETE LINE LEFT
^Q   CURSOR RIGHT TAB           ^K   DELETE LINE RIGHT
^E   CURSOR UP LINE             ^Y   DELETE WHOLE LINE
^X   CURSOR DOWN LINE           ^I   PUT TAB IN FILE
^^   CURSOR TOP/BOT SCREEN      ^N   PUT CRLF IN FILE
^B   CURSOR RIGHT/LEFT LINE     ^@   DO NEXT CHR 4X
^W   FILE DOWN 1 LINE           ^P   NEXT CHR IN FILE
^Z   FILE UP 1 LINE             ^V   NEXT CHR(S) TO VIDEO
^R   FILE DOWN SCREEN           ESC  EXIT VIDEO MODE
^C   FILE UP SCREEN             ^J   DISPLAY THIS

In character input mode, these host key mappings help mirror Word-Master's control sequences:

Keyboard key            Word-Master Ctrl Sequence
----------------------------------------------
Insert                  ^O   INSERTION ON/OFF
Delete                  ^G   DELETE CHR RIGHT
Cursor Left             ^S   CURSOR LEFT CHAR
Cursor Right            ^D   CURSOR RIGHT CHAR
Cursor Up               ^E   CURSOR UP LINE
Cursor Down             ^X   CURSOR DOWN LINE