Docs / Launching PRG files
Mechanism
Set the default in Settings ▸ File handling, under Mechanism (F1 / dbl-click).
| Mechanism | Behaviour |
|---|---|
| Mount A | The default. Mounts the parent disk image on drive A, like a real 1541, then loads the file. LOAD"$",8 lists the disk afterwards. |
| Mount B | Same, on drive B. Useful when you want drive A free for another disk. |
| Inject | Sends the file through the Ultimate's REST API straight into RAM. Fastest path. No drive state changes. |
The F1 cell on the key bar always tells you what will happen for the selected file - for example Load A & Run, Play for a SID or Insert for a cartridge.
Pre-reset
Settings ▸ File handling ▸ Pre-reset sets what happens before every launch:
- None - launch into the current C64 state. Safest default.
- Hard reset - reset the machine first, for a clean BASIC prompt.
- Reboot Ultimate - full firmware reboot. Disconnects active sessions. Only offered when Allow Reboot-Ultimate as a pre-reset is ticked; it is off by default.
Post-action
The arrow next to the Run button in the toolbar picks the post-action: Load and Run, Load only, Inject and Run or Inject only.
- Run - executes RUN after load. Default for most users.
- Load only - leaves the C64 at the BASIC ready prompt for inspection.
F1 and friends
F1 alone runs the configured default. Hold modifiers to override:
| Keys | Action |
|---|---|
| F1 / Enter | Default mechanism and post-action |
| Shift+F1 | Same, from the other drive (A ↔ B) |
| Ctrl+F1 | Run, even when the default is load only |
| Alt+F1 | Load only (no run) |
| F9 / Shift+F9 | Mount the disk on drive A / B without running |
| Ctrl+F12 | Hard reset, then run |
| F12 / Shift+F12 | Hard reset / reboot the Ultimate |
Running in an emulator
No Ultimate, or just want a quick look? The Run on section of the toolbar's Run menu switches the launch target from the C64U to an emulator. Ready-made profiles cover VICE (x64sc, x128 and VSID), Denise, Hoxs64 and CCS64; installed emulators are detected, and you can add your own on the Settings ▸ Emulators tab. F1 then reads Run ▸ <emulator> and F9 attaches the disk instead of mounting it. Ctrl+Enter and Alt+Enter open the selected file in the emulator (autostart / attach only) whatever the target.
SID tunes and Compute! Sidplayer .mus files play the same way, on the Ultimate's SID chip or in an emulator. More on the hardware side on the Ultimate page.