[kot_manul]

You're correct; slot 6 for instance is $C600. If you crashed to the system monitor you could boot a disk by entering C600G (with the 'G' standing for 'go to').

IIRC the disk controller had firmware that loaded the first 256 byte sector from disk into memory.

[Dwedit]

If you crashed to the monitor, you could hit Ctrl+B and get back to BASIC, then type IN#6 to boot the disk.

[Joe_Cool]

Yeah. It was neat. But it rebooted in under a second so a complete crash was no biggie.

RAM wasn't even cleared so usually no (or limited) data loss.

I thought it was PR#6 (redirect output) to boot from the disk controller in slot 6. I wonder what redirecting input would do.

[raw_anon_1111]

That was it at the AppleSoft BASIC prompt (or IN#6). But the parent poster commented on how to do it from assembly.

[Joe_Cool]

There is an even quicker way from the monitor:

6 CTRL+P

Will instantly divert output to slot 6. (and boot the disk if there is hardware there)

[Polizeiposaune]

Both worked to start a boot from the disk controller in that slot.