Drive command
From C64-Wiki
Drive commands are commands sent to a Commodore floppy drive. Using commands, disks can be formatted, files deleted, drive number changed (until powerdown typically), programs can get uploaded and executed in the drive (typically done by fastloaders), and many other things. In case an error occurs when executing the command, the red drive LED starts to flash, and a more verbose error message can be fetched from the drive.
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[edit] List of standard drive commands
Each drive comes with an own set of commands. However, normal floppies (VC-1541/70/71/81) share a standard command set, and even newer drives (SD2IEC etc.) support these commands and many more.
- NEW/N - Format a floppy disk
- Syntax: "N:label,id"
- label may be up to 16 characters long. id must be two characters. If id is omitted, the directory of the disk will be erased (disk must be formatted already).
- RENAME/R - Rename a file
- Syntax: "R:newname=oldname"
- SCRATCH/S - Delete files
- Syntax: "S:file"
- Wildcards "*" and "?" are supported.
Side note for assembler programmers: Drive commands have no terminating character - instead, the drive starts interpreting the string sent to it once UNLISTEN or CLRCHN is called (see KERNAL ROM).
[edit] Sending drive commands
Drive commands can be sent in a number of ways. Most disk copy programs or other disk utility programs include an extra menu point for sending drive commands, too.
[edit] C64 BASIC V2.0 / C128 BASIC V7.0
The C64's BASIC V2.0 does not provide a convenient way of sending drive commands. However, one can open a command channel to the drive, send the command, and close the channel:
OPEN 1,8,15,"command":CLOSE 1 :REM send command to drive 8
An example:
OPEN 1,8,15,"N:NEWDISK,01":CLOSE 1 :REM format disk in drive 8 with label NEWDISK and disk id 01
Reading the error message from the drive is even a bit more complicated as one has to read the error message using INPUT# which BASIC does not allow in direct mode, so an own small BASIC program has to be written:
10 OPEN 1, 8, 15 :REM Open Error/Command Channel 20 INPUT#1, EN$, ER$, TR$, SC$ :REM Read Message 30 CLOSE 1 :REM Close Channel 40 PRINT "ErrNr: "; EN$ :REM Display Results 50 PRINT "Error: "; ER$ 60 PRINT "Track: "; TR$ 70 PRINT "Sector:"; SC$ RUN
[edit] Final Cartridge 3
Using the FC3, commands can be sent using the new DOS"command BASIC command. Error messages get displayed by DOS without parameters.
The FC3 implements some non-standard floppy commands (fast format, change disk label TODO: add exact commands).
DOS"N:NEWDISK,01 :REM format disk in drive 8 with label NEWDISK and disk id 01
[edit] JiffyDOS
Using Jiffy, commands can be sent using @command (or @"command for S-JiffyDOS). Error messages get displayed by @ without parameters.
@N:NEWDISK,01 :REM JiffyDOS: format disk in drive 8 with label NEWDISK and disk id 01 @"N:NEWDISK,01 :REM S-JiffyDOS: format disk in drive 8 with label NEWDISK and disk id 01
[edit] Action Replay
Similar to Jiffy, the Action Replay cartridge provides an @command command for sending drive commands.
Similar to the FC3, the Action Replay implements some additional commands (N: fast format and C: TODO: unknown). If you want to prevent these command strings to be parsed by the AR instead of the drive, use @"command to send the command.
@N:NEWDISK,01 :REM fast format disk in drive 8 with label NEWDISK and disk id 01 @"N:NEWDISK,01 :REM standard format disk in drive 8 with label NEWDISK and disk id 01
