An OS4 port of the CBM 1541 filesystem by Michael Krause:
http://aminet.net/package/misc/emu/FS1541-13

Installation:

Copy CBM1541FileSystem SYS:L/
Copy def_CBM0.info ENVARC:Sys/

Usage:

Example DOSDriver for mounting .d64 files with diskimage.device is
included. Simply drag the ICBM0 file into either SYS:Devs/DOSDrivers or
SYS:Storage/DOSDrivers.

For using it with another device than diskimage.device you must modify the
Device/Unit information in the icon tooltypes (currently these are set to
diskimage.device unit 2).

Changes:

2.3 (27-Oct-2010)
 - Removed obsolete filesystem code for providing a virtual Disk.info file and
   added a nicer default icon to the archive instead

2.2 (23-Sep-2010)
 - Updated to use AllocDosObject/FreeDosObject instead of AllocVec/FreeVec for
   allocating/freeing volumes and file locks
 - Added code for freeing volume nodes after removing them
 - Added support for ACTION_SHUTDOWN packet

2.1 (21-Sep-2010)
 - Now uses standard FileSysStartupMsg instead of custom startup string for
   device/unit data
 - Renamed from 1541-Handler to CBM1541FileSystem
 - Added support for ACTION_COPY_DIR_FH, ACTION_PARENT_FH and ACTION_EXAMINE_FH
   packets

1.4 (3-Dec-2007)
 - Ported to OS4
 - Fixed several, not memory related, "not enough memory" errors

--- original readme ---

Forget all those nasty tools to read files from 1541 disks:

FS1541 is a full-blown AmigaDOS file system, which reads and writes the CBM
1541  disk  format.   The  CBM 1541 floppy drive has been the standard disk
drive  for the C64 computer series, and many people still have disks flying
around.   In  order  to  process  disks  directly, you need the >Catweasel<
floppy  disk  controller  and a 5.25 inch drive, without it you have to get
"fmsdisk.device" from Aminet or somewhere, which lets you operate on ".d64"
disk image files.

Complete source in C is included.

V1.3 (01-Jan-99) (most changes by John "Graham" Selck)
- Improved error handling. Finally retries on errors are done.
- BAM handling is more secure now.
- Slightly adjusted block allocation algorithm
- Support for illegal directory filetypes
- Some minor bug fixes.