verifyfd is a CLI tool for AmigaOS 2.04 and newer that tests floppy disks
for defects. It writes a series of byte patterns across the entire disk
surface, reads them back, and reports any sector that does not compare
equal.

WARNING: verifyfd is DESTRUCTIVE. It overwrites the complete contents of
the disk in the selected drive. Make sure the disk holds no data you wish
to keep, then confirm the prompt before the test begins.

The following passes are run, in order:

    1. 0x00 fill
    2. 0xFF fill
    3. 0xAA fill
    4. 0x55 fill
    5. address-in-data

The address-in-data pass encodes the absolute byte offset of each 32-bit
word into that word. This catches seek and track-positioning errors that
uniform fill patterns cannot detect.

For every track verifyfd writes the pattern, flushes it to disk, reads it
back, and compares. On a mismatch it prints the cylinder, side, sector,
byte offset, and the expected and actual values, then stops. Underlying
trackdisk.device errors (write-protect, seek error, bad checksum, ...) are
reported with a readable message. The test can be interrupted at any time
with Ctrl-C.

Usage:

    verifyfd <unit>

where <unit> is the floppy drive number 0..3 (0 = DF0:, 1 = DF1:, ...).

Requirements:

    - AmigaOS 2.04 (Kickstart V37) or newer
    - a double-density floppy drive (80 cylinders, 2 heads, DD)

The executable is a single file and can be run from any location.

License:

    MIT. See the included LICENSE file for details.

Contact:

  Mastodon: https://mastodon.online/@daspilker
  E-mail:   aminet@daniel-spilker.com
  Web:      http://www.daniel-spilker.com

 PERMSSN    UID  GID    PACKED    SIZE  RATIO METHOD CRC     STAMP          NAME
---------- ----------- ------- ------- ------ ---------- ------------ -------------
-rwxr-xr-x     0/0        3131    5136  61.0% -lh5- 35c6 May 31 07:33 verifyfd
---------- ----------- ------- ------- ------ ---------- ------------ -------------
 Total         1 file     3131    5136  61.0%            May 31 16:32