Craig's Parallel Cyclic Redundancy Check is a neat bit of code for the Commodore 64 that will give you the CRC value of a file on your floppy drive.  Just edit the F$ value on line 1 to match the name of the file on the disk you want the CRC for.

CRC32 is an error checking program. When run, the program will ask for the name of a file. It will scan the file and report the "CCITT CRC-32" value. When transferring a program over a modem or with a copy program, you can run this program on that file before and after to make sure you got a 100% identical copy. Docs are on the disk. This program will work both on a c64 and c128.

File Tester 2 examines files on a disk for file, length, link and BAM errors.  It won't work with Relative Files (REL) or GEOS files (VLIR).

Written by Will Corley, Kwiksum is a file utility that lets you get the total bytes, blocks and checksum value for a file.

New Directory by Kevin Hisel (August 2nd, 1986) - Not to be confused with the other "New Directory" utility posted on this site that lets you change the order of files on a disk, this utility instead will tell you some useful information about the files on a disk, such as the starting Track & Sector and the total space used by all the files.  It's also handy because once loaded, it hangs out in memory at location 49152 so that you can change disks and just SYS 49152 to run it again.  This might come in handy if used in conjunction with a disk checker such as "Disk Tester v1.0" to find out exactly which file is in a bad area of the disk so you can at least salvage the other files.

Rescratch can save your bacon if you accidentally delete a file.  This quick fix will unscratch your file.

This tools is along the lines of a crc32 check but uses it's own formula. Basically you run it on a disk, select the files you want checks for and it creates a file called "sacaid diskccheck" on the disk that you use to check the files after a transfer. The fastloader built into this tools doesn't work with VICE.

TrackSaver by Wayne Schmidt (1986) - This is a neat little utility that will let you buffer up 5 tracks and save them to a file that can be sent to someone else for examination.  The program can be used to write those tracks back to another disk for analysis.  Instructions are built into the program.

Written by Rick Kephart and released on September 6th, 1989. Unsplatter will fix files that weren't properly closed and have an * in the directory.

Written by Will Corley. Vitals will analyze a file on disk and give you the following info: file type, block size, number of bytes, start address, starting track & sector.