Compucolor file system

The Compucolor file system was used on Compucolor II disks, a 5 1/4" floppy disk format. Some details of the format are documented in the "tech info" link below.

The program code that handled the file system was burned into ROM on the CompuColor computer, so it was fixed in structure and unable to be upgraded without hardware replacement.

Directory records started in sector 0 (sectors on the disk were numbered from 0 to 399), with the first directory sector containing the number of directory sectors (usually 3) and a disk volume label along with 5 directory entries; subsequent directory sectors had 6 directory entries. Filenames were 6 characters plus a 3 character extension/filetype. Sectors (directory and file content) were assigned sequentially, and file deletions required moving the remainder of the disk contents backward to preserve the contiguousness; this required memory buffering which used the display memory temporarily, causing odd screen displays while the operation was in progress. Saving a file multiple times resulted in multiple versions being saved, with sequential revision numbers.

Documentation

 * Compucolor tech info
 * Maintenance manual: has some technical info
 * Podcast about CompuColor