Computer Interfacing

Magnetic recording principles and methods

When a write operation takes place, the new file is re-

corded at the next free sector onwards, and its name and

other details are written into the directory. In the event

that a file of that name already exists, the original file

may be modified to include a .BAK extension to the end

of its file name, and in this original form will still exist

while the new version is added to the disk.

The operation of deliberately erasing a file, say by issu-

ing the ERASE command, does not actually affect the

recorded data at all. It merely erases the entry for that

file in the directory, so allowing further file