VERIFY= (CONFIG.SYS Command)
Purpose: This causes DOS to enable or disable a low-level disk function
which checks each disk sector after it is written.
The Verify command does the same thing
ON turns on write-verification (maximum safety).
OFF turns it off (better speed).
The default setting is VERIFY=OFF.
■ You can do this in your program via DOS fn 2eH (set/reset verify).
■ Verify ON does NOT compare written data to data in memory. It performs
an INT 13H 04H (verify sectors) on data after it is written. That fn
compares the ECC▲ recorded in the sector with the ECC calculated by the
■ Internally, DOS toggles VERIFY ON when it writes FAT and directory
information. Leaving VERIFY ON all the time will degrade disk
performance, especially on floppy diskettes.
See Also: CONFIG.SYS Commands