Commodore 128 System Manual page 325

comma and a number, checks the program on the device with
that number (1 for tape, 8 for disk). The relocate flag is the same
as in the LOAD command. It verifies the program from the
memory location from which it was SAVEd. (See also DVERIFY.)
EXAMPLES:
VERIFY
Checks the next program on the tape.
VERIFY " HELLO"
Searches for HELLO on tape, checks it against memory.
VERIFY " HELLO", 8,1
Searches for HELLO on disk, then checks it against memory.
VERIFY"lastfile"
Searches tape for lastfile checks it, reports an error if there is no
match. You can then save your new program after it, without
erasing previous programs.
NOTE: If a graphic area is allocated or deallocated after a SAVE,
VERIFY and DVERIFY will report an error. Technically this is
correct. BASIC text in this case has been moved from its original
(saved) location to another address range. Hence, VERIFY, which
performs byte-to-byte comparisons, will fail, even though the
program is valid.
VOL
Define output level of sound
VOL volume level
This statement sets the volume for SOUND and PLAY
statements. VOLUME level can be set from 0 to 15, where 15 is
the maximum volume, and 0 is off. VOL affects all voices.
EXAMPLES:
VOL 0 Turns volume off.
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