INSTRUCTIONS FOR"VCKSUM"
& "MCKSUM". VCKSUM &
MCKSUM VERIFY AND MAKE
CHECKSUMS FOR EXTENDED
MEMORY FILES. PROVIDE A
PROGRAM FILE NAME AT
"FILE NAME?" PROMPT AND
A CHECKSUM IS COMPUTED
AND PLACED AT THE END OF
THE PROGRAM IN EXTENDED
MEMORY. GETP OR GETSUB
WILL THEN RECOVER THE
PROGRAM. IF GETP OR
GETSUB WOULD NOT RECOVER
THE PROGRAM BEFORE THE
VCKSUM, THE PROGRAM MAY
HAVE ALTERED OR MISSING
STEPS.MCKSUM WILL CREATE
A CHECKSUM AT THE END OF
A DATA OR ASCII FILE.
THIS CHECKSUM CAN BE
OVERWRITTEN BY NORMAL
FILE ACCESS FUNCTIONS,
THUS VCKSUM IS INTENDED
FOR DATA VERIFICATION
PRIOR TO DATA USE AND
MCKSUM IS FOR
CHECKSUM CREATION AFTER
AFTER DATA FILE USE.
WHEN CREATING SUCH FILES
INCREASE FILE SIZE BY
1 REGISTER TO PREVENT
MCKSUM FROM OVERWRITING
STORED DATA. REQUIRED
EQUIPMENT: DEVIL MODULE
AND EXTENDED MEMORY.