10

The zeropage address 10 ($0A in hexadecimal) holds a flag to indicate whether a LOAD or VERIFY is being perfomed: These two operations are quite similar (the former reads bytes from a logical file and stores them in RAM, whereas the latter reads bytes from the file and compares them to what is already in RAM), and thus are handled by the same routine in KERNAL. To distinguish between the two operations, a flag is stored in this address:

• If a LOAD is to be performed, i.e. reading bytes to store them in RAM, this address should contain a zerobyte.
• To do a VERIFY, i.e. "proofreading" the stream of bytes in the file, this address should contain any non-zero value.