Commodore VIC-20 User Manual page 40

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The VIC 20 User Guide
Care of Cassette Tapes
When you use a new tape, balance the tension on the tape by fast
forwarding it to the end and then rewinding it to the beginning. This will
help prevent load errors.
Buy short tapes: 15 to 30 minute at most. This will not only reduce your
search time when running programs from the middle of your tapes, but will
ensure that you are using thicker and stronger tapes that are less likely to
stretch or break with use. Stay away from bargain brands; they tend to cause
load errors more often than high quality, low noise tapes.
Store your cassettes in a cool, dry place, away from any magnetism.
NOTE:
One of the most hazardous places to store tapes is on or near
your television, which produces a magnetic field strong enough to alter the
data they contain. Never touch the oxide coating on the tape itself; the
surface is easily scratched and can be damaged by the oils in your hands.
Cassette Tape Write·Protect
You can avoid recording (writing) over programs you want to save by
write-protecting them. Look at Figure 1-8; each cassette tape has two
write-protect tabs, one tab for each side of the tape. Breaking out a tab locks
out the
REC
(Record) key on the Datassette. Should you decide, after
breaking out a write-protect tab, that you do want to record a program on
that side of a tape, simply put a piece of tape over the write-protect opening.
DISK DRIVES
The VIC 20 can use any of the Commodore disk drives, but the model
1540 disk drive (Figure 1-10) has been designed to interface directly with the
VIC 20 through its serial port. The other drives must use a plug-in IEEE
interface cartridge to connect to the VIC 20. Table 1-3 shows the specifica-
tions for the 1540 disk drive.
The 1540 disk drive can store 174,848 bytes of data per diskette.
It
accomplishes this by putting more blocks of data on the outer (longer)
tracks of the diskette than do other disk drives.