Reusing An Old Diskette; Organizing A Diskette Library; Backups - Commodore 1541 User Manual

number of the.1541, normally 8; the drive number, always 0 on the 1541; any
desi ~
name for the diskette, up to 16 characters in length, followed by a
2
character diskette
In
number. The Close command is often optional; just don't Open that same file agai
without Closing it the first time. .
1
EXAMPLE:
OPEN 15,8,15,"NO:MY FIRST DISK,Ol" : CLOSE 15
Note: the chattering or thumping noise you hear just after the disk New commClll!
begin. s is entirely
no~al.
The disk must be sure it is at track 1, which it assures b)
stepping outward 45 times (on a 35 track diskette .) The noise you hear is the hea1
assembly hitting the track I bumper after its inevitable anival .
HOW TO PREPARE A NEW DISKETTE: BASIC 3.5
A diskette needs a pattern of magnetic grooves in order for the drive's
read/wri~
head to find things on it. This pattern is not on your diskettes when you buy them , bu
adding it to a diskette is simple once you know to do it. Here is the procedure:
FORMAT FOR THE HEADER COMMAND
HEADER "diskette name" ,lid,Ddrive #,Udevice #
Where "diskette name" is any desired name for the diskette, up to 16 characters ir
length; "id" is a
2
character diskette
ID
number; "drive #" is the drive number,
0
u
omitted (as it must be on the 1541); and "device#" is the disk's device number, assumel
to be 8 if omitted . As described in the next page, "id" is optional if (and only iO tlK
diskette has been previously formatted on a 1541 . Also, the
ID
must be a string literal ,
no
a variable or expression, and may not include Basic reserved words . Thus, ",IFI" canna
be used because If is a Basic keyword, and ",l(A$)" is not allowed because A$ is
1
variable. " ,IA$" is allowed, but the ID number will be the letter "A" plus a dollar sigr
($),not the contents of the variable A$. If you need a variable
ID
number, use the Basic :
form of the format command .
EXAMPLE:
HEADER "MY FIRST DISK,lOl,DO"
Note: the chattering or thumping noise you hear just after the Header
comm~
begins is entirely normal. The disk must be sure it is at track 1, which it assures b)
stepping outward 45 times (on a 35 track diskette). The noise you hear is the heac
assembly hitting the track 1 bumper after its inevitable.anival.
REUSING AN OLD DISKETTE
After you have once formatted a particular diskette, you can re-format it as thopgh
1
were brand new at any time, using the above procedures. However, you can also chan8'
its name and erase its programs more quickly and easily by omitting the
ID
number it
•
16
your fonnat command . By leaving off
the ID number,
the format command will finish in a
few seconds instead of the usual
90
seconds .
ORGANIZING A DISKETTE LIBRARY
Though you may not believe it now , you will eventually have dozens, if not hundreds
of diskettes . You can ease life then by planning now . Assign each diskette a
unique ID
number when you format it. There are diskette cataloging programs you can buy, that
store and alphabetize a list of all your file names , but are of limited value unless your
diskette ID numbers are unique
.
At least two valid approaches are used in assigning
ID numbers
. One starts at
00 with
the first diskette, and continues upward with each new diskette, through 99, and then
onward from AA through
ZZ .
Another organizes diskettes within small categories, and
starts the ID number for each diskette in that category with the same first character, going
from Oto 9 and A to Z with the second character as before. Thus, all "Tax " diskeues
could have ID numbers that begin with "T." Either approach works well when followed
diligently.
While on this subject , may we suggest you choose names for diskettes on the same
basis , so they too will be unique , and descriptive of the files on them .
BACKUPS
When to do a Backup
Although the 1541 is far more reliable than a cassette drive under most circum-
stances, its diskettes are still relatively fragile, and have a useful life of only a few years in
steady use . Therefore, it is important to make regular backups of important programs and
files. Make a backup whenever you wouldn't want to redo your current work. Just as you
should save your work every half hour or so when writing a new program, so you should
also back up the diskette you 're using at least daily while you are changing it frequently .
In a business, you would make an archival backup every time important information was
due to be era ed , such as when a new accounting period begins.
How to do a Backup
We have included programs on the Te t/Demo diskette that can be used for similar
purposes . These programs are described further in Appendix E.
How to Rotate Backups
Once you begin to accumulate backups , you'll want to recycle older ones. One good
method is to date each backup . Then retain all backups until the current project is fini shed .
When you are sure the last backup is correct , make another backup of it to file. and move
all older backups to a box of diskettes that may
be
reused .
One other popular approach, suited to projects that never end, is to rotate backups in
a
eh ·
am, wherein there are son backups , father backups . and grandfather backups . Then .
when another backup is needed , the grandfather
di~kette
is reused, the father becomes the
grandfather, and the son becomes the father. ·
h Whichever approach is used , it is recommended that the newly-made backup become
~t
diskette that is immediately used , and the diskette that i known to
be
good should be
th ed away as the backup . That way , if the backup fail s, you 'II know it immediately, rather
an after all the other backups have failed some dark day .
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