Copying Programs; Validating The Diskette - Commodore 1541 User Manual

NOTE:
Du~I
dri".'es mai:e
full~r
use of this command, copying programs from one
dis~c
to another in a single disk unit. To do that on the 1541, refer to Appendix E to find
programs that you need.
COPYING PROGRAMS: BASIC 3.5
. The Copy command allows you to make a spare copy of any program or file
ot
diskette. However, on a single drive like the 1541, the copy must be on the same disk
which means it must be given a different name from the file copied. The source file
other files on the diskette are not changed. Files must be clo ed before they are copic
Although the 1541 supports a Concatenate option, Basic 3.5 doesn't have a
spe~
command for it. The Basic 2 syntax from the previous page may be used instead. ·
FORMAT FOR THE COPY COMMAND
COPY Ddrive #,"old file" to Ddrive #,"new file",Udevice #
where "D" is the drive number (always
0
on the 1541,) " new file" is the copy ,
"o
file" is the original, and "U"
is the device number. If omitted, the drive number
defa~
to
0
and the device number (unit) to
8.
EXAMPLES:
After renaming a file named "BOOT" to "TEMP" in the last section's example,
1
can use the Copy command to make a spare copy of the program elsewhere on
u
diskette, under the original name:
COPY "TEMP" TO "BOOT"
To copy a file on a second disk drive, we would use:
COPY "ORIGrNAL" TO "BACKUP'',U9
NOTE: Dual drives make fuller use of this command, copying programs from one diske1
to another in a single disk unit. To do that on the 1541, refer to Appendix E to find rl
programs that you need .
VALIDATING THE DISKETTE: BASIC 2
The Validate command recalculates the Block Availability Map (BAM) of
d
current diskette, allocating only those sectors still being used by valid, properly-clo
files and programs . All other sectors (blocks) are left unallocated and free for re-use,
ar
all improperly-closed files are automatically Scratched. However, this bare descript ion
its workings doesn't indicate either the power or the danger of the Validate
command. I
power is in restoring to good health many diskettes whose directories or block availabili'
maps have become muddled . Any time the blocks used by the files on a diskette
plus ~
blocks shown as free don't add up to the 664 available on a fresh diskette , Validate
needed, with one exception below . Similarly, any time a diskette contains an improper!'
38
oscd
file (splat file), indicated by an asterisk(*) next to its file type in the directory, that
'~sk
tte needs to be validated. In fact, but for the one exception below, it is a good idea to
di
·~te
diskettes whenever you are the least bit concerned about their integrity.
\'all The exception is diskettes containing Direct Access files, as described in Chapter 7 .
1
direct access (random) files do not allocate their sectors in a way the Validate
M:mand can recognize . Thus, using Validate on such a diskette may result in un-
c~ocating
all direct.access files,
wit~
loss of all their c?ntents
wh~n
other files_
~e ad~ed .
~
Jess specifically instructed otherwise, never use Vahdate on a diskette containing direct
n
ess files . (Note: these are not the same as the relative files described in Chapter 6.
~idate
may be used on relative files without difficulty.)
FORMAT FOR THE VALIDATE COMMAND
PRINT#\5 , "VALIDATEO"
or abbreviated as
PRINT#15 ,"VU''
where "O" is the drive number (always
0 on the 1541.) As usual, it is assumed file 15 has
been
opened to the command channel on the 1541 .
EXAMPLE:
PRINT#l5, "VO'
VALIDATING THE DISKETTE: BASIC 3.5
The Collect command in Basic 3.5 is the same as the Validate command in Basic 2.
It recalculates the Block Availability Map (BAM) of the current diskette , allocating only
those sector still being used by valid, properly-closed files and programs . All other
sectors (blocks) are left unallocated and free for re-use, and all improperly-closed files are
automatically Scratched . However, this bare description of its workings doesn't indicate
either the power or the danger of the Collect command . Its power is in restoring to good
health many diskettes whose directories or block availability maps have become muddled.
Any time the blocks used by the files on a diskette plus the blocks shown as free don ' t add
up to the 664 available on a fresh diskette , Collect is needed (with one exception below .)
Similarly, any time a diskette contains an improperly-closed file (splat file) , indicated by
an
asterisk (*) next to its file type in the directory , that diskette needs to be collected . In
fact, but for the one exception below, it is a good idea to collect diskettes whenever you
are
the least bit concerned about their integrity . Just note the number of blocks free in the
diskette's directory before and after using Collect, and if the totals differ, there was indeed
a
problem, and the diskette should probably be copied onto a fresh diskette file by file ,
Using the Copy command described in the previous section , rather than using a backup
cornrnand or program.
M
The exception is diskettes containing Direct Access files, as described in Chapter
7.
OSt direct access (random) files do not allocate their sectors in a way Collect can
recognize . Thus , collecting such a diskette may result in un-allocating all direct access
39