Radio Shack TRS-80 model III Owner's Manual page 43

You may
want
to
use create
to
prepare
a
file
which
will contain a
known
amount
of
data. This
will usually speed up
file
write operations.
File reading
will also be
faster, since pre-allocated
files are
less
segmented
or dispersed
on
the disk
—
requiring
less
motion
of
the read/write mechanism
to locate the
records.
Examples
CREATE DATAFILE/BAS <REC=300, LRL=0)
Creates
a
file
named
datafile/bas, and
allocates space
for
300
256-byte
records.
CREATE NAMES/TXT. IRIS
(
LRL=64
iREC
=
50
)
Creates a
file
named
names/txt
protected by
the
password
iris.
The
file will
be
large
enough
to contain 50
records, each
-64 bytes long,
CREATE PAYROLL/BAG
Creates
a
file
named
payroll/bas
but
allocates
no
space
to
it.
Sample Use
Suppose you
are
going
to store personnel information
on no more
than
250
employees, and each
data record
will
look
like
this:
Name
(Up
to
25
letters)
Social Security
Number
(11
characters)
Job
Description
(Up
to
92
characters)
Then
your
records
would
need
to
be
25
+
1 1
+
92
-
128 bytes long.
You
could
create
an
appropriate
file
with
this
command:
CREATE PERSONNL/TXT
(
REC
=
250
,LRL= 128
)
Once
created,
this pre-allocated
file
would
allow
faster writing than would
a
dynamically
allocated
file,
since
trsdos would
not have
to
stop writing
periodically
to allocate
more
space
(unless
you exceed
the
pre-allocated
amount).
DATE
Reset or Get
Today's Date
mm/dd/yyi$
the specification
for
the
month (mm),
day
(*M)
and
36