Radio Shack TRS-80 Owner's Manual page 141

Fie
Access
This section
is
divided into
four
parts:
1
Creating
files
and assigning buffers
—
open and
close
2.
Statements
and
functions
3.
Sequential
i/o
techniques
4.
Random
i/o
techniques
If this is
your
first
experience with disk
file
access,
you should concentrate
on
parts
1 ,
3
and
4,
perhaps
just
skimming through
part
2
to get
a general idea of
how
the functions
and statements
work.
Later
you can go back
to part
2 and
learn the details
of statement
and function syntax.
Creating
Files
and
Assigning Buffers
During
the initialization
dialog,
you
type
in
a
number
in
response
to
how many
files?
The number you
type
in
tells
basic
how many
buffers to
create to
handle
your
disk accesses (reads
and
writes).
Each
buffer
is
given
a
number from
1
to 15. If
you
type:
HOW MANY
FILES? 3V
(ENTER)
basic
sets
aside 3 buffers,
numbered
1,2,3.
You
can think
of a buffer
as
a waiting area
that
data
must
pass
through
on
the
way
to
and from
the disk
file.
When
you want
to
access a particular
file,
you
must
tell
basic
which
buffer
to
use
in
accessing that
file.
You must
also
tell
basic
what kind of access
you want
—
sequential output, sequential input, or
random
input/output.
All
this
is
done
with the
open
statement,
and
"undone"
with
the
close
statement.
OPEN
Open
a
Fie
open
mode,
buffet, file,
record-length
i
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carting
si
the frs? ^c-sit, ij
#<?
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'*
^-
^'- r,r -
it
will
be created.
123