Chapter 21 Meet Your Disk - Tandy TRS-80 Owner Manual & Programming Manual

MEET YOUR
DISK
Note: Upgrading your
tape
system?
Note
the
differ-
ence:
SAVE
stores
a
program
on
disk;
CSAVE
stores
it
on tape
I
RUN
CENTER)
MEMORY
VS
DISK
STORAGE
To
those of
you
new
to
computers,
we
would
like to
expound
a
little
on computer "memory."
If
you
already
know what
it is,
skip
down
to
the
next
heading
—
"Loading
a File
from
Disk!'
Whenever
you
type a
BASIC
program
line
and
press
(ENTER)
,
the
Computer
automatically puts
it
in its
memory. Once
it's
in
memory, you can do
things with
it.
For example,
type:
RUN
[INTER]
Your
Computer PRINTs:
STORE
ME IN
ft
DISK FILE
AND
YOU'LL NEVER LOSE
ME
To
list
the
program
as
you have
it
above, type:
LIST
dNTEFD
Memory
is
where
the
Computer
keeps track
of
everything
you
tell
it.
Once you
put your
infor-
mation
in
its
memory,
the
Computer
can
print
it,
rearrange
it,
combine
it,
or
any
of
the other things
you
want done with
it.
Later
on, you'll
probably
want
to
put other
things,
such as
your mailing
list,
in
memory. To
do
this,
you'll
need
to
write or
purchase
a
program
written
especially for
that application.
This
"application
program"
will
get the
Computer
to
put the
infor-
mation
you type
into
memory.
The important thing
to
remember
about
memory
is
that
turning
off
your
Computer
erases
it.
Once
memory
has been
erased, there's
no
way
to
recover
it.
The
only
way
to
keep
a
permanent
copy
of
what
you've typed into
memory
is
by
storing
it
on a disk
(or tape).
LIST
[
ENTER)
Although
NEW
erased the
program
from memory,
"SIMPLE/PRO"
is still
safely stored
on your
disk.
You can put
"SIMPLE/PRO"
back
into
memory
anytime you
want by
"loading"
it
from
disk.
To do
this,
type LOAD "SIMPLE/PRO"
[ENTER]
.
Again,
you'll
hear
some
promising noises
from
your disk
drive.
The Computer
is:
•
reading the directory to find
where "SIMPLE/
PRO"
is
stored.
going
to
that location
on
the disk
and reading
the
contents of
"SIMPLE/PRO."
•
putting
"SIMPLE/PRO"
into
its
memory.
You can
now
type one
or
both of these
commands
to
verify that
"SIMPLE/PRO"
is
in
memory:
LIST
(ENTER)
RUN
(ENTER
)
LOADING
A
FILE
FROM
DISK
Type NEW
[ENTER)
to
erase everything
in
your
Com-
puter's
memory. To
make
sure everything's erased,
you can type one
or
both
of these
commands:
MORE
ABOUT
MEMORY
VS
DISK
STORAGE
If
you're
still
a
little
fuzzy
about what's in
memory
and
what's
on your
disk, try this exercise.
You've
9