Radio Shack TRS-80 Owner's Manual page 33

TRSDOS
m
Description of
TRSDOS
What
Is
TRSDOS?
trsdos
(pronounced "triss-doss")
stands for
"trs-80 Disk Operating System.'
It
fulfills
three
roles:
1
Master
Program
2.
Command
Interpreter
3
Program Manager
As
the
master program, trsdos
enables the
microprocessor and
its
various
components
to
interact
efficiently.
The components
include:
•
Random
Access
Memory
(ram),
trsdos
reserves space
for
its
own
needs and
allocates
space
for user
programs.
•
Disk
Drives,
trsdos
interfaces
with
the
disk
hardware and provides
a
file
system for storing
system and
user data
on
diskettes.
•
Input/output devices.
These include
the
keyboard, video
display, printer,
and
rs-232~c
equipment.
trsdos
is
also a
command
interpreter.
Whenever
it
displays
TRSDOS
READY,
you
may
enter
commands
that
control
how
the
system works. These
are
known
as
"library"
commands.
In
its
role as
program manager,
trsdos
will
load
and run system or user
programs. During
this
time, the
system
or user
program
is
in
control
of
the
Computer.
Figure 7
illustrates the relationships
between
these three
roles.
Where
Does
BASIC
Fit
In?
Referring
to
Figure
7,
you'll see that
Disk basic
falls
under
the
"language
package"
category.
Disk basic consists of
some
general
enhancements
to
Model
III
basic, plus
the
disk input/output capability.
It
uses
Model
III
basic (stored
in
rom) whenever
possible.
For
instance, the
Model
III
basic
rom
includes
all
of the
mathematical
functions.
If
you're used
to the
non-disk system,
there's
one
difference
you should
understand
from
the
beginning:
In the
non-disk system, basic
is
in
control
when
you
start-up. In the disk
system,
however, trsdos
is
in
control
when
you
start-
up.
You have
to
tell
trsdos
to
load
and run basic.
Only
then
can you begin
running
a
program
written
in
basic.
17