Radio Shack TRS-80 model III Owner's Manual page 24

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
1
'
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