Tandy TRS-80 4D - Page 11

Chapter
1
How
Computers
Work
Your
disk
system
consists of
hardware and
software.
The equipment
is
the hardware.
The
instructions
that
tell the hardware
what to
do
are
software,
also
called programs
or systems.
As you
can see,
hardware and
software
are
dependent upon
each other.
Computer
Hardware
This picture
shows
the
parts of the
hardware
and
how
they relate to
each
other:
\#*
Keyboard
Memory
V
-
nSSi!
4t
-_-
^
Processor
-*
Diskette
Keyboard.
For entering
information
into
the
computer.
Screen and
Printer.
For
receiving
information
from
the computer.
Memory.
For
storing
information and
software
inside
the
computer.
There are
two kinds
of
memory:
•
Random access
memory
(RAM)
—
for tem-
porary storage
of
information and
software
that you
enter.
When you
turn off
the com-
puter,
the contents of
RAM
disappear.
•Read-only
memory
(ROM)
—
for perma-
nent storage
of
essential,
built-in
software,
such as
the software
that
tells
the computer
what to do
when you
turn
it
on.
You
cannot
change
the contents
of ROM.
1