C H A P T E R 3
The ORIC Microdisc System
I N T R O D U C T I O N
W h e n you purchase an O R I C microdisc system you get (in addition to
this User Guide) a disc drive unit for 3 inch microdiscs, a p o w e r unit and
a 3 inch microdisc. You will need to purchase some additional
microdiscs for storing data, your dealer should be able to supply these.
T H E DISC O P E R A T I N G SYSTEM
The microdisc which is supplied is called the 'system disc' and on each
side is written a set of c o m p u t e r p r o g r a m s which are known collectively
as the Disc Operating System (DOS) and without which the microdisc
system will not work. When you connect up and switch on (see C h a p t e r
4) the D O S is loaded into the c o m p u t e r R A M automatically. Once this
has h a p p e n e d you can give instructions to the c o m p u t e r telling it how to
use the microdisc drive(s). In addition to the D O S , there is also a lot of
information on the system disc, in the form of 'help' pages and we shall
tell you how to use these in C h a p t e r 5.
L e t ' s talk a little m o r e about the D O S and what it does. The D O S is in
fact seventeen completely separate p r o g r a m s (all of which p e r f o r m
different microdisc functions) and there are seventeen different
instructions which you can give to the c o m p u t e r (one for each D O S
p r o g r a m ) . We will not discuss the microdisc instructions in detail at the
m o m e n t , this comes later in C h a p t e r 5.
When you type in an instruction, the c o m p u t e r selects the appropriate
D O S p r o g r a m f r o m its R A M and then 'runs' the p r o g r a m , which results
in the instruction being carried out. W h e n the instruction is completed,
control of the system is returned to the k e y b o a r d so you can type in
a n o t h e r instruction.
