Tandy 1000 Programmer's Reference Manual page 50

Chapter 1 I System Calls
SelectDisk
Select Disk Function Call OEH
Selects the specified drive as the default drive.
Entry Conditions:
AH
=
0EH
DL
=
new default drive number
( ' 0
=
A,
1
=
B , etc.)
E xi t Conditions
:
AL
=
number
of
logical drives
Macro Definition:
s e l e c t - d i s k m a c r o d i s k
m a v d l , d l s k [ - 6 4 1
m o v a h , 0 E H
int 21
H
e n d m
Example:
The following program selects the drive not currently se-
lected in a 2-drive system.
f u n c - 0 E H : c u r r e n t - d i s k ; s e e F u n c t i o n 19H
c m p a l , 0 0 H ; d r i v e A s e l e c t e d ?
l e s e l e c t -
b ; y e s ,
s e l e c t
B
s e l e c t - d i s k "R"
;THIS F U N C T I O N
I m p c o n t i n u e
s e l e c t -
b :
s e l e c t - d i s k
"E"
; T H I S
F U N C T I O N
c o n t i n u e :
48