Atari 800

146 User's H andbook to the Atari 400/ 800 Computers
Table 5-1. I/O Operations
Operation
Device
Number
Operation Type
Program R eco rder
4 input
8
output
Keyboard
4
input
Printer
8
output
Editor
8 output :screen
input: keyboard
12
output :s creen
input:scre en
13
output :screen
Disk
4
Input
6
read disk directory
8
output, n ew file
9
output, append
12
input and output, update
Interface
5
co ncurrent input
8
block output
9
co ncurrent output
13
conc urrent input and output
The third argument of an OPEN statement indicates a special
operation. The special operation code is usua lly O. Generally, the
third argument is only used when opening the screen display for
a graphics mode .
If any of the first thr ee arguments of an OPEN statement are not
integers, they are rounded off.
The fourth argument of an OPEN statement is the device name.
The device names
us ed by Atari computers are listed below. The
device name and file specification (if present) must be enclosed
in quotation marks.