SOFTWARE COMPARISON OF 
CURRENT "ANALYTICAL PLOTTERS" 
Model operating common Real Time orient. Real Time 
system area loop programs cycle 
AP/C-3 1,6 X 0,6. K 6 K disk 352 m sec 
  
U.S. 1 
Anaplot 
Traster 77 
AP/C-3T 
AP/C-4 
Planie. C 100 12 K 1,5 K 6 K 20 m sec 
Stereodicom. 
"DIGITAL STEREOCARTOGRAPHS" 
20m sec 
" STEREOCORDS" 
Stereocord l seo display 
0,15 seo caleul. 
Table 5 
The classical real time program is as shown for the AP/C-3; 
Figure 3 
due to real time cycle restrictions of 32 msec at machine cycle 
times of 3600 nsec one previously had to branch off into several 
loops in which slow changing expressions (such as photo and model 
corrections as well as panel interrogation and input output) were 
reached every 6 x 32 = 192 msec. 
Figure 4 
Today multiprogrammable priority interrupts now permit working 
at various priority levels. The machine does not need to wait 
for one fixed clocked interrupt, but it can finish high priority 
computations first and then work on lower order priorities.