173 
than abort the task (or go to.another terminal) he may suspend it 
2 and run the overlooked task in its place. When all the required 
results are available the suspended task may be restarted. 
BATCH VS. INTERACTIVE SOFTWARE Many image processing algor- 
ithms require substantial processing time, ranging from minutes to 
hours, depending on the size of images and complexity of the algor- 
ithms. In order to make most efficient use of the user's time, such 
a task is divided into an operator interaction section and a proces- 
sing section. The operator interaction task guides the operator 
through the selection of processing parameters, and when complete, 
creates a batch control file containing. the selected parameters. 
The processing task reads this batch control file and performs the 
actual processing. An ARIES batch scheduler task (available only 
with A2ASP/X software) controls the Scheduling of the processing 
tasks. 
There are several benefits to this approach. For one thing, 
the actual processing of a job does not have to take place immedi- 
ately after the operator interaction. It can be delayed until a 
more suitable time, such as at night, when the System is less heav- 
ily loaded. In addition, the processing does not have to take place 
on the same system as the interaction. Thus a network workstation 
can perform the operator interaction portion of a job, and then sub- 
mit the actual processing to the host, which may be a more powerful 
processor, or may possess a required peripheral. 
The use of the batch concept allows expensive peripherals, 
such as image recorders and tape drives, to be interfaced to the 
host but to be accessed via user interaction on & network work- 
station. The A2ASP software package makes all peripherals in the 
network accessible from the user's system.