Spoolers
The Reality Spooler manages the transfer of print data from Reality user processes to one or more output devices. It enables multiple users to share multiple output devices, including printers and tape units, and allows each user to dispatch print data to a device as if they had sole use.
Print jobs are generated by the Reality processors TCL, English, PROC, and DataBasic.
The following flow takes place when you want to use the printer in Reality:
print job --> Formqueue --> Despooler --> Printer
A Formqueue is the destination where you can send a print job. Formqueue assigns a set of tasks to the print job when it is created. These details entail the page skip between jobs, the width and length of the paper and so on. The job can be moved to another queue as these details are applied only when the printing job is complete.
Despoolers are assigned to formqueues to take print jobs from the head of the queue and to output them to a specific output device.
Multiple formqueues can be serviced by a single despooler, according to pre-assigned priorities. Also, multiple Despoolers can service a single formqueue. The print job at the head of the queue is despooled by the first Despooler able to take it.
An example of the print job command is as follows:
Four types of output device can be assigned to a Despooler:
-
SYS - A system printer device, configured in the host system spooler and shared by host and Reality database users.
-
PTR - A network printer, private printer (UNIX only) or port device (UNIX only), driven by Reality.
-
TAPE - A tape device configured in the Reality environment.
-
FILE - An ordinary Reality file.
A simplified diagram to explain the spooler configuration is as follows:
Reality printers are used to print pharmacy labels and receipts. An example would be when payments are done and you ask for a print-out of the receipt, it prints it out. The printer is connected to the Reality printer in the back-end.
An example of how a print job looks like when it's in queue is as follows: