IBM 1800409-001A - Manual (Page 398)

Spooling Overflow
The spool overflow option (Administration/Disk Operations
menu) specifies the maximum space reserved for spooling
overflow on the hard disk, if one is available.
When a print job is sent to your printer, a portion of that job is stored
in the spooling buffer (Administration/Memory/K Mem for Spool
menu) while the rest of the job is being printed. If all the memory
in the spooling buffer is being used and the spool overflow option
is enabled, the printer stores the overflow from the spooling buffer
in a reserved area of the hard disk. Even if you have a hard disk,
you should allocate as much RAM to the spool buffer as possible
for increased throughput.
Reserving a 10-20 MB portion of the hard disk for spooling
overflow works well for most printing environments. If too much
of the disk is dedicated to spooling, the printer’s performance might
actually be hindered because the printer tries to fill the overflow
space before passing the job to the processor.
PS Protocol
Your printer supports a new protocol for communication between
the printer and a host computer over a serial, parallel, or optional
interface connection. This new protocol is called PS protocol. This
binary communications protocol allows any 8-bit binary value
(0-255) to be treated as data, while allowing a few of the values to
function as special control characters. When communicating 8-bit
binary data in binary or binary fixed mode, the printer uses the
quoting mechanism of the binary communications protocol (BCP)
to distinguish between the special control characters and print job
binary data.
Appendix D
D - 1 0 A d d i t i o n a l T e c h n i c a l I n f o r m a t i o n