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Section C:
Utility Programs
****************
*
$SPOOL
*
****************
C.l9. $SPOOL - Background Print Services
Presumably,
the $SPOOL utility is one of the most pleasing features
of
your EOS operating system.
The purpose of this program is to print your
files at the printer while you are busy doing other jobs. The program is
started
by
a command line.·
If you want to print a file in
background
mode, you enter:
$SPOOL filename
If $SPOOL was able to start printing that file, it notifies you:
Printout started.
If background print is already active, the message reads accordingly:
Spooler already active.
If the file to be printed was not found, it reads:
File not found.
In
order to avoid any unnecessary pre-processing of
the
file,
$SPOOL
does .some additional work.
The tab stops found in the file are automat-
ically expanded to the current system tab stop setting.
This means that
there
is
a
tab stop every eight columns unless you have
changed
the
setting by means of the
=>
$CONFIG utility.
Furthermore, $SPOOL inserts
a
form feed every 64 lines.
You may,
however,
activate an option
to
suppress form feeds.
There are,
almost inevitably, some disadvantages with $SPOOL: operating
the printer slows down screen output somewhat. Of course, the printer is
no
longer
available
for your current program as
long
as
background
printing
is in progress.
If you want to address the printer
directly,
either
by
a program or
by
the "PRINTER ON
11
command
(please
refer
to
section
B),
nothing at all will happen.
Printer output is simply
ig-
nored.
It
is self-evident that a print program of this kind cannot do
without
some means of control. The following options are available with $SPOOL:
EOS User's manual
Daeumling & Zimmermann
Page 96
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