George Gwilt wrote:
>> PAR_WAIT      (presumably something to do with parallel port)

> This is part of SMSQ/E but its definition is not in my QPC2 manual.  
> The code seems to set a pause for a period of time. Perhaps the  
> author knows what  for?

That would be Tony.

According to the QDOS Classic docs:

PAR_WAIT (port, wait cycles) sets the length of time that the parallel
port drive will wait for the printer to be ready before it gives up
and lets the Q40 do something else. This has no effect in FIFO mode,
but in original PC mode it allows the buffer in the printer to be
stuffed in bursts. The default value is 0. The larger the value, the
higher the probability that a more than one byte of data can be sent
on each interrupt, but the higher the load on the machine.

If the IO card does not provide IRQ7 and the machine is busy,
PAR_PULSE with have a much greater effect than if IRQ7 is used and/or
the machine is idle.

PAR_WAIT 2,20        give the printer on PAR2 a high priority.
PAR_WAIT 0           . . . set PAR 1 use the minimum of processor time.

For an Epson Stylus COLOR Pro printer, PAR_PAUSE 10 and PAR_PAUSE 50
improved the transfer speed by 30% on an idle machine: the rate was
primarily determined by the printer. On a busy machine with no
interrupts, PAR_PAUSE 10 improved the transfer speed by a factor of 3
and PAR_PAUSE 50 improved the transfer speed by a factor of 5. The
speed of other tasks in the machine was reduced. Q40 Hard Disks

As far as I can see it does not have any effect in the latest SMSQ/E
versions at all.


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