DMF32 line printer timing

[stevens at hsi.UUCP]

We just plugged our LP27 into the line printer port of the DEC DMF32
and the results are impressive.  I ran a 2,000 line print file using
the original 4.2 lp driver (using the LP11 interface), our enhanced
4.2 lp driver and the DMF32 lp driver.  Our enhanced 4.2 lp.c removes
all the calls to lpcanon() and avoids calling lpoutput() for every
character, expanding the function in-line for speed.  The DMF32 lp
driver was posted to the net a few months ago by Colorado State.
The results are:

	LP11, 4.2 lp.c			50.1 system seconds
	LP11, enhanced 4.2 lp.c		17.7
	DMF32 lp			 1.4

The user times for the "cat file >/dev/lp" were all zero and the clock
times were all 1:57 (for a printer speed of 1,032 lines/min).

If you do a lot of printing on a busy system, get the DMF32.

	Richard Stevens
	Health Systems International, New Haven, CT
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