jet@karazm.math.uh.edu (J. Eric Townsend) (07/03/90)
How do I circumvent this? I'm using the KIP/CAP software to drive laser printers, which requires tricking lpd into sending all of its data to the input filter and never seeing it again. Part of this includes telling it the printing device is /dev/null. If I want to print on two different printers at the samet time, one has to wait because the other has an exclusive lock on /dev/null. It seems odd to me that SunOS allows you to get an exclusive lock on the bit bucket... J. Eric Townsend -- University of Houston Dept. of Mathematics (713) 749-2120 Internet: jet@uh.edu Bitnet: jet@UHOU Skate UNIX(r)
dudek@ksr.com (Glen Dudek) (07/06/90)
In article <9540@brazos.Rice.edu> jet@karazm.math.uh.edu (J. Eric Townsend) writes: > >How do I circumvent this? I'm using the KIP/CAP software to drive laser >printers, which requires tricking lpd into sending all of its data to the >input filter and never seeing it again. Part of this includes telling it >the printing device is /dev/null. If I want to print on two different >printers at the samet time, one has to wait because the other has an >exclusive lock on /dev/null. I had the same problem when we upgraded to Sun OS 4.0.3 - I worked around it by creating a device for each printer which has the same major and minor device number as /dev/null, e.g. mknod /dev/laserwriter1 c 3 2 Since the exclusive lock is on the inode, having a separate inode for each printer solves the problem. Glen Dudek dudek@ksr.com
guy@uunet.uu.net (Guy Harris) (07/08/90)
>I had the same problem when we upgraded to Sun OS 4.0.3 - I worked around >it by creating a device for each printer which has the same major and >minor device number as /dev/null, The same issue came up on the "sun-managers" list; one of the correspondents (not a relative, as far as I know :-)) claims there is an even easier solution: X-From: Michael Harris - NYC SE <uunet!east.sun.com!michael.harris> X-Subject: Re: Lock on /dev/null ... Make the lp entries in printcap null instead of /dev/null or dummy files like this: ps|lp|lw|postscript|PostScript:\ :lp=:\ :rm=lprhost:\ :rp=lp:\ :sd=/var/spool/ps:\ :lf=/var/spool/ps/ps-log: It works fine. HTH mh