Re: Printing: printcap vs. interface scripts
- From: spcecdt@xxxxxxxxxx (John DuBois)
- Date: Tue, 06 Feb 2007 17:25:42 -0000
In article <45c8b131$0$22111$db0fefd9@xxxxxxxxxxxxxx>,
Ian Wilson <scobloke2@xxxxxxxxxxxxx> wrote:
Nachman Yaakov Ziskind wrote:
As far as I know, the lpstat or lp command that you invoke, will eventually
invoke another lpstat or lp that is specific to the printing-system for the
specified printer.
Yes, that's correct. Those parts of the print systems that conflict (lp,
lpstat, cancel, lpmove) are replaced by front ends that invoke one of two back
ends under /usr/lpd.
AIUI /etc/printcap is BSDish and was originally used on BSDish Unixes for both
local and networked printers. When SCO added LPR/LPD to their SysVish O/Ss they
only used printcap for remote LPR/LPD printers. I think it resulted in a bit of
a hybrid mess of two different printing models
Indeed.
, but a worse mess[1] was to come
when OSR6 lets you have both CUPS and SYSV printing installed :-)
[1] By which I mean potential for confusion.
Probably true, but in at least one respect the OSR6 situation is better.
In the 507 MP that added CUPS, if you install CUPS yet another layer of
redirection is added: front ends that invoke either the CUPS or SYSV binaries,
where the SYSV binaries are either the binaries for the lpsched system or the
front end binaries for the lpsched/lpd system, if you've previously installed
lpd. The actual CUPS and SYSV binaries are under /usr/lib/lp. This shuffling
around of binaries based on whether you've installed lpd and cups is quite
messy.
In OSR6 it's at least somewhat cleaned up, in that there is no more moving
binaries around! When the OS is installed you get front ends that select
between interfaces for the cups, lpsched, and lpsched/lpd systems. Switching
between the systems is something that's done dynamically via arguments to the
front-ends or by configuration in /etc/default/lpd. Whether the lpd, CUPS, and
lpsched systems is installed determines only whether those back ends are
available to be switched between.
The lpsched/lpd front end system was kept because it allows at least those two
print systems to be merged in the sense that their front ends can select a
back-back-end by knowing which printers are supported by each, while between
CUPS and those systems the selection must be explicit.
Of course, CUPS supports lpd printers, so if you don't have legacy interface
scripts and such you can just use CUPS and forget about the other systems.
John
--
John DuBois spcecdt@xxxxxxxxxx KC6QKZ/AE http://www.armory.com/~spcecdt/
.
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- Printing: printcap vs. interface scripts
- From: Nachman Yaakov Ziskind
- Re: Printing: printcap vs. interface scripts
- From: Nachman Yaakov Ziskind
- Re: Printing: printcap vs. interface scripts
- From: Ian Wilson
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