[cups.development] CUPS 1.6

[Michael Sweet]

Bernd,

On 2012-09-07, at 12:00 PM, Bernd Krumböck <b.krumboeck at universalnet.at> wrote:
> ...
> I'm a bit confused:
> * Why CUPS 1.6 drops so many useful features?

CUPS 1.6 dropped one specific feature - cupsd-managed automatic remote queues, in favor of them being managed by libcups instead.  This specifically affected CUPS browsing, which requires a process to be running in the background constantly looking for and advertising shared printers, but its days were numbered already because of its issues in the face of wireless and unmanaged networks.

LDAP and SLP will make a comeback in a future release of CUPS, through the new libcups APIs introduced in CUPS 1.6 and through an improved cupsd implementation that we are working on.

> * Where is an artikel about all changes?

The "what's new in cups 1.6" documentation is all we have, aside from two years worth of presentations at the Linux Foundation's OpenPrinting summits.

> * How will CUPS handle deprecations in future?

Deprecation is a step towards removal.  The automatic creation and removal of remote queues in cupsd was removed after being deprecated in CUPS 1.5 (although at the time we did not have a formal replacement in CUPS 1.5, all of the major Linux distros were shipping cupsd with Avahi support since CUPS 1.4)

We deprecated many of the filters that used to be in CUPS, and donated them to the Linux Foundation's cups-filters project.  This project has also replaced some of the CUPS filters that used to be used on Linux with newer versions and provides a common set of filters specific to Linux and other open source operating systems.

Another example of deprecation is PPDs and PPD-based printer drivers - we officially deprecated these things in CUPS 1.6, and have many of the changes in place needed to function without PPDs in CUPS 1.6.  At some point in the future (not soon, but not forever) we will have the software and printer support to allow us to cut the cord, although that migration might also result in another donation to the cups-filters project to continue PPD support indefinitely.

> In the past I created some patches for CUPS:
> * Complete rewrite of LDAP browsing
> * Some German translations
> * Some patches for porting CUPS on HP-UX
> 
> (all together took many weeks)
> 
> 
> Don't get me wrong, but why should someone work on CUPS in future (except Apple employments or user)?

We *do* appreciate everything you have contributed over the years, and I hope you will continue to do so in the future.  Just understand that our goal is to continue making printing better and easier - sometimes this means making some serious architectural changes to keep CUPS relevant for today's and tomorrow's computing worlds, and that may mean dropping some of the excellent contributions from hundreds of developers around the world.  Sometimes things are gone forever, and sometimes it just takes time to re-integrate things with the new architecture.  And for translations they generally need to be re-done for every major release because so many messages get added, changed, or removed.

More to the point, I am closely involved with IPP Everywhere which calls out LDAP, SLP, SSDP, and WS-Discovery as potential discovery protocols for IPP printers and have a vested interest in seeing that CUPS is both a conforming server and client implementation.  So you can expect to see your LDAP contributions gain new life as we re-add support for it in a future CUPS release.

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Michael Sweet, Senior Printing System Engineer, PWG Chair