[sane-devel] SANE2 standard completion

Johannes Meixner jsmeix at suse.de
Tue Apr 1 13:03:08 UTC 2008


On Mar 28 18:40 Julien BLACHE wrote (shortened):
> ... I think it'd really be better to have the
> frontends be entirely isolated from the backends, as I explained
> already.
> This would provide a central point (saned) handling the hardware
> entirely

To avoid confusion with the cupsd, I like to mention that
the cupsd does not talk to the hardware (i.e. the printer).

In CUPS there are so called "backends" which talk to the
final destination of a print job (usually the printer but
often also a network service like IPP, LDP, or SMB), see

Furthermore I like to mention that the HP printer and scanner
driver HPLIP had in the past such a kind of daemon "hpiod"
which did the actual hardware I/O.

There have been several drawbacks with such a daemon so that
HPLIP dropped the daemon and uses now a library "libhpmud"
which does the actual hardware I/O.

I.e. perhaps in the end a library is better than a daemon?

Perhaps the crucial question is not whether the hardware I/O
is done via a library or via a daemon but to get the frontends
be entirely isolated from the backends regardless if this is
implemented via a daemon or via an additional I/O-library?

I think when a driver for all-in-one devices moved from
a daemon to a library, it might indicate that this is also
true for plain scanner drivers?

Kind Regards
Johannes Meixner
SUSE LINUX Products GmbH, Maxfeldstrasse 5, 90409 Nuernberg, Germany
AG Nuernberg, HRB 16746, GF: Markus Rex

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