hardware:: tag matching lib plans

Enrico Zini enrico at enricozini.org
Mon Jan 16 13:07:43 UTC 2012

On Mon, Jan 16, 2012 at 09:30:41AM +0100, Michael Vogt wrote:

> for the software-center I'm currently looking into building a lib that
> can match a debtag hardware:: tag (like hardware::storage:dvd) to the
> capabilities of the actual computer. This will allow us to show
> information in the GUI like: "This software requires a touchscreen,
> but the computer does not have one." [2]

I like the idea. In fact, the whole hardware::* tag could be managed by
the maintainers of the detection library, effectively as part of that
project. The two things will give each other meaning.

> For this I would like to talk about some new tags that look useful in
> this context:
> Tag: hardware::input:touchscreen
> Description: Requires a touchscreen input

That's uncontroversial and I've added it:

  Tag: hardware::input:touchscreen
  Description: Touchscreen

I'd avoid wording the description as 'Requires', since it sounds better
if it makes a difference in the life of the user: "it's something that
allows you to use/tweak your touch screen".

> Tag: hardware::storage:cd:writer
> Description: Compact Disc writer
> (or hardware::storage:cd-writer ?)
> Tag: hardware::storage:dvd:writer
> Description: Digital Versatile Disc writer

This is something that I would prefer to get via a combination of
different tags: use::viewing/use::editing, for example, to distinguish
between cd/dvd players and cd/dvd writers. If that strategy gives
wrong results, then we can consider adding special tags.

> Here are two more that are a little more difficult. The tag would
> embed a number that the lib parses then. I'm not sure how well that
> fits into the general schema of debtags. If its does not fit I wonder
> if it could be done as a private extension to the system? Would we
> prefix it in some special way?
> Tag: hardware::memory:{1,2,4,8}GB
> Description: Requires at least N amount of RAM 
> Tag: hardware::video:opengl:{2,3,4.1,4.2}
> Description: Requires at least N opengl level to run

It sort of fits as long as you have 'at least' and you don't need to add
all the tags to say 'up to'.

The biggest problem I can see is that tags are not assigned to specific
versions of packages, so if game foo needs opengl 4.2 only since
foo-3.0, that's something you can't encode with debtags at the moment.

Things could be fixed by putting tags in debian/control, at some point.
It could be time to reevaluate that option, but even if we started
working on that now, I don't think it's going to happen before at least
6 months.

The other issue I see is that the logic isn't very extensible: if
tomorrow you need to track another hardware feature that requires a <=
or >= comparison and not just an 'has tag' one, then you're stuck. OTOH,
if such needs arise, then it's time to design a specially crafted
control file header, but at least tags took us to that point.

 - -

More ideas for hardware tags can come from looking at:
(I'm sorry it it still misses a 'next page' option)



GPG key: 4096R/E7AD5568 2009-05-08 Enrico Zini <enrico at enricozini.org>
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