HAL 0.1 release

Joe Shaw joe at ximian.com
Fri Oct 10 21:56:07 EEST 2003

On Thu, 2003-10-09 at 19:06, David Zeuthen wrote:
> > The bottom line is, I don't think we can make "Category" be both general
> > enough to be useful on its own (that is, not just another capability),
> > but specific enough to contain enough information for low level
> > implementation.
> Remember (category, subcategory) or bus-class are always derived from
> bus-specific properties so low-level implementations does not need this
> to work.
> There is one special case where the UI will need to know about category,
> namely when you draw the device tree. 

Can you give an example?  I can picture a couple different trees, but
none needs to know about "Category" in my mind.  The first is the bus
topology view, which would be something like:

  `-- USB Devices
     `-- Mouse
     `-- Olympus Digital Camera
  `-- PCI Devices
     `-- Video Card
     `-- SCSI Controller
        `-- Seagate SCSI drive
        `-- Plextor CD-R
  `-- IDE Drives
     `-- IBM Deskstar

and so on.

Another is a device "type" view.  For this, I suspect that for specific
types of devices it's more of a list than a tree.  For example, list all
of the cameras, or list all the storage devices.  If you wanted to set
up a tree for this, it's going to be somewhat arbitrary anyway:

  `-- Cameras
     `-- Olympus Digital Camera
  `-- Storage
     `-- IBM Deskstar
     `-- Olympus Digital Camera
     `-- Seagate SCSI drive

or whatever.  But for these you use capabilities.  For the other one,
you use bus-specific properties.

The point is, having both category and capabilities seems to me like an
arbitrary distinction.


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