Block a physical property?

[Pierre Ossman]

Artem Kachitchkine wrote:

>
> Block *capability* is interesting because OS has special use for them:
> filesystems can be mounted (only) on block devices, etc.
>

Yes, to mount something it has to have block capability, but block
capability doesn't guarantee a mountable device. See below...

> Physical devices can have block capabilities. We can't merge block
> with storage because block capability can be presented by non-storage
> devices. One example is partitioned disk: you can access entire disk
> vie its block capability or you can access individual partitions, if
> the OS presents partitions as separate block devices.
>

I wasn't suggesting that storage complete replaces block. As you say
non-storage devices can have block device nodes. What I was suggesting
was that every class that needed to tell about a block device node would
have its own properties, like storage.device and volume.device. Since
the information that a device has a block device node is useless if you
don't know what kind of device it is, it kind of makes the 'block'
namespace useless. It has been abstracted too much in my opinion.

Rgds
Pierre