At 01:48 PM 12/28/2000 -0500, Todd Vierling wrote:
>On Thu, 28 Dec 2000, Chuck Silvers wrote:
>
>: actually this change is not completely backward compatible.
>: if someone has created device nodes with those upper minor bits set
>: (ie. for /dev/sd385792385a or whatever the number turns out to be),
>: then those device nodes would no longer refer to the same device
>: after this change.  to me, this falls into the same category as
>: the problem that __BROKEN_CONFIG_UNIT_USAGE indicates, that we make
>: assumptions about the usage of device minor numbers.  in this case
>: the assumption is that the upper bits of the minor number have not
>: been used by anyone anywhere.
>
>: the only completely backward-compatible way to increase the number
>: of partitions is to create a new device major number for each current
>: device major that uses part of its minor as a partition.
>
>There comes a point where supposition leads into ludicrous situations, and
>this is one of them.  If the extra partition bits are placed sufficiently
>high in the minor number to provide a reasonably large number of units (say,
>16384 drives?), someone will have had to create nodes with ridiculously
>large unit numbers to conflict with them.

Not only that, 1.6GB of memory would be needed for the cd_devs array.  That's
not probable.

--
Matt Thomas               Internet:   matt@3am-software.com
3am Software Foundry      WWW URL:    http://www.3am-software.com/bio/matt/
Cupertino, CA             Disclaimer: I avow all knowledge of this message