Date: Tue, 24 Aug 1999 16:22:44 -0700 (PDT) From: Matthew Dillon <dillon@apollo.backplane.com> To: David Greenman <dg@root.com>, FreeBSD Hackers List <freebsd-hackers@FreeBSD.ORG> Subject: Re: Possibility of increasing default MAXPARTITIONS from 8 to 16 Message-ID: <199908242322.QAA19396@apollo.backplane.com> References: <199908242254.PAA16075@implode.root.com> <199908242303.QAA19246@apollo.backplane.com>
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:: It seems reasonable to me, although there may be issues with finding a bit
::in the minor number - I think they've pretty much all been taken.
::
::-DG
::
::David Greenman
:
: Cripes! Now that is really annoying. da0a is 4,0 and da1a is 4,8.
:
: -Matt
minor device number:
t = type
u = unit (upper bits split off from lower)
s = slice (assuming only 8 slices)
0 noslice
1 whole disk
2-5 s1,s2,s3,s4
6-8 unused
p = partition
- = cannot be used
tttttttu uuusssss -------- uuuuuppp minor layout for disks
11111111 11111111 -------- 11111111 mask for uminor
Our only hope as far as I can tell is to take the upper two bits of the
slice (bits 19 and 20) and use them for the partition instead.
As far as I can tell, only slices 0-5 are used, requiring only 3 bits.
Can someone check my work? Are bits 19 and 20 unused by any disk
devices?
-Matt
Matthew Dillon
<dillon@backplane.com>
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