Re: SCSI device numbering

H. Peter Anvin (hpa@freya.yggdrasil.com)
3 Jul 1996 01:07:46 GMT


Followup to: <m0uakow-00020gC@kb5yvf.usl.edu>
By author: jms@pobox.com (Johnie Stafford)
In newsgroup: linux.dev.kernel
>=20
> ac> Purpose Bits Normal Extreme
> ac> controller 4 <=3D 1 2
> ac> bus 4 =3D=3D 0 1

Extreme known is 3, actually.

> ac> device 8 <=3D 2 4=20
>=20
> What about wide SCSI? It does 16 devices.

Actually he is allowing up to 256 devices here (2^8). 3 bits would be
normal, 4 wide, and SCSI-32 would require 5 bits.

> ac> lun 8 =3D=3D 0 3
> ac> partition 4 <=3D 3 4

This is inadequate. The 4-bit partition limit in SCSI has shown too
restrictive. =20

However, since Linus is suggesting using the major for the controller
(a very good idea, IMHO) 12+20 should be enough. I still would prefer
32+32.

-hpa
--=20
PGP public key available - finger hpa@zytor.com
I don't work for Yggdrasil, but they sponsor the linux.* hierarchy.
"The earth is but one country, and mankind its citizens." -- Bah=E1'u=
'll=E1h
Just Say No to Morden * Save Babylon 5: http://www.babylon5.com/cmp/sup=
port/