Subject: Re: Disk size...
To: None <>
From: der Mouse <mouse@Rodents.Montreal.QC.CA>
List: port-vax
Date: 09/24/1998 13:45:53
> Just curious... what are the limits (if any) on the size of a disk
> supported by NetBSD (Vax, or otherwise).  Just wondering since I seem
> to remember that SunOS 4.x and Solaris <2.3 didn't like any drive
> over 2Gb...  will NetBSD support a 4Gb drive? 9Gb?

NetBSD certainly supports a "4G" drive; the machine I'm sending this
from is a NetBSD/sun3 machine whose main disk is 8386733 sectors long
(that's 3.9991+G, for those who don't want to bother with the

IIRC, SunOS never had problems with drives >2G; what it couldn't
tolerate was a *single filesystem* >2G.  Additionally, some machines'
boot ROMs can't use 10-byte CDBs and hence require that all blocks
involved in the boot process fall in the first 1G of their drives.

NetBSD has definitely lifted the 2G filesystem size limit; the NetBSD
limit is probably on the order of 2^41 bytes (disk block addresses
within the filesystem are 32-bit numbers; I'm not sure offhand whether
they're frag numbers or sector numbers, but the difference is only a
factor of two).  There is probably also a 2^41 limit on the size of a
disk pack (whether real or CCD/VND-faked) because everything gets
converted to 32-bit sector addresses, 512-byte sectors.  (Actually, on
a 64-bit machine this limit is probably 2^73, not 2^41, but that's not
relevant to VAXen.)

There's another limit near 2^64 bytes (a number of things use 64-bit
offsets internally), but that's well above the 2^41 limit.

					der Mouse

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