System V file systems

[pri=-10 Stuart Lynne]

In article <917 at vsi.COM> friedl at vsi.COM (Stephen J. Friedl) writes:
>In article <8338 at rpp386.Dallas.TX.US>, jfh at rpp386.Dallas.TX.US (The Beach Bum) writes:
}> I have never seen a realistic benchmark [ multi-process, multi-file, random
}> access ] validate the claims BSD FFS puts forward - except to the extent that
}> having the larger block size dictates.  And soon USG Unix will have 2K blocks
}> so expect that advantage to diminish.
}
}These are available now.  System V Release 3.1.1 for the 3B15 has
}had 2k blocks for some time, and Sys V Rel 3.2.1 for the 3B2 just
}came out with it.
}

My obsolete Callan Unistar running Unisoft 5.0 (a *very* early variant of
System V, possibly about release 0 or -1) with vintage binaries from 1983/1984
supports 1, 2 and 4 block file systems (that's .5/1/2 kb).

I would suggest that various releases of System V have supported 2k blocks
as long as there has been a System V. It just seems up to the porting house
as to whether they thought it was needed for a particular machine and worth
using.

In the case of the Callan they provided the 2kb support for use with SMD
drives (although they will work on other drives as well). 

Unfortunately they shipped the system to generate .5kb blocks for all file
systems as the default. You have to gen your own to use either 1kb or 2kb.
To make things worse the boot ROM only knows about the .5kb blocks so you
are stuck with that for your root partition (it's a fixed size too).

At least on a slow 68010 with mediocre drives the difference between 1 and
2kb blocks is not that great (although both were a big improvement over
.5kb). I use 1kb to help minimize the impact of the block buffers on my 2MB
of RAM.


-- 
Stuart.Lynne at wimsey.bc.ca {ubc-cs,uunet}!van-bc!sl     Vancouver,BC,604-937-7532