What kind of things would you want in the GNU OS

[Root Boy Jim]

? From: Paul Hite <paul at prcrs.uucp>

? > In article <19981 at adm.BRL.MIL> rbj at dsys.ncsl.nist.gov (Root Boy Jim) writes
? > >
? > >I seem to remember something about a UNIX port to a big machine (Cray?
? > >370?) that used 4k bytes/inode. Guess where small files were stored?

? I believe that I know the paper that Root Boy Jim remembers.  But I'll
? bet that he confused a couple of things.

It won't be the first or the last time :-)

? I found the paper in the AT&T Bell Labs Technical Journal Oct 1984
? Vol. 63 No.8 Part 2.  (This is one of the 2 all-unix issues.  These two
? issues have been reprinted and are available now as "Unix Readings" or
? something.)

? The paper is titled "A UNIX System Implementation for System/370"  by
? W. A. Felton, G. L. Miller and J. M. Milner.  And, Jack, the paper is
? dated Jan 9, 1984.

That's the ticket!

? A couple of quotes:

? 	UNIX file systems on System/370 are in format identical to 
? 	standard UNIX file systems, except that the block size has
? 	been enlarged to 4096 bytes.

? But later:

? 	Files of less than 493 bytes are stored directly in the
? 	corresponding inode.

Hmmm. That would seem to imply an inode size of 512, with 20 bytes of
mode/uid/gid/links/size/etc info. Exactly one sector.

? The paper doesn't get more explicit than that about inode size.  I believe
? that they were just using large blocks with regular sized inodes.  They 
? put small files in the inodes because they were afraid of wasting space
? with big blocks.  They didn't have any "fragment" concept.  They actually
? call the fast access a "side effect".

No wonder. 128 direct blocks gives you 1/2 Meg of directly accessible data.
Another side effect is that if the buffer cache was modified to treat
inode and data blocks differently (512 and 4k sizes), when a buffer was
locked for I/O it wouldn't lock out all the other inodes in that buffer.

? Paul Hite   PRC Realty Systems  McLean,Va   uunet!prcrs!paul (703) 556-2243
?                       DOS is a four letter word!

	Root Boy Jim is what I am
	Are you what you are or what?