Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!cmcl2!adm!xadmx!rbj@dsys.ncsl.nist.gov From: rbj@dsys.ncsl.nist.gov (Root Boy Jim) Newsgroups: comp.unix.wizards Subject: What kind of things would you want in the GNU OS Message-ID: <20100@adm.BRL.MIL> Date: 23 Jun 89 22:11:34 GMT Sender: news@adm.BRL.MIL Lines: 53 ? From: Paul Hite ? > In article <19981@adm.BRL.MIL> rbj@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?