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- Path: sparky!uunet!gatech!darwin.sura.net!jvnc.net!rutgers!faatcrl!iecc!Postmaster
- From: johnl@iecc.cambridge.ma.us (John R. Levine)
- Newsgroups: comp.arch
- Subject: Re: OS/MFT and Macintosh (was: ..History)
- Message-ID: <9209031044.AA00288@iecc.cambridge.ma.us>
- Date: 3 Sep 92 14:44:36 GMT
- References: <PCG.92Aug27125826@aberdb.aber.ac.uk>
- Sender: Postmaster@iecc.cambridge.ma.us
- Organization: I.E.C.C.
- Lines: 25
-
- >smith> OS/MFT provided a "flat" file system.
- >
- >Really? That's news.
-
- It's true, mostly. Recall that each disk had a VTOC which kept the actual
- name, position, and type of a file (excuse me, data set) and there was a
- global catalog which optionally recorded what on disk or tape a file resided.
-
- The VTOC on each disk was entirely flat. You could use any 44 characters
- in the name that you wanted. It was set up so the name was the key in each
- VTOC record so the OS could use the channel's "search for equal key" to run
- down the VTOC and find an entry.
-
- The catalog, on the other hand, was indeed tree structured so if you wanted
- to catalog a file, its name had to consist of dot-separated components each
- of no more than 8 characters, and no name could be a component-wise prefix
- of another. But it appears that in most installations, people were very
- sloppy about using the catalog ("but if I catalog this file, I have to check
- with every other programmer to make sure he's not using the same name on
- another disk pack!") and there were a lot of strange flat names.
-
- Regards,
- John Levine, johnl@iecc.cambridge.ma.us, {spdcc|ima|world}!iecc!johnl
-
- PS: Followups to comp.arch.history, if it ever exists.
-