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From: cc1@ucla-cs.ARPA (Michael Gersten)
Newsgroups: net.micro.amiga
Subject: Re: AmigaDos...
Message-ID: <12005@ucla-cs.ARPA>
Date: Tue, 29-Apr-86 13:34:42 EDT
Article-I.D.: ucla-cs.12005
Posted: Tue Apr 29 13:34:42 1986
Date-Received: Fri, 2-May-86 07:29:06 EDT
References: <1076@h-sc1.UUCP> <160@cbmvax.cbmvax.cbm.UUCP>
Reply-To: occ4mgk@oac.ucla.edu, cc1@ucla-cs.UUCP (Michael Gersten)
Distribution: net
Organization: Ucla Computer Club (disclaimer)
Lines: 37

In article <160@cbmvax.cbmvax.cbm.UUCP> daveh@cbmvax.UUCP (Dave Haynie) writes:
>In article <1076@h-sc1.UUCP> breuel@h-sc1.UUCP (thomas breuel) writes:
>>A complaint, and two questions:
>>
>>I have philosophical problems with the AmigaDos file system.
>>The file system appears to be optimised for finding a named entry
>>quickly and for making directories small and cheap: the directories
>>are hashed and do not contain the filenames. This means that for
>>wildcard expansion and select-file-dialog-box'es, one block has
>>to be read for each entry in a directory.
>
>Cheap directories are important on a small-disk machine.  And at least this
>method allows for essentially unlimited directory sizes, unlike other DOS
>systems popular on microcomputers today.
>

*** THOSE ARE NOT CHEAP DIRECTORIES ***
They are VERY expensive. 512 bytes per file entry, plus another 512
for the directory itself. My model 1 (it is NOT trash-dos) needs only 32
bytes per file (plus one for hash byte); it can support directories
with no more space needed.
(But it does, like unix, has only a fixed number of 'inodes' (fde's,
file directory entries. Max of 224. And no, it has no directory support,
but no more space would be needed.)

Now, here's a real question. Take a typical AmigaDos disk, and a typical
Unix file system, and a typical ms-dos disk. Compare the % overhead
on each, where overhead is defined as
  space used   -   data (in bytes)
   ------------------
	space used

and compare. My guess is that Amiga will come out with a high overhead.

disclaimer | ihnp4!ucla-cs!cc1 | Michael Gersten | Joke: 412
-- 
Views expressed here may not be those of the Computer Club, UCLA, or anyone.