Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!samsung!uunet!zephyr.ens.tek.com!gvgpsa!treehouse!andyp
From: andyp@treehouse.UUCP (Andy Peterman)
Newsgroups: comp.sys.mac.system
Subject: Re: Limit on number of files/resources per volume?
Message-ID: <645@treehouse.UUCP>
Date: 14 Nov 90 20:02:58 GMT
References: <424@sickkids.UUCP>
Organization: The Tree House
Lines: 30

In article <424@sickkids.UUCP> daniel@sickkids.UUCP (Daniel Guerin) writes:
>I am planning to put a large number of small files on a single
>unpartitioned large disk.  I remember reading somewhere that there
>was some upper limit on the number of files that one could put on
>a single volume.  
>Could somebody tell me if there are such limitations, and if so what
>they are.  I could not find any limit documented in IM or the technotes.

The theoretical limit is  65536 files.  The data for a file is stored in
an allocation block, which is a multiple of 512 bytes.  If a file saves
just one byte, then it uses up an entire allocation block.  Since a
volume can only have a maximum of 65536 allocation blocks, then this
would seem to be the maximum number of files.

However, since an allocation block is a multiple of 512, then a volume
may not be able to hold a full 65536 blocks.  For example, an 80 Meg
volume would use an allocation block of 1536 bytes each and could hold
about 54600 blocks.  This would be your limit on this volume assuming
each file had only one fork and that fork had 1536 bytes or less.

I don't believe the HFS directory system has a file limit, although as
you add files, the directory will increase in size using up some of the
allocation blocks as it goes.

Hope this helps...

-- 
Andy Peterman                       |   Opinions expressed
treehouse!andyp@gvgpsa.gvg.tek.com  | are definitely those of
(916) 273-4569                      |      my employer!