Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!rice!uw-beaver!Teknowledge.COM!unix!hplabs!hpfcso!hpfcmgw!hpfcse!hpupnja!markf
From: markf@hpupnja.HP.COM (Mark Fresolone)
Newsgroups: comp.sys.hp
Subject: Re: DIRECTORY (3C) strangeness
Message-ID: <1520002@hpupnja.HP.COM>
Date: 26 Nov 89 02:47:54 GMT
References: <616@mmlai.UUCP>
Organization: HP Piscataway, NJ
Lines: 18

The 'ls' command has us all spoiled!  It turns out that directory entries
are not actually stored in any order.  The directory(3) routines simply
report 'em as they see 'em.

Entries are kept rather primitively in a static array.  At the beginning of
a directory's life, files appear in creation order.  However, when a file or
directory is "removed", its entry is simply marked unused (traditionally,
inode == 0).  The next file created fills the first available unused slot,
allocating a new block of entries when necessary.

To visualize the behavior, create a directory, and then create and delete
files, using "strings ." or "od -c ." between operations.

Good coding!

#include <disclaimer.h>
Mark Fresolone
hplabs!hpfcse!hpupnja!markf