From mboxrd@z Thu Jan 1 00:00:00 1970 From: forsyth@caldo.demon.co.uk To: 9fans@cse.psu.edu Subject: Re: [9fans] Re: ideal plan9 laptop MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Message-Id: <20020130163357.531D619992@mail.cse.psu.edu> Date: Wed, 30 Jan 2002 16:31:53 +0000 Topicbox-Message-UUID: 4952323c-eaca-11e9-9e20-41e7f4b1d025 >>Also my 9load in (/n/9fat) has the 'a' [append] bit on. This must be a bug. The file attribute flags used by the DOS file system do not map directly to those used by Plan 9. Since there is no concept of user or group, permission changes via wstat (see stat(2)) will fail unless the same (read, write, execute) permissions are specified for user, group, and other. For example, removing write permission in Plan 9 corresponds to setting the read-only attribute in the DOS file system. Most of the other DOS attributes are not accessible. Setting the exclusive use flag (CHEXCL) in Plan 9 corre- sponds to setting the system use attribute in the DOS file system. Such files are not actually restricted to exclusive use, but do merit special treatment that helps in the cre- ation of boot disks: when dossrv allocates a new block for such a file (caused, say, by a write that fills the file's last allocated block), it succeeds only if it can arrange for the file to be stored contiguously on disk. Since other operating systems do not guarantee that system files are laid out contiguously, the CHAPPEND mode bit is set in file stat information only when the file is currently contiguous. Attempts to set the CHAPPEND mode bit explic- itly will cause dossrv to try to make the file contiguous, succeeding only if this is possible.