*BSD News Article 7260


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From: cgd@eden.CS.Berkeley.EDU (Chris G. Demetriou)
Newsgroups: comp.unix.bsd
Subject: Re: 386BSD -- What happened to my loadfd command?
Date: 31 Oct 92 16:49:20
Organization: Kernel Hackers 'r' Us
Lines: 39
Message-ID: <CGD.92Oct31164920@eden.CS.Berkeley.EDU>
References: <Oct.29.18.06.59.1992.22100@ocean.rutgers.edu>
	<1992Oct30.091651.10922@ntuix.ntu.ac.sg>
	<1992Oct31.164546.13101@cs.wisc.edu>
NNTP-Posting-Host: eden.cs.berkeley.edu
In-reply-to: jcargill@oka.cs.wisc.edu's message of Sat, 31 Oct 1992 16:45:46 GMT

In article <1992Oct31.164546.13101@cs.wisc.edu> jcargill@oka.cs.wisc.edu (Jon Cargille) writes:

   In article <1992Oct30.091651.10922@ntuix.ntu.ac.sg> eoahmad@ntuix.ntu.ac.sg (Othman Ahmad) writes:
   >andy Rowan (rowan@ocean.rutgers.edu) wrote:
   >: 
   >: Or, another solution, is there any way to mount a dos-formatted
   >: floppy as a filesystem (a la 'mount /pcfs' in SunOS)???
   >: 
   >I do not like it. It makes OS more complex to understand. 
   >It is already being done for CDROM, but it is meant for SCSI driver only
   >. If only we have mtools style for CDROM. It will be easier for me to
   >understand and modify.
   >

   I think your reason for not liking it is pretty weak.  Sure, virtual
   memory, the FFS, and a host of other useful things make the OS more
   complex, too.


Actually, i think it's arguable that adding a new filesystem
adds *NO* complexity to the system; all you *should* have to
do is add a few table entries.

That's why the vnode abstraction was introduced; code
for a filesystem shouldn't be tangled w/code for another
filesystem.

Unfortunately, they didn't get the vnode interface quite right
in net/2: the inode routines aren't done thru a switch.
(while i'm sure that's great for performance, it makes it
damned hard to write a new filesystem which is more or
less like an existing filesystem, w/o copying all of the routines.)

Chris
--
Chris G. Demetriou                                    cgd@cs.berkeley.edu

"Sometimes it is better to have twenty million instructions by
        Friday than twenty million instructions per second." -- Wes Clark