Simplest (practical) file system?

From: Fred Cisin <cisin_at_xenosoft.com>
Date: Sun Jul 27 16:23:00 2003

On Sun, 27 Jul 2003, Bob Shannon wrote:
> >I thought that you said that you wanted PRACTICAL
> Yes, practical, like RT-11 was (is).

> >It is unusual for somebody to set out to write a file system who isn't
> >already familiar with what's been done before. (some say that UCSD P
> >system was the last time that one was written by people who had no idea
> >what they were doing)
> Its unusual for anyone to try to write a file system without a lot of
> modern fluff added too.

That was what Jobs intended for the Lisa. backfired.


> >Putting the DIRectory at the beginning of the usable space simplifies a
> >few things.
> Not an option for actual HP hardware. HP's cold-boot roms load an
> intermediate loader program from
> track 0, and this intermediate loader (like MS-DOS's) then loads the O/S
> into memory. So to be compatible
> with HP's cold boot mechanisim track 0 holds the start of the intrim loader.

Of course it is an option. IFF you want. "Beginning of usable space"
would mean immediately following whatever fixed location stuff there is.
MS-DOS and MAC DIR follows the boot record.
DEC Rainbow MS-DOS follows a "boot track"


> >Decide the DIR structure.
> >Fixed size for each FPDE (File Primary Directory Entry) avoids some
> >unnecessary hassles.
> Yep, probably 32K words, given the vintage of the machines and their
> maximum logical memory capacity.

This is fixed size for the directory ENTRY, NOT file allocation. Some
systems, mostly in order to accomodate long filenames, use a variably
sized entry in the directory.


> RT-11 works just fine, and it does not have the level of 'fluff' found
> in many modern file systems.

Then it sounds like the decision is made!
Received on Sun Jul 27 2003 - 16:23:00 BST