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Newsgroups: bit.listserv.i-amiga
Date:         Wed, 9 Sep 1992 16:23:14 +1000
From:         "David Johnson,
              CSIRO Div. Wool Tech." <DJOHNSON@GEEL.DWT.CSIRO.AU>
Subject:      Re: FastFileSystem is haunting me........!

On Wed, 9 Sep 1992 16:05:40, fulton@LATCS1.LAT.OZ.AU writes

> >
> > Does anyone know how to use the FastFileSystem on KS1.3 (A500) with
 floppies?
> >
>
>  You can't under 1.3
>

you can too! I haven't done it, but I know several people who use it all
the time. (I got a hard disk before I had to work it out for myself ;-) ).
There's a file on wuarchive called ffsfloppy.lha which tells you how to
do it. It's just a matter of getting the right mountlist entry. The only
catch is that ffs needs to be told when a disk is changed. In the archive
is a program to do just that, so you don't even need to 'diskchange' all
the time.

Here is an abridged version of the readme file in the archive:
(I hope Martin doesn't mind me posting an edited version)


------------------------------- CUT HERE ---------------------------------------

(*======================================================================*)
(*           AutoDiskChange: A program to run FFS on floppies           *)
(*======================================================================*)
(*        Copyright ) 1988 Martin Taillefer, All Rights Reserved        *)
(*                   This is freely redistributable                     *)
(*======================================================================*)
(*      Version: 1.00           Author : Martin Taillefer               *)
(*      Date   : 12-Oct-88      Changes: Original                       *)
(*======================================================================*)

[stuff deleted]

FFS: The Fast File System
-------------------------
The Fast File System is an alternate file systen developed by Commodore to
replace the BCPL file system used up to this point. The initial release of
FFS (as shipped with the 1.3 enhancer kit) is geared towards non-removable
media such as hard disks, or RAD: (another 1.3 goodie). This means that FFS
doesn't directly support floopies.


The Problem: Swapping floppies
------------------------------
In all fairness, FFS does work on floppies. There is a problem though: it
doesn't notice when you swap floppies. This steems from the fact that FFS
currently expects to be run on non-removable media only. This means you can
easily corrupt floppies by writing data to a disk which was meant for
another disk since FFS doesn't know that you changed floppy and may have a
corrupt view of the floppy in the drive.


The First Solution: DISKCHANGE
------------------------------
The 1.2 release of AmigaDOS saw the apparition of the DISKCHANGE command.
This was mainly meant for 5'25 inch drive users. It turns out the command
can also be used to inform FFS whenever a disk is changed. This means that
every time you change a floppy, you have to send a DISKCHANGE command. This
is quite annoying, and risky. If you forget a DISKCHANGE only once you can
damage two floppies!


The Second Solution: AUTODISKCHANGE
-----------------------------------
AutoDiskChange is a small program that you run in the background. Every time
you change a floppy it will send the appropriate information to FFS to tell
it that a disk has changed. This puts FFS on the same level as the normal
file system.

[stuff removed]

Why FFS on floppies?
--------------------
FFS will allow you to store 4.9% more data on the same floppy. It will also
do disk directories quite a bit faster. Disk reads and writes are speeded up
a little, but not that much. This is due to hardware limitations. One area
where a big difference can be perceived is when doing 2 or more disk
transactions simultaneously. If you're saving some data to floppy in DF0:
and reading stuff to the RAM disk from DF1:, there will be virtually no
slowdown of either the write or read operations. This is in contrast with
the old FS. Note that performing two disk operations on the same floppy still
results in HORRIBLE performance loss.

[lots removed...   i.e. how to do it!]

------------------------------- CUT HERE ---------------------------------------

Hope this clears things up


dave   +----------------------+------------------------------------------------+
+------+                      |  CSIRO Division of Wool Technology             |
| David Johnson               |  PO Box 21, Belmont, Australia, 3216           |
| djohnson@geel.dwt.csiro.au  |  +61 52 472-651 (voice)   +61 52 472-657 (fax) |
+-----------------------------+------------------------------------------------+
     Most men are within a finger's breadth of being mad.        - Diogenes
================================================================================
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