The Datafile PD-CD 4/DATAFILE_PDCD4.iso/utilities/utilsf/fcfs/!FCFS/!Help

Text File | 1995-09-26 | 13.2 KB | 342 lines

                  ==========================================
                  FCFS (1.01) - FileCore Image Filing System
                  (C) Nick Craig-Wood and Sergio Monesi 1995
                  ==========================================

FCFS is an image filing system that allows you to read FileCore disc images.
This means that you can 'copy' a whole floppy or hard disc image (ie all the
disc's sectors) to your harddisc and then access it as if it were a
directory.  FCFS provides a desktop front end for the (multitasking)
creation and restoration of disc images.

FCFS requires RISC OS 3.10 or later (it has been fully tested on Risc PC)
and supports interactive Help.

FCFS is SHAREWARE.  If you use it for more than 30 days you must register;
see 'Conditions of use' for more info.


Index
-----

- Introduction
- FCFS images
- Making images
- Restoring images
- Multitasking operations
- Using images
- Disclaimer
- Bugs and Limitations
- History
- Credits
- Conditions of use
- Contacting the Authors


Introduction
------------

Why would anyone want to copy a FileCore disc into an image file?  Well FCFS
was conceived to do this for 2 main reasons.

Firstly when backing up a hard disc onto another hard disc, it was noticed
that FileCore took about 10 times longer to copy the contents of the disc as
it did to read and write all the sectors at a low level.  This is because
FileCore is creating file and directories, altering the directory images and
generally having to do a lot of work.  FCFS allows you to copy an entire
disc (floppy or hard) to a file, sector by sector, very quickly.

The second use of FCFS is to write these files back to a disc.  This might
be used by a PD library, which keeps a lot of disc images on hard disc, and
when it wants to write them to floppy just uses FCFS to do so.  This again
is much quicker than copying the files directly.

An image filing system was then created to read the files out of these
images (as if they were still attached as a disc drive).  The image filing
system is read only for the time being though.

FCFS is used every day by one of the authors for backing up his 420 Mb disc
onto an external SCSI disc.  This chore which used to take nearly an hour,
is all over in 8 minutes!  The created image is then readable with the image
filing system.


FCFS images
-----------

FCFS images are files of type FCD or FileCore.  This file type hasn't been
allocated for us by Acorn, but it was allocated for FileCore and so our use
is probably OK.  If you know otherwise then let us know!

FCFS images come in two types, compressed and un-compressed.  The
un-compressed image has _all_ the sectors on the disc, used and unused, and
if the FCFS image filing system ever becomes write as well as read then it
will only be able to write to this type of disc.

The compressed disc image has had all the unused sectors removed from it,
making it smaller.

For example, if you had a disc with (from Free space display)

    Free: 125 Mb
    Used: 280 Mb
    Size: 406 Mb

An un-compressed image would be 406 Mb in size and a compressed image would
be 280 Mb in size.


Making images
-------------

Clicking with Select on the iconbar icon will open the 'Make Image' window.
To create a new FCFS image from a disc you need to select the source disc
(using the pop-up menu), choose the Image type, the filename and drag the
icon to a filer window.

FCFS will copy the disc sectors (only the used ones) to the image file (see
also Multitasking operations) and when the copying is finished the image is
ready to be opened.

This is the only way to create FCFS images: there are floppy copy programs
that can save the disc image to a file but FCFS can't access them (even if
they are filetyped correctly) since they don't include some data that is
essential for FCFS.  (It may be possible to write a converter though, ask
the Authors!)


Restoring images
----------------

Once you have created an image, you can restore its content to the original
disc (or to any other filing system) just using the filer (ie drag the files
from the image to the disc).  However, this is a rather slow process
(especially on floppies), so if you need to do this, you can use the
'Restore Image' window (opened by clicking Adjust on the iconbar FCFS icon).

To use this, just drag an FCFS image to this window (its details will be
shown), choose the destination disc using the pop-up menu and click on
Restore.

FCFS will copy the image content (only the used 'sectors') to the
destination disc (see also Multitasking operations) and when the copying is
finished the disc will be an exact copy of the original one (ie the disc
that generated the image).

Be careful when you use this feature, since it will completely remove the
content of the destination disc and will replace it with the content of the
FCFS image.  If the destination disc is not empty, FCFS will prompt you for
confirmation before performing this operation.

FCFS can restore an image only to a disc whose 'shape' is equal to the
image's shape (ie equal to the shape of the disc that generated the image).
In other words, you can't restore an image of a 40Mb HardDisc to a 100Mb
hard disc, nor you can restore a 800Kb floppy image to a 1.6Mb floppy or
vice versa.

However, you can restore a 800Kb floppy image to a 800Kb RAM disc since
their shape is similar (FCFS will tell you that the shape is different, but
you can click on 'Continue' and restore it anyway), but you can't restore a
1.6Mb floppy image to a 1.6Mb RAM disc because of RAM disc limitations (it
doesn't support the bootblock).


Multitasking operations
-----------------------

In both the Make and Restore window you can find a Multitask button.  If it
is selected, the making or restoring of the FCFS image will be performed in
a multitasking fashion, so you can get on with something else at the same
time.

You can use the Timeslice icon to change the time (in centiseconds) that
FCFS will use to read/write to the disc/image before it gives the control
back to the other tasks (ie high value means faster image making/restoring
but slow desktop operations).  Values between 5 and 20 are recommended.

While the image is deing made or restored another window will appear which
shows the progress so far and allows the options of pausing and aborting the
operation.  When the operation has finished this window will display
statistics about transfer rates etc.

If you selected a non-multitasking operation then Escape will abort it.

Before creating an image, if the Multitask option is set, FCFS will try to
'lock' the disc to avoid changes being made to it during the copying
process. If there are files open for writing, FCFS can't lock the disc and
will ask you if you want to continue or abort the operation.  If you choose
to continue, remember that you should avoid writing to or modifying the disc
in any way, otherwise the image will probably be corrupted. If the locking
operation succeeds you can read the disc as usual but you can't create,
delete or modify any files.


Using images
------------

Once you have created an image then you can use this image exactly as if it
were the original disc, the only limitation being that it will be read only.

The FCFS image file icon is suggestive of a directory icon.  This is
deliberate since the image file has the attributes both of a directory and a
file.  You may copy the file about just like a normal file, however you may
double click on it to open it like a directory.  It works in exactly the
same way as DOSFS.

FCFS has two quit options leading off "Quit" on the iconbar menu.  "Filer
only" and "Filer and FS".  The first quits just the desktop front end - you
will still be able to use the FCFS image files.  The second quits the image
filing system also and after that you will not be able to use the FCFS image
files without reloading FCFS.  Clicking on the main "Quit" option is
equivalent to "Filer only".


Disclaimer
----------

In normal operations FCFS is not a dangerous program since it doesn't write
anything to the disc.  However, when restoring an image, it completely
removes the destination disc's contents, so if you use it on the wrong disc
by accident, you will be sorry!

If for any reason (either your mistake or a bug in FCFS) it causes you a
loss of data, we are sorry for you but WE WILL NOT BE HELD RESPONSIBLE.

Use FCFS at your own risk.


Bugs and Limitations
--------------------

FCFS can only read from image files, not write to them.  If the demand is
there then we may consider adding this.


History
-------

0.00 -- 24Mar94
* The first version of the FCFS filing system:  itself a FileCore filing
  system.  However a huge problem appeared: FileCore isn't re-entrant!  So it
  would work over a network quite happily but not on a local FileCore disc.

1.00 -- 20Sep95
* First fully working version, with an image filing system (with its own
  code to read from FileCore disc images), image creation and restoration.

1.01 -- 26Sep95
* Fixed a bug that prevented some files (especially fragmented ones) from
  being correctly read from an image.
* Now works with new FSes running with old FileCore.


Credits
-------

We'd like to thank the following people who contibuted in some way to the
development of FCFS:
- Martin J Ebourne for his memory allocation functions, used in the desktop
  frontend and his module code.
- Jason Williams (and all the other collaborators) for DeskLib.
- Dave Lawrence, Mike Brown and George Foot for being diligent beta testers.


Conditions of use
-----------------

FCFS (The Software) is Copyright (C) Nick Craig-Wood and Sergio Monesi 1995
(the Authors) and may not be used or copied except as in accord with the
terms and conditions below.

You may NOT Make the Software available to any third party EXCEPT with these
terms and conditions imposed on said party.

You MUST make sure the Software is distributed whole, intact and unmodified,
including all the files in the original distribution.

If you use the Software for more than 30 days then you MUST register the
Software (see below).  You may NOT copy (except for personal use) the
Software if it has been registered, and you may NOT give to any third party
any registration keys you have been issued with.

You may NOT sell, hire or include the Software in a package which is sold or
hired, modify, translate, disassemble, decompile, reverse engineer, or create
derivative works based upon the Software or include whole or part of the
Software into other works.

The Software is supplied "as is", the Authors make no warranty, express or
implied, as to the merchantability or its fitness for any particular
purpose.   It may or may not perform in accordance with the documentation or
your expectations.

In no circumstances will the Authors be liable for any damage, loss of data,
profits, goodwill or for any indirect or consequential loss arising out of
the use of the Software, or inability to use the Software, even if the
Authors have been advised of the possibility of such loss.

These conditions supersede any prior agreement, oral or written, between you
and the Authors relating to the Software.

You agree that except for written separate agreements between the Authors
and you, this agreement is a complete and exclusive statement of the rights
and liabilities of the parties.

You acknowledge that you have read this agreement, that you understand this
agreement, and by loading, running or copying the Software you agree to be
bound by this agreement's terms and conditions.


Registering the Software:

To register you simply have to send one of the Authors a registration fee
(in the form of bank notes or sterling cheques drawn on a UK bank) of not
less than 10 pounds, 30.000 lire, 35 marks, 20 US dollars, 100 francs,
50 Nlg or equivalent.  If you want you can include a disc and, say, 2 pounds
for mail costs, and you will be sent the latest version of the Software
along with some other PD programs.

In return you will be given a registration key.  This is a number of 10
digits or less and can be used to register the Software.

To register your Software select the register option from the main menu,
type in your name as you specified it to us in the box that appears (Case,
punctuation and spaces are important) and your registration number.  Press
the Save button. This will register the software in your name.

This has two functions

  1) It removes the start up message
  2) It burns your name into the program info box, so we will know if you
     give away a registered copy of the program.

If you want to unregister the program (before you give it to a friend maybe)
then make sure the registration key field is clear and press Save.

Registration keys will unlock future versions of the Software unless the
Authors decide otherwise.


Contacting the Authors
----------------------

Post:  Nick Craig-Wood              Sergio Monesi
       26 Wodeland Avenue           Via Trento e Trieste 30
       Guildford                    20046 Biassono (MI)
       Surrey GU2 5JZ               Italy
       UK

EMail: [e-mail]         [e-mail]
                                    [e-mail]
                                    [e-mail]

BBS:   Arcade (0181 654 2212)
       User 939 (Nick Craig-Wood)

WWW:                                http://cdc8g5.cdc.polimi.it/~pel0015/


If you want to send e-mail to the development team then do so at

  [e-mail]