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1996-02-27
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AllowBad 0.5 (ßeta version)
© Mikolaj Calusinski 1995. Freeware.
User Manual
Introduction
------------
AllowBad is freeware (see 'Distribution') and copyright 1995-1996 by Mikolaj
Calusinski. All rights reserved.
*****************************************************************************
IMPORTANT!
IF YOU ARE A FASCIST OR NAZI YOU ARE *NOT* ALLOWED TO USE THIS PROGRAM!!!
*****************************************************************************
Distribution
------------
[The following text has been derived and adjusted from 'FileMaster 3.0.guide'
© Toni Wilen 1995 (I don't want to reinvent the wheel). I hope Toni, you don't
mind.]
AllowBad may be distributed freely, providing the following criteria are met:
- None of the files in the AllowBad distribution archive may be modified or
omitted.
- No money is charged for it apart from media and small handling fee.
- AllowBad may be included in freely distributable software libraries,
including the Fred Fish collection and CD-ROM distributions of the Aminet
FTP site contents.
- AllowBad may not be bundled with any commercial hardware or software
product without prior written consent from the author.
- You may not reverse-engineer or modify the AllowBad executable on disk or
on memory except for compressing it.
Disclaimer
----------
[The following text has been derived from 'FileMaster 3.0.guide' © Toni Wilen
1995 (I don't want to reinvent the wheel). I hope Toni, you don't mind.]
THIS PRODUCT IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. ALL RISKS AND
DAMAGES, INCIDENTAL OR OTHERWISE, ARISING FROM THE USE, MISUSE, OR INABILITY
TO USE THIS PROGRAM ARE ENTIRELY THE RESPONSIBILITY OF THE USER. THE AUTHOR
DOES NOT MAKE ANY GUARANTEES OR REPRESENTATIONS REGARDING THE CORRECTNESS,
RELIABILITY, ACCURACY, CURRENTNESS, ETC. OF THIS PROGRAM. THE AUTHOR WILL NOT
ACCEPT RESPONSIBILITY FOR ANY DAMAGE OR LOSSES RESULTING FROM THE USE, MISUSE,
OR INABILITY TO USE THIS PRODUCT.
What is that for?
-----------------
This program was written as a replacement for good, but old BFormat 4.0. Its
purpose is to format disks of any *floppy-based* devices, which have hard
(media) error on them. Such disks cannot be formatted (and hence utilized) by
system 'Format', so only thing you could do was getting rid of them.
Optionally, you could use BFormat of course, but such prepared disks were very
unstable under AmigaDOS, and gave 'read-write' errors quite often. This was
because of way BFormat works - it allocates only blocks which appeared to be
corrupted, leaving rest of the track for use by filesystem. It sounds quite
logical and give you more free space on disk but doesn't work that well with
floppies. For safety of stored data it is better to avoid whole track
regardless whether there is only one or more bad blocks on it. That is the way
AllowBad handles the errors - it masks the tracks, not blocks.
AllowBad should be able to format disks in all floppy-like devices, which have
the following parameters (and these are checked when device type is determined
to be floppy or not):
- number of surfaces must be 2
- starting cylinder (LowCyl) *must* be 0
- ending cylinder (HighCyl) must not be higher than 81
- block per track can be any number above three (so at least four)
- block size must be standard (512 bytes)
- device must use AmigaDOS filesystem (0x444F53XX - 'DOS')
- max unit number is 3 (ranging from 0 to 3)
The above should rule out all harddisks (if you want to format damaged
harddisk use BFormat or Quarterback), CDROMs, etc. AllowBad works (and has
been tested) with trackdisk (DFx:) and diskspare [(c) 1992-1994 by Klaus
Deppisch] (DSx:) devices. It should support all possible future devices which
comply to the specs mentioned.
The program is aware of high density (HD) floppies and should support them,
but unfortunately I was unable to test it (hence the ßeta status of AllowBad).
Please, report all the possible bugs to the address found at the end of this
document.
You can format RAD: device with AllowBad (as long as it complies to above
specs) but this does not make much sense.
Requirements
------------
As most of nowadays programs, AllowBad requires at least version 2.04 of
operating system. Reasons are obvious: it is much easier for programmer (me)
to code the whole thing and AllowBad works only with FFS types of disk (1.3
doesn't support FFS floppies directly). If you want to use DIRCACHE filesystem
you need OS 3.0 or higher (however AllowBad can format dircache disks under
2.04, too).
AllowBad also requires some free memory; its amount depends on device. For
further details see 'Way of operation' section.
Limitations
-----------
AllowBad is somehow a little bit more tollerant than other programs of its
kind - it can properly format and initialize disks, which have tracks 0 and\or
root damaged! The only requirement for such disks is the ability to read\write
first two block on track 0 (ie. bootblocks) and one block on middle track of
disk (ie. rootblock). So, if you have for example the disk which has damaged
only block number 3, there is a good chance AllowBad will be able to
initialize this disk and make it available for file storage (with low side of
track 0 allocated as bad). But remember: such a disk is extremely vulnerable
and unstable. Be sure not to store any important files on it!
This version of AllowBad is meant as a CLI command and cannot be used from
Workbench (it has no GUI, so no pain I think).
Usage
-----
Standard template (can be obtained via use of question mark) looks like this:
AllowBad DRIVE/K/A,NAME/K/A,INTL=INTERNATIONAL/S,DIRCACHE/S:
As you can see only two parameters must be specified - drive name and name you
want your disk to have. Drive name is standard doslevel device name such as
'df0:', 'ds1:', etc., case insensitive. Must end with colon. Name of the disk
must not exceeded 30 chars (this limit is imposed by current version of
AmigaDOS). Names longer than permitted will simply be truncated. If you want
the filename to contain spaces, you must use quotes. Remaining two parameters
are optional and pertain to type of filesystem used while initializing the
disk. INTL (equivalent to INTERNATIONAL) denotes INTL FFS (DOS3) and DIRCACHE
- DC FFS (DOS5), respectively. If you use both of them at the same time
DIRCACHE will be used (DC implies INTL anyway). When none of switches is
present the disk will be formatted with default normal FFS (DOS1).
For some technical reasons OFS types of filesystem are not supported. I hope
you can live with it however.
While formatting, the program can be interrupted with CTRL-c. If this is so,
execution is terminated with RC (return code) set to 5 (WARN) and mesage
'***BREAK' is printed.
Way of Operation
----------------
At start AllowBad checks whether the parameters issued by user are correct
(they are obtained through standard ReadArgs() function). At this analizing
stage, availability of disk unit is also confirmed. If disk is not in use,
AllowBad immediately allocates it (by Inhibit() function). Else program quits
with error message 'AllowBad failure: object is in use'. Unfortunately some
programs (such as great disk editor DPU 1.5 or recovery utility Quarterback
Tools 2.2) ignore the fact that the drive is inhibited by someone else and
allow you to work with such a drive. This could lead to interference between
those programs and AllowBad, resulting in incorrectly formatted/initialized
disks. This is NOT my fault, but programmers of those utilities! My advice is
not to use any disk utility while AllowBad executes.
If everything went okay (and there is a write-enabled disk in drive) two
memory buffers are allocated (and these are the only memory allocations made
by the program) - first buffer is the three times of one track in size
(calculated as follows: 3*BlocksPerTrack*512), and the second one is 83 bytes.
Thus currently the most 'memory-hungry' situation I can think of will be HD
disk formatted using diskspare.device [(c) 1992-1994 by Klaus Deppisch]. In
this case AllowBad will need 3*24*512+84 (= 36948) bytes of free memory. The
kind of allocated memory (chip, public, etc.) depends of flags parameter in
device's FileSysStartupMsg (you can specify it in BufMemType parameter in
mountlist).
Because Allowbad is system friendly, it uses standard device calls for
accessing the disk (via IORequest). First, each track of disk is formatted
(using command #11 - FORMAT) with special data pattern. Then (after flushing
device buffers for reliability) contents of this track is read back from disk
and compared with pattern data. If operation is successful, the same track is
written with zeros and once again verified. During all of this program informs
briefly about what is going on. Each error encountered is notified in the
second buffer and the appropriate message is diplayed. Each track can be
accessed up to four times, so AllowBad undoubtedly is not the fastest
formatter around. But when dealing with corrupted media, reliability is what
counts, not time.
When formatting completes, AllowBad attempts to initialize the disk - first
boot blocks are written (and verified) then so is root. If above could be
done, disk state info (as obtained during format stage) is analyzed and place
for other control blocks is determined. These blocks include: - dircache info
block (if DIRCACHE switch was specified), bitmap block, file info block and
eventually some file extension blocks. The last two can be needed only if
there were errors detected.
AllowBad masks corrupted areas using dummy file which pretends to occupy all
the bad tracks. This keeps the AmigaDOS filesystems from using those places
and you can store files the same way as on good (error free) disks. To avoid
confusion the file is protected from reading, updating, deleting, etc. and
should remain as such (don't play with this file - it IS completely faked and
does not contain anything intreresting!) The name of the file is 'dummy.bad'.
Because of way AllowBad works (and I can't think of anything better, can you?)
disks prepared by it can *only* be used under DOS, even that with some
limitations. Don't try to diskcopy to such a disk! Use DOS command 'copy' or
any file managing program instead. Also, don't try to optimize bad disks with
Reorg or like. If you want fast directory listings use dircache (OS 3.0
rules!) And remember that AllowBad DOES NOT repair anything - it only allows
bad disks to be used while they actually still remain bad!
On completion AllowBad informs you about number of blocks allocated (this not
includes boot, root, DC, bitmap and FIB blocks).
Bugs
----
During my tests (well, not very intensive) no bugs were detected, which does
not mean there aren't any. If you find any error or have some ideas of
improvement (or if you simply wanna chat a little, receive the source, etc.)
please contact me!
Contact address
---------------
Unfortunately, I still have no direct access to Internet (must buy a modem
first) so you can reach me only by snail mail, sorry. Here is my address:
Mikolaj Calusinski
ul. Olsztynska 113/117
42-200 Czestochowa
POLAND
I hope you find this little proggy useful. Have fun!
Mike.
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