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- *** ***
- *** RECLAIM (Version_2 -- June 1993) ***
- *** ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ***
- *** ***
- *** ( renders useable the 2 clusters that ***
- *** TOS "loses" on formatted floppies ) ***
- *** ***
- *** ( Freeware by W. Alan B. Evans [wabe@ukc.ac.uk] ) ***
- *** ***
- *** ( May NOT be distributed without accompanying RECLAIM.TXT ***
- *** NOR commercially distributed without Author's permission ) ***
- *** ***
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-
-
- For some reason best known to Atari, TOS "wastes" 4 sectors (or 2
- 1024 byte clusters) of formatted disk space. For example, with the standard
- double-sided Atari format we have 1 bootsector, 2 sets of fats each 5
- sectors long and a root directory which is 7 sectors long. The disk is
- formatted to 80 9-sector tracks on both sides i.e. 1440 512-byte sectors
- in all. Since the "disk management" accounts for 18 of these, one might
- reasonably expect there would be 1422 left over to hold data i.e. we'd
- expect 711 clusters of data. But NO! - as is well-known there's only 709
- clusters available for data. What has TOS done with the other 2? I'm sure
- I don't know - I've never seen any explanation for this documented! But
- there _MAY_ be a good reason - and, IN CASE THERE IS, and in any case
- as this software is FREEWARE, I give NO GUARANTEES WHATSOEVER for any
- consequences that might arise out of using RECLAIM. Therefore, it would
- be wise to be wary (esp. with valuable data) until one has gained full
- confidence in the usage of RECLAIM. All I can say is that I have
- personally been using RECLAIM for some while with no adverse-effects.
-
- The idea for RECLAIM is originally in the RDY sourcecode of Mark
- Williams Co.'s "RDY" ramdisk utility. Whilst upgrading the latter recently
- (Version_4 of RDE is now available at a.a.) I noticed that a little trick
- which the author of RDY called a CLUSTERHACK allowed the ramdisk to reclaim
- these 2 lost clusters back from TOS. Basically the strategy is exceedingly
- simple viz. alter the boot parameter block info to signal a total sector
- number which is 4 more than actually exists and to MARKBAD the last two
- FAT clusters. It occurred to me that this might also work on Floppies
- and, indeed, it seems to. However I know of no formatter program that will
- format floppies in this "RECLAIMed" state.
-
- You can use a disk editor ( DISK DOCTOR, KNIFEST etc. ) to do the
- alterations. However, altering the format with a disk utility involves some
- intricate calculations to locate the last two fats' positions etc. etc.
- and a small error could cause loss of data. RECLAIM.TOS simplifies & speeds
- up this task. At the prompt you simply insert a normally formatted disk
- and RECLAIM will do these conversions and modify the disk so that you will
- end up with 2 kbytes more of free space on it. Of course, it checks to see
- if the disk has previously been altered and, in that event, will tell you
- and alter nothing. Note also that disks containing data can also have
- their missing sectors RECLAIMed - with no harm to the data.
-
- Beware though of utilities that wipe out the entire fat tables
- (e.g. DISK TOOL ( DT.TTP ) with option "-w" ). Most (all?) utilities that
- do this ignore the possible presence of MARKED BAD clusters. Hence using
- DT.TTP or similar will wipe out the MARKBAD marks and thereafter the disk
- would signal to TOS that it has valid sectors that, in fact, do not exist.
- In the same vein, if you use a Disk Utility sector editor (such as DISKDOC)
- you should not try to read the last four sectors declared by the BBPB (that
- don't really exist) else you may hear "grating" sounds from your diskdrive
- before TOS complains. If one uses the SEEKUP patch (by Martin Osieka) to cure
- the "grating" diskdrive sounds, which is a bug in TOS 2.06 when fitted to
- older ST's without HD-drives, one finds that trying to read nonexistent
- sectors results in the default values of whatever SEEKUP alters (FLOPRATE
- etc.) being re-established - so, if you must do this, be prepared to run
- SEEKUP again to keep your diskdrive "harmonious".
-
- After converting a disk with RECLAIM, one should strictly tell TOS
- that the media has been changed. RECLAIM _does_ do this though I see no
- great reason to, since all we've released are two clusters at the high end
- - so that the worse that can happen is that a file that should fit on your
- (enlarged) disk might actually fail to do so as TOS is unaware of the 2
- extra clusters.
-
- I know of no other pitfalls....(perhaps someone can enlighten me)
- but, meantime, good luck RECLAIMing what's rightfully yours! By the way,
- I've used the ICE packer to pack RECLAIM.TOS which "just" gets it below
- 2 clusters in size. How appropriate! - take a full floppy, apply RECLAIM
- to it, and your gained space is just enough to store RECLAIM.TOS!!
-
- P.S.: The last sentence applied before I added a check to see if there
- was any data on the disk - and, ONLY IF THERE IS NO DATA, RECLAIM gives
- you the option of changing the No. of Fat Sectors (FSIZE) and No. of Root
- directory sectors (ROOT) the default being NO CHANGE. As is well-realised
- 5 FAT-sectors is too much to cover all the usual Double sided formats (3
- is sufficient) - and so by trimming these down there is further scope for
- obtaining more DATA sectors. BUT, be careful here, TOS sometimes fails to
- recognise a media change, so if you keep swapping floppies with different
- management structures, it _MAY_ get confused. So my advice to beginners is
- to KEEP THE DEFAULT VALUES (FSIZE=5 and ROOT=7 usually) and just be content
- to RECLAIM the 2 lost clusters. So the program now is ~2800 bytes (ICE-
- packed) and calls itself RECLAIM V_2 ( V_1 was never distributed).
-
- W. Alan B. Evans. (June 93).
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