🚀 go-pugleaf

In-reply-to:  Scott Udell <UD140469%NDSUVM1.BITNET@wiscvm.wisc.edu>

    I've recently been running into some trouble with disk space
    dissappearing from my double sided disks.

The FAT and directories do take some space away from the total,
but the 72K you report seems excessive, and the fact that you have
LESS space after deleting a file suggests that you might be having disk
problems.  I believe that DOS will mark a block in the FAT as unusable
if it decides the block is bad.  Perhaps your disk head is dirty or the
drive has gotten out of alignment so that DOS frequently encounters 
unreadable blocks.  Does this happen on freshly formatted disks or only
ones that you have had around for awhile?  You can try deleting everying
from the disk and see if you again have 726,016 bytes available or some
smaller number.

Another possible source of space lossage results from having many
short files.  Blocks on the disk are allocated 2 sectors at a time,
so each file uses up at least 1024 bytes.  I think the SHOW INFO
desktop function reports only the bytes actually contained in the
file, so the unused bytes at the end of each file are also disappeared
space.  Thus, 116 files, each with an average of 512 unused bytes at the
end, could easily account for another 59,000 missing bytes.

If you are still using TOS in RAM, then it is possible that you are
overwriting TOS in a way to cause disk problems.  I also used to have
mysterious floppy problems when I was running TOS in RAM on an early 520ST.
Those problems have not occurred on my 1040's with TOS in ROM, suggesting
that there might also have been a TOS bug that was fixed in the ROM version.
Anyone at Atari want to comment on this?

--Mike Fischer <fischer@yale.arpa>


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