Hi Sellam,
What does "Gap in sectors" under Anadisk mean
anyway?
It means that ANADISK saw gaps in the sector numbering.
For example, it might have seen sectors:
1 2 3 4 6 7 8 9
In this case there is a "gap" which is sector #5 missing.
Note, it is entirely possible to format a diskette with
missing sectors - but most people didn't do it - it most
likely indicates that ANADISK failed to read one sector,
which is why it reports this as a warning.
Is this just a case of disks that are just old and
wearing out or
something weird with my drive?
The higher the track, the smaller the "circle" on the disk with the
data, hence the more densly packed the bits are - which can lead to
more errors - this is also the area where head alignment etc. can be
most critical, and worn drives do tend to give more errors on the
inner tracks.
But it's may also be a incompatibility between the diskette format and
the PC disk controller (I am assuming this is the 8" drive that you
have hooked up to a PC).
The PC disk controller cannot handle gaps sizes as small as some
other systems did - For example, I find that Cromemco disks do not
read reliably on my PC. The interesting thing is that certain sectors
consistantly do not read on one PC, while DIFFERENT sector(s) may not
read reliable on a different PC.
When I was working on my replacement for TELEDISK (which I still have
not gotten back to), I found that I could sometimes read all the sectors
by re-reading the same track multiple times (however at that point you
lose the ability to detect the exact interleave), but sometimes even
reading the track 50 times would not yield all the sectors. On a different
PC, I could read a different set of sectors with about the same
reliability. One thing I wanted to add to the program was the ability to
merge multiple images read from different PCs into one to "collect" all
the sectors.
I also found that slowing the drive slightly can make a big improvement
on reading some types of disks...
(and of course - none of this may actually relate to the problem you are
having ... just some of my experiences to help you figure it out)
If you format a disk from the PC can you read it back reliably?
Regards,
Dave
--
dave04a (at) Dave Dunfield
dunfield (dot) Firmware development services & tools:
www.dunfield.com
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