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Weak sector data: Difference between revisions

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= Weak disk data =
= Weak disk data =


Some copy protections have what is described as `weak, random or floated' data.
Some copy protections have what is described as 'weak', 'random' or 'floated' data.


Each  time the 'weak' sector is read one or more bytes will change, the value
Each  time when the 'weak' sector is read one or more bytes will change. Their value
may be random between consecutive reads of the same sector.
may be random between consecutive reads of the same sector.


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Weak sectors used by [[Speedlock]] copy protection family for [[ZX Spectrum +3]] disks.
Weak sectors used by [[Speedlock]] copy protection family for [[ZX Spectrum +3]] disks.


Usually weak sector data used with other things for copy protection:
Usually weak sector data combined with other unusual things for copy protection, such as:
* different sector length for different tracks
* different sector length for different tracks
* different sector length within a drack
* different sector length within a track
* deleted sectors
* sectors marked as deleted
* sectors with CRC error
* sectors with CRC error
* wrong sector header informations e.g.:
* wrong sector header informations e.g.:
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Unfortunately, disk images with recorded weak sector data is very rare (There is no any disk image with weak sector data on [http://www.worldofspectrum.org/ WoS]).
Unfortunately, disk images with recorded weak sector data is very rare (There is no any disk image with weak sector data on [http://www.worldofspectrum.org/ WoS]).


So if a game read the same sector repeatedly than semulators assume that sector has weak data..
So if a game read the same sector repeatedly than simulators assume that this sector has weak data..
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