Weak sector data

Revision as of 17:57, 13 February 2016 by Szaszg (talk | contribs)

Weak disk data

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

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.

Weak data recorded with only modified hardware, so you cannot copy these disks without 'crack' the copy protection.

Only two disk image formats (Extended DSK and UDI 1.1) can store this type of data.

Copy protection

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

Usually weak sector data combined with other unusual things for copy protection, such as:

  • different sector length for different tracks
  • different sector length within a track
  • sectors marked as deleted
  • sectors with CRC error
  • wrong sector header informations e.g.:
    • track number
    • too long sector length

Disk images with weak sectors

Unfortunately, disk images with recorded weak sector data is very rare (There is no any disk image with weak sector data on WoS).

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