disk_error/22_READ_ERROR                               disk_error/22_READ_ERROR
 
 NUMBER
     22

 MESSAGE
     READ ERROR

 DESCRIPTION
     Data block not present.
 
     The disk controller has been requested to read or verify a data block 
     that was not properly written. This error message occurs in conjunction 
     with the BLOCK commands and indicates an illegal track and/or sector 
     request.