CORE(V)                      9/10/73                      CORE(V)


     core - format of core image file


     UNIX writes out a core image of a  terminated  process  when

     any  of  various errors occur.  See signal (II) for the list

     of reasons; the most common are memory  violations,  illegal

     instructions,  bus  errors, and user-generated quit signals.

     The core image is called ``core''  and  is  written  in  the

     process's  working  directory  (provided  it  can be; normal

     access controls apply).

     The first 512 bytes of the core image  are  a  copy  of  the

     system's  per-user  data  for  the  process,  including  the

     registers as they were  at  the  time  of  the  fault.   The

     remainder  represents the actual contents of the user's core

     area when the core image was written.  At the moment, if the

     text  segment  is  write-protected  and  shared,  it  is not

     dumped; otherwise the entire address space is dumped.

     The actual format of the information in the first 512  bytes

     is  complicated.   A  guru  will  have  to  be  consulted if

     enlightenment is required.  In general the debugger  db  (I)

     should be used to deal with core images.


     db(I), signal(II)