The first problem I would suspect on a disk where list stuff is being logged
in the  one known  under the  poetic name of  "DISK m(cuu)  IS FULL".  Given a
return code 113 from EXECIO, you can  issue a HELP EXECIO command and discover
that 113  = 100 + nn,  where 'nn' =  13 is the  return code from the  disk I/O
operation. If you have a look at the CMS paper doc (which are rather unwieldy,
so let's say  you have a look  at DMSBWR ASSEMBLE instead), you  will find out
that rc=13 means DISK FULL. It is an  old IBM standard return code by the way.
I am not surprised  that moving the disk to another volume  does not solve the
problem. Some huge mail  is being received that fills up  the log disk, that's
all. And  in that  instance 1.5l  would have transferred  the mailfile  to the
postmaster and held the list with notification being sent out.
 
  Eric