Ferret utility - forum topic by Raja_KT

Hi,
I know that Ferret utility automatically manages Teradata file system. It works on data levels as vproc,table, subtable,WAL log,disk and cylinder. We can run scandisk from supvr, define scope. We can use showblocks and showspace. How often this work has to be done by the DBA?
Also may I know the reason(s), why WAL a log and not a table?
 
Thanks and regards,
Raja