run RMAN without TAPE

--error
RMAN> delete backupset 163;

allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=134 devtype=DISK
released channel: ORA_DISK_1
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of delete command at 04/05/2008 15:11:35
ORA-19554: error allocating device, device type: SBT_TAPE, device name:
ORA-27211: Failed to load Media Management Library

--solution

RMAN> allocate channel for maintenance type disk;

allocated channel: ORA_MAINT_DISK_1
channel ORA_MAINT_DISK_1: sid=134 devtype=DISK

RMAN> delete backupset 163;


List of Backup Pieces
BP Key BS Key Pc# Cp# Status Device Type Piece Name
------- ------- --- --- ----------- ----------- ----------
167 163 1 1 UNAVAILABLE DISK /apps/oracle/rmanbackup_area/c-3491152056-20080419-01

Do you really want to delete the above objects (enter YES or NO)? yes
deleted backup piece
backup piece handle=/apps/oracle/rmanbackup_area/c-3491152056-20080419-01 recid=7 stamp=652487787
Deleted 1 objects