Storage
Data storage
- Each object consists of a metadata file (.bkm file created from the .trk and .not
files) with a unique alphanumeric name that matches the identifier of the NOTIS
bibliographic record describing it plus one or more sound files.
- Example:
- Bibliographic record: AAT8375
- Metadata file: AAT8375.bkm
- Sound file (CD 1): AAT8375A
- Sound file (CD 2): AAT8375B
- Sound file (CD3): AAT8375C
Playback Server
- 120 GB of SCSI hard disk storage
- Acts as a cache for the most recently used audio files
- Files are loaded onto the cache before playing
- A program runs nightly to remove the oldest files
Archive Server
- Stores compressed sound files on tape cartridges in an automated tape library
- IBM 3494 Tape Library Dataserver
- Two IBM 3590 Magstar tape drives
- IBM RS/6000 J30 SMP server running IBM's ADSTAR Distributed Storage
Manager (ADSM) software.
- 200 3590 tape cartridges (each holding 10 GB of data)
Statistics
- Usage statistics show:
- An average of 80% of the sound files requested by users are already on the
playback server
- The percentage of sound files requested from the playback server is higher when
overall usage is higher indicating that our predictions were correct: heavy spurts of
usage of sound recordings in the IU Music Library are related to many students
choosing the same selection for course listening.
- The average amount of time a user waits to have a selection retrieved from tape is
under 3 minutes.