Operator`s manual

Model VR240 Audio Logging Recorder
January 2000
4-7
*Channel Hour equals one (1) channel recording continuously for one hour
4-13. HARD DISK DRIVE.
Each VR240 comes standard with an internal hard disk drive. As of the time of writing (Nov 99),
the standard hard disk drive capacity is 4GB. The precise definition of GB (gigabyte) depends
on the drive manufacturer. Everyone agrees that a KB (kilobyte) is 1024 bytes, but some say
that a MB (megabyte) is 1000KB, some say it is 1024KB, and some might say it is 1,000,000
bytes. In this manual we say 1MB = 1024KB. In the VR240, each 100MB of storage on the
hard disk drive represents about 14.5 channel-hours.
The VR240 stores the most recently recorded audio material on the hard disk drive. This
provides three major operational benefits:
1) You can listen to material from the hard disk drive without disturbing tape drive operation
(“instant recall” is simply a quick way to start playback from the hard disk).
2) If the VR240 runs out of tape, you have several hours of time to change tapes without
any loss of material.
3) If you need to listen to material that is not on the hard disk, you can suspend recording
on a tape drive, use the tape drive for playback, and resume recording without losing
anything.
Another benefit of the hard disk drive in the VR240 is that it prolongs the life of the tape drives.
Here’s why: a DDS tape drive is either “streaming” (recording data on tape at a fixed rate of
about 500KB per second) or it is stopped. If you back up your computer’s disk drive to a DDS
tape, your computer reads files from your disk (which is much faster than a tape drive) and
sends them to the tape drive as fast as the tape drive can accept the data; a 1GB disk drive
takes about 30 minutes to copy, and the tape “streams” the entire time, only stopping when the
copy is finished. This is what the tape drive is designed for. In a logging recorder, the average
rate of data from active channels is much less than the tape drive’s streaming rate, which
means the tape drive must start and stop many times before a tape is full. In the VR240, the
hard disk is used to manage the data to maximize streaming and minimize the number of starts
and stops, which prevents excessive wear of the tape transport. Eventide loggers provide this
benefit – other loggers do not.