System Description
1-3
Compaq Confidential – Need to Know Required
Writer:
Bob Young
Project:
Compaq StorageWorks SSL2000 Series Library Reference Guide
Comments:
Part Number:
187193-001
File Name:
b-ch1 System Description.doc
Last Saved On:
4/17/00 9:09 AM
The SmartScale Storage architecture gives you a truly scaleable library that
can smoothly expand to meet your growing storage needs. You can start with a
system configured to your present requirements, confident that as your storage
needs evolve, adding units and extending the PTM can easily modify the
Library. Add drives for faster performance or magazine space for greater
capacity, as needed. Then just turn on the power, and immediately the system
updates the system map so the host is informed of the expanded capability.
The SmartScale Storage architecture has built-in redundancy so that if the
master unit fails, a slave unit (slave 0) can be configured to take over as the
master unit. This is done without having to make hardware changes except
moving the motor cable to the new master.
Tape Cartridge Magazine Mail Slot
If your host software permits, you can use the front slot in the tape cartridge
magazine (the first slot you see when you open the door) as a mail slot for
inserting or removing a single cartridge without interrupting host operations in
progress. The mail slot is implemented as the SCSI IMPORT/EXPORT
commands.
SCSI Interface
The unit presents the following to the host:
■
A single SCSI medium changer device with a single SCSI medium
transport element
■
A number of SCSI storage elements equal to the total number of
cartridge magazine slots
■
A single SCSI import/export element
■
A number of SCSI data transfer elements equal to the total number of
drives in the library
Multi-Server Data Sharing
A host computer with a SCSI controller connected to a bus is a SCSI initiator.
The Library is a SCSI target. SCSI rules permit multiple initiators on a single
bus. Therefore, with the proper host software, it is possible to connect multiple
hosts to a single Library over a single SCSI bus. This allows multiple hosts to
operate the library robotics, loading and unloading cartridges as each host
requires.