Library manufacturers will be coming out with new products in the next year that will no longer require a
SCSI connection to control the robot, but each tape drive will still require a dedicated Fibre Channel link to the SAN.
The
SCSI bus is supported via cabling that can handle up to 15 devices per channel in series.
A number of special options--such as alphanumeric display panels, control keypads for setting
SCSI IDs, and termination and wide
SCSI connectors--can be added to firmware and hardware.
SAN's closest competition comes from
SCSI extender makers, such as Apcon Inc and AC Technologies.
(1)Daisy-chaining is the ability to connect one device to a PC small computer system interface (
SCSI) card and connect a second device (e.g., another CD-ROM drive, hard drive, tape drive, magneto-optical drive, or combination) to the first.
In the meantime, CPAs should consider installing
SCSI boards.
Requirements like these for large volume data storage, compounded by fast query requirements are stretching the processing capability of parallel
SCSI technology.
The Ultra160 uses a SPI-3 third generation parallel
SCSI interface, which adds five new features: (1) Fast-80 or a data bus speed running at 80 MHz; (2) Cyclic Redundancy Check (CRC)--a common error checking protocol, which is used to ensure data integrity as a safety measure since transfer speeds were being increased, leading to the possibility of data corruption; (3) Domain Validation, which improves the robustness of the process by which different
SCSI devices determine an optimal data transfer rate; (4) Quick arbitration and selection (QAS), which represents a change in the way devices determine which device has control of the
SCSI bus.
"Adaptec has validated its Serial Attached
SCSI controllers for compatibility with PMC-Sierra's maxSAS expander product family," said Paul Vogt, director of Internal Storage Business Line for Adaptec.
SCSI (pronounced "scuzzy") is a intelligent interface which knows what types of devices are connected to the computer and how to deal with them.
"By using Ultra160
SCSI technology within our workstations, we're providing new levels of I/O performance and reliability that our customers demand," said Dave Du Pont, manager of Kayak product marketing at Hewlett Packard.
Despite much talk of alternatives such as fibre channel, Ultra DMA, USB and Firewire,
SCSI still predominates in the server and workstation market - and with
SCSI support built into Windows NT, the shift from Unix to Intel and NT isn't affecting its growth.