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Today, more and more computer systems are taking advantage of the performance benefits of SCSI peripherals. Now, as SCSI-2 reaches finalization and with SCSI-3 under development, manufacturers, systems integrators and software developers are coming up against functional limitations in the way software-driver protocols facilitate communications between computer platforms and their SCSI peripherals.
A more robust protocol is needed to augment the performance capabilities of today's systems and to meet the needs of future systems. Such a protocol should be non-proprietary in its structure, it should unlock SCSI/systems performance, and it should facilitate the mixing and matching of multi-vendor host adapters and multi-vendor peripherals--hard disks, tape drives, CD-ROMs, scanners, and printers--to reflect the range of product capabilities offered by today's SCSI peripheral vendors.
Until now, Adaptec's SCSI protocol, ASPI (Advanced SCSI Programming Interface), has been the accepted systems/protocol solution; in the eyes of many it has become a de-facto standard by providing a workable, common interface that helped get SCSI-1 off the ground. But as operating systems have become more open and compatible with one another in their functionality, as applications programs have become more complex and robust, and computer networks have become more the rule instead of the exception, the ASPI feature-set has certain limitations.
ASPI is also a proprietary protocol, and as such, will always carry a set of inherent risks for SCSI manufacturers trying to develop competitive products for a dynamic marketplace.
ANSI-APPROVED STANDARD
What is needed is an open SCSI protocol that is specifically designed to implement systems and network performance requirements for today's configurations, one that will enhance the performance features of emerging SCSI-2 protocol and accommodate SCSI-3 development. The approach developed by the ANSI committee of SCSI manufacturers is the Common-Access Method (CAM). CAM offers a number of advantages over ASPI, not the least of these is that it is an ANSI-approved standard. As such, it is open to all vendors and developers equally and can be updated and improved by committee vote of the manufacturers themselves, providing the level of security needed to commit to innovative product design without undue risk in the marketplace. To date, CAM has received support from such companies as NCR, Apple, IBM, DEC, Novell and Future Domain.
As one of the first SCSI-bottleneck solutions,...