The CS4-SAX from EKF is a CompactPCI® based Dual Ultra2 SCSI hostadapter, suitable for attachment of LVD/SE 16-bit peripherals as Raid-systems, high performance hard disks and streamer tape drives. Provided with two independent ports, both channels can be dedicated to LVD devices, or alternatively one channel can be used to support mixed performance SE devices.

The CS4-SAX provides up to 160MBps aggregate SCSI throughput. Optimum performance therefore is achieved when the SAX is operated in a 64-bit CPCI backplane, but 32-bit legacy systems also profit from the power of this SCSI controller.

LVD (low voltage differential) signalling technology allows an overall cable length of the SCSI bus up to 12m. LVD and SE (single ended) devices are sensed automatically by the SAX, and the SCSI interface is self-configured to match the peripherals SCSI operating mode. Compatibility is maintained to all previous SCSI standards, e.g. Fast and Ultra SCSI. The board is provided with two external VHDCI receptacles and one internal HDSUB connector; so external and internal devices can be connected simultaneously.

Comprehensive software support as well as PCI plug&play technology care for effortless installation of the CS4-SAX under nearly all popular operating systems.

The CS4-SAX allows for connecting up to 2x15 peripherals with 16-bit (Wide) interface. For flexible cabling, the SAX is provided with SCSI connectors for both internal and external use. All of the SCSI connectors can be used together at the same time. The dual VHDCI receptacle SCSI_X is mounted to the front panel of the CS4-SAX for attachment of external devices to the SCSI channels A and/or B. The HDSUB connector SCSI_I is provided for internal use (channel A only). Peripherals, attached to any of the SCSI connectors, are sensed by a logic circuitry. If the logic detects the CS4-SAX to be either end of the SCSI bus, the local SCSI terminators are activated.

8-bit (Narrow) SCSI peripherals need an adapter (connector or cable) in order to reduce from 68 to 50 leads.

The jumperless board is built around the LSI Logic (Symbios) SYM53C896 SCSI processor. Being also compatible to the SYM22910 hostadapter board, the CS4-SAX can be used with all LSI Logic software (e.g. the Device Management System SDMS). Therefore, existing SYM22910 drivers for operating systems as Windows or Linux are valid also for the CS4-SAX.

The CS4-SAX provides a Flash Extended BIOS, thus enabling operating system boot from any SCSI drive. The Flash-EEPROM can be field upgraded at any time by means of a utility program. The CS4-SAX is additionally equipped with two serial EEPROMs, saving configuration parameters of each of the two SCSI channels (e.g. for SCAM support).

In order to ease system integration, several LEDs show important board status information:

The CS4-SAX sources the voltages for the on-board and external SCSI terminators (TERMPOWER), fused by Polyswitches (reversible fuse).

SCSI Bus data and control signal integrity will be improved by the SCSI controller chip using the Symbios Tolerant™ filtering technology, thus minimizing the influence of a critical SCSI cabling (poor cables, mixed cable types, noisy environment).

The CS4-SAX is provided with a 64-bit CPCI interface, giving a nominal bandwidth of 266MBps in a suitable system (P1/P2 backplane). This is more than enough to handle the theoretical aggregate maximum 160MBps SCSI data stream.

Actually, the SCSI buses operate with considerably lower data transfer rates. Usual configurations dedicate one of the SCSI channels to mixed performance SE devices, while the other channel is reserved for the LVD devices only (this is done because an SE peripheral on a SCSI bus forces all LVD devices into the legacy single ended mode). The SE organized SCSI bus however operates with a maximum of 40MBps (20MBps if 8-bit narrow devices). Furthermore, most peripherals by far do not reach the maximum data transfer rates when accessed outside their local caches due to latency periods. Therefore, the CS4-SAX is an outstanding choice also for 32-bit CPCI systems with a nominal bandwidth of 133MBps.

A toolset already mentioned, but worth to be more intensively discussed is the Symbios SCSI Device Management Software SDMS, running on the CS4-SAX without any modification. SDMS is a package of utilities and drivers, including ASPI, RAID, or removeable media support for popular disk operating systems. As a resident part of the SDMS, basic routines are contained within the on-board Flash Extended BIOS. Like any other BIOS routine, this resident software does not depend on an individual OS, but allows standalone operation and diagnostics instead, e.g. low level harddisk formatting or SCSI bus configuration. In order to obtain up-to-date information or download the latest firmware release, the LSI Logic website should be visited.

The CS4-SAX is a 3U (single size) Eurocard. For 6U CompactPCI® systems there is a mechanical kit available, expanding the front panel to 6U (CR9-ADAPT).

It is not necessary to discuss the advantages of SCSI here, such as superior data throughput at minimal CPU load. With the CS4-SAX, any CompactPCI® system can profit from dual Ultra2 SCSI performance. The CS4-SAX is an affordable, highly reliable industrial grade product, and - last not least - fast and smoothly to be installed.