HP B160L, B132L, B180L manual Scsi Bus Differences, Fast, Wide, Ultra, Wide-SE

SCSI Connections

SCSI Bus Differences

SCSI Bus Differences

A Small Computer Systems Interface (SCSI) bus is an IEEE standard bus for connecting your workstation to internal and external SCSI devices running at different speeds, singly or in combination. Examples of these SCSI devices are 4-mm DDS-format tape drives, CD-ROM drives, and Winches- ter hard disk drives.

There are three types of SCSI buses available with this workstation - a nar- row single-ended SCSI (NSE SCSI) bus, and a fast, wide differential SCSI (FWD SCSI) bus or an ultra, wide, single-ended SCSI bus. Table 17 shows the specification differences between these SCSI buses, and Table 18 shows the SCSI addresses, ID numbers, and arbitration priorities for each.

CAUTION:Do not mix single-ended, fast, wide and ultra, wide-SE SCSI devices on any one bus type. Doing this will cause a system failure.

Table 17		SCSI Bus Differences
		Data Bus	Maximum	Maximum	Device	Controller
	Transfer Rate				Physical	Embedded
		Width	Addresses*	Cable Length
					Location	or Optional
	Single-Ended
		8 bits	8	6.0 meters	Internal and	Embedded
	Up to 5 Mbytes
	per second			(19.6 feet)	external
	Fast, Wide
		16 bits	16	25 meters	Internal	Optional
	Up to 20 Mbytes
	per second			(82 feet)	and
					external
	Ultra, Wide-SE				Internal
		16 bits	16**	2.0 meters	and	Embedded
	Up to 40 Mbytes
					external
	per second			(6.56 feet)
	* Address 7 is reserved for host controller use on both buses.
	** Only 2 external devices allowed (total of 4 devices).

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