SCSI-1

SCSI-1

(hardware)
The original SCSI, as opposed to SCSI-2 or SCSI-3.
References in periodicals archive ?
There are three SCSI standards: SCSI-1, SCSI-2 and SCSI-3.
The American National Standards Institute (ANSI) ratified the first standard in 1986 calling it SCSI-1. SCSI-1 did not share a common standard which caused equipment incompatibilities.
SCSI-2 was a definitive enhancement over SCSI-1. SCSI-2 featured a wider data bus doubling in size from 8- to 16-bit supporting 16 devices.
Passive termination is rarely used today because it was designed for low-speed and short distance SCSI-1 devices.
Table 1: Maximum SCSI cable lengths STA TERM Max Bus Bus MAXIMUM BUS LENGTH Max Speed, Width, Number of Mbytes/Sec Bits SE HVD LVD SCSI IDs Slow SCSI (SCSI-1) 5 8 6m 25m -- 8 Fast SCSI (SCSI-2) 10 8 3m 25m -- 8 Fast Wide SCSI 20 16 3m 25m -- 16 Ultra SCSI (SCSI-3) 20 8 1.5m 25m -- 8 Ultra SCSI 20 8 3m 25m -- 4 Wide Ultra SCSI 40 16 1.5m 25m -- 16 Wide Ultra SCSI 40 16 3m 25m -- 4 Ultra2 SCSI 40 8 -- -- 12 * 8 Wide Ultra2 SCSI 80 16 -- -- 12 * 16 Ultra160 SCSI 160 16 -- -- 12 * 16 Ultra320 SCSI 320 16 -- -- 12 * 16
A single-ended SCSI-1 device can be connected through an expander to a high-performance LVD SCSI Ultra32O or Ultra64O SCSI bus.
Initial disks, which were capable of transferring data at 1MB/sec, were adequately supported by the initial 5MB/sec SCSI-1 interface.
Q: How do I properly terminate a chain that goes from SCSI-2 to SCSI-1? We have a new system with a dual-channel, on-board SCSI controller.
Where did half of the connectors go between the SCSI-2 and SCSI-1 connectors?
With today's Ultra2SCSI, disk arrays can be plug-and-play backward compatible all the way to SCSI-1 of 1984 and forward compatible to Ultra160/m and possibly beyond, which ensure investment protection well into the next five years.
The large 50 pin connector in SCSI-1 has shrunk to a 68 pin VHDCI connector and the data rates increased to 160MB/sec.
SCSI-1 is often lumped together with SCSI-2 as a basic starting level.