| [ CnUnix ] in KIDS 글 쓴 이(By): hello (Yang S.S.) 날 짜 (Date): 1996년03월08일(금) 07시26분47초 KST 제 목(Title): [Re] SCSI-3 위에서 언급한 것 중에서도 약간의 차이가 있을수 있으니 Unix Review의 원문의 일부분을 보여드리겠습니다. SCSI-3 Interconnects The current SCSI-3 specification centers on four interconnect technologies : SCSI-3 Parallel Interface(SPI), Fibre Channel Physical and Signaling Interface(FC-PH), IEEE P1394 High Performance Serial Bus, and Serial Storage Architecture Bus(SSA-PH). SPI is the closest to today's SCSI-2 specification because both are parallel technologies. This is beneficial for current users of SCSI-2 systems and peripherals because SCSI-3 is backward compatible with SCSI-2 and SCSI-1. FC-PH, IEEE P1394, and SSA-PH introduce serial data transfers into the SCSI mix. Serial SCSI benefits users in several ways. First, the cables(only six wires) and connectors(six pins) have been simplified. This translates into a lower cost for users and integrators because not only are the cables and connectors less expensive, but the expensive silicon SCSI chips required are much smaller(one section of each chip controls each pin - fewer pins, fewer sections). Also, because serial SCSI has a new device=addressing mechanism, more devices can be connected to a bus. SSA-PH benefits users because it involves a lower cost to system integrators and allows more devices to be connected to a bus. Because SPI is backward compatible, it is ideal for those who have sizable investments in SCSI-2 equipment, since it integrates SCSI-2 and SCSI-3 devices provides more functionality due to the improvement in commands and data-transfer rates. Physically, the evolution from SCSI-2 to SPI is relatively simple : all cables, connectors, and termination essentially remain the same. SPI also uses the terms Fast-20 Narrow, Fast-20 Wide, and Ultra SCSI. Fast-20 Narrow is an 8-bit bus with a maximum data transfer rate of 20MB/sec. Fast-20 Wide is a 16-bit bus with a maximum data transfer rate of 40MB/sec. A lot of confusion surrounds the term Ultra SCSI. Ultra SCSI is often spoken or written of in place of SCSI-3, but the two terms are not equivalent. Rather, Ultra SCSI refers to the subset of the SCSI-3 Parallel Interface. Simply put Ultra SCSI is another term for Fast-20 Wide; the two terms are synonyms. The Fibre Channel Physical and Signaling Interface(FC-PH) provides high-speed serial data transmission (100MB/sec) over significant distances. FC-PH has solved the cable-length problem of SCSI-2(6m) by allowing data to be transferred over distances of up to 10km. The cable used for FC-PH(either optical fiber or metal cable for shorter distances) is small in diameter, utilizes a small connector, and can support bidirectional communication. FC-PH fully supports the SCSI-3 standard, making it easier for system integrators to adopt. 헥헥... 더이상 치기 힘드네요. 이하의 내용은 특이한 사항은 없고 SSA-PH, IEEE P1394 High Performance Serial Bus를 설명했는데 SSA-PH의 device를 붙일 수 있는 한계는 128개로 늘어났다는 것이 좀 특이하네요.. 더욱 자세한 것은 Unix Review March 1996 Page39-44까지를 참조하세요. 제목은 SCSI-3: The Next Stop On The I/O Bus입니다. ------------------------------------------- 안녕하세요? <o>------< HELLO e-mail : ssyang@metro.telecom.samsung.co.kr ------------------------------------------- |