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SCIS. By Tracen Vail Hour 2 PC networking. Small Computer System Interface . SCIS. SCSI is a type of interface used for computer components such as hard drives, optical drives, scanners and taps dive.
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SCIS By Tracen Vail Hour 2 PC networking
SCIS • SCSI is a type of interface used for computer components such as hard drives, optical drives, scanners and taps dive. • While the less expensive IDE technology is built into motherboard, SCSI is a technology that must be added by purchasing a SCSI controller
SCIS IDE • SCSI is a faster, more robust technology than IDE, and has traditionally been utilized in servers. • Aside from speed, another great advantage over IDE is that the SCSI card can connect 15 or more devices in a daisy chain.
SCSI-2, Fast SCSI (8-bit Narrow) Ultra 160 SCSI (16-bit Wide) 160 MB/sec to 10 MB/sec Ultra SCSI (8-bit Narrow) Ultra 320 SCSI (16-bit Wide) 320 MB/sec 20 MB/sec Ultra Wide SCSI (16-bit Wide) 40 MB/sec Ultra2 SCSI (16-bit Wide) 80 MB/sec How fast can it go
Evolved • As SCSI technology has evolved, different varieties have emerged with varying benchmark speeds. The various versions utilize different pin connectors. • Therefore, it is important to match the right SCSI controller to the desired SCSI components. For example, if a drive is SCSI Ultra 320, a SCSI-I controller will not work with it.
For a server • For a server, SCSI can be a great choice for a RAID (Redundant Array of Independent Disks), as additional drives can be added as needed. • As of fall 2005, high-end SATA or Serial ATA drives with data transfer speeds of 150 MB/sec can be comparable to an Ultra 160 SCSI RAID.
Serial ATA (SATA) • SATA overcomes the performance barriers in current PATA technologies while maintaining PATA’s cost-efficiency. SATA’s faster data throughput, • greater bandwidth and improved performance (150MB/sec) promotes greater chipset and silicon component integration.
SCIS • SCSI cards and devices are available wherever computer components are sold. SCSI is widely used in mid- to high- performance workstations and servers. SCSI offers faster transfer rates than ATA/IDE, the most commonly used interface in desktop PCs. ATA/IDE is generally easier to implement and less expensive than SCSI but does not offer as many features.
sata • SATA allows for thinner, more flexible cables and lower pin counts. This will offer computer manufacturers the ability to design systems with cables that are simple to route and install, improving thermal designs and facilitating smaller form factor systems. It also enables easier, more flexible cable routing management and the use of smaller connectors than possible with existing PATA technology.
Fibre Channel-Arbitrated Loop (FC-AL) • FC-AL is an exceptionally high bandwidth industry-standard interface for use in high-end servers and similar demanding applications. FC-AL adapters tend to cost more than SCSI adapters. FC-AL uses fiber optic cabling in a loop configuration to produce maximum transfer speeds of 200 MB/s and connects up to 127 devices as far as 10 kilometers apart, enabling secure remote data storage. FC-AL devices can also be dual ported to provide two simultaneous input/output sessions,
There are three components in anySCSI system • ControllerThe controller is the heart of SCSI. It serves as • the interface between all of the other devices on • Device • Cable
pins • DB-25 (SCSI-1) • 50-pin internal ribbon (SCSI-1, SCSI-2, SCSI-3) • 50-pin Alternative 2 Centronics (SCSI-1) • 50-pin Alternative 1 high density (SCSI-2) • 68-pin B-cable high density (SCSI-2) • 68-pin Alternative 3 (SCSI-3) • 80-pin Alternative 4 (SCSI-2, SCSI-3) • SCSI-1: The original specification developed in • 1986 • SCSI-2: An update that became an official • standard in 1994, a key component of SCSI-2 was
How it works • When an end user or application sends a request for data, the operating system creates the appropriate SCSI commands, which then go through encapsulation and, in some circumstances, encryption. A packet header is added to the resulting IP packets, and the data is transmitted, typically over an Ethernet connection. When a packet is received, it is decrypted and disassembled, separating the SCSI commands and the data request. The SCSI commands are sent on to the SCSI controller, and from there to the storage device. Because iSCSI is bi-directional, the protocol can also be used to return data in response to the original request.