Specials
Connectors
AMP Connectors, Original Packaging 50% off We have in stock from a cancelled project 10,000 SC Single
Mode ceramic AMP connectors (AMP # 504-646-2). The initial cost to us was $4 ea. We are willing to sell them for $2 ea. Please call 1-800-590-9965 or E-Mail us at
info@cables-unlimited.com Cables
SCSI I, II, III Cables Specials
Call and mention the web site for special pricing on SCSI cables:
C ables Unlimited is your One-Stop O.E.M. source for a wide variety of:
- SCSI I cables
- SCSI II cables
- SCSI III cables
WE ARE THE MANUFACTURER!
All cables can be custom-made to your specifications. Please contact us to inquire about your SCSI cable needs, and our special pricing. SCSI vs. ATI SCSI SCSI-2, developed to improve speed and compatibility among different SCSI devices,
became a standard in 1991. With a bus width of eight bits and bus speed of 5MHz, total throughput worked out to about 5MB per second.
SCSI-2 was succeeded by various flavors of the specification. Fast SCSI moved the bus speed up to 10MHz, and Wide SCSI expanded the bus width to 16 bits (in SCSI
lingo, "Wide" means a 16-bit bus). Fast Wide SCSI has a 16-bit wide bus, a bus speed of 10MHz and a peak transfer rate of 20MB a second.
Ultra SCSI, which replaced Fast SCSI, offers a 20MHz, 8-bit bus, enabling a peak transfer rate of 20MB per second. Ultra2 SCSI raises the bus speed to 40MHz.
Ultra2 Wide SCSI, with a 40MHz, 16-bit bus, is capable of 80MB-per-second throughput. Ultra160/m SCSI, also called Fast-80 SCSI or Ultra3 SCSI, maintains the
40MHz bus speed, but again doubles the throughput to 80MB per second. The Ultra3 Wide SCSI protocol extends the peak transfer rate to 160MB per second. On the
horizon is Ultra 320 SCSI, which promises a peak transfer rate of 320MB a second.
ATA
ATA, which stands for Advanced Technology Attachment, is extremely inexpensive to manufacture, and has become the most common storage interface on personal
computers. Compaq developed ATA in 1985 as a low-cost attachment for hard drives.
In 1986 manufacturers took steps to place the ATA interface and controllers on the
PC motherboard, and the modern implementation of ATA was born.
Around 1994, the original ATA became a bottleneck as drives and PC systems
became faster and required more address space. Western Digital developed the more-ambitious Enhanced IDE (EIDE) interface, which featured numerous
enhancements beyond extra speed, such as support for larger drives and added support for ATA Packet Interface (ATAPI). ATAPI is the standard by which
CD-ROMs, tape drives and other packeted transfer devices are attached to the same ATA controllers as hard disks.
Fast ATA and EIDE (minus ATAPI) both contributed to ATA-2, which became part of the official standard in 1996. ATA-3, introduced in 1997, provided support for
even-larger drives. A year later, ATA-4, often called UMDA/33, UMDA or Ultra ATA, boosted transfer speeds to 33.3MB per second and added official ATAPI support.
ATA-4 also introduced Direct Memory Access (DMA) and Ultra DMA
ATA-5, also called ATA/66 or UMDA/66, currently ships on most systems, boosting
the peak transfer speed to 66MB per second. It also implements an 80-pin connector and can support drives larger than anything conceivable in the near future. ATA/100
is becoming popular now, as drives and controllers start to become more popular.
In conclusion, ATA tends to be designed with an eye on the bottom line. SCSI's
primary goal is performance.
|
