internet.com
You are in the: Small Business Computing Channelarrow View Sites +
Small Business Technology
» ECommerce-Guide | Small Business Computing | Webopedia | WinPlanet |  »Close
Webopedia.com
Enter a word for a definition... ...or choose a computer category.
 
 

menu
   Home
   Term of the Day
   New Terms
   Pronunciation
   New Links
   Quick Reference
   Did You Know?
   Categories
   Tech Support
   Webopedia Jobs
   About Us
   Link to Us
   Advertising
  

talk to us
   Submit a URL
   Suggest a Term
   Report an Error

internet.com
Developer
Downloads
International
Internet Lists
Internet News
Internet Resources
IT
Linux/Open Source
Personal Technology
Small Business
Windows Technology
xSP Resources
Search internet.com
Advertise
Corporate Info
Newsletters
Tech Jobs
E-mail Offers
commerce
  Be a Commerce Partner
 
 
 
 
 
 
 
 
 
 
 
 
 
 

SCSI
Last modified: Monday, September 20, 2004 

(sku´zē) Short for small computer system interface, a parallel interface standard used by Apple Macintosh computers, PCs, and many UNIX systems for attaching peripheral devices to computers. Nearly all Apple Macintosh computers, excluding only the earliest Macs and the recent iMac, come with a SCSI port for attaching devices such as disk drives and printers.

SCSI interfaces provide for faster data transmission rates (up to 80 megabytes per second) than standard serial and parallel ports. In addition, you can attach many devices to a single SCSI port, so that SCSI is really an I/O bus rather than simply an interface.

Although SCSI is an ANSI standard, there are many variations of it, so two SCSI interfaces may be incompatible. For example, SCSI supports several types of connectors.

While SCSI has been the standard interface for Macintoshes, the iMac comes with IDE, a less expensive interface, in which the controller is integrated into the disk or CD-ROM drive. Other interfaces supported by PCs include enhanced IDE and ESDI for mass storage devices, and Centronics for printers. You can, however, attach SCSI devices to a PC by inserting a SCSI board in one of the expansion slots. Many high-end new PCs come with SCSI built in. Note, however, that the lack of a single SCSI standard means that some devices may not work with some SCSI boards.

The following varieties of SCSI are currently implemented:

  • SCSI-1: Uses an 8-bit bus, and supports data rates of 4 MBps
  • SCSI-2: Same as SCSI-1, but uses a 50-pin connector instead of a 25-pin connector, and supports multiple devices. This is what most people mean when they refer to plain SCSI.
  • Wide SCSI: Uses a wider cable (168 cable lines to 68 pins) to support 16-bit transfers.
  • Fast SCSI: Uses an 8-bit bus, but doubles the clock rate to support data rates of 10 MBps.
  • Fast Wide SCSI: Uses a 16-bit bus and supports data rates of 20 MBps.
  • Ultra SCSI: Uses an 8-bit bus, and supports data rates of 20 MBps.
  • SCSI-3: Uses a 16-bit bus and supports data rates of 40 MBps. Also called Ultra Wide SCSI.
  • Ultra2 SCSI: Uses an 8-bit bus and supports data rates of 40 MBps.
  • Wide Ultra2 SCSI: Uses a 16-bit bus and supports data rates of 80 MBps.
  • E-mail this definition to a colleague

    Sponsored listings

    Spectrum Systems: Computer Servers - Supplies server architecture products and systems including tower servers, rackmount servers, server cases, enclosures, and server chassis.

    PSSC Labs: RAID Drives - Lower power. Lower A/C Requirements. Lower Noise. PSSC Labs custom configured servers and clusters are integrated for your specific needs and budget.

    Cables To Go: SCSI Cables - Big selection: internal or external SCSI, VHDCI, terminators, adapters, controller cards. Same day shipping if ordered by 4 pm.


    For internet.com pages about SCSI . Also check out the following links!

    Related Links

    Hard Disk Interfaces and Configuration 
    Describes the different major interface standards currently used by hard disks (and other devices). Provides sections about the IDE/ATA and SCSI interfaces. This page is from "The PC Guide."

    Storage Basics -- SCSI Part I 
    This article looks at SCSI as a technology, discusses some of the more popular SCSI standards and examines SCSI device numbering.

    Storage Basics -- SCSI Part II 
    This article focuses on SCSI implementation considerations such as signaling, termination and connector types.

    All About SCSI
    Provides an introduction to SCSI and discusses SCSI evolution, standards, termination, and configuration.

    Fast Hard Drives Page
    This user page contains a collection of links to benchmark resouces, controllers, disks, distributors, newsgroups, vendor white papers, and reviews and FAQs for hard drives.

    SCSI FAQs
    Addresses questions and answers collected from the comp.periphs.scsi newsgroup.

    SCSI Library
    News, technical information, FAQs regarding SCSI.

    SCSI Trade Association Home Page
    Includes news items, white papers, articles and specifications, as well as an area with answers to technical questions about the SCSI interface.

    Small Computer Systems Interface (SCSI) Overview
    Describes SCSI standards, protocols and transfer modes, host adapters, and configuration and cabling. This page is from "The PC Guide."

    What Kind of SCSI Do I Have?
    Helps users determine if they have single-ended SCSI or a differential SCSI interface.

    Sponsored listings

    Overland Storage: SCSI RAID - REO Series disk-based storage easily connects to Ethernet (iSCSI) or Fibre Channel networks for seamless integration into existing backup environments

    Siemens Industrial Automation: SCSI Adapters and Terminators - PROFINET offers decentralized IO, peer-to-peer communications, data visibility, machine safety, and motion control on one Industrial Ethernet network.

    QVS: SCSI Switches & Cables - Manufactures cables and connectivity products for the computer and communication industries. SCSI cables double shielded to support maximum speed.

    Excel Meridian Data: SCSI RAID - Offers a wide variety of network storage solutions, including SCSI RAID products designed to meet requirements in terms of price and performance.

    L-com Connectivity: SCSI Adapters and Terminators - Factory direct online merchant offering cabling, connectors, and network equipment, including SCSI adapters and terminators.

    related categories

    Buses

    Miscellaneous Standards

    Peripheral Devices

    related terms

    ASPI

    bus

    daisy chain

    Fibre Channel

    graphical user interface

    interface

    iSCSI

    LUN

    port

    SAS

    SCA

    SCAM

    SMDI

    TCQ


    webopedia
    Give Us Your
    Feedback


    Shopping
    SCSI Products
    Compare Products,Prices and Stores

    Shop by Category:
    Storage Controllers
    913 Model Matches

    Hard Drives
    2812 Model Matches

    Cables and Connectors
    748 Model Matches

    Scanners
    93 Model Matches

    Drive Cases
    509 Model Matches



    JupiterWeb networks:

    internet.comearthweb.comDevx.com graphics.com

    Search JupiterWeb:

    Jupitermedia Corporation has three divisions:
    Jupiterimages, JupiterWeb and JupiterResearch


    Legal Notices, Licensing, Reprints, & Permissions, Privacy Policy.

    Jupitermedia Corporate Info | Newsletters | Tech Jobs | Shopping | E-mail Offers