The Small Computer Systems Interface
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WWW Virtual Library for SCSI The Small Computer Systems Interface |
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SCSI: Bus and Interface
The roots of SCSI go back to 1979, when the disk drive manufacturer Shugart was looking for a new universal interface for future disk drives. The goal of the effort was to develop an interface that supported logical block addressing rather than head/cylinder/sector, 8-bit parallel data transfer instead of analog serial and generic commands rather than a couple of control lines. This interface was called SASI (Shugart Associates Systems Interface). The SASI specification included some 6-byte commands and a single-ended interface.
In late 1981, Shugart along with NCR, presented SASI to the ANSI committee X3T9.2, which accepted it as a project, now called SCSI. In the following development period, many major improvements over SASI have been added to the SCSI draft. This includes the ability of devices to compete for the bus (arbitrate) and to free the bus (disconnect/reselect) temporarily during command execution. Also it was now possible to have more than one host adapter on a SCSI bus. By 1984 a draft proposal was presented to ANSI for approval. At that time there were already many devices on the market that adhered more or less to this proposal. In 1986, SCSI was approved by ANSI as document X3.131-1986. This first official version is today referred to as SCSI-1. SCSI-1 included 6- and 10-byte commands, the single-ended and differential interface options and synchronous and asynchronous data transfer.
SCSI: Bus and Interface
Get the Nitty Gritty About SCSI Article helps get you up to speed on what's happening with SCSI. Gives a background for the standard, its technology, and how it compares to other standards. From Tech Republic, written by Scott Lowe MCSE.
Advanced Horizons Article called SCSI Explained includes: why it came about, bus width and speed, types and other benefits of SCSI.
SCSI Termination Tutorial Written to help users understand common field issues that one might run into when connecting a SCSI drive (or drives) to various kinds of SCSI buses, whether cable or backplane.
End-User SCSI Disk Performance with Parallel and Non-parallel Files This report describes a series of experiments to investigate the performance of SCSI disks as seen by the application programmer. You will need to choose a download format.
All About SCSI What is SCSI? An article by DataPro.
SCSI Information From Arizona State University.
IP-Over-SCSI The purpose of IP Over SCSI is to connect two or more computers with SCSI interfaces using the IP protocol.
Expanding the SCSI Bus Nov. 97 Article from Computer Technology Review written by Marc D. Brooks, details how SCSI bus can be expanded to perform more complex applications. Summarizes LVD/HVD usage, LUNs, compatibility issues, and the future of SCSI.
Let's Talk About SCSI SCSI basics including features, history, differentiators and applications. (will open as .pdf)
SCSI Common Codes and Values Informative summaries for several of the more commonly used codes and coded values are included as annex information in the SCSI Primary Commands - 2 (SPC-2) draft standard.
Linux High performance SCSI & RAID: What is SCSI?
IDE Vs. SCSI Article detailing the differences by David Risley.
SCSI-3 Standards Architecture Chart reflects the currently approved SCSI-3 project family. All projects are in T10, except Fibre Channel is in T11 and 1394 is in IEEE.
On-Line Extraction of SCSI Disk Drive Parameters This report describes a suite of general-purpose techniques and algorithms for acquiring the necessary data from SCSI disks via the ANSI-standard interface. You will need to choose a download format.
PC Webopedia - SCSI Information An online encyclopedia and search engine dedicated to computer technology.
Pictures of SCSI Connectors Common SCSI bus connectors. Table courtesy of Paralan Corp and Quantum Corp. At STA's site.
Reference Charts Tables containing: SCSI bus width/maximum data rates, maximum bus length with device addressing, cable lengths meters/feet and SCSI technologies comparison of maximums. From SCSI Masters.com.
SCSI Supplier List Supplier list at the STA of, STA members, non-members.
SCSI Terms and Terminology STA-endorsed terms & terminology for SCSI parallel interface technology.
SCSI From Wolfgang Schulte's SCSI information guide.
STA - The SCSI Trade Association SCSI (Small Computer System Interface) has been an official industry standard for 12 years. It continues to evolve in order to meet the demands of the most sophisticated systems. The standard recognizes virtually every peripheral type and takes advantage of newer hardware and more intelligent controllers. The data path has been widened and tranfer speeds have been increased to keep pace with system requirements.
T10 Home Page T10 is a Technical Committee of the National Committee on Information Technology Standards. NCITS is accredited by, and operates under rules that are approved by, the American National Standards Institute.
What is SCSI? from Storage Search Written by Performance Technologies.
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