HARDSOF

NORTHBRIDGE

Also known as the memory controller hub (MCH) in Intel systems (AMD, VIA, SiS and others usually use ‘northbridge’), is traditionally one of the two chips in the core logic chipset on a PC motherboard, the other being the southbridge. Separating the chipset into the northbridge and southbridge is common, although there are rare instances where these two chips have been combined onto one die when design complexity and fabrication processes permit it.

The northbridge on a particular system’s motherboard is the most prominent factor in dictating the number, speed, and type of CPU(s) and the amount, speed, and type of RAM that can be used. Other factors such as voltage regulation and available number of connectors also play a role. Virtually all consumer-level chipsets support only one processor series, with the maximum amount of RAM varying by processor type and motherboard design. Pentium-era machines often had a limitation of 128 MB, while most Pentium 4 machines have a limit of 4 GB. Since the Pentium Pro, the Intel architecture can accommodate physical addresses larger than 32 bits, typically 36 bits, which gives up to 64 GB of addressing (see PAE), though motherboards that can support that much RAM are rare because of other factors (operating system limitations and expense of RAM).

A northbridge typically will only work with one or two different southbridges. In this respect, it affects some of the other features that a given system can have by limiting which technologies are available on its southbridge partner.

The northbridge hosts its own memory lookup table (I/O memory management unit), a mapping of the addresses and layout in main memory. The northbridge handles data transactions for the front side bus [[FSB), the memory bus and the AGP port.

The northbridge will have a different model number, even though they are often paired with the same southbridge to come under the collective name of the chipset.

The Intel Hub Architecture (IHA) has replaced the northbridge/southbridge chipset. The IHA chipset also has two parts: the Graphics and AGP Memory Controller Hub (GMCH) and the I/O Controller Hub (ICH). The IHA architecture is used in Intel's 800 series chipsets, which is the first x86 chipset architecture to move away from the northbridge/southbridge design.

SOUTHBRIDGE

Also known as the I/O Controller Hub (ICH) in Intel systems (AMD, VIA, SiS and others usually use 'southbridge'), is a chip that implements the "slower" capabilities of the motherboard in a northbridge/southbridge chipset computer architecture. The southbridge can usually be distinguished from the northbridge by not being directly connected to the CPU. Rather, the northbridge ties the southbridge to the CPU

FUNCTIONS:

• PCI bus. The PCI bus support includes the traditional PCI specification, but may also include support for PCI-X and PCI Express.
• ISA bus or LPC Bridge. Though the ISA support is rarely utilized, it has interestingly managed to remain an integrated part of the modern southbridge. The LPC Bridge provides a data and control path to the Super I/O (the normal attachment for the keyboard, mouse, parallel port, serial port, IR port, and floppy controller) and FWH (firmware hub which provides access to BIOS flash storage).
• SPI bus. The SPI bus is a simple serial bus mostly used for firmware (e.g., BIOS) flash storage access.
• SMBus. The SMBus is used to communicate with other devices on the motherboard (e.g. system temperature sensors, fan controllers).
• DMA controller. The DMA controller allows ISA or LPC devices direct access to main memory without needing help from the CPU.
• Interrupt controller. The interrupt controller provides a mechanism for attached devices to get attention from the CPU.
• IDE (SATA or PATA) controller. The IDE interface allows direct attachment of system hard drives.
• Real Time Clock. The real time clock provides a persistent time account.
• Power management (APM and ACPI). The APM or ACPI functions provide methods and signaling to allow the computer to sleep or shut down to save power.
• Nonvolatile BIOS memory. The system CMOS, assisted by battery supplemental power, creates a limited non-volatile storage area for system configuration data.
• AC97 or Intel High Definition Audio sound interface
• Baseboard Management Controller

HARD DISK DRIVE

A hard disk drive (HDD), commonly referred to as a hard drive, hard disk, or fixed disk drive,^[1] is a non-volatile storage device which stores digitally encoded data on rapidly rotating platters with magnetic surfaces. Strictly speaking, “drive” refers to a device distinct from its medium, such as a tape drive and its tape, or a floppy disk drive and its floppy disk. Early HDDs had removable media; however, an HDD today is typically a sealed unit (except for a filtered vent hole to equalize air pressure) with fixed media.^[2]

HDDs (introduced in 1956 as data storage for an IBM accounting computer^[3]) were originally developed for use with general purpose computers. In the 21st century, applications for HDDs have expanded to include digital video recorders, digital audio players, personal digital assistants, digital cameras and video game consoles. In 2005 the first mobile phones to include HDDs were introduced by Samsung and Nokia.^[4] The need for large-scale, reliable storage, independent of a particular device, led to the introduction of embedded systems such as RAID arrays, network attached storage (NAS) systems and storage area network (SAN) systems that provide efficient and reliable access to large volumes of data.

HARD DISK

JUMPER SETTINGS

Jumper settings determine the order in which EIDE hard drives

and other devices attached to a single interface cable are

detected by a computer system. On SATA hard drives, jumper

settings enable or disable enterprise-level features.

Setting the jumpers correctly on a hard drive requires the

proper placement of a plastic-encased, metal jumper shunt over

two pins on the hard drive jumper block, as shown in Figure 1.

SATA Hard Drive Jumper Settings

WD SATA hard drives are factory set for workstation/desktop

use. For enterprise storage requirements, the jumpers can be set to

enable spread spectrum clocking or power-up in standby modes.

WD SATA drives are shipped from the factory either with or

without a jumper shunt in the spread spectrum clocking (SSC)

enable/disable position (on pins 1 and 2). It is not necessary

to add or remove the jumper shunt on the drive for

workstation/desktop use. For enterprise storage enviroments, use

the following advanced settings:

SSC Mode (Default 1): spread spectrum clocking feature enabled

or disabled. Default 1 setting is disabled or jumper shunt placed

on pins 1–2. Removing the jumper enables the spread spectrum

clocking feature.

SSC Mode (Default 2): spread spectrum clocking feature enabled

or disabled. Default 2 setting is disabled or no jumper shunt

placed on pins 1–2. Adding the jumper to pins 1–2 enables the

spread spectrum clocking feature.

EIDE Hard Drive Jumper Settings

WD EIDE hard drives are factory set with Cable Select (CSEL)

jumper settings. The CSEL jumper setting protocol requires

the use of a special interface cable. All hard drives in a

CSEL-compliant system have the jumpers set in the same position.

Not all computer systems support Cable Select. The

Master/Slave jumper setting protocol must be used if a system does

not support CSEL or if CSEL support cannot be determined. The

Master/Slave protocol works regardless of whether or not the

system, devices, or cable selects CSEL.

Some systems with legacy BIOSs lock up on initial boot or

report a smaller drive capacity than the actual capacity of the hard

drive. In such cases, alternate jumper settings must be used in

conjunction with WD’s Data Lifeguard Tools software.

Three common jumper setting configuration protocols are

used for EIDE drives:

! Single: the hard drive is the only device on the IDE interface

cable.

! Master/Slave: the hard drive is either a Master (C:/) drive or a

Slave drive in a multiple-drive system.

! Cable Select (CSEL/CS): jumper settings are the same on all

hard drives in a system (both single- and multiple-drive

systems); however, a special CSEL cable must be used, and the

host system must support CSEL. WD EIDE hard drives are

factory set for Cable Select configuration.

Note: Not all computer systems and motherboards support the

CSEL option.

Cable Select System Support

Consult the system documentation or contact the system

manufacturer to determine whether a computer supports CSEL.

Checking the jumper position on an existing hard drive or

other EIDE device (such as a CD-ROM drive) is another method

to determine whether a system supports CSEL. If a diagram or

explanation of jumper settings on top of the hard drive or IDE

device verifies that it is jumpered for Cable Select, then the system

supports CSEL protocol.

The Master/Slave configuration protocol must be used when a

system does not support CSEL or when CSEL support cannot be

determined.

Note: Even when the system, devices, and cable support CSEL,

using jumpers on the hard drive(s) for Master/Slave protocol still

works.

Single Hard Drive Installations

To install your new WD hard drive as the only hard drive in

your system, use jumpers as shown in Figure 3.

Cable Select Installations: Connect the hard drive to the black

connector at the end of the IDE interface cable.

Figure 3. EIDE Single Hard Drive Jumper Settings

Dual Hard Drive Installations

To install your new WD EIDE hard drive with an existing hard

drive or CD-ROM on the same interface cable, be sure all drives

are jumpered as shown in Figure 4.

Note: Not all hard drive manufacturers use the same jumper

configurations. To install a new WD hard drive on the same

interface cable with a non-WD hard drive, obtain jumper setting

information from the manufacturer of the non-WD hard drive.

Figure 4. EIDE Dual Hard Drive Jumper Settings

Cable Select Installations: connect the intended boot drive (the first

hard drive to be detected) to the black or end connector of the IDE

interface cable. Connect the storage drive (the second hard drive to

be detected) to the gray or middle connector of the IDE interface

cable.

Master/Slave Installations: to install your new WD hard drive with

an existing drive on separate IDE interface cables, leave the

jumper(s) in default positions for possible future use. The system

recognizes each drive as a single, stand-alone drive. Master/slave

jumper settings are used only when there are two devices on the

same IDE interface cable.

Reduced Power Spinup (RPS)™ Mode

Implementation of RPS requires a jumper on the 4-pin jumper

block of a WD 2.5-inch EIDE drive. To configure the drive for

RPS mode, place a jumper shunt on pins B–C as shown in

Figure 5. A 2.54 mm mini jumper shunt (low profile) is required.

Multiple hard disks

To install your new WD EIDE hard drive with an existing hard

drive or CD-ROM on the same interface cable, be sure all drives

are jumpered as shown in Figure 4.

Note: Not all hard drive manufacturers use the same jumper

configurations. To install a new WD hard drive on the same

interface cable with a non-WD hard drive, obtain jumper setting

information from the manufacturer of the non-WD hard drive.

DATA STRUCT

Magic Square

A magic square is a square array of numbers consisting of the distinct positive integers 1, 2, …,arranged such that the sum of thenumbers in any horizontal, vertical, or main diagonal line is always the same number (Kraitchik 1942, p. 142; Andrews 1960, p. 1; Gardner 1961, p. 130; Madachy 1979, p. 84; Benson and Jacoby 1981, p. 3; Ball and Coxeter 1987, p. 193), known as the magic constant

If every number in a magic square is subtracted from , another magic square is obtained called the complementary magic square. A square consisting of consecutive numbers starting with 1 is sometimes known as a “normal” magic square.

The unique normal square of order three was known to the ancient Chinese, who called it the Lo Shu. A version of the order-4 magic square with the numbers 15 and 14 in adjacent middle columns in the bottom row is called Dürer’s magic square. Magic squares of order 3 through 8 are shown above.

The magic constant for an th order general magic square starting with an integerand with entries in an increasing arithmetic series with differencebetween terms is

(Hunter and Madachy 1975).

It is an unsolved problem to determine the number of magic squares of an arbitrary order, but the number of distinct magic squares (excluding those obtained by rotation and reflection) of order , 2, … are 1, 0, 1, 880, 275305224, … (Sloane’s A006052; Madachy 1979, p. 87). The 880 squares of order four were enumerated by Frénicle de Bessy in 1693, and are illustrated in Berlekamp et al. (1982, pp. 778-783). The number ofmagic squares was computed by R. Schroeppel in 1973. The number ofsquares is not known, but Pinn and Wieczerkowski (1998) estimated it to beusing Monte Carlo simulation and methods from statistical mechanics. Methods for enumerating magic squares are discussed by Berlekamp et al. (1982) and on the MathPages website.

A square that fails to be magic only because one or both of the main diagonal sums do not equal the magic constant is called a semimagic square. If all diagonals (including those obtained by wrapping around) of a magic square sum to the magic constant, the square is said to be a panmagic square (also called a diabolic square or pandiagonal square). If replacing each numberby its squareproduces another magic square, the square is said to be a bimagic square (or doubly magic square). If a square is magic for , , and , it is called a trimagic square (or trebly magic square). If all pairs of numbers symmetrically opposite the center sum to , the square is said to be an associative magic square.

Squares that are magic under multiplication instead of addition can be constructed and are known as multiplication magic squares. In addition, squares that are magic under both addition and multiplication can be constructed and are known as addition-multiplication magic squares (Hunter and Madachy 1975).

Kraitchik (1942) gives general techniques of constructing even and odd squares of order . Forodd, a very straightforward technique known as the Siamese method can be used, as illustrated above (Kraitchik 1942, pp. 148-149). It begins by placing a 1 in any location (in the center square of the top row in the above example), then incrementally placing subsequent numbers in the square one unit above and to the right. The counting is wrapped around, so that falling off the top returns on the bottom and falling off the right returns on the left. When a square is encountered that is already filled, the next number is instead placed below the previous one and the method continues as before. The method, also called de la Loubere’s method, is purported to have been first reported in the West when de la Loubere returned to France after serving as ambassador to Siam.

A generalization of this method uses an “ordinary vector”that gives the offset for each noncolliding move and a “break vector”that gives the offset to introduce upon a collision. The standard Siamese method therefore has ordinary vector (1,and break vector (0, 1). In order for this to produce a magic square, each break move must end up on an unfilled cell. Special classes of magic squares can be constructed by considering the absolute sums , , , and . Call the set of these numbers the sumdiffs (sums and differences). If all sumdiffs are relatively prime toand the square is a magic square, then the square is also a panmagic square. This theory originated with de la Hire. The following table gives the sumdiffs for particular choices of ordinary and break vectors. ordinary vectorbreak vectorsumdiffsmagic squarespanmagic squares

(1, )(0, 1)(1, 3)none

(1, )(0, 2)(0, 2)none

(2, 1)(1, )(1, 2, 3, 4)none

(2, 1)(1, )(0, 1, 2, 3)

(2, 1)(1, 0)(0, 1, 2)none

(2, 1)(1, 2)(0, 1, 2, 3)none

A second method for generating magic squares of odd order has been discussed by J. H. Conway under the name of the “lozenge” method. As illustrated above, in this method, the odd numbers are built up along diagonal lines in the shape of a diamond in the central part of the square. The even numbers that were missed are then added sequentially along the continuation of the diagonal obtained by wrapping around the square until the wrapped diagonal reaches its initial point. In the above square, the first diagonal therefore fills in 1, 3, 5, 2, 4, the second diagonal fills in 7, 9, 6, 8, 10, and so on.

An elegant method for constructing magic squares of doubly even orderis to draw s through eachsubsquare and fill all squares in sequence. Then replace each entryon a crossed-off diagonal byor, equivalently, reverse the order of the crossed-out entries. Thus in the above example for , the crossed-out numbers are originally 1, 4, …, 61, 64, so entry 1 is replaced with 64, 4 with 61, etc.

A very elegant method for constructing magic squares of singly even orderwith(there is no magic square of order 2) is due to J. H. Conway, who calls it the “LUX” method. Create an array consisting ofrows of s, 1 row of Us, androws of s, all of length . Interchange the middle U with the L above it. Now generate the magic square of orderusing the Siamese method centered on the array of letters (starting in the center square of the top row), but fill each set of four squares surrounding a letter sequentially according to the order prescribed by the letter. That order is illustrated on the left side of the above figure, and the completed square is illustrated to the right. The “shapes” of the letters L, U, and X naturally suggest the filling order, hence the name of the algorithm.

Variations on magic squares can also be constructed using letters (either in defining the square or as entries in it), such as the alphamagic square and templar magic square.

Various numerological properties have also been associated with magic squares. Pivari associates the squares illustrated above with Saturn, Jupiter, Mars, the Sun, Venus, Mercury, and the Moon, respectively. Attractive patterns are obtained by connecting consecutive numbers in each of the squares (with the exception of the Sun magic square).

I.M..

SOURCE:WIKIPEDIA

Theodor Holm Nelson (born 1937) is an American sociologist, philosopher, and pioneer of information technology. He coined the term “hypertext” in 1963 and published it in 1965. He also is credited with first use of the words hypermedia, transclusion, virtuality, intertwingularity and teledildonics. The main thrust of his work has been to make computers easily accessible to ordinary people. His motto is:

A user interface should be so simple that a beginner in an emergency can understand it within ten seconds.

Ted Nelson promotes four maxims: “most people are fools, most authority is malignant, God does not exist, and everything is wrong”. (See chapter II, 3rd paragraph, 3rd and 4th sentence in: “The Curse of Xanadu”[1].)

Nelson co-founded Itty bitty machine company, or “ibm”, which was a small computer retail store operating from 1977 to 1980 in Evanston, Illinois. The Itty bitty machine company was one of the few retail stores to sell the original Apple I computer. In 1978 he had a significant impact upon IBM’s thinking when he outlined his vision of the potential of personal computing to the team that three years later launched the IBM PC[5].

Ted Nelson is currently working on a new information structure, ZigZag[6], which is described on the Xanadu project website, which also hosts two versions of the Xanadu code. He is also currently developing XanaduSpace[7] - a system for the exploration of connected parallel documents (an early version of this software may be freely downloaded from [3]. He is a visiting fellow at Oxford University - based at the Oxford Internet Institute - where he works in the fields of information, computers, and human-machine interfaces.

He is the son of the late Emmy Award-winning director Ralph Nelson and the Academy Award-winning actress Celeste Holm.

Tim Berners-Lee

Sir Timothy John Berners-Lee OM KBE FRS FREng FRSA (born 8 June 1955) is an English computer scientist credited with inventing the World Wide Web. On 25 December 1990 he implemented the first successful communication between an HTTP client and server via the Internet with the help of Robert Cailliau and a young student staff at CERN. He was ranked Joint First alongside Albert Hofmann in The Telegraph’s list of 100 greatest living geniuses.[2] Berners-Lee is the director of the World Wide Web Consortium (W3C), which oversees the Web’s continued development, the founder of the World Wide Web Foundation and he is a senior researcher and holder of the 3Com Founders Chair at the MIT Computer Science and Artificial Intelligence Laboratory (CSAIL).[3]

Timeline1976A Physics graduate of The Queen’s College, Oxford University, UK. Principal engineer with PlesseyTelecommunications in PooleFounding.

1980First hypertext system called “Enquire”

1981-1984Director of ImageComputer Systems

1989Started at CERN, Geneva Switzerland and writes his “www proposal”

1990Invents World Wide Web server and client software for NeXTStep.

1995Received a “Kilby Young Innovator” award by the The Kilby Awards Foundation and was a co-recipient of the ACM Software Systems Award.

July, 1996Was awarded a Distinguished Fellowship of the British Computer Society

CurrentlyThe Director of the W3C and also a Principal Research Scientist at the Massachusetts Institute of Technology Laboratory for Computer Science (MIT LCS).

A director of The Web Science Research Initiative (WSRI) [5], and a member of the advisory board of the MIT Center for Collective Intelligence[1][6]

Berners-Lee believes the future of Semantic Web holds immense potential for how machines will collaborate in the coming days. In an interview with an Indian publication, he shared his views as:

“It is evolving at the moment. The data Web is in small stages, but it is a reality, for instance there is a Web of data about all kinds of things, like there is a Web of data about proteins, it is in very early stages. When it comes to publicly accessible data, there is an explosion of data Web in the life sciences community. When you look about data for proteins and genes, and cell biology and biological pathways, lots of companies are very excited. We have a healthcare and life sciences interest group at the Consortium, which is coordinating lot of interest out there.”[citation needed]

He has also become one of the pioneer voices in favour of Net Neutrality..[8]

He feels that ISPs should not intercept customers’ browsing activities, the way companies like Phorm do. He has such strong views about this that he would change ISPs to get away from such activities.[9][10]

Inventing the World Wide Web

This NeXT Computer was used by Berners-Lee at CERN and became the world’s first Web server.

While an independent contractor at CERN from June to December 1980, Berners-Lee proposed a project based on the concept of hypertext, to facilitate sharing and updating information among researchers.[18] While there, he built a prototype system named ENQUIRE. After leaving CERN, in 1980, he went to work at John Poole’s Image Computer Systems Ltd in Bournemouth but returned to CERN in 1984 as a fellow. In 1989, CERN was the largest Internet node in Europe, and Berners-Lee saw an opportunity to join hypertext with the Internet: “I just had to take the hypertext idea and connect it to the Transmission Control Protocol and domain name system ideas and — ta-da! — the World Wide Web.”[19] He wrote his initial proposal in March 1989, and in 1990, with the help of Robert Cailliau, produced a revision which was accepted by his manager, Mike Sendall. He used similar ideas to those underlying the Enquire system to create the World Wide Web, for which he designed and built the first web browser and editor (WorldWideWeb, running on the NeXTSTEP operating system) and the first Web server, CERN HTTPd (short for HyperText Transfer Protocol daemon).

The first Web site built was at CERN[20][21][22][23] and was first put online on 6 August 1991. It provided an explanation about what the World Wide Web was, how one could own a browser and how to set up a Web server. It was also the world’s first Web directory, since Berners-Lee maintained a list of other Web sites apart from his own.

In 1994, Berners-Lee founded the World Wide Web Consortium (W3C) at the Massachusetts Institute of Technology. It comprised various companies that were willing to create standards and recommendations to improve the quality of the Web. Berners-Lee made his idea available freely, with no patent and no royalties due. The World Wide Web Consortium decided that their standards must be based on royalty-free technology, so they can be easily adopted by anyone.[24]

Creation of internet

A 1946 comic science-fiction story, A Logic Named Joe, by Murray Leinster laid out the Internet and many of its strengths and weaknesses. However, it took more than a decade before reality began to catch up with this vision.

The USSR’s launch of Sputnik spurred the United States to create the Advanced Research Projects Agency, known as ARPA, in February 1958 to regain a technological lead.[2][3] ARPA created the Information Processing Technology Office (IPTO) to further the research of the Semi Automatic Ground Environment (SAGE) program, which had networked country-wide radar systems together for the first time. J. C. R. Licklider was selected to head the IPTO, and saw universal networking as a potential unifying human revolution.

Licklider moved from the Psycho-Acoustic Laboratory at Harvard University to MIT in 1950, after becoming interested in information technology. At MIT, he served on a committee that established Lincoln Laboratory and worked on the SAGE project. In 1957 he became a Vice President at BBN, where he bought the first production PDP-1 computer and conducted the first public demonstration of time-sharing.

At the IPTO, Licklider recruited Lawrence Roberts to head a project to implement a network, and Roberts based the technology on the work of Paul Baran,[citation needed] who had written an exhaustive study for the U.S. Air Force that recommended packet switching (as opposed to circuit switching) to make a network highly robust and survivable. After much work, the first two nodes of what would become the ARPANET were interconnected between UCLA and SRI International in Menlo Park, California, on October 29, 1969. The ARPANET was one of the “eve” networks of today’s Internet. Following on from the demonstration that packet switching worked on the ARPANET, the British Post Office, Telenet, DATAPAC and TRANSPAC collaborated to create the first international packet-switched network service. In the UK, this was referred to as the International Packet Switched Service (IPSS), in 1978. The collection of X.25-based networks grew from Europe and the US to cover Canada, Hong Kong and Australia by 1981. The X.25 packet switching standard was developed in the CCITT (now called ITU-T) around 1976. X.25 was independent of the TCP/IP protocols that arose from the experimental work of DARPA on the ARPANET, Packet Radio Net and Packet Satellite Net during the same time period. Vinton Cerf and Robert Kahn developed the first description of the TCP protocols during 1973 and published a paper on the subject in May 1974. Use of the term “Internet” to describe a single global TCP/IP network originated in December 1974 with the publication of RFC 675, the first full specification of TCP that was written by Vinton Cerf, Yogen Dalal and Carl Sunshine, then at Stanford University. During the next nine years, work proceeded to refine the protocols and to implement them on a wide range of operating systems.

The first TCP/IP-based wide-area network was operational by January 1, 1983 when all hosts on the ARPANET were switched over from the older NCP protocols. In 1985, the United States’ National Science Foundation (NSF) commissioned the construction of the NSFNET, a university 56 kilobit/second network backbone using computers called “fuzzballs” by their inventor, David L. Mills. The following year, NSF sponsored the conversion to a higher-speed 1.5 megabit/second network. A key decision to use the DARPA TCP/IP protocols was made by Dennis Jennings, then in charge of the Supercomputer program at NSF.

The opening of the network to commercial interests began in 1988. The US Federal Networking Council approved the interconnection of the NSFNET to the commercial MCI Mail system in that year and the link was made in the summer of 1989. Other commercial electronic e-mail services were soon connected, including OnTyme, Telemail and Compuserve. In that same year, three commercial Internet service providers (ISP) were created: UUNET, PSINET and CERFNET. Important, separate networks that offered gateways into, then later merged with, the Internet include Usenet and BITNET. Various other commercial and educational networks, such as Telenet, Tymnet, Compuserve and JANET were interconnected with the growing Internet. Telenet (later called Sprintnet) was a large privately funded national computer network with free dial-up access in cities throughout the U.S. that had been in operation since the 1970s. This network was eventually interconnected with the others in the 1980s as the TCP/IP protocol became increasingly popular. The ability of TCP/IP to work over virtually any pre-existing communication networks allowed for a great ease of growth, although the rapid growth of the Internet was due primarily to the availability of commercial routers from companies such as Cisco Systems, Proteon and Juniper, the availability of commercial Ethernet equipment for local-area networking and the widespread implementation of TCP/IP on the UNIX operating system.

Growth

Although the basic applications and guidelines that make the Internet possible had existed for almost a decade, the network did not gain a public face until the 1990s. On August 6, 1991, CERN, which straddles the border between France and Switzerland, publicized the new World Wide Web project. The Web was invented by English scientist Tim Berners-Lee in 1989.

An early popular web browser was ViolaWWW, patterned after HyperCard and built using the X Window System. It was eventually replaced in popularity by the Mosaic web browser. In 1993, the National Center for Supercomputing Applications at the University of Illinois released version 1.0 of Mosaic, and by late 1994 there was growing public interest in the previously academic, technical Internet. By 1996 usage of the word Internet had become commonplace, and consequently, so had its use as a synecdoche in reference to the World Wide Web.

Meanwhile, over the course of the decade, the Internet successfully accommodated the majority of previously existing public computer networks (although some networks, such as FidoNet, have remained separate). During the 1990s, it was estimated that the Internet grew by 100% per year, with a brief period of explosive growth in 1996 and 1997.[4] This growth is often attributed to the lack of central administration, which allows organic growth of the network, as well as the non-proprietary open nature of the Internet protocols, which encourages vendor interoperability and prevents any one company from exerting too much control over the network

Internet structure

There have been many analyses of the Internet and its structure. For example, it has been determined that the Internet IP routing structure and hypertext links of the World Wide Web are examples of scale-free networks.

Similar to the way the commercial Internet providers connect via Internet exchange points, research networks tend to interconnect into large subnetworks such as the following:

GEANT

GLORIAD

The Internet2 Network (formally known as the Abilene Network)

JANET (the UK’s national research and education network)

These in turn are built around relatively smaller networks. See also the list of academic computer network organizations.

In computer network diagrams, the Internet is often represented by a cloud symbol, into and out of which network communications can pass.

History

Back in 1991 Wi-Fi was invented by NCR Corporation/AT&T (later on Lucent & Agere Systems) in Nieuwegein, the Netherlands. Initially meant for cashier systems the first wireless products were brought on the market under the name WaveLAN with speeds of 1Mbps/2Mbps. Vic Hayes who is the inventor of Wi-Fi has been named ‘father of Wi-Fi’ and was with his team involved in designing standards such as IEEE 802.11b, 802.11a and 802.11g. In 2003, Vic retired from Agere Systems. Agere Systems suffered from strong competition in the market even though their products were cutting edge, as many opted for cheaper Wi-Fi solutions. Agere’s 802.11abg all-in-one chipset (code named: WARP) never hit the market, Agere Systems decided to quit the Wi-Fi market in late 2004.

Wi-Fi: How it works

The typical Wi-Fi setup contains one or more Access Points (APs) and one or more clients. An AP broadcasts its SSID (Service Set Identifier, Network name) via packets that are called beacons, which are broadcasted every 100ms. The beacons are transmitted at 1Mbps, and are relatively short and therefore are not of influence on performance. Since 1Mbps is the lowest rate of Wi-Fi it assures that the client who receives the beacon can communicate at at least 1Mbps. Based on the settings (i.e. the SSID), the client may decide whether to connect to an AP. Also the firmware running on the client Wi-Fi card is of influence. Say two AP’s of the same SSID are in range of the client, the firmware may decide based on signal strength (Signal-to-noise ratio) to which of the two AP’s it will connect. The Wi-Fi standard leaves connection criteria and roaming totally open to the client. This is a strength of Wi-Fi, but also means that one wireless adapter may perform substantially better than the other. Since Windows XP there is a feature called zero configuration which makes the user show any network available and let the end user connect to it on the fly. In the future wireless cards will be more and more controlled by the operating system. Microsoft’s newest feature called SoftMAC will take over from on-board firmware. Having said this, roaming criteria will be totally controlled by the operating system. Wi-Fi transmits in the air, it has the same properties as a non-switched ethernet network. Even collisions can therefore appear like in non-switched ethernet LAN’s.

Advantages of Wi-Fi

Unlike packet radio systems, Wi-Fi uses unlicensed radio spectrum and does not require

regulatory approval for individual deployers.

Allows LANs to be deployed without cabling, potentially reducing the costs of network

deployment and expansion. Spaces where cables cannot be run, such as outdoor areas

and historical buildings, can host wireless LANs.

Wi-Fi products are widely available in the market. Different brands of access points and

client network interfaces are interoperable at a basic level of service.

Competition amongst vendors has lowered prices considerably since their inception.

Wi-Fi networks support roaming, in which a mobile client station such as a laptop computer

can move from one access point to another as the user moves around a building or area.

Many access points and network interfaces support various degrees of encryption to protect

traffic from interception.

Wi-Fi is a global set of standards. Unlike cellular carriers, the same Wi-Fi client works

in different countries around the world.

Multimedia

Multimedia is media and content that utilizes a combination of different content forms. The term can be used as a noun (a medium with multiple content forms) or as an adjective describing a medium as having multiple content forms. The term is used in contrast to media which only utilize traditional forms of printed or hand-produced material. Multimedia includes a combination of text, audio, still images, animation, video, and interactivity content forms.

Multimedia is usually recorded and played, displayed or accessed by information content processing devices, such as computerized and electronic devices, but can also be part of a live performance. Multimedia (as an adjective) also describes electronic media devices used to store and experience multimedia content. Multimedia is similar to traditional mixed media in fine art, but with a broader scope. The term “rich media” is synonymous for interactive multimedia. Hypermedia can be considered one particular multimedia application.

Multimedia may be broadly divided into linear and non-linear categories. Linear active content progresses without any navigation control for the viewer such as a cinema presentation. Non-linear content offers user interactivity to control progress as used with a computer game or used in self-paced computer based training. Hypermedia is an example of non-linear content.

Multimedia presentations can be live or recorded. A recorded presentation may allow interactivity via a navigation system. A live multimedia presentation may allow interactivity via an interaction with the presenter or performer.

Multimedia presentations may be viewed in person on stage, projected, transmitted, or played locally with a media player. A broadcast may be a live or recorded multimedia presentation. Broadcasts and recordings can be either analog or digital electronic media technology. Digital online multimedia may be downloaded or streamed. Streaming multimedia may be live or on-demand.Multimedia games and simulations may be used in a physical environment with special effects, with multiple users in an online network, or locally with an offline computer, game system, or simulator.

History of the term

In 1965 the term Multi-media was used to describe the Exploding Plastic Inevitable, a performance that combined live rock music, cinema, experimental lighting and performance art.[citation needed]

In the intervening forty years the word has taken on different meanings. In the late 1970s the term was used to describe presentations consisting of multi-projector slide shows timed to an audio track.[citation needed] In the 1990s it took on its current meaning. In common usage the term multimedia refers to an electronically delivered combination of media including video, still images, audio, text in such a way that can be accessed interactively.[1] Much of the content on the web today falls within this definition as understood by millions.

Some computers which were marketed in the 1990s were called “multimedia” computers because they incorporated a CD-ROM drive, which allowed for the delivery of several hundred megabytes of video, picture, and audio data.

USAGE:

Multimedia finds its application in various areas including, but not limited to, advertisements, art, education, entertainment, engineering, medicine, mathematics, business, scientific research and spatial temporal applications

SATA

Source:wikipedia.com

SATA

Designed as a successor to the Advanced Technology Attachment standard (ATA), it is expected to eventually replace the older technology (retroactively renamed Parallel ATA or PATA, also known as IDE or EIDE). Serial ATA adapters and devices communicate over a high-speed serial cable.

Capacity 1.5 Gbit/s, 3.0 Gbit/s, 6.0 Gbit/s Style: Serial
Cables and connectors
Connectors and cables present the most visible differences between SATA and Parallel ATA drives. Unlike PATA, the same connectors are used on 3.5-in (90 mm) SATA hard disks for desktop and server computers and 2.5-in (70 mm) disks for portable or small computers; this allows 2.5″ drives to be used in desktop computers without the need for wiring adapters (a mounting adaptor is still likely to be needed to securely mount the drive).
Some commentators have criticized SATA power connectors and data connectors for their fragility and poor robustness — the thin plastic tops of the connectors (see power connector picture at right) can easily break due to shearing force when the user pulls the plug at a non-orthogonal angle, as can the connectors on drives they connect to. In the case of a broken connector on a hard drive, this could result in a complete loss of access to all data stored on the drive.
Power Supply
Standard Connector
The micro connector originated with SATA 2.6. It is intended for 1.8 inch hard drives. There is also a micro data connector, which it is similar to the standard data connector but is slightly thinner. The SATA standard also specifies a new power connector. Like the data cable, it is wafer-based, but its wider 15-pin shape prevents accidental mis-identification and forced insertion of the wrong connector type. Native SATA devices favor the SATA power-connector over the old four-pin Molex connector (found on most PATA equipment), although some SATA drives retain older 4-pin Molex in addition to the SATA power connector.
*ADVANTAGES:
A third voltage is supplied – 3.3 V – in addition to the traditional 5 V and 12 V.
Each voltage transmits through three pins ganged together – because the small pins by themselves cannot supply sufficient current for some devices. (Each pin should be able to provide 1.5 A.)
Five pins ganged together provide ground.
For each of the three voltages, one of the three pins serves for hotplugging. The ground pins and power pins 3, 7, and 13 are longer on the plug (located on the SATA device) so they will connect first. A special hot-plug receptacle (on the cable or a backplane) can connect ground pins 4 and 12 first.
Pin 11 can function for staggered spinup, activity indication, or nothing. Staggered spinup is used to prevent many drives from spinning up simultaneously, as this may draw too much power. Activity is an indication of whether the drive is busy, and is intended to give feedback to the user through an LED.

*DISADVANTAGES:
Adaptors exist which can convert a 4-pin Molex connector to a SATA power connector. However, because the 4-pin Molex connectors do not provide 3.3 V power, these adapters provide only 5 V and 12 V power and leave the 3.3 V lines unconnected. This precludes the use of such adapters with drives that require 3.3 V power. Understanding this, drive manufacturers have largely left the 3.3 V power lines unused. However, without 3.3 V power, the SATA device may not be able to implement hotplugging as mentioned in the previous paragraph.

*ECONOMIC COST
Asus - ASUS SATA Cable- $29.49

IDE CONNECTOR
Integrated Drive Electronics is a standard electronic interface used between a computer motherboard’s data paths or bus and the computer’s disk storage devices. The IDE interface is based on the IBM PC Industry Standard Architecture (ISA) 16-bit bus standard, but it is also used in computers that use other bus standards. Most computers sold today use an enhanced version of IDE called Enhanced Integrated Drive Electronics (EIDE). In today’s computers, the IDE controller is often built into the motherboard.
IDE is one of the most widely-used hard drive interfaces on the market. The fancy name refers to how the technology integrates the electronics controller into the drive itself. While the original IDE standard could only support hard drives containing up to 540 MB of data, the new standard, EIDE (Enhanced-IDE), supports hard drives with over 250 GB of data. It also allows for data transfer rates that are over twice as fast as the original IDE.Another common hard drive interface is SCSI, which is faster than EIDE, but usually costs more per megabyte. Newer hard drives may also use a SATA (Serial ATA) connection, which improves speed and power consumption over both SCSI and IDE.

Source:wikipedia.com

PCT

SOURCE:NET

if you take a slow relaxed approach, discuss, question and research each component as it’s removed, you’ll learn alot. Read the sections on What’s Inside and What You See, fall back on your own knowledge, use the Internet, your books and resource material. It’s impossible to retain all the information, so one of the most important computer skills you can learn is how to research and use your resources to find what you need. Here’s an example of some questions to think about or discuss as you proceed:

Should I document everything I do or everything I remove?
Am I taking the best ESD precautions available to me right now.
When you remove an expansion card what kind of card is it? What kind of expansion slot did it come from? How many bits wide is that slot? What is the bus speed? What does the card do? If there’s any wires attached to the card, what’s the other end attached to and what are the wires or cables for. What kind of port is on the end of the card?
When removing a drive, what kind of drive is it? Is there information documented right on the drive itself? What kind of power connector does it use? Are there jumper settings on the drive? What for? Are any drives connected together or do they all have their own cable? Does it matter which cable I hook up when I reassemble? What are some of the things I know about this particular type of drive?
When removing wires or cables, what are the cables for? Which connectors are actually being used and what could the other ones be for? Are they following the pin-1 rule? Is pin-1 actually designated on the device the cable is attached to? Is it designated in more than one way?
Am I still taking proper ESD precautions and is my antistatic strap still hooked up?
Look at the motherboard again when there’s not so much in the way. Can you point out the CPU? How about the BIOS chip, the battery, cache RAM, keyboard connector? Is it an AT, Baby AT, or ATX format? Is there a math coprocessor? Where is it? Is the system memory supplied on SIMMs or DIMMs? How many pins on the memory module? How many memory slots are thee for each bank of system memory? Is the CPU installed in a ZIF socket or a friction socket? Are there any jumpers on the motherboard? Is there any information silk-screened on the board itself?

This is just an example of the questions you should be asking yourself. Try to come up with lots more. Even if you are not prepared to actually take your computer apart at this time, just take the cover off and ask yourself these questions as you visualize the various steps involved. Remember, not all questions can be answered by a single resource. Look in your notes, check out your manuals and resource material, ask questions.

ESD
Read the section on Electrostatic Discharge and always take ESD precautions. Remember, if you can feel a static shock its probably close to 3000 volts. Some ICs can be affected by as little as 30 volts.
Always use an antistatic wrist strap.
Keep a supply of antistatic bags to place components in as they are removed.
Leaving the computer plugged in is a recommended procedure. However, make sure it’s switched off and remember that the cable going to the remote switch on the front of the case carries AC current at house voltage. Also, ATX motherboards have power to them all the time, even when the switch is off. Before beginning to remove a power supply or an ATX motherboard, always make sure your computer is unplugged.

Before Beginning
You want to make sure you have what you need. Your wrist strap is attached to the computer, you don’t want to have to run to the other side of the room or to another room to get something. Forget about the strap and your computer may follow you.
Have a pen and paper ready. Documentation is real important. After you’ve changed a few jumpers or removed or replaced a few cables and cards, you probably will have to put some back the way they were. If you have documentation, putting things back together can be a simple reverse process. This is true of software troubleshooting as well.
Make sure you have the tools you need and they’re all close by and handy.
Be sure to have a container to keep the screws in so you have them when you want to put things back together.
Make sure you have the resource material, drivers or software that you may need.
If possible, enter the CMOS setup and record the information available. At least record the floppy and hard drive configuration and any settings that may be different from the default. You want to be careful not to remove the battery and lose these settings, but stuff happens.
Disassembly is major surgery, do a full backup of the system. Programs that you have the original disks for can always be replaced, but any upgrades for those programs and any programs that have been downloaded from the Internet may or may not still be available. Bookmarks, e-mail addresses, phone and fax numbers, dial-up connections, DNS settings and networking protocols can be a real pain to replace. Even the best technicians cannot guarantee your data, so back it up. Also, in Windows9x, all the IRQ, I/O addresses, and DMA settings can be found (and printed) from the Device Manager in Control Panel. In Windows98 check out Start/Programs/Accessories/System Tools/System Information.
Close all programs, shut down Windows, and turn off your computer. Then remove the cables from the back of the case.
One other thing: you have to use a little common sense. Don’t necessarily follow this information to the letter, it’s only meant to be a guide. If you think it would be easier to remove some expansion cards before removing the drive bay, then do it. If you can better access the data cables after the drive is out, then do it that way. If it would be easier to disconnect the power cables and remove the power supply before accessing DIMMs or SIMMs …..
I think you get the point. Removing the Cover
The standard way of removing tower cases used to be to undo 4-6 screws on the back of the case, slide the cover back about an inch and lift it off. Manufacturers are beginning to come up with trickier and more intricate methods of assembling these cases all the time. If there is no manual, then a little time taken for careful inspection may be in order. Here are some things to remember:
Don’t Force Anything. If it has to be forced, it will probably break. If there are no screws on the back of the case for the cover, check the plastic faceplate on the front. Some pry off to reveal screws or release levers (remember, careful inspection). If everything on the front has its own bezel around it (including the LEDs) then maybe the plastic front pops off (or maybe the case slides off the front).
If you notice a separation between the sides and the top, then they must come off separately. My favorite ATX case allows you to remove two screws from the back, then slide the side panel to the rear an inch and remove it. The other side removes the same way. It’s a good, solid, well built case.
Make sure any screws removed are for the cover. You don’t want to unscrew the power supply by accident and have it fall inside your computer. That’s a bad thing.
After the case is removed, place it in a safe place, where it won’t get knocked of a table, kicked or stepped on and bent.

Removing Adapter Cards
Again, documentation is very important. Yes, that 16-bit ISA card will probably work in any 16-bit ISA slot, but there may be a reason it’s in that particular one. Document the type of card and which slot it comes from.
Check the card for any cables or wires that might be attached and decide if it would be easier to remove them before or after you remove the card.
Undo the screw that holds the card in place.
Grab the card by its edges, front and back, and gently rock it lengthwise to release it. Do not wiggle it side to side as you can break the card, the slot, or the solder. Sometimes it helps to grasp the inside corner of the card with one hand and place a finger from the other hand under the associated port out the back of the computer to pry up the one end of the card.
Once the card is removed, you may want to record any jumper settings you see, just in case one is accidentally dislodged. Try to store the card in an antistatic bag. If you don’t plan on replacing the card then a cover should be installed over the slot opening.

Removing Drives
Removing drives is not that difficult. They usually have a power connector and a data cable attached from the device to a controller card or a connector on the motherboard. CD-ROMs may have an analog cable connected to the sound card.
The power will be attached using one of two connectors, a large Molex connector or a smaller Berg connector for the floppy drive. The Molex connector may need to be wiggled slightly from side to side while applying gentle pressure outwards. The Berg connector may just pull straight out or it may have a small tab that has to be lifted with a tiny flat screwdriver.
The data cables need to be documented. Remember the pin one rule. Know where each one goes before you pull it out and record its orientation (which side is the stripe on, where is pin 1?). Pull data cables gently and carefully. In other words, don’t yank them off, and pull level and in the direction of the pins.
Now you need to do a little more inspection, can the entire drive bay be removed? Does that particular drive come out the back of the bay or does it slide out the front before the bay is removed. If a bay is removable, you may have to remove some screws or unclip a lever then slide the bay back and off. If the bay is not removable, there should be access ports on the other side of the case that allow for access to those screws (there should be, I’ve seen some that you just about have to remove the motherboard to access these screws). Now you can remove the screws and slide the drive out the back of the bay. If the drive slides out the front of the case, then remove the screws and gently slide it forward. Removing the Memory Modules
Memory modules are one of the chips that can be damaged by as little as 30 volts. Be careful of ESD and handle them only by the edges. SIMMs and DIMMs are removed differently:
SIMM - gently push back the metal tabs holding the SIMM in the socket. Tilt the SIMM away from the tabs to about a 45% angle. It should now lift out. Put each SIMM in its own protective bag.
DIMM- There are plastic tabs on the end of the DIMM socket. Push the tabs down and away from the socket. The DIMM should lift slightly. Now you can grab it by the edges and place it in a separate antistatic bag.

Removing the Power Supply
Make sure it’s unplugged.
All power connectors should be removed, including the connection to the motherboard and any auxiliary fans. Watch the little plastic tabs on ATX connectors (you’ld rather not break them). AT power supplies have a two piece power connector that may be labeled P-8 and P-9. Make note of the orientation. The black wires should be in the middle, black to black.
Remove the connection to the remote power switch at the front of the case. Orientation of the colored wires at this switch is critical. If you remove them, make sure you document well, and during re-assembly plug the computer into a fused surge protector before turning it on (this could save your motherboard and components from melting if you’ve reconnected improperly). If you’re putting the same power supply back, it’s better to remove the entire switch and leave the connectors entact. The remote switch on an ATX form factor attaches to the motherboard.
Remove the four screws at the back of the case and gently slide the power supply out of the case. While removing these screws, hold onto the power supply. You don’t want it falling into the case.

Removing the Motherboard
Document and remove all wire attachments to the motherboard. (Some of these have Pin 1 designations also.)
Most cases have a removable panel that the motherboard is attached to. By removing a couple of screws the panel can be taken off and you can gain much better access to the motherboard. Again, a little investigation can save a lot of trouble.
There is usually 2 or 3 screws holding down newer motherboards. Make sure you’ve got the right ones and remove them.
Motherboards sit on plastic or brass standoffs that keep the traces and solder from touching the metal case and grounding out. Once the screws are removed you can lift the motherboard out. In other cases, the motherboard has to be slid horizontally towards the bottom of the case to unclip the plastic standoffs and then lifted out.
Place the motherboard in an antistatic bagReassembling the Computer

Same Way, Only Backwards
When it comes time to put a computer back together, it’s usually just a matter of reversing the order in which you took it apart. Again, you’re going to visualize each step because there may be an easier way. Is it easier to install the motherboard or the power supply first? Are the RAM DIMMs (or SIMMs) easier to access before, or after the power supply is in. If the motherboard pops out the back on a tray, then install the CPU and the RAM before replacing the tray. If you install the power supply first, then you may be able to clip the power connectors on as you install the motherboard and tray.

Tools
When putting the computer back together (or disassembling it for that matter), there are some basic tools that you’ll find handy. Of course, you’ll need your ESD protection equipment and a phillips screwdriver (keep a flat-head screwdriver nearby, too. A small flashlight and a magnifying glass may come in handy, as well as needle nose pliers. A useful device for any kind of computer work is a small srewdriver with a phillips head on one end and a flat-head on the other (I have no idea what the proper name is for the tool). Once again, you’re not in a race. A good carpenter measures twice, and cuts once. When working on computers you want to double-check everything you install or connect. Before you start, make sure you have taken all your ESD precautions. As you continue, make a conscious effort to remain aware of these precautions.

The Power Supply
A fairly basic installation, just lineup the holes and screw it on. Don’t plug it in yet. Remember, the cable going to the remote switch on the front of the case carries 110 volts AC. If you took the wires off the switch, make sure you connect them just as they were before (I hope you documented). A wrong connection here can burn up your PC. After your power supply is installed, do not plug it in, you may not be able to tell if the switch is on or off and you don’t want to turn the power supply on without a load.

The RAM
DIP memory modules are the hardest to install. Luckily, it’s not done much anymore. SIMMs are inserted at about a 45 degree angle then stoand up until they clip into place. If they don’t clip in properly, maybe you have them in backwards. They’ll usually have a key cut into one side. DIMMs are keyed on the edge connector side, they can only be inserted one way. Once they are lined up, push them down until the locking tabs on the side come up. You may have to support the motherboard from underneath if it looks as though its going to flex too much. COAST modules are also keyed on the bottom and insert much like an adapter card (Coast On A STick memory is cache SRAM).

The CPU
Luckily, CPU sockets aren’t friction fit anymore. If you have a PGA Central Processor (Pentium MMX or Celeron, Cyrix or AMD), it will fit into a ZIFF (zero insertion force) socket. Pin#1 on the chip has to be lined up with pin#1 on the socket. This can be indicated on the socket with an arrow, a #1 silk-screened on the board, or a flattened corner. Usually the CPU will indicate pin#1 with a flattened corner (and, or a dot on top, and, or an arrow on the bottom center of the chip). Unclip and lift the handle, insert the chip, lower the handle and clip it in. If it’s a Pentium II or a Pentium III, it will fit into a Slot 1 socket. These are rectangular in shape and have 242 pins in two rows. They’re keyed, and the cartridge should only fit in one way. Check any documentation that came with the motherboard or CPU, and refer to your notes.

The Motherboard
Most PC cases will allow you to remove the metal tray that the motherboard attaches to by removing 2 or more screws. If you didn’t do that during disassembly then you should familiarize yourself with it now. The plastic standoffs on the motherboard are to keep the solder-side of the board from touching the metal case and shorting out. Usually, it’s better to install the RAM and CPU first to avoid the possibility of flexing the board and cracking solder connections or traces. Orient the motherboard properly and either clip in, or slide in the standoffs until the mounting screw holes line up. Insert the screws that hold the board in place. The screws need to be snug, but do not twist them into the motherboard. You may be able to connect the power to the system board as you install the tray. A power supply with a baby-AT form factor will have two motherboard connectors (P8 and P9). These connectors are keyed but can be reversed. Make sure the black wires on the two connectors are beside each other. Clip the keyed edge in at an angle, then straighten the connector up and slide it on. ATX power connectors slide in until the tab clicks. Once the motherboard and tray are secured in place, you can re-install the wires for the front of the case (refer to your documentation).

At this point, you can install the video card. Do a final check on everything installed. Re-check all installations and connections, attach and plug in the monitor. Turn the computer on. Watch for lights on the front panel. How far does the BIOS POST routine get? Are there any error messages? Is this expected?

One thing that I don’t like to do is to completely re-assemble a computer and then just turn it on. If it doesn’t work at that point, then you have to tear it all apart again to find the problem. Once you’ve installed the power supply, motherboard, CPU and RAM, install the video card, hook up the keyboard and cables and start your computer. Of course, there’s no drives installed and some expansion cards are missing, so you’re going to get errors.

PCM

SOURCE:NET Computer Malpractice
Copyright (c) Cem Kaner. All rights reserved. This was originally published in Software QA, Volume 3, #4, p. 23.
Malpractice is a widely discussed type of lawsuit. Unfortunately, it is also widely misunderstood, with misinformation spread in private discussions, in the press, and in political discussions. For example, several people have insisted to me that software developers are sued “all the time” for malpractice. This is absolutely untrue. Depending on what you’re willing to count as a “computer malpractice” case, the number of successful computer malpractice lawsuits in the United States is between one (1) and five (5).
For the moment, computer malpractice is a losing lawsuit because to be sued for malpractice (professional negligence), you must be (or claim to be) a member of a profession. Software development and software testing are not professions as this term is usually used in malpractice law. Therefore, malpractice suits against programmers and testers fail.
Introduction: Definition of computer malpractice
A malpractice suit involves professional negligence. Computer malpractice involves professional negligence when providing computer-related services. In any negligence suit, the plaintiff must prove:
Duty. If you provide services to someone, you have a legal responsibility (a duty) to exercise reasonable care in providing the services. For example, if you provide consulting services, your duty is to take reasonable care to provide good advice. If you provide data backup and archiving services, your duty is to take reasonable measures to ensure that you copy the right data and that you keep it safe. HYPERLINK “http://www.badsoftware.com/malprac.htm” \l “1″ 1

Negligent breach of the duty. If you gave bad advice, you might or might not have been negligent. To prove negligence, the plaintiff has to show that no reasonable person in your situation would have given the advice that you gave. Similarly, if a data archiving service loses its client’s data, it has probably committed a breach of contract, but it might or might not have committed negligence. To prove negligence, the plaintiff would have to prove that the service didn’t take reasonable measures to safeguard the data.
Consider this example of software support advice. People call you when they have problems running their software. One day, you advise a caller that her problems come from an insufficiently-compatible video card. Actually, the caller has set one of the program’s display options incorrectly and replacing the video card won’t help. Have you committed negligence? Maybe. We can’t tell, just based on these facts, because we don’t know what a reasonable support advisor would have done.
Let’s add three facts. First, suppose that you have a database of common problems and this problem was in the database. Second, suppose that the caller’s description was specific enough that you would have easily found the problem (and the solution) in the database if you looked. Third, suppose that most software support providers would have used this database if they had it. This last point establishes a standard of care - most support advisors would have checked the database. If you don’t check the database, and you provide expensive bad advice, you can be accused of acting unreasonably.
Prevailing standard of care. The fundamental difference between an ordinary suit for negligence and a suit for malpractice lies in the definition of the prevailing standard of care. HYPERLINK “http://www.badsoftware.com/malprac.htm” \l “2″ 2
If someone sues you for ordinary negligence, they will compare your behavior to what any reasonable person would have done under the circumstances.
If they sue for malpractice, they will compare your behavior to what a reasonable member of your profession would have done. Professional standards are much higher and much better documented. (For example, they might be written down in ANSI standards documents.) Therefore, if you act negligently in a professional capacity, it will be easier to prove your negligence by comparing you to other professionals than by comparing you to any reasonably bright and careful person who might undertake to provide the services that you provided.
In complex situations, different reasonable people will collect and evaluate information very differently. This makes the plaintiff’s task difficult but the principle is the same. She’ll have to show that you didn’t approach the problem in any of the ways that reasonable people do, or that no reasonable person would have approached it in the way that you did.
History of computer malpractice suits
Few published court cases involve claims of computer malpractice. Of those that exist, most involve a brief statement by the Court that there is no such thing in the law as “computer malpractice.” Therefore, that aspect of the lawsuit is rejected and the Court moves on to discuss more interesting parts of the case. Here are the main American cases that discuss malpractice in detail.
The case of Chatlos Systems v. National Cash Register Corp. (1979) HYPERLINK “http://www.badsoftware.com/malprac.htm” \l “3″ 3 is the first important computer malpractice case. An NCR salesman did a detailed analysis of Chatlos’ business operations and computer needs, and advised Chatlos to buy NCR equipment. Relying on NCR’s advice, Chatlos bought a system that never provided several promised functions. Chatlos sued. NCR was held liable for breach of contract. In its Footnote 1, the Court discussed Chatlos’ claim of malpractice:
·ð T h e n o v e l c o n c e p t o f a n e w t o r t c a l l e d ‘ c o m p u t e r m a l p r a c t i c e ‘ i s p r e m i s e d u p o n a t h e o r y o f e l e v a t e d r e s p o n s i b i l i t y o n t h e p a r t o f t h o s e w h o r e n d e r c o m p u t e r s a l e s a n d s e r v i c e . P l a i n t i f f e q u a t e s t h e s a l e a n d s e r v i c i n g o f c o m p u t e r s y s t e m s w i t h e s t a b l i s h e d theories of professional malpractice. Simply because an activity is technically complex and important to the business community does not mean that greater potential liability must attach. In the absence of sound precedential authority, the Court declines the invitation to create a new tort.
This refusal to recognize the validity of a lawsuit for computer malpractice has been widely quoted.
The next interesting case was Invacare Corp. v. Sperry Corp. HYPERLINK “http://www.badsoftware.com/malprac.htm” \l “4″ 4 Invacare claimed that it had relied on advice of Sperry employees when it leased a Univac computer and sued for fraud, breach of contract, and negligence. Sperry argued that the negligence suit couldn’t succeed because there is no cause of action for computer malpractice. Bowing to the Chatlos decision, the Court agreed that there is no such thing as computer malpractice. But, the Court said, Invacare wasn’t claiming that Sperry’s acts constituted malpractice. Invacare’s claim was that the system was so inadequate for the job that no reasonable person would have recommended it. This is just a lawsuit for ordinary negligence, not professional negligence, and the Court allowed it to proceed.
In 1985, the Internal Revenue Service ruled that if a program goes beyond purely mechanical assistance in the preparation of a tax return, the author of the program is a tax return preparer. HYPERLINK “http://www.badsoftware.com/malprac.htm” \l “5″ 5 The IRS can fine a tax preparer who acts negligently, or particip a t e s i n f r a u d o n t h e I R S .
·ð W h e n a n i n d i v i d u a l o r a c o m p a n y s e l l s a s o f t w a r e p r o g r a m t o a c u s t o m e r t o a i d i n t h e p r e p a r a t i o n o f a t a x r e t u r n , I R S n o t e d , a c u s t o m e r m a y b e u n a w a r e t h a t t h e p r o g r a m i s i n c o m p l e t e o r i n a d e q u a t e a n d t h e r e f o r e m a y u s e i t t o c r eate an erroneous return.
If using the computer program results in an understatement of tax liability for the taxpayer, the software company may be subject to a penalty. HYPERLINK “http://www.badsoftware.com/malprac.htm” \l “6″ 6
This IRS ruling is not a malpractice ruling, but it addresses an important point in the larger area of professional misconduct, and it reflects a well accepted principle of malpractice. Someone who provides bad legal advice can be sued for legal malpractice whether they’re a lawyer or not. Someone who provides bad medical care can be sued for medical malpractice whether they’re a doctor or not. Someone who provides bad engineering while claiming to be a professional engineer can be sued for engineering malpractice, whether they are licensed as a professional engineer or not. The IRS ruling extended this principle to computer programs that provide professional services. I haven’t seen such a lawsuit yet, but it seems likely that a software company can be sued for legal, medical, engineering, architectural, or other malpractice if it claims to provide these professional services and provides them incompetently.
The recent case of State v. Despain (1995) HYPERLINK “http://www.badsoftware.com/malprac.htm” \l “7″ 7 illustrates the same point. A non-lawyer bought a computer program that printed legal forms. She helped clients fill out the forms. This was held to be the unauthorized practice of law. The Court carefully pointed out that the sale of computer software that merely contai n s ( a n d p r i n t s ) b l a n k l e g a l f o r m s i s n o t t h e p r a c t i c e o f l a w . B u t ( p . 5 7 8 )
·ð t h e p r e p a r a t i o n o f l e g a l d o c u m e n t s f o r o t h e r s t o p r e s e n t i n . . . c o u r t c o n s t i t u t e s t h e p r a c t i c e o f l a w w h e n s u c h p r e p a r a t i o n i n v o l v e s t h e g i v i n g o f a d v i c e , c o n s u l t a t i o n , e x p l a n ation, or recommendation on matters of law. Further, instructing other individuals in the manner in which to prepare and execute such documents is also the practice of law.
If your company provides a program that promises legal, medical, dental, architectural or other professional engineering services and advice, think carefully about what you provide and what your marketing materials claim that you provide. If your program appears to be providing professional services, your company might be sued not for computer malpractice but for legal or medical or dental (etc.) malpractice.
1986 brought the main case (I think it is the only case) that unambiguously recognizes a valid suit for computer malpractice. The Chatlos decision came in New Jersey and was followed in many other States. But laws do differ from State to State. This case, Data Processing Services, Inc. v. L.H. Smith Oil, Corp. (1986) HYPERLINK “http://www.badsoftware.com/malprac.htm” \l “8″ 8, was decided in Indiana. The Court stated that (p. 319):
·ð T h o s e w h o h o l d t h e m s e l v e s o u t t o t h e w o r l d a s p o s s e s s i n g s k i l l a n d q u a l i f i c a t i o n s i n t h e i r r e s p e c t i v e t r a d e s o r p r o f e s s i o n s i m p l i e d l y r e p r e s e n t t h e y p r e s e n t t h e s k i l l a n d w i l l e x h i b i t t h e d i l i g e n c e o r d i n a r i l y p o s s e s s e d b y w e l l i n f o r m e d m e m b e r s o f t h e t r a d e o r p r o f e s s i o n .
T h e C o u r t d e c i d e d t h a t t h i s p r i n c i p l e a p p l i e s j u s t a s w e l l t o c o m p u t e r p r o g r a m m e r s a s i t d o e s t o l a w y e r s , a r c h i t e c t s , b u i l d i n g c o n t r a c t o r s , e t c . I t t h e n u p h e l d a f i n d i n g o f l i a b i l i t y o n D P S ‘ p a r t b y n o t i n g t h a t ( p . 3 2 0 ) :
·ð ( a ) D P S r e presented it had the necessary expertise and training to design and develop a system to meet the needs of Smith; (b) DPS lacked the requisite skills and expertise to do the work; (c) DPS knew it lacked the skill and expertise; (d) DPS should have known Smith was dependent upon DPS’s knowledge and abilities; and, (e) DPS should have foreseen Smith would incur losses if DPS did not perform as agreed.
Diversified Graphics, Ltd. v. Groves (1989) HYPERLINK “http://www.badsoftware.com/malprac.htm” \l “9″ 9 was the next successful malpractice case. Diversified hired the accounting firm of Ernst & Whinney (E & W) to help choose a computer system. Diversified sued for professional negligence & won. In its appeal, E & W argued that Diversified had failed to define the professional standard of care or to show how E & W had violated the standard. Though the Court explicitly stated that this was a computer case (not an accounting case), it determined the standard of care from E & W’s own “Guidelines to Practice” which included management advisory practice standards that had been incorporated by the American Institutes of Certified Public Accountants (AICPA). It’s not a big stretch to hold an accounting firm liable for computing consulting malpractice when the proof of the malpractice is proof of failure to follow AICPA standards.
In 1991, Wang Laboratories was sued for negligence and gross negligence. HYPERLINK “http://www.badsoftware.com/malprac.htm” \l “10″ 10 Wang sold a computer and a service contract to Orthopedic & Sports Injury Clinic. While attempting to fix the computer, Wang’s employee used, and corrupted, the Clinic’s last backup disk, thereby losing five years of the clinic’s medical and accounting data. (Oops.) The contract limited the amount of damages that Orthopedic could collect from Wang, but Louisiana law (and many other States’ laws) allows the plaintiff to recover all damages if the defendant committed gross negligence.