Computer Education

INTERNET
Uses of the Internet
Internet Access
How Information Travels Over the Internet
Network Names and Addresses
Client/Server Architecture
Electronic Mail and News Groups
Other Internet Applications
Bandwidth
History
The Future of the Internet

Computer Memory
Internal RAM
Internal ROM
External Memory
Magnetic Media
Optical Media
Magneto-Optical Media
Cache Memory

HISTORY
Beginnings
First Punch Cards
Beginnings
Precursor to Modern Computer

TYPES OF COMPUTERS
Digital and Analog
Range of Computer Ability

NETWORKS

PROGRAMMING LANGUAGES
Machine Language
Assembly Language
High-Level Languages
FLOW-MATIC
FORTRAN
BASIC

HOW COMPUTERS WORK
Operating System
Computer Memory
Bus
Input Devices
Central Processing Unit
Output Devices

HOW A CPU WORKS
INTRODUCTION
Function
Branching Instructions
Clock Pulses
Fixed-Point and Floating-Point Numbers

HISTORY
Early Computers
Transistor
The Integrated Circuit

THE FUTURE OF THE INTERNET


Several technical challenges must be overcome if the Internet is to continue growing at the current phenomenal rate. The primary challenge is to create enough capacity to accommodate increases in traffic. Internet traffic is increasing as more people become Internet users and existing users send greater amounts of data. If the volume of traffic increases faster than the capacity of the network increases, congestion will occur, similar to the congestion that occurs when too many cars attempt to use a highway. To avoid congestion, researchers have developed technologies, such as Dense Wave Division Multiplexing (DWDM), that transfer more bits per second across an optical fiber. The speed of routers and other packet-handling equipment must also increase to accommodate growth. In the short term, researchers are developing faster electronic processors; in the long term, new technologies will be required.

Another challenge involves IP addresses. Although the original protocol design provided addresses for up to 4.29 billion individual computers, the addresses have begun to run out because they were assigned in blocks. Researchers developed technologies, such as Network Address Translation (NAT), to conserve addresses. NAT allows multiple computers at a residence to “share” a single Internet address. Engineers have also planned a next-generation of IP, called IPv6, which will handle many more addresses than the current version.

Short, easy-to-remember domain names were once in short supply. Many domain names that used the simple format http://www.[word].com, where [word] is a common noun or verb, and .com referred to a for-profit business were mostly taken by 2001. Until 2001, only a few endings were allowed, such as .com, .org, and .net. By 2002, however, additional endings began to be used, such as .biz for businesses and .info for informational sites. This greatly expanded the number of possible URLs.

Other important questions concerning Internet growth relate to government controls, especially taxation and censorship. Because the Internet has grown so rapidly, governments have had little time to pass laws that control its deployment and use, impose taxes on Internet commerce, or otherwise regulate content. Many Internet users in the United States view censorship laws as an infringement on their constitutional right to free speech. In 1996 the Congress of the United States passed the Communications Decency Act, which made it a crime to transmit indecent material over the Internet. The act resulted in an immediate outcry from users, industry experts, and civil liberties groups opposed to such censorship. In 1997 the Supreme Court of the United States declared the act unconstitutional because it violated First Amendment rights to free speech. The U.S. Congress responded in 1998 by passing a narrower antipornography bill, the Child Online Protection Act (COPA). COPA required commercial Web sites to ensure that children could not access material deemed harmful to minors. In 1999 a federal judge blocked COPA as well, ruling that it would dangerously restrict constitutionally protected free speech. The judge’s ruling was upheld by a federal appeals court on the grounds that the law’s use of “community standards” in deciding what was pornographic was overly broad.

The issue reached the Supreme Court of the United States in 2002, and in a limited ruling the Supreme Court found that the community standard provision was not inherently unconstitutional. Supporters of the law welcomed the Court’s ruling. However, opponents noted that the Court had sent the case back to the federal appeals court for a more comprehensive review and had ruled that the law could not go into effect until that review occurred. Some analysts who studied the various opinions written by the justices concluded that a majority of the Court was likely to find the law unconstitutional.

Increasing commercial use of the Internet has heightened security and privacy concerns. With a credit or debit card, an Internet user can order almost anything from an Internet site and have it delivered to their home or office. Companies doing business over the Internet need sophisticated security measures to protect credit card, bank account, and social security numbers from unauthorized access as they pass across the Internet (see Computer Security). Any organization that connects its intranet to the global Internet must carefully control the access point to ensure that outsiders cannot disrupt the organization’s internal networks or gain unauthorized access to the organization’s computer systems and data.

Disruptions that could cause loss of life or that could be part of a coordinated terrorist attack have also become an increasing concern. For example, using the Internet to attack computer systems that control electric power grids, pipelines, water systems, or chemical refineries could cause the systems to fail, and the resulting failures could lead to fatalities and harm to the economy. To safeguard against such attacks, the U.S. Congress passed the Homeland Security Act in November 2002. The new law creates criminal penalties, including life imprisonment, for disruptions of computer systems and networks that cause or attempt to cause death. The law also allows ISPs to reveal subscriber information to government officials without a court-approved warrant if there is a risk of death or injury. It also enables government officials to trace e-mails and other Internet traffic during an Internet disruption without obtaining court approval. Civil liberties groups objected to the lack of court supervision of many provisions in the new law.

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