Montbello Publishing

The disabled fight back

Montbello Publishing - The disabled fight back

NETWORK CABLES

 A local area network or LAN is connected by a sundry of wired media.  The three most popular are discussed in this text:

  1. Coaxial Cable
  2. Twisted Pairs
  3. Fiber Optic

Over the next few pages, I will attempt to explain the cabling options available for LAN construction.

COAXIAL CABLE:

Coaxial cable was the first medium for private LANs.  Coaxial cable comes in two variables, ThickNet and ThinNet.  Coaxial cable or coax was at the dawn of LAN construction the most widely used cabling media.  Coaxial cable in its simplest form, consist of a core made of solid copper surrounded by insulation and a braided metal shield, covered by a rubber vinyl skin.

ThickNet was the first medium; it was relatively rigid with a diameter of roughly half an inch.  It is referred to as Standard Ethernet.  ThickNet coaxial cabling has a single copper conductor at its center.  A plastic layer provides insulation between the center conductor and a braided metal shield.  The metal shield helps to block any outside interference.  The outer skin is strictly for insulation.

 Although coaxial cabling is inflexible and difficult to use, it is very durable and highly suitable for LAN connections.  In addition, it can carry signals—uncorrupted—a greater distance between devices than twisted pair cable.  The maximum range a signal can travel on ThickNet before signal deterioration is 1640 feet or 500 meters.  The maximum transmission rate of ThickNet is 10 Mbps.

The complete description of Coaxail, Fiber Optics, Twisted Pair cabling is found in the book A History of the Computer and Its Networks now available at these retailers  Amazon, Barnes & Noble, and More Books and other fine booksellers on the Internet worldwide

Blaise Pascal

The scientific quest to simplify the tedium of mathematical calculations mechanically did not end with Schickard’s death.  Instead, it began anew in the personage of French scientist and mathematician Blaise Pascal.  Pascal was born near Lyon on July 29, 1623 in the Clermont region about 200 miles south of Paris.  

Without any previous knowledge of the Calculating Clock, Pascal, in 1642, invented the Pascaline.  The Pascaline was different from the Schickard device.  The Pascaline was made entirely of metal.  It was a rectangular box about 36 centimeters (cm) long, 13 cm wide, and eight cm high.  Pascal built several versions of the machine, one with five dials, a second with six dials, and a third with eight dials.  The number of dials on the face of the machine determined the precision of the machine. 

The Pascaline made its calculations using gears and sprockets in the same manner as the odometer displayed on the dashboard of an automobile, before the LED display.  To obtain the precision gearwheels needed to make the calculations with the Pascaline, Pascal trained himself in metal fabrication techniques.  He did this because the local machinists and clockmakers were not accustomed to the precision Pascal required. 

Pascal built the Pascaline for altruistic reasons.  He wanted to assist his father, Etienne Pascal, a tax collector, who was over burdened with the counting of taxes in Clermont (Karwatka, 2004).  Historians infer that Pascal based the design of his calculator on the machines developed by Hero of Alexandria in ancient Egypt (Hoyle, 2004).

To add numbers on the Pascaline, the operator entered the numbers on the rotating dial on the face or top of the machine.  First one number was entered, then the process was repeated with the second, third, fourth number.  The right most dial represented the one’s column; the next column left represented the tens and so forth to last column on the left most digit.  The machine worked in a manner similar to the action of dialing a rotary telephone.  Numbers were entered into the Pascaline by rotating the dial the appropriate number of digits (M. Williams, 1990, p. 39) (Ifrah, 2001, p. 122).

The complete story of Blaise Pascal, Gottfried Wilhelm von Leibniz , and Charles Xavier Thomas de Colmar is found in the book A History of the Computer and Its Networks now available at these retailers  Amazon, Barnes & Noble, and More Books and other fine booksellers on the Internet worldwide

From the chapter: A Brief Course in Electricity

NIKOLA TESLA

Thomas Edison may have pioneered the use of electricity and the electric lamp (light bulb).  But it was the genius of Nikola Tesla that created the modern electric power infrastructure we use today.  His accomplishments when compiled completely overshadow the 1879 accomplishments of Thomas Edison in electric power distribution.  Never the less, it was Edison’s company General Electric that profited the most from Tesla’s genius.  When all the legal and political wrangling had finished, General Electric had dumped Edison and went on to become one of the largest and most profitable corporations in the world.

For all his genius and creativity, Tesla never won the Nobel Prize.  His work with alternating current rivals the genius of Einstein, Bohr, and Marconi.  Tesla throughout his long career filed hundreds of patients on both direct current and alternating current engineering applications.  He received patents for dynamos, generators, alternators, transformers, motors, wireless transmissions (radio), x-rays, and florescent lights.  Yet, he is the forgotten man in the annals of United States history.  A Google search of the Internet shows that only two schools were named in his honor, while every major city in the United States has at least one school named in honor of Thomas Edison.

Nikola Tesla was born in the Austro-Hungarian Empire on July 9, 1856 in a mountainous area of the Balkan Peninsula known as Lika (Cheney, 198, p. 25).  Tesla began his education at home and later attended school in Carlstadt, Croatia where he excelled in studies.  At an early age, Tesla demonstrated his genius by solving mentally problems of integral calculus (Cheney, Uth, & Glenn, Tesla, master of lightning, 1999, p. 9).

How alternating current became the staple of energy in the United States begins with the arrival of Nikola Tesla in New York City in 1884.  Armed only with a letter from a colleague of Edison, Charles Batchelor, as means of introduction, Tesla was able to gain an interview with the great Edison in Menlo Park.  At first, Edison scoffed at the recommendations Batchelor made in the letter.  However, after Tesla was able to elaborate his experiences with electricity and electrical engineering, he won Edison’s favor and received a conditional job offer to work at the Menlo Park laboratory.  The stipulation for employment required Tesla to repair the dynamos Edison had installed on the USS Oregon moored at the New York shipyards.

“Yes indeed,” replied a confident Tesla who hastened to the shipyards and went to work immediately making all the necessary repairs.  Tesla worked feverishly through the night repairing the countless short circuits and broken circuits on the ship.  By dawn, with the assistance of the ship’s crew, he had finished job (PBS, 2004).

Stunned by Tesla’s speed and efficiency, Edison gave Tesla a job at his Menlo Park laboratory.  Tesla’s first assignment from Edison was to redesign the Menlo Park shop.  Tesla completed the task in about a year.  Although an avid proponent of alternating current, Tesla dampened his enthusiasm with innovations to make Edison’s direct-current dynamos more efficient.  Tesla convinced Edison to let him redesigned the DC dynamos to make them more efficient.  Edison—a shrewd, irascible businessman—and always interested in making money, agreed to Tesla’s proposition.  In exchange, Edison agreed to pay Tesla $50,000 if he improved the efficiency of the dynamos.

Several months later, Tesla completed the work on the dynamos and then to his dismay Edison reneged on his payment.  When Tesla asked him to explain, Edison stated he thought Tesla understood the offer was made in jest.  Tesla did not see the humor in the explanation and immediately resigned his Menlo Park position (PBS, 2004) (Morgan Reynolds Inc., 2005, p. 47) (Cheney, Uth, & Glenn, Tesla, master of Lightning, 1999, p. 20).

After leaving Menlo Park, his reputation preceding him, Tesla was able to form several business partnerships.  The first of these partnerships was with a group of crafty investors who established the Tesla Light and Manufacturing Company.  The investors wanted Tesla to focus on improving the system of arc lights already in place in many American and European cities (Jonnes, 2003, p. 11).

On March 30, 1885, Tesla filed for his first patent, a design improvement for the arc lamp that addressed the major problems with its use, the annoying flickering, maintenance costs, and reliability.  The newly formed Tesla Light & Manufacturing Company was a success and making money.  However, when Tesla attempted to persuade the investors fund the building of an electric motor, they balked.  Informing him, they were not interested in such a project.  To compound his difficulties with his new company, the investors refused to pay him for his improvements to the arc light.  Penniless and desperate, Tesla took a job as a ditch digger to provide himself with food and shelter during the winter of 1886-1887 (Seifer, 1998, p. 41) (Morgan Reynolds Inc., 2005, p. 48).

The complete story of Nikola Tesla, Thomas Edison, the incandescent lamp and the War of the Currents are found in the book A History of the Computer and Its Networks now available at these retailers  Amazon, Barnes & Noble, and More Books and other fine booksellers on the Internet worldwide

CPU Architecture

The action performed by the arithmetic-logic unit (ALU) determines what the computer does with a given set of program instructions. The language of the computer is binary numbers; the ALU performs five basic arithmetic operations with these numbers. It manipulates the numbers by comparing, multiplying, dividing, adding, or subtracting the numbers to produce a desired outcome.
To send a letter from the computer keyboard to the computer monitor the ALU compares the series of ones and zeroes to a database of zeroes and ones designated as letters. If it finds a match, loads it to output to the monitor. If the computer does not find a binary match, it compares it to commands already in memory and performs the instructions. The instructions may ask the computer to save to a disk or print on paper.
To get a better understanding of how the ALU accomplishes this task. Think of the old Morse code. Each letter in Morse code was represented by a series of dots and dashes or long and short bursts of electricity. The modern computer system has modified that ideal into a series of zeros and ones first into the ASCII (American Standard Code for Information Interchange) system then later into Unicode. ASCII and Unicode are more complicated than Morse code. For example, ASCII has 256 different combinations of zeroes and ones to represented letters and numbers. Every time the user presses a key, he or she acts as a telegrapher sending a message to the computer system. Every time the ALU reads a code it acts as the receiving telegrapher and records the message, and routes it to the customer or in this case the correct piece of peripheral equipment albeit monitor, printer, disk drive, or hard drive. Each letter has either a binary, octal, decimal, and hexadecimal equivalent used in the same manner as the dots and dashes of Morse code. For instance, with ASCII to write “c-a-t, the computer writes the decimal equivalent 67-65-84.
Computers do not think in decimal numbers. The decimal output is strictly for human consumption. Computers operate in binary code. The most adaptable chunk of information to transport binary equivalents is Hexadecimal. That is because; hexadecimal provides 256 combinations of binary groupings thirty-two 8-bit words or 16 16-bit words. (The larger the word the faster the computer operates.) It is a very simplified manner of describing how Morse code compares to computer operations. For most of us, when we write the computer is reading special instructions given to it by a word processing program to perform a special method of addition known as concatenation to deliver the value of words to the screen (Abd-El-Barr & El-Rewini, 2005, pg. 273). Unicode began replacing ASCII code in 1987.

The complete discussion of the architecture of the CPU is found in the book A History of the Computer and Its Networks now available at these retailers  Amazon, Barnes & Noble, and More Books and other fine booksellers on the Internet worldwide

Computer Operating Systems

The operating system, although it was not defined in either of the Von Neumann and Harvard computer architectures, is as important a component of the modern digital computer as the equipment.  Since the advent of stored memory, the operating system has played a vital role in the operations of the computer as it became more automated.  The purpose of the operating system is to serve as an interface between the hardware of the computer and its human user.  The operating system automates the management and control of computer resources such as memory, input, output, storage, microprocessor operations, device control (mouse), BIOS management, and application management.

Modern operating system software contains four characteristics: redundancy, integrity, scalability, and reliability.  Redundancy is needed because systems need to track and record what it operations.  An operating system has integrity because it must continually calculate solutions.  An operating system needs to be reliable, the average computer will start anywhere from eight to eleven thousand times during its lifetime.  Each start must be like the previous so the operating system must know where it saved data, what equipment is available, and its capacity.  Finally, the software must be scalable for future needs.  The next few pages tell the story of how the modern operating system was created.

The first computers, the ABC, and ENIAC, did not have an operating system as we understand the term today.  Operations of the first general-purpose computer required a team of technicians and engineers to walk through the chassis of the computer flipping switches, changing relays, and manipulating plug boards.  Before memory was added, if reconfiguration was not required, the early behemoths received instructions for a task from a stack of punch cards or spools of punch tape later magnetic tape.  When John von Neumann introduced the EDVAC (Electronic Discrete Variable Automatic Computer) concept of stored memory, the way computers operated began to change.  Instead of massive physical reconfigurations, computers received instructions electronically.  Moreover, the programs were coded with binary codes of zeros and ones, which were kept in the same place that held the data the computer processed.  By letting a program treat its own instructions as data offered the engineer tremendous advantages.  First, it accelerated the speed of the computer.  Second, it simplified the circuitry, and making possible the ideal of programming.

To make the early computers successful, two major innovations were necessary.  The first was the development of a high-level programming language—FORTRAN (Formula Translation) invented in 1957 and two years later COBOL (Common Business Oriented Language)—and a control program or function.  Today the control functions of a computer are called the operating system, or OS.  The concept of a computer operating system began after the advent of the programming.

The first attempt as producing a computer operating system came with the invention of FMS or the Fortran Monitor System.  The Fortran Monitor System controlled mainframe computers with batch programming.  IBSYS was, the equivalent of FMS, it was developed for the IBM 7094 (Tannenbaum, 2002).

The complete history of the computer operating system is found in the book A History of the Computer and Its Networks now available at these retailers Amazon, Barnes & Noble, and More Books and other fine booksellers on the Internet worldwide.

Trojan Horse (computer malware)

If the virus and the worm are the diseases of the cyber world, then the Trojan horse is the contaminated hypodermic needle used to spread the disease.  The Trojan horse is more sophisticated than the previously discussed forms of malware.  A Trojan horse is destructive program that masquerades as a beneficial application such as antispyware.  In contrast to the worm or the virus, the Trojan horse does not automatically replicate itself.  The primary goal of a Trojan horse is to hide on the victim’s computer invisibly carrying out ill will, such as downloading spyware or recruiting zombie computers as part of a Denial of Service or Distributed Denial of Service (DDoS) attack, while the victim continues with their normal activities.  No matter the purpose for having the Trojan infect the victim, the results are similar to the legend created by mythology.

A quick refresher of Greek mythology tells us the Trojan horse originated in Greek Mythology during the Trojan War.  Legend states the Greeks after years of fruitless war with the Trojans feigned defeat by leaving behind a giant wooden horse as a peace offering to honor the gallant defenders of Troy.  The Trojans unwittingly accepted the peace offering and rolled the giant horse inside the city gates.

The Trojans celebrated their apparent victory with a daylong feast of drunkenness.  Meanwhile the Greek soldiers—hidden inside the horse—waited for cover of darkness, then while all of Troy was asleep, emerged from the belly of the horse and opened the gates for the bulk of Greek forces, which had withdrawn to a point at sea just beyond the horizon.

Trojan horse computer malware, like its mythological counterpart, clandestinely emerges to destroy or steal information from computers.  The modern day Trojan horse  is classified into five categories.  However, one must remember authors of malware do not follow rules in accordance with the greater society.  A computer Trojan horse program may be the product of government espionage, criminal enterprise, or criminal mischief.  The five major Trojan horse categories:

1.         Remote Access Trojans

2.         Security Disabler

3.         Data Sending Trojans

4.         Proxy Trojans

5.         FTP Trojans

The complete history of the Trojan Horse and other malware on the Internet  is found in the book A History of the Computer and Its Networks now available at these retailers    Lambert Academic Publishing, Amazon, Barnes & Noble, and More Books and other fine booksellers on the Internet worldwide.

TCP/IP

Transmission Control Protocol/Internet Protocol was developed by the defense department in the early 1970s to counteract the vulnerabilities it recognized in circuit switching data transmission or fixed pathway data transmissions.  To circumvent the apparent weaknesses in its computing services DOD commissioned ARPANET.  In the early 1970s even though IBM still manufactured  90 percent the world’s mainframe computers, only an elite few of the DoD partner universities, corporations, and research centers utilized IBM computers exclusively.  Most relied on cloned IBM computers and brands produced by other companies Digital Equipment Corporation, Honeywell, General Electric, and Data General Computers.  To circumvent compatibility and interoperability issues with its partners, the DOD commissioned the creation of TCP/IP for ARPANET.

TCP/IP is a dual layered suite of protocols that gain popularity through widespread use first as the government-sanctioned standard for ARPANET.  It remained the protocol suite of choice for ARPANET when the government abandoned ARPANET for DARPANET.  It was the protocol suite even after ARPANET transmogrified into NSFNET, which eventually became the Internet.  The first layer of the protocol suite TCP or Transmission Control Protocol takes care of the individual units of data (called packets) that a message is divided into for efficient routing through the Internet.  The second layer is tasked with remembering the originating and receiving addresses of the messages.

TCP/IP is a layered set of protocols similar to but not identical to the OSI Reference Model protocol layers.  TCP/IP consists of almost 100 non-proprietary protocols that interconnect computer systems efficiently and reliably.  The core components protocols with TCP/IP are the following:

a.         Transmission Protocol (TCP)

b.         User Datagram Protocol (UDP)

c.         Internet Protocol (IP)

The complete history of TCP/IP and how it changed the course of modern network computing  is found in the book A History of the Computer and Its Networks now available at these   Lambert Academic Publishing, Amazon, Barnes & Noble, and More Books and other fine booksellers on the Internet worldwide.

William Seward Burroughs

The discussion of the company created by William Seward Burroughs is a vital component in the history of the mechanical adding machine.  It alone was the only 19th century adding machine company capable of making the transition from the Gilded Age (post-Civil War) to the Information Age and the arrival of the transistor.  Some might argue that Victor Technologies, Hollerith Tabulating Machines, and National Cash Register made the transition.  However, let me point out that neither Hollerith Tabulating Machines nor National Cash Register began operations exclusively as a digital calculator company.  The former was essentially a 19th century version of a computer company.  The latter was a cash register company.  Victor Technologies never expanded beyond business calculators.

William Seward Burroughs was born near Rochester, New York in 1855.  Burroughs grew up and lived in and around the cities of Rochester and Auburn New York until 1881.  According to historians (Kidwell, 2000), the Auburn city records indicate that Burroughs worked as a clerk and accountant in several area banks.  While working as a bank clerk at the Cayuga County National Bank, he became interested in creating an adding machine to assist banking clerks and accounting (Massachusetts Institute of Technology, 2002).

Albany city records, also, show he worked in a lumberyard as a boxer and a planar (Kidwell, 2000).  His father, Edmund Burroughs, moved to Saint Louis, Missouri in the late 1870s and William followed him to Saint Louis in 1881.  While working in Saint Louis, the younger Burroughs had several jobs, which provided him with the manufacturing and mechanical skills he needed to succeed later in life.

William Seward Burroughs achieved fame and fortune because of the mechanical calculating machine he invented in 1884 and the company that displays his name.  The adding machine featured the 81-key keyboard format.  It also contained an accumulator at its rear that displayed a running total and a printed record of the input and results.  Burroughs named his new calculator the Arithmometer, receiving a patent on the design in 1888.  In 1886, he and three other men—Thomas Metcalfe, Richard M. Scruggs, and William Pye—founded, in anticipation of the patent approval, the American Arithmometer Company of St. Louis.

In 1889, Burroughs renamed the adding machine the Bankers’ and Merchants’ Registering Accountant.  during the initial test trial of the calculator several flaws were revealed in the machine’s design causing it to fail the trial run.  The setback caused Burroughs and company to simplify the operation and design of its calculator, primarily changing the printing mechanism, and simplifying the operating handle (Kidwell, 2000).

In 1892, he presented a revised version of the Bankers’ and Merchants’ Registering Accountant to the local banking community for a second trail-run.  The second set of tests proved the revisions successful; and, the American Arithmometer Company ordered 100 machines from its manufacturer the Boyer Machine Company for marketing to the local business community.  Despite the machine’s high price, $475, it soon found a niche market amongst the banks and insurance companies of Saint Louis.

American Arithmometer shortened the name of the calculator to the Burroughs Registering Accountant.  In 1895, the American Arithmometer Company assumed responsibility for the manufacture of the Burroughs Registering Accountant, and for the first time, it paid dividends to its investors.

In 1896, American Arithmometer hired William H. Pike as a supervisor to oversee cost reduction and increase efficiency.  He improved the machine and filed three patents in the process on the Burroughs Registering Accountant.  For his efforts, Pike was rewarded with a $40 a week salary and $3000 in bonuses.  Pike was promoted to supervisor of the factory of the newly establish Burroughs Adding and Registering Machine Limited, a subsidiary licensed to manufacture and sell the Burroughs’s machine in Great Britain (Kidwell, 2000).

The complete story of William Seward Burroughs and the other desktop calculator pioneers is found in the book A History of the Computer and Its Networks available  at    Lambert Academic Publishing, Amazon, Barnes & Noble, and More Books and other fine booksellers on the Internet worldwide.

Wireless Networks (Wi-Fi)

IEEE 802.3 CSMA/CD defines connectivity, Ethernet, for the wired LAN, IEEE 802.5 defines Token Ring, whilst the IEEE 802.11 suite of protocols defines connectivity for the wireless local area network or WLAN.  A second agency WECA, Wireless Ethernet Compatibility Alliance, certifies Wi-Fi technology for WLAN.  WECA defines Wi-Fi as any WLAN that aligns with the 802.11 suite of protocols, more specifically 802.11a and 802.11b.  Wi-Fi is short for Wireless.  WLAN works at the narrowband unlicensed industrial, scientific, and medical (ISM) frequency of 2.4 GHz and the UNII (Unlicensed National Information Infrastructure) 5 GHz to ensure no interference with cellphones, broadcast radio, TV antenna and two-way radios are encountered during transmission.

Also certified by WECA is the IEEE 802.11g.  802.11g specifies use at the 2.4 GHz ISM frequency with a bandwidth ranging up to 54 Mbps.  802.11g was certified by WECA in 2003.  Many home office and small office networks utilize the 802.11g.  802.11g is backwardly compatible with the two previous standards 802.11a and 802.11b.

A WLAN employs the 802.11 CSMA/CA method of access instead CSMA/CD used by wired networks; hence it is not truly an Ethernet standard as the names implies.  A point of semantic confusion erupts because the original WLAN was called Ethernet.  It was developed for the packet-switching wireless radio network, ALOHAnet, at the University of Hawaii-Manoa.

For wireless Ethernet CSMA/CD cannot be implemented because of price constraints, distance between access points, and computers transmitting.  Consequently wireless computer networking is based on the CSMA/CA protocol, which regulates when a node receives a packet from a client on the network.  When a client tries to interface an access point (AC) it listens to the AC to ensure no other node is transmitting.  If the channel is clear, the node transmits the packet.  Otherwise, it chooses a random “back-off number” which determines the amount of time the node waits before it will attempt to transmit the packet again.  If the channel is idle, the transmitting node with shortest back-off time gets priority to broadcast.  The Receiver Signal Strength Indicator (RSSI) constantly monitors the node transmission frequency.

There were three standard 802.11 implementation options, Infrared technology (IrDA), Direct Sequence Spread Spectrum (DSSS), and Frequency Hopping Spread Spectrum (FHSS) with a shared data rate of 2 Megabytes per second (Mbps) at 2.4-GHz (Coyle, 2001).

The complete history of wireless networks, Bluetooth, spread spectrum radio technology, the actress Hedy Lamarr, and LAN technology is found in the book A History of the Computer and Its Networks available  at    Lambert Academic Publishing, Amazon, Barnes & Noble, and More Books and other fine booksellers on the Internet worldwide.