Computer Systems History PDF
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Afe Babalola University
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This document provides a historical overview of computer systems, tracing their evolution from early counting methods to the sophisticated digital computers used today. It examines key milestones, and the different generations that have introduced significant advancements in efficiency and capabilities. The document also covers various computer types like digital, analog, and hybrid.
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# Chapter one: Historical Development of the Computer System ## 1.0 Introduction Computers evolve as a result of man's desire to count, compute, and store information concerning their activities. The computer as we know it today is very different from its predecessors. Traditionally computers have...
# Chapter one: Historical Development of the Computer System ## 1.0 Introduction Computers evolve as a result of man's desire to count, compute, and store information concerning their activities. The computer as we know it today is very different from its predecessors. Traditionally computers have been big and bulky but the 70s and 80s have witnessed a tremendous reduction in the size as a result of technological advancement. The history of computers has been the history of development in hardware technology. The events and inventions that have taken place in computing since the Stone Age have been developments in computing hardware. The history of the sophisticated modern computers is very recent, dating back to the early fifties. A chronological listing of events in the computing field is given in the next section. ## 1.1 Summary of the History of Computer **1500 BC:** * Greece - a box or sand tray used to hold pebbles for counting. * Orient - beads strung for counting - origin of the Abacus. * England - stonehenge: a giant astronomical computer. **1617:** * John Napier * Napier’s rods or Napier’s bones: used for mechanically multiplying, dividing and taking square roots. Published the *wonderful world of logarithms* in 1641. **1642:** * Blaise Pascal * Invented a device, Pascal’s Arithmetic machine, with 10 numbered wheels and series of gears similar to today's adding machine, used for counting, adding and subtracting by turning crank. **1673:** * Gottfried Leibnez * Modified Pascal’s ideas into a gear - driven machine that added, subtracted, multiplied, divided numbers and extracted roots. **1804:** * Joseph Marie Jacquard * Introduced the automatic loom (Jacquard’s Loom) that utilized metal plates with punched holes to control weaving pattern. This is the forerunner of modern day automation. **1812-1834:** * Babbage’s D'ference Engine * Charles Babbage in 1812 started work on the first of his two machines, the *difference engine* and the *analytical machine.* Babbage’s Difference Engine was intended to be used in the production of ballistic tables. It was never completed by Babbage but built by George Scheutz. All twenty-century computers incorporate parts of Babbage’s design **1834-1871**: * Babbage’s Analytical Engine * Intended to be the first general-purpose Computer but was never constructed in Babbage’s life time. **1875**: * Frank Stephen Baldwin * Granted first U.S. patent for a calculating machine that could perform the four fundamental arithmetic operations. **1885-1896**: * Herman Hollerith * Designed a code and devices to punch data into cards and to tabulate the collected data. This was used in automating the 1890 U.S. Census. **1933**: * Dr Vannevar Bush * Developed analog machine that was electro-mechanical (used gears but powered by electricity) as distinguished from today’s electronic machines. **1940-1942:** * Dr. John V. Atanasoff and Clifford Berry * They built the ABC (Atanasoff - Berry Computer), the first automatic electronic Computer. **1937-1944:** * Dr Howard Aiken * Built the Mark I or automatic sequence-controlled calculator that was used in Manhattan Project. Hand-operated switch-controlled programming, instructional data. The largest electromechanical calculator ever built. **1945:** * Dr John Mauchley and Dr. J. Bresper Eckert * Built ENIAC (Electrical Numerical Integrator and Calculator). Early all-electronic computing devices. It had 18,000 integrator and calculator. Had to be wired into a permanent panel that was then plugged into the machine. It had no significant storage capability. **1945-1950**: * Von Neuman’s Concept. Developed the concept of storing instructions and data in the memory of the Computer. He was credited with introducing the idea of coding instructions and data in binary **1946-1952**: * EDSAC, EDVAC and IAS * First computers capable of storing instructions and data in memory. EDSAC became the first stored-program computer built at Cambridge University in England in 1944. **1951-1954**: * UNIVAC 1 and IBM 701 * First Computers to be produced in quantity and commercially available. For example in 1950 UNIVAC 1, first assembly line produced 45 machines. **The Stored-Program Concept** The introduction of the stored-program computer marked the beginning of the computers known as the first generation of computers. Von Neumann was often accorded the title "father of the Stored-Program". His work contributed immensely to the invention of the computers that followed. ## 1.2 Computer Generations ### First Generation Computer (1951-1958) The first modern computer was based upon the designs of ENIAC and EDVAC'. UNIVAC I was the commercial electronic computer and was developed by Mauchly and Eckert. This generation of computer employed vacuum tube technology. They are characterised by: * Huge and bulky size; * Instructions were coded mostly in machine language; * Costly to buy; * Expensive to power, requires a lot of energy, generates a lot of heat and hence cooling is extensive; * Often unreliable; * Slow speed of operation; * Limited internal storage (implemented using magnetic drums); * Punched cards were used to enter data into the machines; *Examples: Mark 1, mark II, ENIAC and IBM 650* ### Second Generation Computer (1959-1964) These are characterised by the use of transistors in place of vacuum tubes or valves. This was the result of the 1948 revolution in the electronics industry that led to the invention of the transistor by William Shockley and his team. The transistor is capable of performing the same functions as vacuum tubes or valve (i.e to switch the signals on or off) in a computer. It is smaller in size and consumed only a tiny portion of the energy needed by a vacuum tube or valve. This led to computers becoming very much smaller and consuming less electricity. It employs magnetic cores for its internal storage. Uses English-like computer language for coding instructions e.g Fortran, Cobol. It uses external storage to supplement internal storage (e.g. magnetic disks). Computers emerging using this technology was more compact and cheaper to run then before. In fact they are smaller in size, cost less, generates less heat, requires less air conditioning and more reliable than the first generation. *Examples: Honeywell 400, 800, IBM 1401, 1460.* ### Third Generation Computers (1965-1970) In the early 1960s a new technology was developed, which makes it possible to pack several transistors and other components onto a single component known as silicon chip. The 1970s technology is known as Integrated Circuits (IC). With the advent of ICs the miniaturization of computer hardware becomes astounding. Computers became smaller, cheaper and were then able to be applied to increasingly complex problems, including those of helping design engineers to develop the next generation. This technology prompted the introduction of compatibility and development of minicomputers. In the early 1970s silicon-chip integrated circuit technology were used in the new models of computers developed and they were known as Third Generation Computers. It possesses increased input/output, processing and storage capabilities. It uses time-sharing and multiprogramming and problem and procedure-oriented programming languages. *Examples: IBM360, 370, NCR 315, 35 RMC.* ### Fourth Generation Computer (1971-1990) A latest technology microminiaturization has made it possible to get over a quarter of a million transistors inside a single chip. This technique is known as Very Large Scale Integration (VLSI). The highly powerful and very fast computers based on this technology have become konnas the Fourth Generation Computers. The internal memory employs metaloxide semi-conductor (MOS), laser or bubble memories which is faster and cheaper than core. It is characterised by the use of semi-conductor, laser, bubble memories; multiprogramming and distribuladicessing capabilities; virtual storage, significant application software and significant led to advances in input/output devices. This integration the emergence of the microprocessor, and invibly the microcomputer, (that is computers) and supercomputers (CRAY-1-80-MIPS, and CRAY-X-MP-1 Billion IPS). *Examples: Family of microcomputers, Computer II, Explore 185, Poly 88, Apple I, Compaq PC's* ### Fifth Generation (Period 1990 Till Date) The focus is on the production of computers that utilizes the combination of advances and theories in computer science, electronics and communications. These include the following: * Artificial intelligence and robotics * Expert Systems * Knowledge-based systems * Computer-assisted manufacturing * Automation of industrial processes * Neural networks ## 1.3 Classes of Computer A computer is any device capable of accepting data automatically, applying a sequence of processes to the data and supplying the results of these processes. It is different from other data processing equipment in the following ways: a. Its ability to store repetitive tasks accurately on large volumes of data with the minimum of manual intervention. b. Its ability to perform all of its instructions on large volumes of data processing given the computer a considerable advantage over and above conventional traditional methods of data processing. ## 1.5 Classification of Computers Computers are general-purpose machines with a remarkable ability to process information. The computer has many capabilities, and you determine its specific function by the program you use. This is what distinguishes a computer from a single-purpose machine like a typewriter or calculator. ### 1.4.1 Classification of Computer By Type There are three main categories of computers: * Digital * Analog * Hybrid. #### Digital Computers These are computers, which perform calculations by counting numbers precisely. In a digital computer, data is represented by discrete states ("on" and "off" or yes/no or counting/non counting) of the computer's electronic circuitry. Numbers, letters, and symbols are represented by a code based on the binary system, consisting of two digits, 1 and 0. A digital computer functions by taking discrete logical operations on them. The great peparate entities and perfor functions by making mechanical and logical or of data and to perform various stipulations. The great speed of digital computers is used for corious functions live in its speed. Thus this type of computers is used for commercial data processing. Sciemely high speed computers engaged in the processing of large numbers of mathematical calculations also use digital computers. #### Analog Computers In many cases, raw died varying overa lengchange its value over such a time. Analog computers Incept data as quantities varying over a length of time rather than a series of distinct items each with a unique value. They are used to measure physical quantities as continuous formech Voltage, Temperature, Pressure etc. Analog computers are used for scientific purpose, to measure the results of experiments, or to simulate processes, which can be described in terms of quantities varying according to known rules over a length of time. Analog computers are also used for process control in industrial operations, constantly measuring some varying quantities, for example voltage or gas pressure and controlling operations such as switching off circuits or opening valves when the quantity being measured reaches pre-determined values. They also found use in engineering, e.g. structural design, space - craft control and air - craft flight simulation. It is sophisticated and very expensive machine. #### Hybrid Computers This class of computers combines some of the properties of both digital and analog computers. A varying input accepted by the analog computer can be converted into a series of distinct values, which can be processed by the digital part of the machine. Digital processing is usually faster and more sophisticated than the processing which can be done by analog computers. Thus, hybrid computing gives the advantage of both types of devices. ### 1.4.2 Classification of Computer By Purpose #### Special purpose computers As the name suggests they are computers designed for special purposes only, to solve problems of restricted nature e.g. air traffic control or weapon guidance systems. For example a word processor is a special purpose computer used in the production of office documents, letters, contracts, e.t.c. #### General purpose computers These are computers designed to solve a wide variety of problems within the limitations imposed by their particular design capabilities. They can be adapted to perform particular task or solve problems by means of specially written programs. ### 1.4.3 Classification of Computer By Size The classification of computers by size is daily becoming more difficult as the reduction in the size of computer evolves almost every day as a result of giant stride in technology advancement and development. However, this notwithstanding, the traditional classification into three still stays with others joining as the days roll by. The following sizes are apparent: a. Super computer b. Mainframe c. Mini Computer d. Micro Computer In addition to the above classification, we have hand - held computers and pocket - size computers. #### Supercomputer The largest and fastest conventional maname computers in use today cat is still to permit the solution per second. However astounding these in scene such as such tasks whose pillion instructions perconventional mainframe computers, sed may appear, it is stilltoo slow forecasting, aircraft de by the computer of certain problems e predications. Such take whose solution could make groen simulation and flood or earthy and days to run on conventional machines or are too bigs suit or all. Super computers which are completely different machines or are too bigs to work ats allow the execution of multiple instructions paraliferent designs from conventional com or single instructions the insual alternative mechther than the serial processing of single perform up to 100million instructions per secomechanism. Current super computer space Defence Initiative (the Star Wars Program). #### Main frames Usually, it is very fast and ha giant machine that sing languages concurrently. It con (de both business and scientific processing. Pruire extensive environmental control (i.e. air conditioning, humidity control), special site preparatie false floors for cabling) and voltage stabilizers or standby generators. The main difference between a supercomputer and a mainframe is that a supercomputer channels all its power into executing a few programs as fast as possible, whereas a mainframe uses its power to execute many programs concurrently. In some ways, mainframes are more powerful than supercomputers because they support more simultaneous programs. But supercomputers can execute a single program faster than a mainframe. #### Mini-computers A mini-computer is usually smaller than a mainframe and environmental operating requirements are less demanding. The processing capability of minis usually has less memory and peripheral devices than a main frame. #### Micro-computers A micro - computer is a small computer that can be suitably accommodated on a tabletop. The latest ones can even sit neatly on the user's lap. It has also been extended to hand-held and pocket - size. It has all the basic component of a main - frame or mini. It requires no special site preparation, nor serious extensive environmental control since there is very little cabling and little heat generated. Any room that is comfortable for a human being will usually be suitable for micro. But for the fluctuation and irregular nature of NEPA power supply one would neither need a stabilizer or a standby generator. One additional attribute of micros, particularly the new designs, is that some of them can be battery-operated. | Types | Mini computer | Micro computer | Mainframe computer | | :----- | :------------------------------------------------------------------------------------- | :-------------------------------------------------------------------------------- | :----------------------------------------------------------------------- | | Cost | Less expensive | Least expensive | Very expensive | | Speed | Faster than micro computer | Not as fast as other computers. | The fastest, can execute up to 100MIPS | | Memory | In the range 128kb to 256 | High capacity in the range of MB to GB | 4kbytes | | Capacity | Mid-sized | Portable/smallest | The biggest | | Size | For small businesses | Individual use | Government and large scale businesses | | Uses | For small businesses | Engineering applications (CAD/CAM), desktop publishing, software development, and other types of applications that require a moderate amount of computing power and relatively high-quality graphics capabilities. | | ## Workstation Workstations generally come with a large, high-resolution graphics screen, at large amount of RAM, built-in network support, and a graphical user interface. Most workstations also have a mass storage device such as a disk drive, but a special type of workstation, called a diskless workstation, comes without a disk drive. The most common operating systems for workstations are UNIX and Windows NT. Like personal computers, most workstations are single-user computers. However, workstations are typically linked together to form a local-area network, although they can also be used as stand-alone systems. *Note: In networking, workstation refers to any computer connected to a local-area network. It could be a workstation or a personal computer.* ## Personal Computer (PC) It can be defined as a small, relatively inexpensive computer designed for an individual user. All are based on the microprocessor technology that enables manufacturers to put an entire CPU on one chip. Businesses use personal computers for word processing, accounting, desktop publishing, and for running spreadsheet and database management applications. At home, the most popular use for personal computers is for playing games and recently for surfing the internet. Today, the world of personal computers is basically divided between Apple Macintoshes and PCs. The principal characteristics of personal computers are that they are single-user systems and are based on microprocessors. However, although personal computers are designed as single user systems, it is common to link them together to form a network. In terms of power, there i great variety. At the high end, the distinction between personal computers and workstations ha faded. High-end models of the Macintosh and PC offer the same computing power and graphic capability as low-end workstations by Sun Microsystems, Hewlett-Packard, and DEC. ## Uses of PC i. It is used to produce documents like memos, reports, letters and briefs ii. It is used to calculate budgets and accounting tasks iii. It can analyze numeric function. iv. It can be used for electronic mails v. It can help making schedule and plan projects ## Advantages of PC i. It has faster speed for processing data. ii. It is versatile, it can be used in any establishment. iii. It can deal with several data at a time. iv. It is capable of storing several data. v. Operation is less fatigue. vi. Network is possible, able to link two or more computer together. ## Disadvantages of PC i. It is costly to maintain ii. It is very fragile and complex to handle iii. It requires special skill to operate iv. It can lead to unemployment when used mostly in less developed countries v. Some cannot function properly without the aid of cooling system for example air condition or fan in some locations. ## Case is metal computers can be generally classified by size and chassis / case. The chassis or computer system requires at least as the structural support for electronic components. Every computer system requires at least as the structural support for electronic components. The chassis also contains slots for expansion boards. If you want to insert more boards than there are slots, you will need an expansion chassis, which provides additional slots. There are two basic flavours of chassis designs-desktop models which provides additional slots. There are many variations on these two basic types. After this era then come the era of portable computers that are computers small enough to carry. Portable computers include notebook and subnotebook computers, hand-held computers, palmtops, and PDAs. ## Types of Personal Computers ### Tower model The term refers to a computer in which the power supply, motherboard, and mass storage devices are stacked on top of each other in a cabinet. This is in contrast to desktop models, in which these components are housed in a more compact box. The main advantage of tower models is that there are fewer space constraints, which makes installation of additional storage devices easier. ### Desktop model A computer designed to fit comfortably on top of a desk, typically with the monitor sitting on top of the computer. Desktop model computers are broad and low, whereas tower model computers are narrow and tall. Because of their shape, desktop model computers are generally limited to three internal mass storage devices. Desktop models designed to be very small are sometimes referred to as slimline models ### Notebook computer Notebook computer is an extremely lightweight personal computer. Notebook computers typically weigh less than 6 pounds and are small enough to fit easily in a briefcase. Aside from size, the principal difference between a notebook computer and a personal computer is the display screen. Notebook computers use a variety of techniques, known as flat-panel technologies, to produce a lightweight and non-bulky display screen. The quality of notebook display screens varies considerably. In terms of computing power, modern notebook computers are nearly equivalent to personal computers. They have the same CPUs, memory capacity, and disk drives. However, all this power in a small package is expensive. Notebook computers cost about twice as much as equivalent regular-sized computers. Notebook computers come with battery packs that enable you to run them without plugging them in. However, the batteries need to be recharged every few hours. ### Laptop computer This is a small, lightweight, portable computer — small enough that it can sit on your lap. Nowadays, laptop computers are more frequently called notebook computers. It comes with battery packs that enable you to run them without plugging them in. However, the batteries need to be recharged every few hours. ### Subnotebook computer A portable computer that is slightly lighter and smaller than a full-sized notebook computer. Typically, subnotebook computers have a smaller keyboard and screen, but are otherwise equivalent to notebook computers. ### Personal Digital Assistant (PDA) This is a handheld device that combines computing, telephone/fax, and networking features. A typical PDA can function as a cellular phone, fax sender, and personal organizer. The most popular PDA are those that are specifically designed to provide PIM (personal information manager) functions, such as a calendar and address book. Unlike portable computers, most PDAs are pen-based, using a stylus rather than a keyboard for input. This means that they also incorporate handwriting recognition features. Some PDAs can also react to voice input by using voice recognition technologies. PDAs are also called palmtops, hand-held computers (Smartphones, MP3 players) and pocket computers. ### Smartphones This is used to make and receive phone calls. It is also used to connect to the Internet, to check email, and to maintain an electronic appointment book. ## Careers in Computer Science There are plethora of promising careers in the field of computing, some are: a) Software Engineer: Software engineers apply engineering principles and knowledge of programming languages to build software solutions for end users. b) Web developer: A web developer or programmer is someone who takes a web design - which has been created by either a client or a design team - and turns it into a website. c) Computer programmer: A computer programmer is a skilled professional who codes, tests, debugs, and maintains the comprehensive instructions known as computer programs that devices should follow to execute their functions. d) Web master: A webmaster is someone who creates and manages the content and organization of a website, manages the computer server and technical programming aspects of a website, or does both. e) System Analysts: A systems analyst is an IT professional who works on a high level in an organization to ensure that systems, infrastructures and computer systems are functioning as effectively and efficiently as possible. System analysts carry the responsibilities of researching problems, finding solutions, recommending courses of actions and coordinating with stakeholders in order to meet specified requirements. They study the current system, procedures and business processes of a company and creat action plans based on the requirements set. f) Database Administrator: A Database Administrator manages and maintains software databases, such as client records, statistical surveys, census information, user accounts and library catalogs. They provide secure access to databases and manage backup solutions to prevent data loss in the event of a system failure. They may also help develop the stages of a database system. g) Software Developer: Software developers use their programming skills to create new software. They design and write the code used to build everything from operating systems to mobile apps to video games. h) Cloud Engineer: A cloud engineer is an IT professional that builds and maintains cloud infrastructure. i) IT project Manager: An IT project manager is a professional charged with overseeing the process of planning, technology and delegating responsibilities around an organization’s information technology (IT) pursuits and goals. ## Computer Ethic Ethics are a structure of standards and practices that influence how people lead their lives. It is not strictly implemented to follow these ethics, but it is basically for the benefit of everyone that society’s views about what is right and what is wrong. Ethics illustrate society’s views about what is right and what is wrong. Computer ethics: Computer ethics are a set of moral rules and standards that govern the use of computers. It is society’s views about the use of computers, both hardware and software. Privacy concerns, intellectual property rights and effects on society are some of the common issues of computer ethics. The Ten Commandments of computer ethics have been defined by the Computer Ethics Institute. 1. Thou shalt not use a computer to harm other people: If it is unethical to harm people by making a bomb, for example, it is equally bad to write a program that handles the timing of the bomb. Or, to put it more simply, if it is bad to steal and destroy other people’s books and notebooks, it is equally bad to access and destroy their files. 2. Thou shalt not interfere with other people’s computer work: Computer viruses are small programs that disrupt other people’s computer work by destroying their files, taking huge amounts of computer time or memory, or by simply displaying annoying messages. Generating and consciously spreading computer viruses is unethical. 3. Thou shalt not snoop around in other people's files: Reading other people’s e-mail messages is as bad as opening and reading their letters: This is invading their privacy. Obtaining other people’s non-public files should be judged the same way as breaking into their rooms and stealing their documents. Text documents on the Internet may be protected by encryption. 4. Thou shalt not use a computer to steal: Using a computer to break into the accounts of a company or a bank and transferring money should be judged the same way as robbery. It is illegal and there are strict laws against it. 5. Thou shalt not use a computer to bear false witness: The Internet can spread untruth as fast as it can spread truth. Putting out false "information" to the world is bad. For instance, spreading false rumors about a person or false propaganda about historical events is wrong. 6. Thou shalt not use or copy software for which you have not paid: Software is an intellectual product. In that way, ingetobtaining illegal copies of copyrighted software is as bad as photocopying a copyrighted book. There are laws agabyrighted soformation about the copyright owner can be embedded by a process called watermarking into pictures in the digital format. 7. Thou shalt not use other people's computer resources without authorization: Multiuser systems use user id's and passwords to enforce their memory and time limitations, and to safeguard information. You should not try to bypass this authorization system. Hacking a system to break and bypass the authorization is unethical. 8. Thou shalt not appropriate other people’s intellectual output: For example, the programs you write for the projects assigned in this course are your own intellectual output. Copying somebody else’s program without proper authorization is software piracy and is unethical. Intellectual property is a form of ownership, and may be protected by copyright laws. 9. Thou shalt think about the social consequences of the program you write: You have to think about computer issues in a more general social framework: Can the program you write be used in a way that is harmful to society? For example, if you are working for an animation house, and are producing animated films for children, you are responsible for their contents. Do the animations include scenes that can be harmful to children? In the United States, the Communications Decency Act: was an attempt by lawmakers to ban certain types of content from Internet websites to protect young children from harmful material. That law was struck down because it violated the free speech principles in that country’s constitution. The discussion, of course, is going on. 10. Thou shalt use a computer in ways that show consideration and respect: Just like public buses or banks, people using computer communications systems may find themselves in situations where there is some form of queuing and you have to wait for your turn and generally be nice to other people in the environment. The fact that you cannot see the people you are interacting with does not mean that you can be rude to them. ## Computer Laboratory Rules and Regulations There are regulations guiding the use of computer laboratory, the list here is not exhaustive. i. Students are prohibited to enter the lab unless authorised. ii. Food is generally not allowed in the computer lab. iii. Drinks are not allowed in the computer lab. iv. Be responsible when using equipment, software and facilities in the lab. v. Behaviours and activities that disturb other users or disrupt the operations of the lab are not allowed. vi. Switch offal power supplies before leaving the lab. vii. The lab should be kept clean and tidy at all times. viii. Chairs and stools are not to be moved from their original position.