LECTURE 1 - Fundamentals of ComputerComputer Defined An electronic device designated to manipulate useful information An electronic device, operating under the control of instructions stored in its own memory unit, that can accept data, process data arithmetically and logically, produce output from the processing, and store the results for future useGenerations of ComputersFirst Generation (1952 – 1958) Awesome in size Controlled by thousands of vacuum tubes or valves Consumes great amount of power that often resulted in overheating and failure The operators cannot recognize whether the breakdown was in the programming or in the machine Information were stored on punched cards as well as on magnetic tapesThe language level used was machine language which used numbersSecond Generation Computer (1959-1964) Development of assembly or symbolic language Development of high level language such as Fortran (1954) and Cobol (1959) allowed programmers to give more attention to solving problems Uses transistors (used less power and did not get so hot quickly)Third Generation Computers (1965-1970) Uses Integrated Circuit, commonly known as the silicon chip, which revolutionized electronic If later progressed to Large Scale Integration (LSI), where few chips could replace several hundred thousands of transistorsFourth Generation Computer (1971-present) Uses microprocessor, a chip which contains all the main electronic components of a compound
If made possible to build computers to enormous logical capacity and reliability, more cheaply and in a very small space Very Large Space Integration (VLSI) was achieved Microprocessors led to the development of microcomputersHistory of Computers 500 BC – the Chinese invented the Abacus, considered to be the first computer device, which can perform simple addition and subtraction operations. 1617 – John Napier, a Scottish mathematician, invented the NAPIER’S Bone – a table of logarithms made of ivory 1630 – William Oughtred, an English mathematician, invented the SLIDE RULE, a device made of wood with movable scales arrange to slide opposite each other 1642 – Blaise Pascal, a French mathematician, invented the PASCALINE – the first mechanical calculating machine 1694 – Gottfried Wilhelm von Leibniz, a German mathematician. His machine, the LEIBNIZ MACHINE, considered of a stepped cylinder that could perform the four fundamental operations and square root. 1801 – Joseph Marie Jacquard, a French weaver and designer, devised the JACQUARD LOOM which used hole-punched cards. This machine wove variety of patterns 1822 – Charles Babbage, an English mathematician and is known to be the “Father of Modern Computer”, invented the DIFFERENCE MACHINE. This machine was capable of computing mathematical tables and solves polynomial equation 1833 – Charles Babbage also invented the ANALYTICAL MACHINE designed to perform complex mathematical calculations. This was considered to be the first general purpose computer 1887 – Herman Hollerith, an American statistician and founder of Tabulating Machine Company (now called International Business Machine or IBM) invented the CENSUS MACHINE 1892 – William Seward Burrough, an American inventor, designed a key-driven machine that produced a hardcopy. This was called ADDING/CALCULATING MACHINE. 1944 – Burrough invented the MARK 1 or ASCC (Automatic Sequence Controlled Calculator) machine that contains more than 15,000 vacuum tubes some of which are 3 feet tall
1945 – John Presper Eckert, Jr. and William Mauchly from the University of Pennsylvania invented the ENIAC (Electronic Numerical Integrator and Computer) that had the capacity of 5,000 computations per second 1948 – The IBM developed a more different design than the ENIAC – the SSEC (Selective Sequence Electronic Calculator) 1950 – Eckert Jr. and Mauchly again developed a machine The UNIVAC 1 (Universal Automatic Computer)which could perform 10,000 computations per second. The IBM again developed a machine that could perform 100,000 computations per second and can store data internally. The machine was the IBM 704 1963 – Digital Equipment Corp. introduced the PDP-8, regarded as the first successful minicomputer 1977 – Two young computer enthusiasts, Steven Jobs and Steve Wozniak, collaborated to create and build their Apple II computer on a makeshift production line in Job’s garage 1981 – IBM introduced its hat into the personal computer ring with the announcement of the IBM PC. It sold 35,000 on its first year of release.Applications of Computers In the scientific and engineering fields, it provides inexpensive and accurate computation for better designs of devices or machines and more discoveries made in less time In the business world, it is used in the preparation of payrolls, in recording accounts receivables, in keeping tracks or inventions In banks, insurance companies, hospitals, and government offices, records are computerized Large firms and offices such as PLDT, Meralco and MWSS prepare invoices with computers Provide instantaneous and accurate data for airlines, hotels and check-out counters in the department stores Now becoming an everyday tool not only in the offices but in homes as wellCharacteristics of Computer It is a machine – can only do things for it was designed It is electronic – runs on electrical energy through its electronic components It is automatic – runs continuously once started It can manipulate data – following specified instructions, it can perform arithmetic functions and can compare data
It has memory – the ability to read instructions and store these It has logic functions – can produce results after instructions were fed into itComputer Limitations Dependence on prepared instructions Inability to derive meanings from objects Inability to generate information It cannot correct wrong instructionsWhy Computers Sometimes Fail GIGO (Garbage In Garbage Out). Computer error may result from erroneously entered input. Programs contain errors or “bugs” that do not become evident until a specific set of circumstances arises. “Users” do not understand each other’s needs or have not communicated successfully. Improper controls can lead to sabotage the company and invasion of privacy Lack of standard results in problems when an organization obtains new equipment, hires new computer professionals, and attempts to provide some consistent set of procedures to be adopted by its computing staff Manufacturer fails to supply needed spare parts, trained technicians, or that particular machine model is no longer in productionClassification of ComputersClassification by purpose General-Purpose Computers - A computer that has the ability to store different programs of instructions and thus to perform a variety of operations. Special-Purpose Computers - A computer designed to perform one specific taskClassification by Type of Data Handled • Digital Computers – a machine that specialize in counting of items that are distinct from one another, e.g. Text, integers, morse code • Analog Computer – machine that deals with quantities that are continuous variable. This means that no individual elements can be identified from any other element, e.g. Light, voice, and video
• Hybrid Computers – machine that combines the measuring capabilities of the analog computer and the logical and control capabilities of the digital computerClassification of Computers Acc. to Capacity Microcomputers –capable of handling small, single-business applications such as sales analysis, inventory, billing and payroll. Minicomputers – They can do operation like airline reservations Medium-size Computers – They can serve the needs of a university. Large Computers –They can be used in government agencies and in the development of space technology Supercomputers – machines that have capabilities far beyond even the traditional large- scale systems. They are essential for applications ranging from nuclear weapon development to accurate weather forecasting.