LESSON 1: INTRODUCTION TO COMPUTING (1)
WHAT ARE COMPUTERS?
Computers have been around since the Chinese Abacus. They are here to stay. There is a certain feel and flow to the logic that directs their activities.
Electronically, all computers work about the same. Computers vary widely in size and use. However all computers are similar in what the hardware does. So-called microcomputers (like your desktop Personal Computer (PC)) are designed for personal use, relatively low price, and modest data processing tasks.
Minicomputers are moderate sized (a small refrigerator size) and perform more complex tasks with larger amounts of data. Minicomputers might be used in a small engineering office or a local bank branch to send transaction data to a head office computer.
Mainframe computers are large, expensive and process billions of characters of data rapidly and fill entire rooms.
Finally, supercomputers are built to minimize distance between circuit boards and operate at very high speed for complex uses such as designing airplanes, animating complex movie sequences graphically or solving complex engineering formulas having billions of steps mathematically. Supercomputers are built for raw speed. SuperComputers are the main servers in the Internet System.
Some terms apply to all computers. INPUT is how data gets into a computer. The keyboard and mouse are familiar INPUT devices. OUTPUT references how data is provided from the computer. A Monitor or printer are good examples of OUTPUT devices.
PRIMARY STORAGE or MEMORY is the computer’s immediate data storage area - usually this is in small integrated circuit chips which hold data ONLY while power is supplied. This PRIMARY STORAGE area is thus temporary. More permanent SECONDARY STORAGE is used when computer power is off or when data overflows primary storage. This is usually floppy or hard disk drives but can include paper tapes, punch cards, or even non-volatile magnetic bubble memories.
A computer system includes computer hardware, software and people. A computer is a device capable of solving problems or manipulating data by accepting data, performing prescribed operations on the data, and displaying the results in the desired form. The computer is a useful tool for data (or Information) Input, storage, processing and output.
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HISTORY -HOW, WHERE, WHEN DID IT ALL START?
The first computational device was the abacus. This has been in continuous use for thousands of years. During the 1600's the Pascal adding machine was developed. This was a mechanical device that laid the groundwork for today's odometers and gas meters. The 1800's saw many machines developed that were controlled by punch cards - weaving looms. The theoretical basis for electronic circuitry was developed in the mid 1800's.
In 1947, just after the first electronic computer was built, the transistor was invented, enabling the birth of vastly less expensive, more reliable computers. Even with transistors, computers were still too complex and costly for widespread use until the advent of the integrated circuit (IC) in 1961 made truly inexpensive computers possible at last.
From this point forth there were many firsts as computers became less mechanical, smaller, faster and cheaper. In 1971, IC technology progressed to a point where a complete central processing unit - the heart of the computer - could be integrated on a single piece off silicon, giving birth to the microprocessor. The microprocessor led to the personal computer. The Personal Computer is distinguished by its size, cost, and applications for small business and the home. The first one appeared in January 1975 and was the Altair 8800 kit. Only hobbyists bought these. Then the Radio Shack TRS 80 and Apple computers hit the market as the first pre-assembled microcomputers.
Market growth remained sluggish until two business students - Dan Bricklin and Dan Fylstra - developed a program to run on Apple computers to handle the tedious recalculations in their school assignments. This program was called VisiCalc and is the forerunner to the spreadsheet program Lotus 123.
With VisiCalc as a useful tool, Apple sales took off. Apple became the standard because all programs were written for Apple. Today in the US, Apple still dominates the school market.
In 1981 IBM introduced its PC. IBM’s legacy still dominates the industry today. The PC was unable to run Apple software. Unlike Apple or other IBM products, the IBM PC had an open architecture. This means the technical details of how it operated were published with the product's introduction. This permitted hundreds of companies to write software (programs) for the IBM PC and a variety of hardware accessories. Adding IBM's sterling reputation, the open architecture did enable rapid market penetration. The microcomputer was no longer a toy, it was a business tool.
The open architecture also allowed for the generation of a host of lower cost compatible computers. IBM had traded quick initial market entry for eventual erosion of market share. In both instances, the consumers' benefit. In the early 90s Computers were applied variously in the fields of Science, Technology and Space exploration.
Initially, PCs revolutionized how businesses are run, but today, computers deepest impact are felt in the merging of Communications and Information. The emergence of the World Wide Web and the explosion of Internet usage is having far-reaching effects on all aspects of society.
Success and progress in all spheres of life, is now driven by Information and Technology. The future is bright, but it is up to every user of the technology to see that it is used to positive effect.
Lets go back to basics:
WHY DO WE USE COMPUTERS?
This similar to asking why do we use cars? But too many people and organizations purchase and use Computers for the wrong reasons. Computers are practical tools to be used in helping you get results.
Computers are needed where:
1. There is a need for a more accurate and cost effective knowledge to assist decision making. Success and progress is now being determined by your access to information and how you use that information to get results.
2. It is impossible to get results due to either time constraint or sheer magnitude of work involved.
3. It will reduce the mental and physical effort in tackling certain tasks.
4.There is intense competition and there is a need for cost efficiency through the elimination and reduction of inefficient practices.
5.There is a need to assist in enhancing Customer service.
6.There is a need for correct forecasting of market trends to ensure business survival.
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COMPUTER APPLICATIONS
Due to technological developments, Computers are now used in virtually all spheres of life. Here are a few of the application areas:
SCIENCE & TECHNOLOGY (S&T)
Computers are used in S&T to promote advances that could be useful to mankind, i.e. discovering better and more efficient ways of doing things. They are especially useful for humanly intractable calculations and simulation experiments. This is especially critical in situations where it would be too risky or expensive to directly carry out the required operation. For example, in Space exploration, underwater exploration, testing of new drugs, etc. Computers enable S&T professionals can carry out their practical procedures using faster, more accurate and safer methods.
EDUCATION
Computers are useful for promoting learning experiences. From the toddler to the full grown adult, educational Computer tools are available. Computers are useful for learning about Computers and learning about other subjects, i.e. using Computer Assisted Learning software. Learning is usually interactive and can be reinforced over and over.
For children, the advent of Multimedia, has made learning fun. They often don’t realize it when they’re playing that they are also learning.
BANKING & FINANCE
Computers are very useful for handling financial transactions, most especially the storage and processing of huge amounts of information kept by financial institutions. Computers enhances Customer service, through the provision of uptodate and timely information for their Customers.
Computers additionally assist with the monitoring of operational costs, to ensure cost effectiveness and profitability of operations.
In some financial institutions, Computers are used to identify trends and provide timely information for present and future management decision making.
RECREATION
On your average PC, you can play a variety of games. You know what they say about Jack. All work and no play, makes Jack a ......
With the games, you could be the sole player, play against the Computer or you and a friend could play against each other.
SECURITY
Computers are useful for storing information about crimes, criminals and suspects. This can be very useful in Crime detection and prevention. Such systems can be interfaced with photograph capturing and fingerprint systems. They can also be linked to mobile radio communication systems over a wide area to enable in the fast and efficient sharing of information on Criminal activities. Such systems would possess enquiry facility for historical and analytic purposes.
There so many other areas where the impact of the Computer is being felt such as Medicine, Law, Sports, Entertainment, Media, Building, Construction, etc.
In every situation the Computer performs different functions relating to Information storage, input, output and processing. It is no wonder that productive Computer based activity is referred to popularly as Information Technology. What are Computers? A computer system includes computer hardware, software and people.
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HARDWARE versus SOFTWARE
What is the difference between computer hardware and software?
HARDWARE
In simplest terms, hardware is the physical parts associated with a computer - the electronic, magnetic, and mechanical devices (monitor, keyboard, printer, micro chip boards, floppy drives, cables and physical pieces of a system. These INPUT/OUTPUT DEVICES allow the operator to interact with the computer.
SOFTWARE
Sets of programs (stored sets of instructions) that govern the operation of the computer system and make the hardware perform. These programs (instructions) tell the hardware how to do a particular task such as word
processing, games, database management, etc. Although these instructions are usually stored inside a piece of hardware (e.g., software instructions stored inside a circuit chip or floppy drive) but they are nevertheless software.
In a way, Software refers to the instructions that enable an otherwise dead machine to understand your inputs and transform them into desired outputs. Computer hardware by itself lacks personality; this is determined by the software. Word processing software turns the computer into a word processor, accounting software turns the computer into an accounting tool, etc.
Lets discuss a bit about Software before we go back to Hardware. There are two major types of software: Operating system software and Applications software.
Operating system software (like DOS, UNIX or Windows 95) performs very elemental housekeeping instructions (e.g., where is the monitor, how can I keep track of what data is on which track or sector of a floppy drive, whether more than user can work on the system at the same time e.g. UNIX.)
The operating system that all IBM and compatible PC's use is called DOS (sounds like floss). DOS is software that allows the terminal, printer, computer and mass storage systems (floppy disks) to work together as a unit, and controls the execution of programs. It also allows you to do housekeeping chores regarding managing disks and files.
Applications programs perform tasks on a higher level (e.g., word processing Spreadsheet, Games, Database Management, Accounting, Payroll programs are applications.) Generally an application software package uses the lower level operating system (DOS) to do routine tasks (e.g., your word processing application uses the lower level DOS operating system frequently to write and store data on a disk.
And what is a Database?
A database is a collection of information that is organized for ease of reference. For example, your address book is a database, just as an inventory of goods, a list of all churches in your state or your staff list.
Before Electronic processing of information, databases had to be maintained on paper stored in file folders that were kept in filing cabinets. With Electronic DataBase Management Systems (DBMS), information stored electronically and be recalled instantly and accurately.
And now lets go back to Hardware:
HARDWARE
CENTRAL PROCESSOR UNIT (CPU)
Heart of the PC - it contains the microprocessor. The CPU is a set of miniaturized circuits that does all the "thinking". It controls the interpretation (arithmetic-logic unit) and execution (control unit) of instructions. The CPU in conjunction with Random Access Memory (RAM) comprise the computer's "brain". The CPU does the "thinking / calculating" while RAM contains the instructions or "memories".
It is the CPU that largely determines the operating speed of the computer. The type of processor on your PC will determine the nature of functions it can carry out and the speed at which instructions are carried out. For example, while a 286 processor would struggle to load Windows 3.1, a 486 processor loads it easily. Additionally, a 286 processor is obviously incapable of running most new software. Pentium processor are now as fast as 200 MHz.
Now the good stuff. Lets read on and want delve into great complexity. Now it’s time to delve deeper into the heart of the computer. The central processing unit or CPU is the "brains" of every computer. On the PC, the CPU is simply a tiny integrated circuit. It is the control center and contains two circuit elements to perform tasks plus several special locations or memory areas called registers which hold instructions.
Registers, located within the CPU chip are temporary storage locations which hold instructions. Secondly, the arithmetic logic unit or ALU is the location within the CPU where basic math and logic operations take place (such as addition and subtraction.) Finally, the control unit is a portion of the CPU which directs all elements of the computer. It does not add or subtract like the ALU, it only directs the activity.
Despite this seeming complexity, a basic fact remains: all digital computers can only add and subtract two numbers: zero and one! Let’s back up a bit. For purposes of digital computer electronics, internally a computer can only respond to two things: on and off - just like a light switch. These electronic states of being might actually be a positive and negative voltage or a high and low voltage stored in a series of transistors etched in silicon on a chip, but to the computer the logic is on or off. Two conditions, that is all.
Back in the human world we can represent these as one and zero (1 and 0). A special branch of mathematics deals with calculations of numbers represented by 1 and 0 which is called binary arithmetic.
We rarely think of 0 as a number since we consider it NOTHING.) To computers ZERO is always a number!!!
To a computer these binary numbers march together in a long string, one after another. Remember, the CPU has only two numbers to work with: 1 and 0
These eccentricities appear odd, but to the computer they are shortcuts which simplify calculations and keep things to 1’s and 0’s. It is this simple system of on and off (like light switches) which make computers and their odd binary system so FAST!
WHAT IS THE DIFFERENCE BETWEEN A BIT AND A BYTE?
The IBM PC and its clones generally use 8 bits (electrical pulses) to make up a byte (computer word.) A ninth "odd bit" is used for error checking (parity testing) to make sure the other eight bits are not accidentally erased or lost during storage or use by the computer.
Bits are like alphabet characters and bytes are like the words made up from alphabet characters. Bits and Bytes are used to measure information by the computer.
BIT
Smallest unit of information recognized by the computer. BIT is short for Binary Digit. A Binary Digit can be either a 0 or a 1. Several bits make up a byte.
BYTE
A group of 8 BITS. This grouping of adjacent binary digits (bits) is operated on by the computer as a unit. Computers use 1 BYTE to represent 1 character such as a letter of the alphabet, a number, a punctuation mark, a space, etc. A BYTE is also a unit of measure since it represents 1 character.
For example, when the letter "A" is pressed, the keyboard actually sends the following to RAM: 10000001 - a set of 8 bits.
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TUTORIAL QUESTIONS (WHAT ARE COMPUTERS? (1)
1. State 5 areas where computers are used and describe how they are used in these areas
2. What do you understand by Input and Output? How do they go hand in hand?
3. State 5 specific situations where it is necessary to use computers, and state why.
The phenomenal Development in the Applications of Computers in all facets of life has been due more to Hardware Advancements than Software Developments. COMMENT.
4. What do you understand by binary arithmetic?
5. Of what value are bits and bytes in the computer world? Give 3 practical examples.
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