Introduction to Computers

What is a computer?

• Computers perform tasks or calculations according to instructions or programs.
• Electronic computers were first introduced in the 1940s, and were huge machines that required teams to operate.
• Current computers are thousands of times faster than early machines and are small enough to fit in your pocket.
• Computers function through an interaction of hardware and software.
• Hardware includes the physical parts that can be seen and touched.
• The CPU (central processing unit), also known as the microprocessor, is the most important piece of hardware and translates instructions and performs calculations.
• Hardware items, such as monitors, keyboards, mice, and printers, are often called hardware devices.
• Input devices like mice and keyboards are used to process input.
• Color monitors and printers are examples of output devices to display output.
• Computers are indispensable, and millions of people use them worldwide.
• Word processing software automatically corrects spelling and grammar errors and allows the use of copy/paste features, making it easier to create and print documents.
• The internet connects almost all the computers in the world and offers fast/convenient access to information, enabling communication and video conferencing.
• Digital video and audio composition/editing have been simplified by computers, allowing creation of short or full-length films and 3D models.
• Desktop publishing allows users to create page layouts for entire books.
• Computers are used in medicine for diagnosis, learning cures, MRI, surgery, and storing patient data.
• Computers can perform over a million mathematical calculations per second.
• Computer software is used for all financial transactions to provide security, speed, and convenience.
• Online booking for travel is available for tickets and hotel reservations.
• Software is widely used in telecommunications and is embedded in mobile phones.
• Software is embedded in almost every weapon for controlling flight, targeting missiles, and controlling access to atomic bombs.
• E-learning software is used as an alternative to books.
• Online gambling is available as opposed to going to a casino.
• Online exams are available with instant results.
• Shops and supermarkets use software to calculate bills.
• Taxes can be calculated and paid online using computers, which can be used for accounting and predicting future business trends with artificial intelligence software.
• Software is used in major stock markets for online trading.
• Fully automated factories run on software.
• Certificates allow for easy generation, creation, and change of layouts.
• ATM software authenticates the user and dispenses cash.
• Matrimonial sites allow users to search for suitable partners.
• Websites offer access to the latest or old news.
• Alumni websites allow users to reconnect with classmates.
• Robots are controlled by software.
• Washing machines and microwave ovens operate using software.
• Software is used for planning/scheduling by storing contact information and scheduling appointments/deadlines.
• Greeting cards can be sent and received for different occasions.
• Software aids in making umpiring decisions and simulation software helps sportspeople practice their skills; also used to identify flaws in technique.
• Pilots train on software that simulates flying.
• Supercomputers analyze and predict weather.

Different Types of Computers

• Computers are categorized as analog, digital, and hybrid based on their operational principle.
• Analog computers are almost extinct, because they perform several mathematical operations simultaneously, using continuous variables and mechanical/electrical energy.
• Hybrid computers combine both digital and analog computers and use digital segments to perform process control by converting analog signals to digital ones.
• An example of hybrid computers include WWI bomber bombsites, which used a series of continuous gears to factor airplane speed/altitude, and computers used to measure a patient’s heartbeat in hospitals.
• Hybrid machines are generally used in scientific applications or industrial process control.
• Mainframe computers are used in large organizations for highly critical applications such as bulk data processing and ERP.
• Most mainframes can host multiple operating systems, operate as virtual machines and replace small servers.
• Microcomputers possess a microprocessor and CPU, occupying less space than mainframes.
• When supplemented with a keyboard and mouse, microcomputers are known as personal computers.
• RAM, a monitor, keyboard, and other input-output devices are packaged in a microcomputer.
• Microcomputers are suitable for single-user tasks on desks or tables.
• Personal computers come in forms such as desktops, laptops, and personal digital assistants.
• Desktops are intended for use in a single location, and spare parts are readily available at lower costs.
• Desktops are popular for daily use in workplaces and households.
• Laptops are similar to desktops but miniaturized and optimized for mobile use.
• Laptops can run on a single battery or external adapter, and have built-in keyboards, touchpads, and LCDs.
• Personal Digital Assistants (PDAs), also known as palmtops, are handheld computers with touch screens and memory cards.
• PDAs can be used as portable audio players, web browsers, and smart phones, with Bluetooth or Wi-Fi communication.
• Minicomputers lie between mainframes and microcomputers in terms of size and processing capacity and are called mid-range systems or workstations.
• The term "minicomputer" became popular in the 1960s for smaller third-generation computers.
• 12-bit PDP-8 minicomputer, from Digital Equipment Corporation, was the first successful minicomputer.
• Supercomputers are used for calculation-intensive tasks in quantum physics, mechanics, weather forecasting, and molecular theory.
• Parallel processing and memory hierarchy give supercomputers large transaction processing powers.
• Wearable computers can be worn on the body and are used in behavior modeling and human health studies.
• Military/health professionals use wearable computers in their routines for tracking human actions when users' hands and sensory organs are engaged.
• Wearable computers are consistently in operation and constantly interact with the user.

Different Operating Systems

• An operating system (OS) is software that consists of programs and data, which runs on computers, manages computer hardware resources, and provides services for application software execution.
• The OS is the most important type of system software because, without it, a user cannot run an application program unless it is self-booting.
• An OS has a brand name and brands has different versions.
• Common OS brands include Windows and Mac.
• Other operating systems include UNIX/Linux, Google Chrome OS and Novel.
• Before Windows, Microsoft used DOS, which was a non-GUI OS.
• Windows versions include: Windows CE, Windows 3.x, Windows 95, Windows 98, Windows 98 SE, Windows ME, Windows NT, Windows 2000, Windows XP, Windows Vista and Windows 7.
• Mac versions are: Apple DOS 3.1, Apple System 1-7, Mac OS 8, Mac OS 9, Mac OS 10 and Mac OS X.
• UNIX/Linux was created in 1957 at Bell Labs to support a computer center running batch jobs, and the BESYS operating system was created to deal with these needs.
• UNIX/Linux has many variations or brands that have evolved since then.
• Brands of UNIX/Linux are BSD, FreeBSD, SCO/Caldera, Red Hat, Solaris and Linux.
• Linux was not started until 1991, but it is the most noted UNIX OS.
• Today's computers are multi-user, multiprocessing, multitasking and multithreading.
• Multi-user operating systems allows multiple users to use the same computer at the same and different times.
• Multiprocessing operating systems are capable of supporting and utilizing more than one computer processor.
• Multitasking operating systems can allow multiple software processes to run at the same time.
• Multithreading operating systems can allow different parts of a software program to run concurrently.

Basic Components

• The basic components of a computer include the motherboard, CPU, RAM, hard disk or drive, optical drive, video card and power supply.
• Components are usually found within the tower of a desktop computer.
• These are referred to as "hardware".
• Hardware can be thought of as the actual physical components that go into the computer.
• "Software" refers to the programs and systems that operate within the hardware.
• The motherboard is the "heart" of the computer, fundamental with every other component attached to it.
• The different components use the motherboard to communicate and work with each other.
• The motherboard has a series of slots, sockets and connectors for attaching the components of a PC.
• Memory, accessory cards, and CPU are often installed directly onto the motherboard.
• Drives and peripherals communicate with the motherboard through wired connections.
• Motherboards differ in features, speed, capacity, CPU supported, size, shape and layout, and is known as "form factor".
• The CPU stands for Central Processing Unit, serves as the brain of the computer and is often referred to as the "processor" or the "chip".
• It is found under a heat sink and fan and sits directly on the motherboard.
• The CPU directs, coordinates, communicates with other components, and performs all of the "thinking" involving mathematical calculations translated by software into useful functions.
• Ram stands for Random Access Memory, that comes as modules in predefined amounts in one, two or four slots on the motherboard.
• The memory chips store information temporarily, for short term use by the CPU for files used by the CPU.
• RAM memory is entirely different from the hard disk "memory" because hard disks store information permanently.
• The graphics card or video card translates information into graphics and text on the monitor screen.
• Most motherboards include a slot specifically designed for the graphics adapter called the AGP slot (Advanced Graphics Port).
• Modern graphics adapters incorporate memory on the card for performance.
• The power supply provides power to the other components, and is positioned at the back top corner of the computer case.
• The power supply has a fan to keep itself and the computer cool.
• A hard disk is much like a filing cabinet, because programs and data are stored stored on it and the computer accesses them as needed.
• When the computer accesses the hard drive, it is reading and moving the stored information into the RAM memory.
• The original file is left undisturbed on the hard disk until saved.
• When the computer stores or "saves" information, it writes the data to the hard disk and replaces or modifies the old file with the new information.
• The optical drive is often called a DVD drive or a CD drive and sits at the front, easily allowing a laser to read/write information to CDs/DVDs.