Health and Safety is crucial to the effective operation of a computer. Stress is widely accepted as a common and possibly the most dangerous aspect of using a computer.
It is possible to use a computer safely if a few simple rules are maintained.
Musculoskelatal problems can occur when improper office equipment is used. Chairs should be adjustable so that legs are at a right angle. The back should have good support for the spine and lower back. The seat should swivel and be made from fabric that is porous.
Eye strain can be caused by staring at a fix object for extended periods of time (like a computer). People who use glasses may have to get their prescriptions changed and people who use bifocals can find that the line interferes with the screen and trifocals triple the problem. Regular users of computers may develop focusing problems. Temporary colour distortion has also been reported.
A safe working environment is crucial. Ventilation is an integral part of the new technological workplace. Though standards are set by the manufacturer of computer equipment the modern office has many different pieces of equipment. All electronic equipment emit some level of electromagnetic field which, on it's own, most likely isn't a concern but when combined with other equipment can create hazardous working environments. Pregnant women should take extra care when working around electromagnetic fields. Like any piece of equipment, computers should have scheduled maintenance.
Stress is caused by many things including poor or inadequate training, monitoring, fear of new technology, lack of control over work, physical problems, hardware problems causing delays, poor layout of work space and the myriad of other problems that people experience that combine to create stressful situations.
Time away from the computer during the work day is crucial! This gives the body a chance to stretch and gives the eyes a chance to rest. Breaks should be scheduled and followed with great discipline. Computers, even more so than television, have a mesmerizing effect on the user so that it is easy to work right through breaks without noticing.
Friday, 18 November 2011
1. PURPOSE OF A COMPUTER: TURNING DATA INTO INFORMATION Very simply, the purpose of a computer is to process data into information. • Data: Data consists of the raw facts and figures that are processed into information—for example, the votes for different candidates being elected to student-government office. • Information: Information is data that has been summarized or otherwise manipulated for use in decision making—for example, the total votes for each candidate, which are used to decide who won.
2. DIFFERENCE BETWEEN HARDWARE & SOFTWARE You should know the difference between hardware and software. • Hardware: Hardware consists of all the machinery and equipment in a computer system. The hardware includes, among other devices, the keyboard, the screen, the printer, and the “box”—the computer or processing device itself. Hardware is useless without software. • Software: Software, or programs, consists of all the electronic instructions that tell the computer how to perform a task. These instructions come from a software developer in a form (such as a CD, or compact disk) that will be accepted by the computer. Examples are Microsoft Windows and Office XP/Vista.
3. THE BASIC OPERATIONS OF A COMPUTER Regardless of type and size, all computers use the same four basic operations: (1) input, (2) processing, (3) storage, and (4) output. To this we add (5) communications. • Input operation: Input is whatever is put in (“input”) to a computer system. Input can be nearly any kind of data—letters, numbers, symbols, shapes, colors, temperatures, sounds, pressure, light beams, or whatever raw material needs processing. When you type some words or numbers on a keyboard, those words are considered input data. • Processing operation: Processing is the manipulation a computer does to transform data into information. When the computer adds 2 2 to get 4, that is the act of processing. The processing is done by the central processing unit—frequently called just the CPU—a device consisting of electronic circuitry that executes instructions to process data. • Storage operation: Storage is of two types—temporary storage and permanent storage, or primary storage and secondary storage. Primary storage, or memory, is the internal computer circuitry that temporarily holds data waiting to be processed. Secondary storage, simply called storage, refers to the devices and media that store data or information permanently. A hard disk or CD/DVD is an example of this kind of storage. (Storage also holds the software—the computer programs.) • Output operation: Output is whatever is output from (“put out of”) the computer system—the results of processing, usually information. Examples of output are numbers or pictures displayed on a screen, words printed out on paper by a printer, or music piped over some loudspeakers. • Communications operation: These days, most (though not all) computers have communications ability, which offers an extension capability— in other words, it extends the power of the computer. With wired or wireless communications connections, data may be input from afar, processed in a remote area, stored in several different locations, and output in yet other places. However, you don’t need communications ability to write letters, do calculations, or perform many other computer tasks.
Posted by ismi'maryam at 12:31
Wednesday, 16 November 2011
Now they come in a variety of shapes and sizes, which can be classified according to their processing power: supercomputers, mainframe computers, workstations, microcomputers, and microcontrollers.
supercomputers are high-capacity machines with thousands of processors that can perform more than several trillion calculations per second.These are the most expensive and fastest computers available.More recently they have been employed for business purposes—for instance, sifting demographic marketing information—and for creating film animation.
The only type of computer available until the late 1960s, mainframes are water- or air-cooled computers that are vary in size from small, to medium, to large, depending on their use. Mainframes are used by large organizations—such as banks, airlines, insurance companies, and colleges—for processing millions of transactions.Often users access a mainframe by means of a
terminal, which has a display screen and a keyboard and can input and output data but cannot by itself process data. Mainframes process billions of instructions per second.
Introduced in the early 1980s, workstations are expensive, powerful personal computers usually used for complex scientific, mathematical, and engineering calculations and for computer-aided design and computer-aided manufacturing. Providing many capabilities comparable to those of midsize mainframes, workstations are used for such tasks as designing airplane fuselages, developing prescription drugs, and creating movie special effects.Workstations have caught the eye of the public mainly for their graphics capabilities, which are used to breathe three-dimensional life into movies such as WALL⋅E and Harry Potter.The capabilities of low-end workstations overlap those of high-end desktop microcomputers.
Microcomputers, also called personal computers (PCs),that can fit next to a desk or on a desktop or can be carried around.They either are stand-alone machines or are connected to a computer network,such as a local area network.A local area network (LAN) connects, usually by special cable, a group of desktop PCs and other devices, such as printers, in an office or a building. Microcomputers are of several types: desktop PCs, tower PCs, notebooks (laptops), mobile internet devices (MIDs), and personal digital assistants— handheld computers or palmtops. DESKTOP PCs
Desktop PCs are older microcomputers whose case or main housing sits on a desk, with keyboard in front and monitor (screen) often on top.
The Mac Mini has the smallest desktop microcomputer case, just 6.5 inches square and 2 inches tall.
Tower PCs are microcomputers whose case sits as a “tower,” often on the floor beside a desk, thus freeing up desk surface space. Some desktop computers, such as Apple’s iMac, no longer have a boxy housing; most of the computer components are built into the back of the flat-panel display screen.
Notebook computers, also called laptop computers, are lightweight portable computers with built-in monitor, keyboard, hard-disk drive, CD/DVD drive, battery, and AC adapter that can be plugged into an electrical outlet; they weigh anywhere from 1.8 to 9 pounds.
A new category of mobile devices, smaller than notebook computers but larger and more powerful than PDAs (see below), mobile internet devices (MIDs) are for consumers and business professionals. Fully internet integrated, they are highly compatible with desktop microcomputers and laptops. The initial models focus on data communication, not voice communication.
Personal digital assistants (PDAs), also called handheld computers or palmtops, combine personal organization tools— schedule planners, address books, to-do lists—with the ability in some cases to send email and faxes. Some PDAs have touch-sensitive screens. Some also connect to desktop computers for sending or receiving information.
Posted by ismi'maryam at 02:36