COMPUTER BASICS

Many people believe that knowing how to use a computer, is one of the basic skills

needed to succeed in the workplace. In order to use the computer it is necessary to

understand how the computer works.

COMPUTER HARDWARE

Defination:Physical components of computer is called hardware.

OR

Basically Computer hardware refers to the physical aspects of the computer; the computer parts that are

tangible and can be touched.

COMMON HARDWARE COMPONENTS

• The Motherboard and things directly attached to it.• Computer chassis and screen, preferly with standard

sizes (i.e. ISO A4 for notebook chassis).• Storage Media• Other peripherals

CLASS 1 COMPONENTS

CPU

• The CPU (Central Processing Unit) is the 'brain' of the computer.

• It's typically a square ceramic package plugged into the motherboard, with a large heat sink on top (and often a fan on top of that heat sink).

• All instructions the computer will process are processed by the CPU.

CASE

• Most modern computers have an "ATX form factor" case in which ATX-compatible power supplies, Mainboards and Drives can be mounted.

• The Mini-ITX is much different in important ways unlike its relatives the Micro-ATX and the Flex-ATX. The mainboard size can be up to 170mm x 170 mm which is smaller than the Flex and Micro-ATX can be. Usually at less than 100 watts, the Mini-ITX PSU is energy efficient. The Mini-ITX is also backward-compatible with the Flex/Micro-ATX models.

POWER SUPPLY

• All computers have some sort of power supply. This converts the supply voltage (AC 110 or 220V) to different voltages such as DC 5V, 12V and 3.3V. These are needed inside the computer system by nearly every component inside the computer.

• The power supply also has an exhaust fan that is responsible for cooling the power supply, as well as providing a hot air exhaust for the entire case. Some power supplies have two fans to promote this effect.

• It is important to buy a power supply that can accommodate all of the components involved. Some may argue that it is the most important part of a computer, and therefore it is worth spending the money to get a decent one.

MOTHERBOARD

• The Motherboard (also called Mainboard) is a large, thin, flat, rectangular fiberglass board (typically green) attached to the case. The Motherboard carries the CPU, the RAM, the chipset and the expansion slots (PCI, AGP - for graphics -, ISA, etc.).

• The Motherboard also holds things like the BIOS (Basic Input Output System) and the CMOS Battery (a coin cell that keeps an embbeded RAM in the motherboard -often NVRAM- powered to keep various settings in effect).

RAM• Random Access Memory (RAM) is a memory that the

microprocessor uses to store data during processing.

• This memory is volatile (loses its contents at power-down). When a software application is launched, the executable program is loaded from hard drive to the RAM.

• The microprocessor supplies address into the RAM to read instructions and data from it. RAM is needed because hard drives are too slow to operate with the speed of a microprocessor.

• Some of the types of RAM are SDRAM, DDR RAM, Rambus RAM, SIMM, DIMM.

CLASS 2 COMPONENTS: STORAGE

HARD DRIVE

• A hard drive consists of one or more magnetic platters or disks and a read arm with two electromagnetic coils for each disk.

• Each hard disk is divided into many sectors, each containing a certain amount of data. As of now, it is the cheapest and most common way to store a lot of data in a small space.

CD-ROM DRIVE

• Compact Disc Read Only Memory (CD-ROM) is a standard format for storing a variety of data. A CD-ROM holds about 700 MB of data.

• The media resembles a small, somewhat flexible plastic disc. Any scratch or abrasion on the data side of the disc can lead to it being unreadable.

FLOPPY DISK DRIVES

• 8" Floppy Disk: In the late 1960s IBM invented the 8-inch floppy disk. This was the first floppy disk design.

• 5.25" Floppy Disk: This disk was introduced some time later, and was used extensively in the 1980s.

• 3.5" Floppy Disk: This storage medium is the most common of those listed in this section, still in somewhat wide use today. Floppy disks hold from 400 KB up to 1.44 MB. The most common types found are 720 KB (low-density) and 1.44 MB (high-density).

CLASS 3 COMPONENTS: PERIPHERALS

DISPLAY DEVICE

• Includes computer monitors and other display devices. CRTs and LCDs are common.

• LCDs are a more recent development, and are gradually replacing CRTs as they become more affordable.

• LCD's in addition to being lighter also use less energy and generate less heat.

KEYBOARD

• A keyboard is an input device which is connected to a computer and used to type instructions or information into the computer. Typically, a keyboard has about 100 or so keys.

• Keyboards differ between languages. Most English-speaking people use what is called a QWERTY layout.

• This refers to the order of the top row of keys. Some foreign languages (i. e. German) use QWERTZ, where the Z and Y are switched.

• Modern keyboards sometimes have extra controls such as volume, and keys that can be programmed to bring up programs of the user's choice.

MOUSE

• A user interface device that can enable different kinds of control than a keyboard, particularly in GUIs.

• It was developed at the Xerox PARC (Palo Alto Research Center) and adopted and made popular with the Apple Mac.

• Today, nearly all modern operating systems can use a mouse. Most mice (sometimes the plural is 'mouses' to prevent confusion with the rodent) are made from plastic, and may use a ball to track movement, an LED light, or a laser.

DIFFERENT TYPES OF SOFTWARES

brief definition of each type, and the differences between them

RETAIL SOFTWARE

• This type of software is sold off the shelves of retail stores. It includes expensive packaging designed to catch the eye of shoppers and, as such, is generally more expensive.

• An advantage of retail software is that it comes with printed manuals and installation instructions, missing in hard-copy form from virtually every other category of software. However, when hard-copy manuals and instructions are not required, a downloadable version off the Internet will be less expensive, if available.

OEM SOFTWARE

• OEM stands for "Original Equipment Manufacturer" and refers to software sold in bulk to resellers, designed to be bundled with hardware.

• For example, Microsoft has contracts with various companies including Dell Computers, Toshiba, Gateway and others. Microsoft sells its operating systems as OEM software at a reduced price, minus retail packaging, manuals and installation instructions. Resellers install the operating system before systems are sold and the OEM CD is supplied to the buyer. The "manual" consists of the Help menu built into the software itself. OEM software is not legal to buy unbundled from its original hardware system.

SHAREWARE

• This software is downloadable from the Internet. Licenses differ, but commonly the user is allowed to try the program for free, for a period stipulated in the license, usually thirty days.

• At the end of the trial period, the software must be purchased or uninstalled.

• Some shareware incorporates an internal clock that disables the program after the trial period unless a serial number is supplied.

• Other shareware designs continue to work with "nag" screens, encouraging the user to purchase the program.

PUBLIC DOMAIN SOFTWARE

• This is free software, but unlike freeware, public domain software does not have a specific copyright owner or license restrictions.

• It is the only software that can be legally modified by the user for his or her own purposes.

TYPES OF APPLICATION SOFTWARE

Application software utilizes the capacities of a computer directly to a dedicated task. Application software is able to manipulate text, numbers and

graphics.

WORD PROCESSING SOFTWARE

• Computers have made typing papers a breeze for those of us who do not know how to type!

• We can make mistakes left and right and be able to fix them on the computer before we print the paper.

• We can save a paper as a file on a diskette and keep it for future reference.

• We can modify papers in a flash and we can even include pictures in our papers.

SPREADSHEET SOFTWARE

• A spreadsheet (or spreadsheet program) is software that permits numerical data to be used and to perform automatic calculations on numbers contained in a table.

• It is also possible to automate complex calculations by using a large number of parameters and by creating tables called worksheets.

PRESENTATION SOFTWARE

• Presentation software is becoming more commonplace for teaching, seminars, staff meetings and other functions.  The use of data projectors means effective presentations can be prepared with little effort.  Creating a successful presentation is not hard if a few guidelines are followed.

• A presentation is a sequence of slides. A slide show is a presentation run in front of an audience. Displayed from a computer through a projector on a screen, a presentation would usually be shown in full screen size. A presentation can contain text, graphics, audio, video, and links to other programs.

DATABASE SOFTWARE

• A database is an organized collection of data. The data are typically organized to model relevant aspects of reality in a way that supports processes requiring this information. For example, modeling the availability of rooms in hotels in a way that supports finding a hotel with vacancies.

• Database management systems (DBMSs) are specially designed applications that interact with the user, other applications, and the database itself to capture and analyze data.

FEATURES OF AN OPERATING SYSTEM

You now have read about the various kinds of operating systems that are part of computers ranging from a humble

mobile phone to a mighty supercomputer taking up an entire building.

But they share some common features, some of which are more important than others depending on the type of operating system

• Scheduling : The task of handling how active processes are making efficient use of the CPU processing cycles is called scheduling. There are many ways of doing this, which is covered in another mini-website.

• Memory Management : The operating system has to make sure that applications are able to run in the amount of memory available and that they do not interfere with one another. There is a separate mini-website on this topic.

Allocation of resources : The operating system will provide a working area for each user.

Keeping track of usage : The cost of using large computers is shared amongst the users. So the operating system will have an accounting / tracking system in place

Data and User security : Each user has to be authenticated with an username and password (network and multi-user operating system).

Managing input / output : Data and applications are stored on secondary storage devices such as hard disks, optical drives, magnetic tape when not in use. The operating system has a file management system that allows the user to organise their files, to move, delete and copy files as they wish.

FEATURES OF MICROPROCESSOR

Microprocessor is the controlling unit or CPU of a micro-computer, fabricated on a very small chip capable or performing ALU operations and communicating with

the external word connected to it.

• Cost : The most important characteristics of a microcomputer is its low cost. It is a well established fact that with the advancement of technology, the cost does not increase proportionately with the complexity.

• Size : The second important features of a microprocessor is its small size. As a result of improvement in fabrication technology, VLSI, electronic circuitry has become so dense that a minute silicon chip can contain hundred and thousands of transistors constituting the microprocessor.

• Power Consumption : The another important characteristics is its low power consumption microprocessors are normally manufactured by Metal-Oxide semiconductor technology, which has the feature of low power consumption.

• Versatility : The versatility of a microprocessor results from its stored program mode of operation. Keeping the same basic hardware , a microprocessor-based system can be configured for a number of applications simplify altering the software program. This also makes it very flexible

• Reliability: Another important property of VLSI devices which has also been in herniated by microprocessors is extreme reliability . It has been established that the failure rate of an IC is fairly uniform at the package level, regardless of its complexity.