Input Devices 2

Joysticks

Many games require a joystick for the proper
playing of the game. There are many different types, the more sophisticated
respond to movement in 3 axis directions, as well as having a number of
configurable buttons. Like most things in life you get what you pay for with
joysticks and it is worth investing in a good, strongly constructed model,
especially bearing in mind that children will hammer these devices whilst
playing games.

Voice input for PCs (microphones)

Early voice recognition systems offered very poor results, due to the
limitations of the software combined with hardware limitations. It takes an
awful lot of CPU processing power to convert the spoken word into text that
appears on the screen. Things are changing rapidly however and recent systems
allow you to talk to a PC and see text appear on the screen. Most of these
systems require an initial training period, where you train the software to
respond to your particular voice. While still not perfect this is a key
technology of the future.

Web Cams

Ever since it was invented, the Web has become increasingly interactive. You can
now use a small digital movie camera (a Web cam) mounted on the PC monitor to
allow two-way communication involving not just text communication but sound and
video communication as well. While not yet considered a standard piece of PC
kit, it is only a matter of time …

Digital Cameras

A digital camera can be used in the same way a traditional camera can, but
instead of storing images on rolls of film which require developing, the images
are stored digitally in memory housed within the camera. These pictures can
easily be transferred to your computer and then manipulated within any graphics
programs that you have installed on your computer. Currently they are limited by
the quality of the image recorded and the number of pictures that you may storewithin the camera.

Input Devices

Identify some of the main devices for inputting data into a computer such as: mouse, keyboard, trackball, scanner and more .

The Mouse
The mouse came into common use on a PC with the introduction of the Microsoft
Windows operating system. Before this, the operating system (DOS) would normallybe controlled via the keyboard. These days it is vital to be a competent mouseuser. There are many different types of mice, a commonly used model now has asmall wheel on it which when combined with the correct software allowsadditional functionally and fine control over the use of your applications.

The Keyboard

The keyboard is still the commonest way of
entering information into a computer. There are a number of different types,
including those specially designed for use with Microsoft Windows. The quality
of the keyboard is often overlooked when buying a PC; it should be robust and
easy to use.

Tracker Balls

A tracker ball is an alternative to the traditional
mouse and favored by graphic designers. Tracker balls often give much finer
control over the movement of the items on the screen. They may take a while to get used to if you are used to the traditional mouse, but offer a lot in terms
of added flexibility

Scanners

A scanner allows you to scan printed material and convert it into a file format
that may be used within the PC. You can scan pictures and then manipulate these inside the PC using a graphics application of your choice. In addition, you can scan printed text and convert this not just to a picture of the text but also
to, actual text that can be manipulated and edited as text within your
word-processor. There are a number of specialist programs, generically called
OCR (Optical Character Recognition) programs that are specifically designed for
converting printed text into editable text within your applications.

Touch Pads

A touch pad is a desktop device and responds to pressure. Used in conjunctionwith a special pen they can be used by graphic artists wishing to createoriginal, digital artwork.

Light Pens


A light pen is used to allow users to point to
areas on a screen and is often used to select menu choices.

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computer memory is measured

Know how computer memory is measured; (bit, byte, KB, MB, GB, TB). Relate
computermemory measurements to characters, files and directories/folders

Basic Units of Data Storage:
It is important to realize that the term digital computer
refers to the fact that ultimately the computer works in what is called binary.
Humans work in tens (because we have 10 fingers). To use the jargon humans work
in base 10. A digital computer uses the numbers 0 and 1 (or on and off if you
prefer). When we talk about computer storage, either the amount of memory (RAM)
or the hard disk capacity we are talking about numbers that are multiples of 0
or 1.

Bit: All computers work on a binary numbering system, i.e. they process data in ones or zeros. This 1 or 0 level of storage is called a bit. Often hardware is specified as a 32-bit computer, which means that the hardware can process 32 bits at a time. Software is also described as 16 bit, 32bit or 64 bit software.

Byte: A byte consists of eight bits.

Kilobyte:A kilobyte (KB) consists of 1024 bytes.

Megabyte: A megabyte (MB) consists of 1024 kilobytes, approximately 1,000,000 bytes.

Gigabyte: A gigabyte (GB) consists of 1024 megabytes, approximately 1,000,000,000 bytes.

Terabyte: A terabyte (TB) consists of approximately 1,000,000,000,000 bytes.

Files: Data and programs are stored on your disk as files. There are different types of files, such as the files that you store your data in, the files that contain your programs and also files used to
store your operating system (such as Microsoft Windows).

Directories (folders):Directories or folders are used to group files with a similar theme together. For example, you could have a folder called “Accounts” containing all your accounting related files, or a folder called “Customers” containing correspondence with your customers. Folders can also contain sub-folders to further divide files. The uppermost level folder is often referred to as the “root” folder (or directory). Sometimes you may see a diagrammatic representation of folders, as illustrated below

In this example, we have the root folder at the top. Below this are three sub-folders called Data, Programs and Games.
Records: A record is a collection of data held within a file. It is the sort of storage unit used by a database. For more information, please see the ECDL module concerned with databases.

computer memory

Understand different types of computer memory such as RAM (random-access memory), ROM (read-only memory) and distinguish between them

What is RAM

Random Access Memory (RAM) is the main
'working' memory used by the computer. When the operating system loads from disk
when you first switch on the computer, it is copied into RAM. The original IBM
PC could only use up to 640 KB of memory (just over half a megabyte), whereas a
modern computer can effectively house as much RAM as you can afford to buy.
Commonly modern computers are supplied with over 128 MB of RAM. As a rough rule,
a Microsoft Windows based computer will operate faster if you install more RAM.
When adverts refer to a computer having 128 Mbytes of memory, it is this RAM
that they are talking about. Data and programs stored in RAM are volatile (i.e.
the information is lost when you switch off the computer).

What is ROM

Read Only Memory (ROM) as the name suggests is a special type of memory chip
that holds software that can be read but not written to. A good example is the
ROM-BIOS chip, which contains read-only software. Often network cards and video
cards also contain ROM chips.

What is the ROM-BIOS

The 'Read Only Memory Basic Input Output System' chip is a chip located on the
computer's system (mother) board, which contains software. This software
performs a variety of tasks. When you first switch on the computer the ROM-BIOS
software performs a self-diagnostic to check that the computer is working OK.
This software then loads your operating system from the disk into the RAM.

What is flash BIOS

Most modern computers are actually supplied with a flash BIOS rather than a
ROM-BIOS. This chip contains exactly the same type of in-built software, but has
the advantage that the software on the chip can be upgraded. This upgrade is
achieved by simply running a small program supplied by the computer
manufacturer.

What is video (graphics) memory

The picture that you see on your screen is a form of data and this data has to
be stored somewhere. The on-screen pictures are held in special memory chips
called video memory chips; these chips are usually located on the video card. A
modern computer will be supplied with several Megabytes of video memory.

Central Processing Unit

(The CPU )

(Central Processing Unit)

The CPU is the brains within your computer. It performs most of the calculations
within the computer and is responsible for the smooth running of

your operating system (Microsoft Windows) as well as your application programs, such
as word-processors, spreadsheets and databases.

There is a small amount of memory associated with the CPU, which it uses to perform
these operations. It also accesses and uses the main

memory(RAM - Random Access Memory) within your computer. In many ways, the CPU is the
single most important item within your computer

that governs the overall speed of your computer. The CPU's speed is measured in MHz.
This relates to the frequency that the CPU runs at and the

higher the MHz rating of your CPU the faster your computer will run. To give you some
indication of how PCs have advanced over the years, the

original IBM PC released in 1981 ran at less than 5 MHz while modern PCs can run at
speeds well in excess of 2000 MHz. Note that 1000 MHz is the same a 1 GHz.

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Memory

What is computer memory

You can store data on your hard disk, while data that is being processed is
stored in RAM (Random Access Memory).

Data that is stored on a hard disk can be permanent, while data in RAM is only
temporary. Normally when people

talk about memory in relation to a PC, they are talking about RAM.

What is Performance ?

Computer Performance

Know some of the factors that
impact on a computer’s performance, such as: CPU speed, RAM size, the ..number of applications running

CPU Clock speed
The computer clock speed governs how fast the CPU will run. The higher the clock speed the faster the computer will work
for you. The clock speed is given in megahertz (MHz). The original IBM PC ran at
4.77 MHz whereas modern PCs will run at over 2000 MHz, which gives you an idea
of how far things have progressed since the introduction of the original PC. The
higher the MHz speed the faster the computer.

RAM size
As a rule the more memory you have the
faster the PC will appear to operate. Windows also uses the hard disk a lot so
logically the faster the hard disk can operate then again the faster the PC will
appear to run

Hard disk speed and storage

Hard disks are also measured by their speed, defined by the disk access time, which
is measured in milliseconds. The smaller this access time the faster the hard
disk will store or retrieve data. The data storage capacity of hard disks
continues to increase as new products are released. The disk storage capacity is
measured in Gigabytes (GBytes). 1 GByte is equivalent to 1024 Mbytes.

Free Hard Disk Space

To get the most out of your Windows based PC, you not only need a fast hard disk but
also a large hard disk with plenty of "spare space". This is due to the fact
Windows is constantly moving data between the hard disk and RAM (Random Access
Memory). Microsoft Windows will create many so-called “temporary files” that it
uses for managing your programs. In fact, if you have very little free hard disk
space you may find that Microsoft Windows will not be able to run your programs
at all.

De-fragmenting Files

If you are running Windows you may
find that if you click on the Start menu, select Programs, and then select the
Accessories / System tools group, there is a de-fragmentation program. Running
this periodically may noticeably speed up the operation of your PC. When you use
a PC, over a period of time the files get broken up into separate pieces that
are spread all over the hard disk. De-fragmentation means taking all the broken
up pieces and joining them back together again.

Multitasking considerations

Windows is a multitasking system, which means that it can run more than one program at a time. However the more programs that are running at the same time, the slower each one will run. To some extent
this slowing effect depends on what each program is doing. Editing a large, full
color picture for instance can take up a lot of CPU time

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Main Parts 5

Modems

A modem is a device that is used to attach your computer to the telephone system. The modem converts data into sound that is sent over the telephone line, the receiving modem turns the sounds back into data. If you wish to connect to the Internet, you will need a modem.

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Printers

Modst data is printed once you have created it and there are a vast number of different printers available to accomplish this. Most common are ink jet and laser printers both of which can now produce colored output (at a cost).



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Scanners

Scanners allow you to scan printed materials into your computer, which can then be stored within the computer. These pictures can then be altered, resized and printed as required.

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Recordable CDs

CD-ROMs are read-only devices, but increasingly people are purchasing a special type of CD drive unit that allows you to record data, music or video to your own CDs. These devices require the purchase of special CDs that you can write to, called CD-R
(Compact Disc – Recordable).

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Tape backup

A tape backup unit allows for regular backing up of your data. These tapes can store a vast amount of data at a low cost. DAT (Digital Audio Tape) devices are commonly used for backups. The DAT tapes that they use can backup enormous amounts of data (i.e. over 4 GBytes per tape). The devices are also fast and reliable.

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PCMCIA

Portables by their very nature are very compact and require smaller than standard parts such as hard disks and CD-ROM drives. Many portables are supplied with special adaptor sockets that enable what are called PCMCIA compatible hardware to be connected to them. PCMCIA components tend to be more expensive than standard computer parts that are designed for more bulky desktop computers


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