Chapter 1 Information Technology PDF

Chapter1 Information Technology Chapter1 Information Technology Hardware Concepts Hardware The term hardware refers to the physical components of your computer such as the system unit, mouse,...

Chapter1 Information Technology Chapter1 Information Technology Hardware Concepts Hardware The term hardware refers to the physical components of your computer such as the system unit, mouse, keyboard, monitor etc. What is a personal computer?  IBM invented the PC (Personal Computer) way back in 1981.A computer is an electronic device that receives input, store it for a period of time, operating it according to asset of instructions (known as program) and gives the user with an output. Capacity: Large hard disks combined with a large working memory (RAM) Speed: Fast. Normally measured in GHz. Costs: Getting cheaper by the day. Typical Users: Home users, large and small office users. Education, Doctors. In fact just about everyone needs to know how to operate a PC these days. Laptop computers  Laptop computers, as the name implies, are small portable computers which can run on batteries as well as mains power. They use special screens, rather than the traditional bulky VDUs (Visual Display Units), which allows for longer battery life as well as portability. A newer term, “Notebooks”, simply indicates a VERY small laptop. These are especially popular with salespersons on the move or people giving presentations. While they tend to still be more expensive than an equivalent Desktop computer, they can now match the power of a Desktop computer. Capacity: Large hard disks combined with a large working memory (RAM) – Often less powerful than for a PC of equivalent price. Speed: Fast. Normally measured in GHz. Often speed specifications are less than for a PC of equivalent price. Costs: Components need to be much more compact, so there is a price overhead when compared to a PC of equivalent power. Typical Users: Business users, people on the move, educational users. Parts of a computer 1 Chapter1 Information Technology You should understand some of the basic elements that make up a computer including: - Central processing unit (CPU) - Types of memory - The hard disk - Input and output devices The CPU  The CPU (Central Processing Unit) is normally an Intel (or equivalent) and it is one of the most important components within your computer. It determines how fast your computer will run and the CPU speed is measured by its MHz or GHz speed. Thus, a 2 GHz Pentium is much faster than say a 1 GHz Pentium CPU. It is the CPU which performs all the calculations within the computer, when running programs such as word-processors, spreadsheets and databases. The CPU contains following elements: Control Unit: The control unit is responsible for controlling the sequencing and timing of the other elements making up the CPU. Arithmetic Logic Unit (ALU): The ALU performs the mathematical calculations using data stored within the CPU registers. Registers: The registers are memory storage areas within the CPU that hold the data that is worked on by the ALU. BUS: The computer bus transports data between the memory and registers. Memory (RAM)  The RAM (Random Access Memory) within your computer is where the operating system is loaded to when you switch on your computer and also where your applications are copied to when you start an application, such as a word processor or database program. When you create data, (e.g. letters and pictures), these are initially created and held in RAM and then copied to disk when you save the data. 2 Chapter1 Information Technology ROM-BIOS  The ROM-BIOS (Read Only Memory - Basic Input Output System) chip is a special chip held on your computer's system (mother) board. It contains software which is required to make your computer work with your operating system, for instance it is responsible for copying your operating system into RAM when you switch on your computer. Disks  You use disks to store any data that you create. This can range from a memo created within a word processor to a video file created using a video camera. There are many different types of disk. The Hard (Fixed) Disk  Hard disks are the main, large data storage areas within your computer. Hard disks are used to store your operating system, your application programs (i.e. your word processor, games etc) and your data. They are much faster than CD/DVDs and can also hold much more data. Hard disks are installed within the system unit of your computer. Input/output ports The Input and Output ports are normally located at the back or on the side of your computer. These include ports such as USB, serial, parallel, network and FireWire ports. You plug cables into these ports to connect your computer to other devices, such as printers, scanners and cameras. Universal Serial Bus (USB) Port  The Universal Serial Bus is a relatively new item within the PC. You will see one or more USB sockets at the back of the system unit, allowing you to plug in devices designed for the USB. These devices include printers, scanners and digital cameras. Memory sticks 3 Chapter1 Information Technology can also be plugged into a USB port allowing you to copy data to or from your hard disk. Serial Port  The serial port is a socket located at the back of your computer which enables you to connect items to the computer, such as a modem. They are commonly labelled as COM1 or COM2. Parallel Port  The parallel port is a socket located at the back of your computer which enables you to connect items to the computer, such as a printer. It is commonly labeled as LPT1 or LPT2. NOTE: The parallel port used to be the main way the computer connected to a printer. These days you are more likely to use a USB cable to connect the computer to a printer. Network Port  The network port allows you to plug a „network cable‟ into your computer, which then lets you communicate with other computers connected to your local network or to other computers via the Internet. Computer Performance Factors affecting computer performance  There are a wide range of factors that can affect the performance of your computer. These include CPU speed, RAM size, type of graphics card processor and memory plus the number of applications running. It is important to realize that it is not just the speed of the CPU that affects the overall performance of your computer. There is no point in having a very fast CPU if the other parts of a computer may slow down the real world performance. 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 higher the MHz speed the faster the computer. 4 Chapter1 Information Technology 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” which 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 which 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 which 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 high definition video for instance can take up a lot of CPU time. CPU speeds  The speed (operating frequency) of the CPU is measured in megahertz (MHz) or gigahertz (GHz). The higher the value the faster the CPU will operate. The original IBM PC released way back in 1981 ran at 4.77 MHz whereas modern PCs can run at over 4000 MHz, which gives you an idea of how far things have progressed. 5 Chapter1 Information Technology  1 MHz means that the device will run at one million cycles per second. 1 GHz is a thousand times faster, so that 1 GHz = 1000 MHz. Memory and Storage What is computer memory? You can store data on your hard disk, while data which is being processed is stored in RAM (Random Access Memory). Data which 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.  RAM  ROM-BIOS  Video (graphics) memory The picture which 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. Measurement of storage capacity  It is important that you understand a little about the measurements used to define storage capacities: Bit: Computer are digital. This means they work by processing ones and zeros. The basic one or zeros is called a bit of information. Byte: There are eight bits in a Byte. KB - Kilobyte: There are 1024 bytes in a KB (also called a KByte) Powers of Two K (kilo) =210, M (mega) =220, G(giga)=230, T(tera)=240. 6 Chapter1 Information Technology Types of storage media  These days there are a range of storage media to choose from including CDs, DVDs, USB flash drives, memory cards, internal hard disks, external hard disks, network drives and on-line file storage. Some are more suitable than others for a particular job, for instance a flash drive is great for quickly transferring relative small amounts of data from one computer to another.  Internal hard disks  External hard disks As the name suggests these are secondary hard disks that you can plug into your computer. They are normally connected via a USB cable. They are available in a range of speeds and storage capacities and are an ideal way to back up your data, such as photos or movies.  CDs Most computers are now supplied with a CD-ROM (Compact Disc - Read Only Memory) drive. CD-ROM discs look exactly like music CDs but contain computer data instead of music. The advantage of a CD-ROM is that it can hold a vast amount of data (equivalent to the storage capacity of over 450 floppy disks).  DVDs Short for "Digital Versatile Disk”. Similar to CD-ROM drives but allows you to use DVD disks, which contain vastly more information than a traditional CD- ROM disk. These also transfer the data from the disk to the computer far faster, allowing you to watch movies on your computer screen. A CD-ROM can store 650 MB of data, while a single-layer; single-sided DVD can store over 4 GB of data.  Recordable CD & DVD drives CD-ROMs are read-only devices, but increasingly people are purchasing a special type of CD drive unit which allows you to record data, music or video to your own CDs. These devices require the purchase of special CDs to which you can write, called CD-R (Compact Disc – Recordable).  USB flash drives (memory sticks) 7 Chapter1 Information Technology Flash drives plug into the USB port and when viewed via the Windows Explorer, look just like any other drive. They are supplied in a range of sizes with the 1 GB devices being a very cheap way of transferring relatively small amounts of data between computers.  Memory cards A memory card (also called a flash memory card) is a card containing memory chips that is often used in devices such as digital cameras, telephones, music players, video game consoles, GPS system and similar devices where there is a need to store data in a compact from, often using a battery power source. There are a number of different types of memory cards with different storage capacities. Many new PCs have built-in slots for different types of memory cards.  Floppy disks (diskettes) Floppy disks are also known as diskettes. They are very slow compared to hard disks or CD- ROMs, and hold relatively small amounts of data (1.44 Mbytes). Sometimes people will backup (i.e. copy) important data from their hard disk to floppy disks. Input Devices Input devices allow you to input information to the computer and include things such as the keyboard and mouse.  Keyboard The keyboard allows you to type information into the computer..  Mouse you use the mouse to select drop down menus, to point and click on items, to select items and to drag and drop items from one place to another.  Scanners A scanner allows you to scan printed material and convert it into a file format which may be used within the PC.  Tracker balls 8 Chapter1 Information Technology A tracker ball is an alternative to the traditional mouse and favored by graphic designers.  Touch pads A touch pad is a desktop device and responds to pressure. Used in conjunction with a special pen they can be used by graphic artists wishing to create original, digital artwork.  Web cams 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.  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 which you have installed on your computer.  Microphones It takes an awful lot of CPU processing power to convert the spoken word into text which appears on the screen. Output Devices Includes items such as screens (monitors), printers, speakers and headphones.  Traditional computer monitor An output device. The original computer monitors were TV type screens on which you viewed your programs. They were supplied in different sizes, common sizes range from 15" to 21" screens.  Flat screen computer screens Traditional computer monitors are based on the same sort of technology which is used within a television screen. More recently, flat screen computer screens have become available. These take up a lot less room on a desk and use less energy than the traditional, more bulky monitors.  Projection devices 9 Chapter1 Information Technology These are projection devices which can be attached to your computer and are useful for displaying presentations to a group of people. They are best used in combination with presentation programs, such as Microsoft PowerPoint.  Speakers and headphones Most computers are sold with the capability to add a pair of speakers to your system unit. In fact, in some cases, the computer screen may have speakers built directly into the unit.  Printers Most data is printed once you have created it and there are a vast number of different printers available to accomplish this. Input and output devices Some devices are both input and output devices. A modem can be used for downloading information from web sites and receiving emails. It can also be used for uploading and sending emails. A touch screen can display a menu system (output device), and accept input when people touch the menus displayed on the screen. Software What is software?  The software is the collection of instructions which makes the computer work. For instance, when you type in words via the keyboard, the software is responsible for displaying the correct letters, in the correct place on the screen. Software is held either on your computer‟s hard disk, CD-ROM, DVD or on a diskette (floppy disk) and is loaded (i.e. copied) from the disk into the computers RAM (Random Access Memory), as and when required. What is an operating system?  The operating system is a special type of program which loads automatically when you start your computer. The operating system allows you to use the advanced features of a modern computer without having to learn all the details of how the hardware works. There are a number of different types of operating system in common use. The IBM PC (Personal Computer) was introduced way back in 1981 and was originally supplied with an operating system called DOS (Disk Operating System). To complicate matters further, there are a number of different types of Windows. Most people are today running either Windows XP or Windows Vista. 10 Chapter1 Information Technology  UNIX and Linux are other examples of operating systems which may be run on PCs. Examples of software applications  An application program is the type of program which you use once the operating system has been loaded.  It is important that you recognize examples of application programs covering the following areas: - Word processing - Spreadsheets - Databases - Presentations - E-mailing - Web browsing Networks Network Types  LAN (Local Area Network) A LAN (Local Area Network) is a system where by individual PCs are connected together within a company or organization. For instance if ten people are working together within an office it makes sense for them all to be connected. In this way, the office can have a single printer and all ten people can print to it. In a similar way, other devices such as modems or scanners can be shared. Even more useful is the ability to share information when connected to a network.  WLAN (Wireless Local Area Network) A WLAN (Wireless Local Area Network) allows you to connect to other computers within your LAN using wireless technology.  WAN (Wide Area Network) A WAN (Wide Area Network) as the name implies allows you to connect to other computers over a wider area (i.e. the whole world). 11 Chapter1 Information Technology  Client/server networks This term relates to the type of network where resources are kept centrally on the server and used locally by the client. The server tends to be a very powerful PC (or group of PCs), while each client workstation, which the users have, is less powerful.  Internet The Internet is a global network of interconnected networks. The unique thing about the Internet is the sheer amount of information which you can access from it. Data Transfer Downloading from & uploading to a network  You can „download‟ data from a network, for instance you can download a file from a web site. Another example of downloading would be copying a file from another computer on your Local Area Network to the hard disk on your computer.  Uploading refers to copying data from your computer to another computer, either on your local area network or on your company web site. Data transfer rate measurement  When you download or upload data the speed of the data transfer is measured by the amount of data that is transferred per second. Common transfer rate units are: -Bits per second (bps). Very slow connections will be quoted in bits per second. - Kilobits per second (kbps). - Megabits per second (mbps). High speed data transfer is measured in megabits bits per second. Internet connection options Most people will connect to the Internet via a phone line or via a cable connection. There are however a range of Internet connection options including: Phone line: The most common type of Internet connection. Your computer is connected to a modem which connects to the phone line. Cable: The same cable that supplied TV channels can also supply your Internet connections. Often cable gives you very high speed Internet access. 12 Chapter1 Information Technology Mobile phone: This is often very expensive and mainly appeals to the younger Internet users. The connection is established via special, Internet compatible phones. Wireless Hot Spots: Many public places, such as shopping malls, hotels, airports and restaurant chains now offer wireless access to the Internet. This is sometimes free but is normally charged via your credit card as a fixed rate per time period. Often you cannot download materials, you can just browser the Web or view your emails. Satellite: If you live in a very remote area, your only way to connect to the Internet may be via a satellite link. This may require large satellite dishes and expensive specialized equipment. The cost of the Internet connection may also be high. Security Identity/Authentication Computer logon user name (ID) and password.  Passwords: If your computer has a password which prevents other users from accessing it then do NOT give this password to anybody else. Do not write the password on a card and prop this up next to the monitor and above all do not attempt to hide your access passwords on the underside of your desk (this is the first place most criminals would look if trying to break into your system). Make sure you do not forget your passwords; in many cases, data cannot be recovered once the password is lost.  User IDs and passwords: A User ID is normally used to logon to a computer, or computer network. It uniquely identifies you to the network. In addition you use a password which is only known to you. The password guarantees that no one can access the network and impersonate you (in theory). Once you have logged on (i.e.connected) to the rest of your computer network, you will have been assigned access rights to the network. Your network administrator will have defined these access rights.  Password policies Your password is the only thing which will prevent someone else logging into a computer using your user ID and impersonating you. It is important to choose a password which cannot be easily guessed by other people. Ideally a password should be at least 8 characters long & contain a mixture of words and numbers. Data Security  Off-site backups 13 Chapter1 Information Technology It is no good backing up your data only to leave the item which you backed up to next to the computer; if someone steals your computer it is likely that they will also steal your backups too. If you have a fire, then again you will lose your backups if the backups are stored next to the computer. Ideally, backups should be stored off-site at a safe location. At the very least, consider storing your backups in a fireproof safe, which will give some protection against fire damage. Why do you need to back up your computer?  The most important thing which you store on your computer is information. Often the contents of a hard disk can represent years of work. If the hard disk stops working one day you could lose all those years of work. For this reason it is VITAL that you take regular backups of the information which is stored on the computer. In large organizations this backup procedure is normally performed automatically by your computer support team, where the data is normally held on a centralized, networked computer.  In smaller organizations, it is often up to the individual to organize some sort of data backup. If nothing else is available, copy your files to a USB memory stick or CD/DVD disk and make sure that these backups are stored away from the computer, ideally off-site. If there is a fire and your office burns down, if your backup disks are stored next to the computer they too will be incinerated. Organizing your computer for more efficient backups  When you think about it, you have a computer containing many programs and also a large amount of data which you have created, and then it is only the data which really needs to be backed up. If you create a folder structure which contains only data then only this directory (plus any sub-directories of this directory) needs to be backed up. Complete vs. incremental backups  A complete backup means that you backup all the data on your computer. This has the advantage that the entire hard disk can be backed up, but suffers from the disadvantage that this process can take a long time if your computer contains a lot of data. An incremental backup means that once a week you can perform a complete backup, but every night for the rest of the week, you only backup files which have been newly created or modified since the last backup, saving time. With the right backup software, this process is automatic, and normally you only have to select full or incremental. What is a firewall? A firewall is a system that secures your network from access by unauthorized users. A firewall can be implemented via software, hardware or by a 14 Chapter1 Information Technology combination of the two. If you are using broadband for Internet access, it is vital that some sort of firewall is in place to stop people trying to hack into your computer.  Data theft issues You should take steps to prevent data theft and be aware of the following issues:  User name and password: Always use a login ID and password to access your computer.  Physically securing your computer: In some cases the computer may be secured to a desk by a cable and locking device. While this will help prevent physical thief of the computer it does not restrict access to sensitive data stored within a computer.  Portable disks and memory sticks: Many companies ban the use the potable disks or memory sticks as they can be used to copy data from a computer and then carried out of the office for improper use by criminals.  What if your laptop is stolen? If there was no start-up password then all the data on the computer could be at risk. The same goes for important/sensitive documents; if these were not individually password protected they could also be vulnerable. If you work within a large organization, always report an incident of this type immediately to your technical support department. Viruses  Computer viruses Viruses are small programs which hide themselves on your disks (both diskettes and your hard disk). Unless you use virus detection software, the first time that you know that you have a virus is when it activates. Different viruses are activated in different ways. BEWARE: Viruses can destroy all your data.  Computer virus infection issues Viruses hide on a disk and when you access the disk (either a diskette or another hard disk over a network) the virus program will start and infect your computer. The worst thing about a computer virus is that it can spread from one computer to another, either via the use of infected disks, or over a computer network. The Internet allows you to access files from all over the world and you should never connect to the Internet unless you have a virus- checking program installed on your computer. It is vital to keep your virus monitoring software up to date. Many anti-virus programs, such as Norton 15 Chapter1 Information Technology Anti-Virus allow you to update the program so that the program can check for recently discovered viruses.  Protecting against computer virus infection  The safest way to use a computer is to not connect it to a Local Area network or the Internet. This is called a 'stand-alone' computer, providing that you do not use disks on that PC which have been used in other computers; this type of computer is virtually immune from any form of intrusion.  Unfortunately it is the ability to connect to other computers or indeed the Internet, which makes the modern computer so versatile and so useful.  Always make sure that all computers require an ID and password to access them. Make sure that all relevant 'security patches' from Microsoft have been applied.  Make sure that the password is long enough, contains a random mixture of numbers and letters, and that the passwords are changed on a regular basis.  What to do if you discover a virus on your computer If you discover a virus on your computer don’t panic. If your virus checker alerts you to a virus, then the chances are that it has caught the virus before the virus could infect your computer and cause damage. For instance you may insert a disk into your computer and the virus checker should automatically scan the disk. If the disk contains a virus, a message will be displayed telling you that the disk is infected, and it should automatically remove the virus. The other common method of infection is via emails.  The limitations of anti-virus software Anti-virus software can only detect viruses (or types of viruses) which the software knows about. As such it is vital that you keep your anti-virus software up to date so that it can detect new viruses which are constantly appearing. 16