Unit 2: Computer Systems

Computer Systems Created By: Alex Walls

Processors The CPU (Central processing Unit) is the brains of the computer, it receives information from the computer whether that is basic or advanced instructions. When it reaches the CPU, it is sent to the memory of the computer, storage and peripheral equipment such as the mouse etc. CPU’s are always covered by a heat sink and fan, the heatsink draws heat away from the CPU to prevent it from overheating which could destroy the computer and result in cost hundreds of pounds and loosing data. It does this so that the heat has more of a surface area to be in contact with rather than just the CPU. Another method of cooling your computer is the fan, the three most common ways a fan cools a computer is by bringing in cool air from outside the computer into the case, drawing hot air out of the computer through the case or moving the cool air across from the heat sink to cool the rest of the computer down.

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Intel® Core™ i7-3970X Processor Extreme Edition

AMD Athlon II X4 630 heatsink and fan

MotherboardThe motherboard lets everything within the computer to work together and communicate, its what everything is connected to and basically is the backbone of the computer. Every computer needs a motherboard, without one, it would be lifeless. The CPU socket is where the CPU chip sits, they can differ in every computer depending on its size and performance. It fits into Pin Grid Array (PGA) which the pins on the CPU would slot into, the amount of pins would determine the speed and size of the CPU. It also contains the slots for the ROM and RAM, these are two of the computers memory slots. The Read Only Memory (ROM)is memory that cannot be changed by a downloaded program or user, the ROM keeps all of its information even after the computer has been switched off. It does this because it stores the instructions for when the computer starts up. The Random Access Memory (RAM) is a fast type of memory in which data, programs, and applications are stored. It allows the user or programmes to access stored data in any order. There are two types of RAM, these being DRAM (Dynamic Random Access Memory) and SRAM (Static Random Access Memory). DRAM has to be constantly refreshed and is used to form a larger system ram space so it is much slower than SRAM. SRAM is used to create the CPU's speed-sensitive cache and is much faster and more expensive.

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Motherboard

Bios The BIOS (Basic Input Output System) has many different functions but its main and probably the most important is to load up the operating system. It gives the microprocessor the instructions the power up, also another task that the BIOS does is the POST (Power On Self Test), this is a test to check if the computers RAM, peripheral devices and other hardware are working correctly. If the test proves everything is working correctly the computer will carry on with the system boot. The information the BIOS and POST needs to start the Personal Computer (PC) up is stored by a small battery-powered chip called a Complementary Metal Oxide Semiconductor (CMOS), it holds some basic information including the date, time, and system configuration settings that the BIOS needs to start the computer. Each local device has its own BIOS with a unique software instructions that allows it to communicate with the CPU. This is called a Local Device BIOS and is part of a peripheral.

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BIOS chip

CMOS chip

Power Supply The power supply is absolutely crucial to the computer, without it the computer will just be a box of plastic and metal. The power supply converts alternating current (AC) electrical power from the mains, to more usable low-voltage direct current (DC) for the internal parts within the computer. Power supply's in todays day and age are now built to obey the ATX Form Factor for motherboards, this means that there are certain specifications for the dimensions, number of ports, power supply type etc to follow. This replaced the AT Form Factor very quickly after its announcement, it also soon became the default form factor which was used within the motherboards and computers at the time and today.

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ATX motherboard

AT motherboard

Hard drive configurationThe hard drive is configured into the Master hard drive and the Slave hard drive, the master hard drive is the authoritive drive and has all of the computer important features stored onto it. It is usually named C: in your computer. The Slave hard drive stores information and is called D:. Once the master/slave relationship is chosen, the direction of control is always from the master to the slave. SATA (Serial Advanced Technology Attachment) is an interface of a computer that connects bus adapters to storage devices like the hard disk. The SATA replaced the older IDE (Integrated Drive Electronics) and have now become more desirable because of its higher specs.

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IDE cable

SATA cable

PortsThere are many ports which extend from the back of the motherboard of a PC which can have peripherals connected. The most simple of the ports is the Serial Port, there are two types of serial ports, the 9-pin and the 25-pin. The serial port it not used as commonly in todays day and age then how it was before. It used to be used to connect such things as modems, mouse, and to connect a network to transfer large data files between two computers. Parallel ports were originally developed by IBM as a way of connecting printers to your computer. The reason its called a Parallel port is because as the date is transferred to the device such as a printer it sends the bits of data parallel to each other rather than at the same time like the serial port. Next and perhaps the most recognisable and most common today is the USB ports. USB stands for Universal Serial Bus, these let you connect many different devices such as, mice, printers, keyboards etc. Most devices used ports such as the serial and parallel I have talked about, but these came with many issues, one of these being they were extremely slow. USB’s were designed to eliminate these problems, now-a-days there are hundreds of devices that can be connected to a computer via USB such as; webcams, mice, hard drives, controllers, phones etc. The PS/2 connector is used to connect things such as the mouse and keyboard, they’re not as common now a days because they have been replaced by USB’s. The purple port was for the keyboard whereas the green was for the mouse.

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Cache and Graphics cardThe Cache is a type of fast memory which is used between the central processing unit (CPU) and the random access memory (RAM). It is used to store the recently used files on your computer. When the processor needs to read or write from a location in memory, it checks if there's a copy of that data is in the cache. If there is, the processor reads from or writes to the cache, which is much faster than reading from or writing to main memory.The Graphics card can also be known as a Video card, it is a piece of hardware that is installed into every computer which is responsible for putting all the pixels in order and together; to do this it takes binary data from the CPU and turns it into an image that we can see on our screens. This card also adds colour, lighting and texture to the pictures that gets displayed onto output hardware like the monitor.

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Graphics Card Cache

AGP, PS2, and North and South Bridge

AGP – The Accelerated Graphics Port, it is based on PCI but it is purposely developed to focus on 3D capabilities. It is much faster than the normal PCI slots for the original graphics cards. They were released in 1997, and now many computers have AGP capabilities.

The ZIF Socket - The ZIF socket is a way of connecting or seating chips such as the CPU, it stands for Zero insertion Force which means there is no pressure needed. Instead its weight means that the chip can just be dropped in and have a lever hold it in place. This is very useful because some parts are very fragile and could bend a pin on the PGA or a part could be malformed.

North and South Bridge – Northbridge and Southbridge are two different chips in a computers motherboard, the Southbridge is the chip that controls all of the computers I/O (Input and output) devices, such as USB devices, audio, serial, the system BIOS, and the IDE channels. Basically all of the functions of a processor except memory, PCI and AGP. Northbridge is the chip that connects the CPU to memory, and it typically deals with the communications among in the CPU.

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Output DevicesPrinters are an output device which transfers different types of raw files to paper from the computer; these are useful for creating graphic images because they can print either a professional copy or a draft onto paper. There are two different types of printers; inkjet and laser printer. The inkjet printers work by dropping thousands of dots of ink onto the paper which create the image. The laser printer produces a series of varying voltages when an image or text has been sent to it. This controls a LED in the printer; this makes flashes of laser when it falls on a charged photo conducting drum. The area with the text or image will be neutralised or oppositely charged. A toner is sprayed onto it; it only goes onto the text or image and is repelled by the background; the paper is now pressed onto the toner and is heated so that it sticks on the paper. Also a digital camera is a output device. Digital cameras are a way of taking still images of anything you want; these are often used to create graphic images because they are easily portable and have a high memory so there can be lots of photos stored on them. When connected to a computer the still images can go onto the drive of the computer or another type of memory; these are used to create graphic images because people can edit them and add effects to the images. The Scanner is a device that optically scans things such as texts, pictures and objects. The most common is the CCD which is a flatbed scanner with a glass pane with a bright light under neath which lights the pane up and a moving array in CCD scanning.

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BUSESA BUS is a collection of wires which data is transferred from one part of a computer to another. All Buses have two parts, an address bus and a data bus. The data bus transfers the actual data from one place whereas the address bus transfers information about where the data should be transferred to. Firstly, the System Bus is used to connect all the internal computer components to the CPU and main memory within the computer. The Core Bus Ratio is the multiplier, the system bus runs at a fixed speed, the processor also runs at a fixed speed. The closer the same speed, the less cycles it has to wait. Basically, the closer the bus speed is to the chip speed the faster the system runs.

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PCI Express bus card slot

Task 02 – Labelled motherboards

What is an OS?The operating system is probably the most important program that runs on a PC. It allows the computer to run other programs, they do things such as recognising input from the keyboard and mouse, sending output to the monitor and controlling external devices. There are five different classifications of different OS’s.•Multi-user: Allows two or more, even up to thousands of users to run programs at the same time. •Multiprocessing : Allows a program to run on more than one CPU•Multitasking : Allows more than one program to run at the same time.•Multithreading : Allows different parts of a single program to run at separate times.•Real time: Responds to input instantly. OS’s such as DOS and UNIX, are not real-time.Command interface operating systems are used by typing commands by typing things such as ‘COPY’ or ‘RENAME’ to allow the command to function. There is also Graphical User Interfaces (GUI) which allow the user to click on images and links which are on the screen to follow the command.

Windows Operating System There have been a lot of different Windows operating systems, all dating back to 2000 to the present day. Windows are different operating systems for computers, Windows ME was the first released which used the Windows OS instead of the older MSDOS, and the most recent is Windows 8. Windows 8 is a very modern OS and is focused around being ‘the best of both worlds’ such being touch screen tablets and your original desktop. Windows is used on most computers now a days and is the leading OS manufacturer in front of Apple. Since windows has developed over the past 28 years it has gained many different features and functions that are familiar with many Windows OS. Since Windows 95, each OS has had a renown ‘Start’ button with the windows logo on it, this has been removed in the new Windows 8 for a ‘Hotcorner’. This is just a different version of the button to take the user to the desktop.

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Windows 95 start menu

Windows 7 start menu

Windows XP start menu

Windows 8 start menu

Microsoft Disk Operating SystemMicrosoft disk Operating System (MSDOS) is a operating system made in 1981 to be used for the IBM PC made by Micosoft. It was a command line interface which meant the user wold have had to type in commands in order to use it, this is unlike modern day OS which use Graphical User Interface (GUI) which allows the user to use images instead of text commands. After the release of Windows ME MSDOS began to not be used as the newer OS took ever.

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This is an example of the start up for MS-DOS command line, this one showing the root of drive C

Apples mobile operating system (iOS)

IOS is the Apple mobile operating system which is used to run apps within the iPhone. Usually and OS comes with preinstalled programs such as Windows Solitaire. It used simple touch screen gestures to operate the device, or ‘accessibility’ settings can be configured. IOS comes with apps preinstalled such as music and video players. Since its release it has gone through numerous updates including things such as: adding new apps, multi tasking, bug fixes, and layout. The current IOS is IOS6, this is available as an update for some previous Apple device owners or it comes as default when bought new. It has many features which are improved or completely different to other IOS’s. Siri is one of the main and most modern features on Apple devices, it was introduced to the iPhone 4S which was running IOS5, it allows user to ask questions or just interact with the device by simply using their voice. Since the iPhone 4S there have been many bug fixes and updates to improve factors such as Siri.

Explain the following software utilities – Virus Protection

Virus protection is a type of software which is designed to protect a computer by detecting and preventing viruses, Trojan horses, worms and malicious malware from entering the computer. There are many different software options available, there are free versions available such as ‘AVG’ and there are payable options such as ‘Norton’ which have more features. Most modern virus software's have bundles with anti-spyware and anti-malware. They update by downloading profiles of viruses so that they can search for them and find them in the hard drive. Also most include a firewall, this is a virtual wall which acts as defense to the computer system. It decides whether items are safe to pass through it or not, users have the ability to say whether they wants something to pass through or not and can give access to certain websites, downloads and users etc.

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AVG Free This is the main navigation screen of AVG 2013 Anti-virus FREE version and it allows the user download more options, update or start a scan

AVG FreeThis is the scan in progress it detects the problems then removes them from the computer.

Explain the following software utilities – Defragmentation

Defragmentation is a process where folders and files are scanned and have the amount of fragmented files removed, this means they are disorganized and not in the correct place. This can result in the system running slower than usual. This process normally organizers files and improves the retrieval time and overall performance, by doing all of this it left a big chunk of free space in the drive which meant that al of the new files to be saved neatly and organized. This would mean that the need for defragmentation would be less common in the future. The way to ‘degrag’ the disk is using the pre installed tool which comes with every computer systems, within the tool you can analyse your disk to see if it needs defragging at the time.

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DefragmentationThis is the first screen the user sees of a Disk Defragmentation tool, it gives the option to configure schedules, analyse the disk or defragment the disk.

DefragmentationThis is the defragmentation in process after it has been analysed, it can take up to a few minutes to a few hours.