Computer Hardware

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Computer and internet technologyComputer HardwareA report forGeoff WingfieldByAndrew Hobbs

06/12/14

Table of Contents1Introduction22Computer Hardware22.1Data transfer and the Computer Bus22.2Microprocessors and heat dissipation52.3Power Consumption53Computer Components and speed64Building a PC95Computer Benchmarking106Telephone and Internet System127Abbreviations158Bibliography15

IntroductionThis report is being written to investigate the properties and electrical theory behind computer hardware and the main components of a computer system. It will also look into the internet and the telephone infrastructure that it is based upon. This will be achieved in five research and analysis tasks, which, more specifically, will take an overview of electrical theory and the common hardware components found inside a modern computer and also investigate data rates, heat dissipation, benchmarking and the internet and telephone system. On top of this, a research task will highlight the pros and cons of building a custom PC and the relative cost of purchasing a ready built PC. Computer HardwareData transfer and the Computer BusThe devices inside a computer are all interconnected with each other to allow each component to communicate with each of the other components. Several groups of copper tracks on the motherboard (PCB), each called a Bus, provide these interconnections. The Motherboard in a PC is the base of the unit, containing the Buses along with all the other electronic circuitry that serve to link together and drive each of the main hardware components needed to provide an Operating System and User Interface. Typically, a PC would have a processor, hard disk drive, RAM, Graphics Card, Optical Drive and a power supply, all connected to the motherboard to allow the PC as a whole to function.

Figure 1Each arrow in the diagram (above) represents a Communication Bus system for the transfer of data between the various hardware components of a PC. The BIOS (Basic input/output system) is the firmware installed on the motherboard to allow the user to access the machines boot options and drives without an operating system. It also manages the hardware power up, checks the system is running ok and chooses (or allows the user to choose) which hardware device to boot from. The speed, at which a computer can run, measured in Hertz, is defined by the speed of each piece of hardware and the highest speed the buses can operate at. The processor will typically be the fastest item in the machine and might run, for example, at 3.1Ghz (Gigahertz) but the Hard drive (where all the data is stored) is a mechanical item and may only run at 7200rpm which equates to a much smaller frequency (or speed). The buses are ultimately limited in speed as well. This is because a bus consists of multiple pairs of tracks. A pair of tracks can be considered like the diagram below.

Figure 2The diagram illustrates that a pair of tracks actually has a resistance, a capacitance and an inductance. The resistance is simply the opposing force, measured in ohms, which the electrons moving through the copper must pass through. A capacitance is present between the two copper tracks because the air between them acts as a dielectric (just like in a normal capacitor), however the capacitance is very tiny. The right hand thumb rule explains that any current carrying wire produces a magnetic field which induces a back-EMF and therefore a secondary current that opposes the first (for an AC signal). Both wires produce magnetic fields which resolve to form a resultant (larger magnitude) magnetic field. For an AC signal, both capacitance and inductance generate forces opposing the flow of electrons depending on the frequency of the signal. This is called reactance (inductive and capacitive). The equations for calculating the reactance based on the capacitance, inductance and frequency along with the corresponding graphs are shown below.

Figure 3: Capacitive and Inductive Reactance (learnabout-electronics.org, 2014)The graphs show that frequency is directly proportional to Inductive reactance and indirectly proportional to capacitive reactance. This means that as the frequency increases, the inductive reactance increases and the capacitive reactance decreases. You can see from Figure 2 that this effectively tends towards a short circuit between the two tracks as frequency increases because the impedance across the capacitor is decreasing and the impedance across the inductor is increasing. So, in conclusion, any parallel bus system will always be limited to a maximum speed because as the frequency of an applied data signal increases the impedance (overall resistance) of the bus increases exponentially and tends towards infinity.Microprocessors and heat dissipationThe CPU or central processing unit is the brains of any computer system. It is made from millions of tiny electronic devices called transistors which are used to complete addition and subtraction of binary numbers millions of times a second. Each transistor is very tiny, some as small as 10nm, but they do have a tiny resistance. As Ohms law states, when a voltage is applied to a resistive load and a current is drawn, energy is transferred with the movement of electrons. Although each transistor only draws a tiny amount of current, and therefore only produces a tiny amount of power, when you add together the power used by all the millions of transistors it equates to a relatively large amount. As with any system that requires power, there is a percentage of wasted energy to contend with. As the electrons travel through the conductor, they bump into each other and transfer the energy they are carrying, however it is not 100% efficient and some is wasted or excess and turned into heat energy. All the tiny amounts of wasted heat from each energy transfer add together to become a large temperature increase. This is why modern CPUs require a large heat sink and lots of fans to draw the heat away from the chip itself and transfer it into the surrounding environment to prevent the chip from overheating and melting.The faster a CPU runs (the higher the frequency of the signal) the higher the impedance of the chip for the same reasons as buses tends towards a maximum speed. Due to the inductive and capacitive nature of electronic devices, impedance increases with frequency and therefore so does current drawn and energy transferred. A higher amount of energy being transferred means a higher amount of wasted energy or excess energy that is given off as heat. Power ConsumptionTo investigate the running costs of an average computer lab in a school or business, assume a PC consumes on average 200 watts per hour for 10 hours a day. A unit of electricity costs 15 pence. How much would it cost to run 20 PCs for a 5 day week? 1000W/Hour costs 15p200W/Hour costs 3pFor 10 hours thats 30pFor 5 days that 150pFor 20 computers thats 3000pSo it costs 30 for 20 computers running at 200W per hour for 10 hours a day during a 5 day week.So to run an average computer laboratory for a week it will use 200kW of power and cost the business 30. Taking into account the number of computer labs in one building or even in one city, or even in the country, a lot of energy is being used and spent. Globally, the impact on the environment will be huge because of all the fuels being burnt to produce the energy required to run all the computers.Computer Components and speedAs previously stated, processors are made up of an intricate network of tiny transistors that work together to perform thousands and thousands of simple operations (like addition and subtraction) a second. Moores law is an observation by Gordon E Moore that the density of transistors in an integrated circuit will double in size every two years. This has proven to be a very reliable forecast and has actually been a target for the developers of processors over the last 30-40 years. This observation accurately portrays how the latest technology is used to optimise the speed of processors. Over the past 40 years, processors have increased in speed exponentially and in proportion to the number of transistors built into a similarly sized package. A package is a piece of silicon die that meets the requirements of the processor specification. The fundamental principle of this process is that the more transistors in a package the more operations per second can be carried out and therefore the higher clock speeds can be achieved. Modern processors have been built to contain multiple cores which allows them to complete multiple operations (or to run multiple threads) at the same time whilst sharing peripheral circuitry with the other cores. Another modern technique to improve overall processor speeds is called Hyper-threading. Hyper-threading still only allows one thread to be completed at a time but it does allow the next thread (operation) to start just after the first so that both operations move through the process staggered. For example, if a single operation runs from point A to Point B to Point C before completion, hyperthreading allows the next operation to start running as soon as the first has left point A to move to point B. In this way the processor becomes a lot more efficient as the number of parts of the processor that are idling is reduced.RAM (or Random Access Memory) is a temporary store of data that is directly connected to the processor with its own dedicated bus system. RAM can be accessed (read/written) much quicker than a Hard Drive as it works from capacitors and transistors and is solid state whereas the hard drive is mechanical and therefore limited in speed by its arm/rotor system. RAM is used to store data from the hard drive that would otherwise have to be accessed often and slow the processor down. Advances in RAM technology have led to the development of multiple different types of RAM and cache memory. Amount of data storage space and the speed at which the memory can be accessed are nearly always inversely proportional. D-RAM (or dynamic RAM) is the standard and contains most of the intermediate data between the hard drive and the processor. Its technology is based on capacitive charging using FET transistors and the data is constantly being refreshed (re-written) as the capacitors In the system will only hold charge for a short amount of time. S-RAM (or static RAM) is based on older bi-polar transistor technology and is used for very fast cache memory.To increase overall computer speed, very fast RAM or cache memory is used at varying levels in the processor which allows for very fast access to progressively smaller amounts of data. In most modern processors there are three levels of cache memory, L1, L2 and L3. L3 cache is located in the processor core and can run at speeds almost rivalling the processor itself but only contains tiny amounts of data. L2 cache sits in the processor but outside of the core, has slightly more storage and is a little slower than L3. L1 cache is external to the processor and acts as an intermediary between the RAM and the processor for data that is accessed most often. Another technological technique to improve speeds is the stack. The stack is a separate section of the RAM dedicated to managing the threads or current operations of the processor. This is necessary because the processor can only run one operation at a time so its designed to swap operations in and out of the stack to achieve almost simultaneous operation.A hard disk drive is a mechanical device used for storing large amounts of data. The basic construction consists of one or more ceramic disc coated in thousands of tiny magnetic filings and an actuating arm with a coil on the end to act as a magnetic encoding head. The arm can either read or write by either using it powered or unpowered. Data is stored by simply manipulating the magnetic filings to either lay one way or the other which represent a 0 and a 1. The manufacturers of hard drives will complete low level formatting which splits the hard drive into sections called sectors or clusters. This is basically a quick reference notation system to allow faster access to the file that is required rather than searching the whole disk. A sector is 512 bytes and a cluster is made up of 8 sectors (4KB). The operating system of the computer system will set up high-level formatting of the hard drive to organise the data storage at a software level.Improvements to hard drive technology include increasing the number of disks and heads in a system to allow for a greater amount of storage and increases to read and write speed. Improvements to speed have been implemented by building in technology to increase the speed at which the physical disc can turn (RPM) and the seek speed of the arm which allows for quicker location of the required data. A certain amount of fast access cache memory or RAM is added to modern hard drives as a much faster intermediary data storage solution between the HDD and the RAM. Frequently used data is preloaded into the cache while the system would otherwise be idling to decrease the access time when the data is called for.Solid State Drives are another form of long term data storage that has been recently developed in an attempt to increase the overall speed of computer systems. The Solid State Drive has no moving parts (as the name suggests) and is based on similar technology to RAM, with capacitive transistors being used to store data rather than physical magnetic filings. The advantages of solid state drives are that much greater access speeds can be achieved because the drive is not limited to the speed of a physical rotating disc or actuating arm. However, SSDs fall down on reliability and longevity. Due to the capacitive nature of SSDs they have a limited number of read/write cycles that is far lower than a conventional HDD which makes them less reliable. Also, as an emerging technology, the SSD is still in feverish development and therefore has a higher price tag than standard HDDs which are near to perfect or as good as they are going to get.Graphics cards have been designed to speed up the computer operation as whole. As there is a developing requirement for large amounts of graphical processing (for games or 3D image manipulation), the standard CPU began to struggle to handle the number of computations need per second. The graphics card, which contains a GPU, V-RAM and its own cooling fans, is built to handle lots of simple graphics computations per second, leaving the CPU to process other normal computer tasks. A GPU is generally slower speed than a CPU but has as many as a thousand cores as opposed to just 1 4 in a normal CPU. V-RAM or Video RAM is a special type of RAM designed to hold graphics data for the GPU to access quickly.Building a PCAn example of a mid-high performance computer that could be used for media manipulation or gaming is the Hermes.(Ukgamingcomputers.co.uk, 2014)Hermes I7 Gaming PC (859.99)It can be purchased pre-assembled and ready to go for 859.99 presuming the user has already obtained a display, keyboard, mouse and operating system. Below is the price breakdown of all the parts needed to compare this with building a custom PC with a similar specification.ComponentPrice (Individual)

Coolermaster CM Storm Enforcer63 (amazon)

Corsair CX750 750W60 (amazon)

Intel Core i7 4790K 4.00Ghz [overclockable]243 (amazon)

8GB Corsair DDR3 XMS3 1600MHz63 (amazon)

Gigabyte Z97-HD3 R2.080 (amazon)

Nvidia Geforce GTX 760 2GB159 (amazon)

Seagate Barracuda 1TB HDD 7200rpm 64mb Cache42 (amazon)

Asus DRW-24B5ST 24x DVD/CD +/- Re-Writer Black14 (amazon)

Total724

On top of these parts a self-build user would also need to purchase Thermal compound, SATA cables, cable management and extra case fans. Factoring in the time taken to put the PC together and the relative risk involved with assembling the processor and motherboard manually without any guarantee of money back if something goes wrong it is clearly better value for money to pay for a pre-built PC. Another advantage of a pre-built machine is the warranty that comes with it, for example, the Hermes comes with a 6 year limited warranty covering component failures due to faulty parts or build quality. It should be noted however, that the Hermes is bought from a retailer specialising in pre-building computers and purchasing a pre-built of this specification from a normal PC retailer could cost more so it pays to shop around. A general trend in building computers is that the more expensive the cost of the build is the more value for money it becomes for a user to build the computer themselves. Computer BenchmarkingHistorically a Benchmark was literally a mark in a bench used for measuring materials to a certain size quickly and accurately. Since then it has become the term used for testing a system against a particular set standard to see how much better or worse that system is relative to the standard.In Computing, a benchmark is generally a series of tests or applications run in a row that are specifically designed to stress the various components of a computer and record the time taken to complete each task and the total time taken and use the results as a measure of performance (or a benchmarking score). There are really two types of computer benchmarking tests: Synthetic Tests and Realistic Tests. Synthetic tests are specifically designed software programs that usually perform very simple assembler level operations repeatedly to stress the hardware at its maximum speed and capacity and measure the time taken to complete the tasks. These types of test can be subject to bias and therefore do not always provide a realistic performance rating (how the computer will actually perform in the real world). Manufacturers of computer hardware can choose to run a specific type of synthetic benchmark test on their system which may have been purpose built to perform exceedingly well at whichever operation that particular benchmark test is using. This will result in a very high benchmarking score that wont be reflected in real world performance and could be misleading to clients and customers.For example, in 2008, Nvidia claimed that theyre GPUs could achieve any operation the new high-end quad core CPUs could and still outperform them. To prove this Nvidia showcased a video transcoding app that used Nvidias GPU to convert video 19x faster than a high end quad core CPU. Very impressive, however, it turned out that the particular application could only utilise one of the four cores on the CPU and when the test was rerun using an industry standard video transcoding application the difference in performance between the two processors was minimal. (Rothman, 2014).A realistic benchmarking test is run from a user environment and usually gives a much more reliable result. Normally, a program or game that is not designed as a benchmark test is used to complete an operation or set of operations repeatedly and then timed to give a measure of performance. For example, a macro (recording of a group of operations) can be set up in Adobe Photoshop to perform the same set of operations on the same image over and over. This can then be timed on multiple hardware configurations to see which performs the best.Using these two tests provides computer users with a quantitative measure for each piece of hardware or a computer system as a whole that can be compared with other hardware or systems to allow for a more accurate method of determining how to build the highest performance computer. It is also useful for users to know the benchmarking score of their PC and/or PC components to allow them to select programs, applications and games that their system can run and it will provide a measure of how well it will run each application or game. For example, the minimum system requirements for Crysis 3 are a Pentium Dual Core E6600 3.06GHz and 2GB RAM. (Game-debate.com, 2014)If the user of a system has an AMD processor how will he/she know if they can run the game acceptably? Checking the benchmarking score of their own CPU and comparing it to a benchmarking score on the Intel Pentium would provide the answer.There are many system benchmarking programs available to download online (Paid for or Free).- NovaBenchDownload

- FutureMarkDownload

- PassMarkDownload

- CPU Benchmark (cpubenchmark.net)Online

One of the most accurate and popular free benchmarking software systems is SiSofts SANDRA 2012. This software provides a multitude of testing options that will either test your system as a whole in a number of different ways or run tests that target individual components whilst minimising workload on other computer components. This software also provides benchmarking scores for other popular hardware components as well as a few example systems for comparison purposes.(PC World, 2014)

Telephone and Internet SystemThe telephone and internet system largely consists of a huge network of routers and cables that connect people together from all around the world. Large telecommunications companies and ISPs (Internet Service Providers) provide networks of routers and switches to control the flow of network traffic and provide links to other telecommunication networks in other regions of the world. At a local level, each household will have a router that is connected to the phone line in some way. This is normally achieved through an ASDL filter which uses Frequency Division Multiplexing (FDM) to separate phone calls, downloads and uploads. The router can usually have unlimited connections (bandwidth and throughput allowing) and each device connected will have its data send over the telephone wire using Time Division Multiplexing (TDM). The phone line is then connected the local exchange by a transmission media, along with all the other properties in roughly the same postcode.Transmission media can vary between standard copper cable (dial-up), coaxial (broadband) or Fibre Optics. Broadband lines allow for multiplexing and is pretty much the standard for modern life. Dial up enables using the internet over the phone line but doesnt facilitate multiplexing which means a user can only use either the phone or the internet and not both at once. Fibre optics is the latest in internet speed developments and uses pulses of light to transfer data instead of electrons through a copper cable. This achieves the fastest possible data connection (the speed of light) but is an expensive system to implement and ultimately the user is still limited by the speeds from the local exchange to the main exchanges and ISPs.The local exchange box will generally be situated no more than a kilometre away. This is because most systems still use copper cabling and the longer the cable the larger the impedance (resistance) to the current carrying the data. The impedance of the wire is calculated using the resistance, capacitance and inductance of the cable along with the frequency of the supplied signal. As the frequency increases so does the impedance so it is necessary to either sacrifice distance of the cable or the frequency of the signal. Bandwidth is a term that comes from analogue electronics and refers to the range of frequencies able to pass through a conductor. In networking, the useful or useable range of frequencies is defined by the -3dB point (or roughly 71% of the maximum signal amplitude). Any electronic media has a frequency response curve, a therefore a bandwidth, that is based upon its characteristic impedance when an AC signal is supplied. So there is a limited (large, but limited) range of frequencies that signals can be sent down a wire.

Figure 4: Bandwidth and -3dB point (Images.elektroda.net, 2014)Throughput is the amount of data being transmitted past a point per second and is the definitive measure of speed in a networked system. Multiplexing is the technique of chopping up the bandwidth to allow multiple signals to be transmitted over the same wire almost simultaneously. There are two types of multiplexing: FDM; and TDM. FDM (Frequency Division Multiplexing) is the technique of using filter circuitry to chop up the available bandwidth into channels of smaller bandwidth. This allows many channels of data to transmit simultaneously and is the principle technology used in ASDL filters to separate phone calls from broadband uploads and downloads on the same phone line to the local exchange.TDM (Time Division Multiplexing) is a method of multiplexing which allows each signal to use whatever bandwidth or frequency range it needs but only provides a set time period for data transmission per channel. A TDM system has a multiplexor at one end and a de-multiplexor at the other which are linked to run in synchronous. The multiplexor manages all the incoming signals by chopping them up and sending a set range of data for each channel one after the other and the de-multiplexor takes each chunk of data and directs it back to its intended destination at the other end.From the local exchange data is sent to larger, centralised exchanges normally located in large towns or cities to be routed to your ISP or telecommunications company for routing towards the destination. Every device connected to internet is allocated an IP address based on the router it is connected too, size of the local exchange and geographical location. Data is sent in packets with a destination IP address to aim for and is routed through large exchanges with each packet potentially taking a different route depending on volume of traffic down each route and availability of servers and routers to point the way.The internet uses a packet switched system to help maintain even traffic flows and good data transfer speeds even at times of peak activity. This is as opposed to a continuous connection based system like the phone system utilises. Any data sent over the internet is chopped into tiny packets of data about 4KB in size and sent individually to its destination. The advantage of this is that any data lost needs simply to be requested again and can be sent very quickly instead of missing data leading to a corrupted file and having to re-download the entire file. Also, individual data packets can be routed the quickest and least busy way to help improve overall traffic flow and keep internet speeds higher.A data packet is normally split into a header, the data and a trailer. The header will contain information like the source IP address, the destination IP address, the file address and a size. The trailer will denote the end of the packet transfer.Whichever OS (Operating System) is being used will contain a protocol stack that is used to packetize data. An application wishing to send data over the internet will load the data into the protocol stack which will establish a connection, chop the data into chunks, interface to the hardware, send each packet one by one (really fast) and wait for acknowledgement of the packets arrival.

Figure 5: Protocol Stack (Novell.com, 2014)

AbbreviationsPCB Printed Circuit BoardRAM Random Access MemoryI/O Input/OutputBIOS Basic Input Output SystemCPU Central Processing UnitSATA Serial Advanced Technology AttachmentUSB Universal Serial BusRPM Revolutions per minuteEMF Electromotive ForceIC Integrated CircuitFET Field effect transistorFDM Frequency Division MultiplexingTDM Time Division MultiplexingOS Operating System

BibliographyLearnabout-electronics.org, (2014). Figure 3: Capacitive and Inductive Reactance [online] Available at: http://www.learnabout-electronics.org/ac_theory [Accessed 1 Dec. 2014].Images.elektroda.net, (2014). Figure 4: Bandwidth and -3dB point. [online] Available at: http://images.elektroda.net/90_1310131721.png [Accessed 28 Nov. 2014].Novell.com, (2014). Figure 5: Protocol Stack. [online] Available at: https://www.novell.com/documentation/nw65/ntwk_ipv4_nw/graphics/con_022a.gif [Accessed 5 Dec. 2014].Rothman, W. (2014). Computer Benchmarking: Why Getting It Right Is So Damn Important. [online] Gizmodo. Available at: http://gizmodo.com/5373379/computer-benchmarking-why-getting-it-right-is-so-damn-important [Accessed 25 Nov. 2014].Game-debate.com, (2014). Crysis 3 System Requirements and Crysis 3 requirements for PC Games. [online] Available at: http://www.game-debate.com/games/index.php?g_id=3953&game=Crysis%203 [Accessed 2 Dec. 2014].PC World (2014). How to Benchmark Your PC for Free. [online] PCWorld. Available at: http://www.pcworld.com/article/258473/how_to_benchmark_your_pc_for_free.html [Accessed 4 Dec. 2014].Ukgamingcomputers.co.uk, (2014). Hermes - i7 Gaming PC | i7 PCs | Gaming PCs & Custom PC desktops - UK Gaming Computers. [online] Available at: http://www.ukgamingcomputers.co.uk/hermes-i7-gaming-pc-p-98.html [Accessed 4 Dec. 2014].Computer HardwareComputer and Internet Technology Report by Andrew Hobbs Year 1 HNC Engineering (Electronic Design) 06/12/14