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Hardware: Putting the system together

1. PAUL MOBBS A practical guide to sustainable IT Unit 3 Noni This unit is one of 12 sections to a A practical guide to sustainable IT a hands on guide to working with everyday technology in an environmentally conscious way The guide has been written by environmental activist and ICT expert Paul Mobbs and was commissioned by the Association for Progressive Comunications APC with the support of the International Development Research Centre IDRC To download the full text of the guide or any of the other units please visit greeningit apc org A practical guide to sustainable IT Author Paul Mobbs Copy editing Alan Finlay Layout proofreading Lori Nordstrom Publication production Karen Banks and Flavia Fascendini Graphic design Monocromo info monocromo com uy Phone 598 2 400 1685 Commissioned by the Association for Progressive Communications APC cr CNS CS a Conducted with support from the International Development Research Centre IDRC 3 IDRC CRDI Canada The views expressed in this publication are those of the individual authors and not necessarily those of APC or IDRC A practical guide to sustainable IT Published by the Association for Progressive Communications APC with support from the International Development Research Centre IDRC South Africa 2012 Creative Commons Attribution 3 0 Licence lt creativecommons org licenses by nc nd 3 0 gt Some rights reserved APC 2
2. sound audio or ethernet use standard fittings these will be easier and cheaper to replace For power supplies especially being able to use a generic power supply means that you can reuse the unit with other equipment when the machine reaches the end of its working life Check that repair is an option rather than whole sale replacement Check that spares for the most likely parts of the equip ment to fail such as rechargeable batteries hard drives cables and connectors are available at a reasonable cost even if it requires a service technician to undertake repairs Does the equipment contain hazardous substances In compliance with recent legislation in Europe and else where goods should indicate whether they contain haz ardous compounds such as mercury cadmium or lead Some manufacturers are also producing goods which are free of PVC and flame retardants Is there are take back trade in option If you rent lease goods you should expect them to be taken back at the end of the lease For goods which are bought check if the manufacturer runs a take back scheme for the machine or the machine s consumables such as ink toner cartridges Does the warranty offer on site service If the device fails you may have to send it back to the manufacturer s service department for repair which is likely to cost time and money Check if the manufacturer can offer a contract with a service company to carry on site repairs as this may
3. Ethernet connector Usually with indicator lights to show when connected in use Firewire port 21 IEEE 1394 firewire socket Alternative format to USB used on some video cameras digital AV equipment S PDIF coaxial output port RCA or phono coaxial connector used to connect digital sound output to home theatre system Usually yellow coded USB port 23 Universal serial bus USB standard type A socket Digital video port 29 pin Digital Visual Interface DVI socket used to connect digital video output to home theatre system video capture devices High definition multimedia interface HDMI HDMI type connector used to connect high definition HD video monitors video games displays Wide RS232 serial port 25 pin D plug Was once used for connecting modems but superseded by Ethernet USB devices a decade or so ago S video port Four pin DIN socket provides video output to a compatible TV video display Hardware Putting the system together 25 A practical guide to sustainable IT This practical guide to sustainable IT offers a detailed hands on introduction to thinking about sustainable computing holistically starting with the choices you make when buying technology the software and peripherals you use through to how you store and work with information manage your security save power and maintain and dispose of your old hardware Suggestions and advice for pol
4. a choice between hardware with a similar specification a longer warranty can represent a more reliably engineered sys tem which is less likely to go wrong Does the manufacturer provide environmental reporting information The issue with environmental reporting such as mea surements of power consumption embodied energy waste production and carbon emissions isn t simply that it gives you extra information to decide between different brands or devices Companies which issue environmental reports are more likely to police the activities of their sup pliers to ensure that they conform with the product stan dard and that ensures that tight environmental stan dards are applied in everyday industry practice Check for non branded equivalents for the equipment Branded goods have the greatest exposure in the me dia but often more generic non branded equivalents are cheaper The spares for non branded goods may also be cheaper and more easily available as they are more likely to be used in a range of consumer goods Warranty periods terms are also important in making a choice be tween branded non branded goods Is the user able to service and repair the device Enquire if the device is a sealed unit or whether the user can easily replace components which might fail over its operating life Check if the device uses proprietary or standard generic cables connectors If a device uses a generic power supply and the connectors e g
5. be cause only small hard drives are accepted by the motherboard This limits the maximum storage available and is a problem because small hard drives a few gigabytes or less are hard to find these days SATA doesn t have these same re strictions as it is designed to handle very large storage capacities and as a recent standard there s no problem getting hold of large SATA compatible hard drives 3 3 8 PC cards front panel connectors and BIOS The AGP 5 and PCI 8 slots are edge connec tors they re designed to have a circuit board slotted into them to extend the functions of the motherboard For most everyday functions you won t need to bother about the slots It s only when you need something out of the ordinary such as an internal modem or something non standard like a data logging or specialist inter face card that you ll need to use these slots An important consideration about PC cards is that they consume power Some such as the high performance AGP card used by the lat est video gaming machines use a very large amount of power a good indication that a card consumes a lot of power is when it has its own cooling fan If you can get by without installing a card in the machine this will minimise power use If you must install a card such as a parallel interface card for an old style printer cable then check with the manufacturer s specifications to find a the card which has a low power consump tion N
6. board so the maximum number of drives is limited by the number of SATA sockets available on the board Figure 3 5 IDE and SATA drive configuration Ghetenenes prererese state 40 way ribbon cable connector Power Jumper connector block Ribbon cable Motherboard d IDE 0 slave device 134sew i E IDE 0 master device Note Not all drives use this order Note that the miniature 21 2 inch hard drives used on laptops operate in the same way as the standard 31 2 inch hard drives used in desktop PCs and come in both IDE and SATA versions If you want to upgrade a laptop hard drive the manual for the machine should tell you what type of drive is used and what capacity of drive the machine is capable of accommodating One very important point adding extra hard disks can add a large power drain to the computer system For that reason you need to have the minimum practi cal number of hard drives to create the amount of data storage required For example a single one terabyte TB hard drive will use less power than two 512 gigabyte GB hard drives If reducing power consumption is important then use just one large hard drive rather than two or three smaller drives The exception would be where you are using another hard drive as a back up for the primary hard drive but as we ll examine in the section on Infor mation storage you can use a removable drive caddy to avoid the need to have th
7. has two sockets called IDEO and IDE1 A 40 wire ribbon cable plugs into a socket and each cable has either one or two connectors so a maximum of four IDE drives can be attached to the motherboard Although all IDE drives work the same way when connected to the ribbon cable for two drives to share the same cable one has to be classed as the master drive and the other as the slave This is done by changing the position of a small jumper connector on the back of the drive If the drives are not correctly selected then there will be a clash when the motherboard tries to talk to them and they won t work Not all drives have the same jumper order to select the drive but the correct order is usually displayed on the top of the drive There is another option called cable select but in many cases that doesn t work Over the last few years a new standard serial ATA or SATA has been introduced This is an improvement over the previous IDE system not only because it gets rid of some of the barriers to the size of drive but it also gets rid of the ribbon cable Having two connectors on a rib bon cable was always difficult to arrange when putting a system together and it also interfered with the air flow needed to cool the drives SATA uses thin cables which are far easier to connect up than ribbon cables and also does away with the need to select the drive using a jump er Instead each drive plugs into a socket on the mother
8. on old computers using the drive is difficult as most operating systems no longer include the programs to make the hardware work Even so many motherboards still include a floppy drive connector 7b it looks like a shorter version of the hard drive IDE connector 7a A hard drive is a spinning aluminium disc or platen coated in a magnetic material The heads travel across the surface of the disk to write data by magnetising spots on the surface or read the stored data by sensing the magnetised areas pass ing beneath the head The disk is enclosed in a hermetically sealed metal housing to prevent dust 31 Wikipedia Hard disk drive en wikipedia org wiki Hard_ disk_drive 32 Wikipedia Computer data storage en wikipedia org wiki Computer_data_storage 33 Wikipedia Floppy disk en wikipedia org wiki Floppy_disk 34 Wikipedia Boot disk en wikipedia org wiki Boot_disk Hard disk drive schematic Rotation 0 Heads Armature Platen disc Armature turns to access tracks across the whole platen particles getting inside The heads hover above the spinning disk at less then the width of a human hair in terms of the scale and speed involved it s been likened to a 747 airliner travelling at full speed about six feet off the ground Particles of dust or worse still a human hair would cause damage to the disk and the heads which is why it s sealed away The metal housing also
9. pixels at all they just dis played characters In terms of the amount of data 28 Wikipedia ASCII en wikipedia org wiki ASCII 29 Wikipedia Unicode en wikipedia org wiki Unicode 30 Wikipedia Accelerated graphics port en wikipedia org wiki Accelerated_graphics_port involved 24 lines of 80 characters at one byte per character is 1 920 bytes Now think of a modern wide screen video display It usually has 1 366 pix els across the screen and 768 from top to bottom Each pixel is capable of representing in excess of a million colours which means each pixel takes 24 bits or three bytes of data to represent its value 1 366 pixels x 768 pixels x 24 bits three bytes is 3 147 264 bytes and given that the screen re freshes its image at least 50 times a second that represents a data flow in excess of 150 megabytes per second In physical terms that s the content of a data CD disc every 434 seconds In fact the AGP slot is designed to handle over 500 megabytes per second equivalent to a blank DVD disc every 834 seconds that s far more data than the mother board s PCI slots can handle which usually have a capacity of 128 megabytes per second The CPU would find it difficult to shift 150 to 500 megabytes a second to the video display and do all the other tasks it needs to perform If you want to play videos or an animated video game without the display jumping and hiccuping all the time then the video display system has t
10. power which is why they produce so much heat However how much power the computer appears to use might not actually be consumed by the computer That s because the quality of power supplies varies and lower quality power supplies can have a very low power factor a value which expresses the amount of power drawn versus that actually used by the equip ment Measuring power consumption and es pecially measuring the power factor can give you an idea of how much power is consumed by all or part of the computer system Whether you choose to upgrade or replace parts of the system then depends on the likely cost savings and the cost of upgrades see box 3 5 Recently anew 80 Plus standard was introduced for power supplies guaranteeing a very high power factor and thus much lower power consumption When replacing power supplies look for an 80 Plus certified unit or browse the web for accredited suppliers 41 Wikipedia Power factor en wikipedia org wiki Power_factor 42 Plug Load Solutions 80 Plus Certified Power Supplies and Manufacturers www plugloadsolutions com 80PlusPowerSupplies aspx Hardware Putting the system together 19 Box 3 5 Power consumption and power factor measurement For mains powered systems the simplest way to mea sure power consumption is to use a plug in power meter These are available for both 230V and 110V supplies and can give a variety of data about the power consumption of the comput
11. protects the sensi tive magnetic materials inside from stray magnetic fields that might affect its operation There are two standards now in common use for PC drives Integrated Drive Electronics IDE or Parallel Advanced Technology Attachment E IDE or parallel ATA and Serial Advanced Tech nology Attachment serial ATA or SATA Any motherboard more than four or five years old will use IDE E IDE 7a a motherboard less then two years old will use SATA 6 although some retain IDE sockets for compatibility those motherboards manufactured between these times will use ei ther and a large number use both There is a third standard drive interface Small Computer System Interface SCSI but that s not commonly found on PC machines It was mostly used on server ma chines because it allowed a large number of hard drives to be connected to the system Early Apple Macintosh machines also used it Compact flash memory cards are used in stead of electro mechanical hard drives on note book and tablet machines and the latest disk 35 Wikipedia Parallel ATA en wikipedia org wiki Paral lel ATA 36 Wikipedia Serial ATA en wikipedia org wiki Serial_ ATA 37 Wikipedia SCSI en wikipedia org wiki SCSI 38 Wikipedia CompactFlash en wikipedia org wiki Com pactFlash 16 A practical guide to sustainable IT Box 3 4 Hard disk drives Most PC hard drives until recently used the IDE stan dard The motherboard
12. take less time to organise 8 A practical guide to sustainable IT reason power hungry They are intended to run computer networks or large internet data cen tres and so are not the sort of machine you d use for general purpose computing Some servers are stand alone boxes rather like a desktop machine For the last decade or so the trend is to shift away from single machines to rack or blade hardware where multiple server machines operate in a single large case In the rest of this unit and the unit on Reuse and reclamation later we ll primarily deal with desk top computers The principles involved in desktop machines also apply to most laptop machines although the hardware is more difficult for the inexperienced user to modify We ll investigate the installation software on the machine in the next section Operating systems What we ll look at below is how a standard desktop machine works how to identify the different parts of the machine and what all that jargon about hard ware specifications actually means There is one golden rule to remember when using computers Computers are stupid At the simplest level computer hardware is a col lection of electrical circuits which need to be told what to do by a computer program The central processing unit CPU of the machine is designed to carry out a set of instructions contained in a computer program Each instruc tion is initiated by giving the CPU one or more num
13. which controls the input output devices on the motherboard It collects together a large quantity of data in its memory buffer and then when there s a gap available on the front side bus it moves the data at high speed into the main memory This allows the CPU and memory to continue operating at high speed without continually being interrupted by data travelling to and from the peripheral devices Hard disk drives have been the main meth od of secondary storage on personal comput ers for over 20 years Before we had hard drives PCs relied entirely on cassette tapes or on floppy disks First the truly floppy 54 inch disks made of a plastic film sandwiched in a card sleeve then the more sturdy 32 inch disks held inside a rigid plastic shell The very first PCs used a floppy disk to boot up the computer with an operating system In fact most operating systems allow you to create a removable boot disk to restart the system in the event of a hard drive er ror although today you might use a CD or a USB stick since floppy drives are now obsolete When complete the system disk could be removed and other disks used to store data were inserted as required Hard disks have the advantage that they are inside the machine and so are not prone to loss or damaged like floppy disks they also op erate at a far higher speed and have a much larger capacity than floppy disks Although you might still find floppy disk drives
14. 01206 SU R EN DIGITAL 162 ISBN 978 92 95096 71 4 HARDWARE PUTTING THE SYSTEM TOGETHER Hardware is the physical components which make up a computer sys tem In this section we ll look at hardware computers and how we can design and arrange the components of computer systems to work more efficiently Today computers come in all shapes and sizes and the electrical technologies on which they are based can have a serious impact on the environment How we plan our need for information and communications and the equipment we use can in turn have an ef fect on the level of these impacts That doesn t just involve what type of machine you use one of the important factors is to maximise the working life of the device before you dispose of it 3 1 WHAT IS COMPUTER HARDWARE F ifty years ago a computer was a collection of electrical hardware which filled a small build ing Today that term encompasses a very broad variety of equipment some of which are the size of a grain of sand The commonest programmable computer devices do not resemble the archetypal vision of a machine with a screen and keyboard Most computers are small and insignificant chips embedded in radios which run the electronics of TVs cars and washing machines If we look at the number of high perfor mance processors which are intended for crunching data many of those are in computer servers telecommunications centres and su percomputers invisibly se
15. 12 Slackware 13 37 P1 gt 166 2128 Gnu Linux Lightweight and live distributions Knoppix 6 4 4 486 gt 90 Puppy Linux 5 2 P1 2166 Slackware 13 37 486 gt 90 Damn Small Linux 486 gt 90 Gnu Linux Text only install e g servers Fedora 15 P3 gt 600 gt 256 Ubuntu 11 04 P3 gt 600 gt 128 Debian 6 P1 gt 100 386 486 386 486 processor or better gt 256 P1 P6 Pentium through to Pentium VI processor or better including 32 bit or 64 bit multi core CPUs gt greater than the minimum for an installation gt greater than equal to the bare minimum required for operation for ease of installation double triple this figure live Live distribution runs from CD DVD so hard disk not required 14 A practical guide to sustainable IT to speed up the operation of the system That s because the more data the processor can hold in the memory the less it needs to access data from the hard disk at a far slower rate Before we move on system memory require ments are often quoted in mega or giga bytes and some new hard disks have a capacity in excess of a terabyte What do these numbers mean Computers use binary numbers or num ber base two Humans use decimal or number base ten Counting in magnitudes of 1 000 the human readable sequence would be 7 1 000 1 000 000 etc The nearest whole value to 1 000 in binary is two t
16. 13 In ancient times before the Pentium ll and the introduction of the ATX motherboard the AT power supply used two connectors side by side 39 Wikipedia BIOS en wikipedia org wiki BIOS 40 Wikipedia ATX en wikipedia org wiki Atx 18 A practical guide to sustainable IT but you re unlikely to run into one of those these days The advantage of the ATX supply is that it gives the computer the ability to turn itself off when it shuts down However the ecological cost is that when the ATX supply shuts down the sys tem it s still consuming a small amount of power to keep the electronics in standby mode ready to start the machine when the user presses the on button Therefore when you ve shut a system down it should also be isolated from the mains power supply Not just because of the power con sumption on older desktop machines usually the power drain is about five to 15 watts about the equivalent of a small low energy light bulb but also because power surges might damage the electronics Note if you use a modem connect ed to a phone line disconnect that too or get a surge protected phone adapter to prevent dam aging power surges coming down the phone line The router unit on a broadband phone connection should unless you get a direct lightening strike prevent power surges reaching the computer The ATX power socket on the motherboard has a lug on one side and the plug on the end of the cable has a small hook t
17. It s expressed as a number be tween 0 and 1 A high value 0 7 or better is very good a fig ure between 0 5 and 0 7 is adequate a figure below 0 5 is poor and you should consider buying a better power supply When measuring the power factor you shouldn t turn the machine on take the measurement and then switch off As the components warm up the power consumption can wander slightly and so its advisable to leave the me ter in place for an hour or so measure the initial power factor measure the total power consumed after at least an hour or two and then measure the power factor again before switching off This provides a more reliable figure for consumption Whether or not it s worth replacing a power supply is a matter of need or cost For equipment that s powered from an off grid supply minimising consumption is very impor tant irrespective of the cost you may choose to replace the power supply with a higher quality alternative off grid power is inevitably more expensive than grid power For a mains power system it s a matter of cost Let s say the system uses 0 25kW h of which half is the computer Figure 3 7 A power monitor box and runs for eight hours a day five days per week 46 weeks per year That s a total consumption of 460kW h year Taking a typical UK electricity tariff as an example at 0 14 kW h that s 64 year If you could improve the power factor from 0 5 to 0 7 that saves around 20 or 12 yea
18. able from hardware manufacturers While each individual module or circuit board is covered by the same intellectual property re strictions as closed hardware assembling these 5 Wikipedia Modding en wikipedia org wiki Modding 6 Wikipedia Hardware restrictions en wikipedia org wiki Hardware_restrictions 7 For example Electronic Frontier Foundation Jailbreaking Is Not A Crime www eff org pages jailbreaking not crime tell copyright office free your devices different elements together to make a computer system is not As we ll examine later this allows greater scope to create a more efficient computer system tailored to the user s needs 3 2 1 Closed hardware as an obstruction to repair and modification The major hurdle in managing the ecological im pacts of closed hardware are the obstacles to changing the components of the system or sim ply being able to repair them affordably Most mobile phones have software based power man agement controls which permit the user to select various modes to reduce the energy consumption of the device but this represents the limit to what is easily legally permitted Other consumer elec tronic devices such as set top boxes and TVs may also have such options built in The general problem is that as the power consumption of individual devices has dropped a greater proportion of the ecological impacts occur during manufacturing If we look at the life cycle impacts over a w
19. and sometimes a fan to keep it cool That s the northbridge 2 a chip that controls communication between 10 A practical guide to sustainable IT Figure 3 3 Physical organisation of a motherboard 1 CPU heatsink fan 2 Northbridge chip 3 Southbridge chip 4 Memory slots x3 5 AGP graphics slots 6 SATA sockets x6 7a IDE sockets x2 7b Floppy disk socket 8 PCI card slots x3 9 Front panel connector 10 CD DVD audio input 11 Battery and BIOS 12 CPU power 13 Main power 14 CPU fan power 15 PS2 keyboard 16 PS2 mouse 17 Printer port 18 Serial port 19 Video port 20 Ethernet port 21 Firewire port 22 Audio ports 23 USB ports x4 the memory the CPU and the rest of the ma chine Some of the latest machines don t have a northbridge because due the problems of trying to increase the speed of the system many of its functions are now carried out by the CPU itself A little further away from the northbridge you should see another fairly large chip that should be the southbridge 3 sometimes especially on fairly new motherboards this has a heatsink on top as well This controls the disk drives and the other peripheral parts of the system 3 3 4 Assessing the speed of the system Whenever you see adverts for computers they always stress the speed of the processor as the most important selling point That s not wrong but it s not necessarily true see box 3 2 While the speed o
20. aptops from certain manufactur ers are a problem as are some brands of scanner printer and imaging devices This is much less of a problem than it used to be as more manufacturers now sell Linux com patible hardware or provide driver software for these de vices on their websites 24 A practical guide to sustainable IT Table 3 3 PC ports and connectors DESCRIPTION PS 2 Keyboard 15 Round six pin PS 2 socket coloured purple on later boards It was the keyboard connector until recently when it was superseded by USB PS 2 Mouse 16 Round six pin PS 2 socket coloured lime green It was the standard mouse pointing device connector until superseded by USB Parallel printer port 17 25 pin D type socket coloured magenta on later boards Superseded by USB SPECTR ERR E tt bt tieistaee RS232 serial port 18 9 pin D plug coloured dark green on some boards Superseded by USB VGA video port 19 VGA graphics output 15 pin D socket coloured dark blue on some boards Audio lines 22 Between two and six 2 5mm stereo audio jack sockets microphone which is usually mono Audio input output from the sound card There are various colour codings in common use Lime green line out front speaker out Light blue line input Pink microphone input Orange centre subwoofer Black rear speaker out Grey side speaker out used with surround sound audio Ethernet port 20 RJ45
21. at drive connected to the sys tem at all times Finally hard drives also produce a lot of heat and in hot climates they can become very hot which can signif icantly shorten the life of the electronic components If a drive is running too hot to touch when in use you should consider adding an extra fan to the system to draw air across the hard drives That might use more electricity but that s not much when compared to the embodied en ergy of the hard drive if the excess heat causes it to fail connector Serial data connector Power connector SATA drive 0 SATA 0 SATA 1 SATA 2 SaTA 3 a Motherboard E w D u m D 5 SATA cables SATA drive 1 Hardware Putting the system together 17 less low power notebook computers These use IDE parallel ATA electronics However there is an issue as to how long lived this technology is especially if the card is used heavily for very long periods Flash drives rather like the USB sticks commonly used with computers work very fast and don t use much power The largest amount of drive space you can organise on the machine is limited by the num ber of hard disks you can attached to the sys tem and how big those drives can be see box 3 4 A problem with IDE was that the mother board could only handle a certain size of hard drive beyond a certain limit the motherboard couldn t address the disk That can be a prob lem when using some older motherboards
22. bers which represent the instruction called the opcode and any data it needs to carry out that instruction call the operand The CPU then executes the instruction and stores the result if any inside its own internal memory called registers or inside the main memory system Without the instructions supplied by the software program the hardware is just an expensive collection of plastic metal and chemically altered silicon connected to a power supply What makes the computer a useful tool is the operating system that controls the hard ware and that provides support for the appli cation programs which the user runs There are various forms of operating system and some are more complex than others but understanding the role and functions of the hardware is an es 20 Wikipedia Central processing unit en wikipedia org wiki Central_processing_unit 21 Wikipedia Operating system en wikipedia org wiki Oper ating_system sential part of understanding the role and func tions of the operating system By understanding the principles of how the functions of the com puter are organised you will be able to work more easily and efficiently and quickly identify faults and problems when things start to go wrong 3 3 2 The motherboard Irrespective of what type of computer system you use all its components are arranged on a circuit board usually a single large board called the motherboard On a desktop computer you
23. board might physically looks like and the important parts are labelled to help you these are referenced in the text be low in curly brackets Let s go through the dia gram and explore what each piece does within the system 22 Wikipedia Motherboard en wikipedia org wiki Motherboard Hardware Putting the system together 9 Figure 3 2 Logical organisation of a motherboard Fast graphics port AGP Microprocessor CPU Front side bus FSB On board 1 0 sound USB IR keyboard mouse on board graphics amp network control BIOS chip Northbridge Input output or Memory controller D 3 f lt 3 i a E R Chipset Southbridge or Disk drive controller controller Expansion slots PCI 3 3 3 The processor and chipset Firstly let s look at the microprocessor or CPU the chipset and the front side bus The CPU is the heart of the machine In the 1950s the cen tral processing unit would have been a cabinet the size of a delivery van containing the racks of circuits which made up the CPU Today it s a single chip about the size of a postage stamp and it has thousands of times more processing power than the van sized CPUs of the 1950s There are many types of CPU available and often what you pay for isn t simply a higher speed it s the amount of extra memory or par allel processing systems that the chip contains For much of their early lives Ma
24. can extend the storage spa ce by adding another hard disk That s the easiest op tion but it will use more power than installing a new larger hard disk but always check the largest size of drive the motherboard can address The drawback of installing a single larger disk is that you have to back up all the data on the system re install the operating software and then put all the old data back again Upgrade the motherboard Many parts vendors sell packs with a compatible mother board processor and memory which is the cheapest way to upgrade the whole system You should be able to reuse the case drives and other parts of the system with the new motherboard If you must install a new power hun gry operating system this is often the cheapest most ecological option Reuse the monitor The life of the monitor is likely if it s cared for to be much longer than the computer unit If you buy a new computer you can save money by reusing your existing monitor Upgrading laptops Laptops are a more technical problem Memory modu les are not always easily available Most 21 2 hard dri ves will work with a range of laptops but always check with the user manual first The most problematic part of laptops is the battery If regularly discharged it can lose a significant amount of storage capacity in 12 18 months If this happens there are suppliers who specialise in battery replacements Whether buying laptop memory module
25. can see the motherboard quite easily if you re move the left side cover for tower cases or the top cover for desktop cases On laptops the motherboard is buried deep inside and you can t get at it without dismantling the whole ma chine so best not to try Even mobile phones and MP3 players are usually designed with a single large board which contains all the main components of the system That s because it s the simplest way to manufacture and assemble the device The easiest way to learn how to manipulate the hardware of a computer system is to get an old desktop computer take it to pieces and then put it back together again When assembling a new computer or recycling an old one you don t work inside the case of the computer it s too cramped a space to work without risking dam age to the components Instead you assemble the separate parts of the computer system on a bench desktop and then when you know ev erything works as it should you dismantle the system and then install each part into the case we ll return to the process for doing this in the unit on Reuse and reclamation Figure 3 2 shows a logical layout of acom puter motherboard It doesn t really look like this and the precise design of motherboards vary but if you look at most motherboards there are various illustrated guides available on the net you ll probably be able to pick out the components listed in this diagram Figure 3 3 shows what a mother
26. cintosh comput ers used a different type of processor to IBM PC style machines That changed a few years ago when Apple adopted the same processor family as the PC the x86 The first generation of x86 processors was produced in 1978 and formed the heart of the first IBM compatible PC which 23 Wikipedia Microprocessor en wikipedia org wiki Micro processor 24 Wikipedia x86 en wikipedia org wiki X86 all later designs emulated We re now up to somewhere around the ninth generation of x86 processor and the range of processors has broadened to include designs for desktops low power versions for laptops basic chips for cheap mass market machines or more advanced ver sions for those who need lots of computing power More specialised computers such as the server machines that run the internet often use more specialised chips that are designed to perform a narrow set of functions at very high speed unlike the standard x86 family of PC chips which are made to perform a wider variety of functions from processing graphics data or doing complex decimal arithmetic If you look around the processor connector on the motherboard 1 you ll see a network of small wires on the board leading away towards other chips on the circuit board That s the front side bus FSB Near to the processor there will be an other large chip on the board usually about an inch 2cm to 3cm square often it has its own small metal heatsink on top
27. companied by a wad of documentation called release notes a list of the fea tures of the new system installation instructions and any significant changes from the previous version It should list the system requirements a specification of the type of processor s the minimum speed of the pro cessor and the amount of memory and hard disk space required to run the operating system When installing a computer or recycling old parts to make a new one you need to have an idea of what Table 3 1 Systems and system requirements Operating system the system is capable of doing To a great extent that is determined by the memory but also by the processor Table 3 1 lists the system requirements for various oper ating systems Consider all these figures the minimum for installation Wherever possible use the fastest processor the largest amount of memory and the largest hard disk drive to make installation and use as simple as possible Note also earlier versions of the Linux distributions listed in the table will require less RAM and HDD space to function Microsoft Windows Windows ME P2 gt 233 Windows XP P3 gt 600 Windows Vista P4 gt 1000 512 Windows 7 32 bit P6 gt 1000 1024 Windows 7 64 bit 2048 nu Linux Graphical installation e g desktop Fedora 15 P4 1000 768 Ubuntu 11 04 P4 gt 1000 OpenSuSE 11 P3 gt 600 256 Debian 6 P4 gt 1000 5
28. cumvent problems such as planned obsolescence in order to ex tend the service life of a product is to find ways of repairing the hardware or reprogramming the firmware the counters or other limiting controls set in the on board programming of the device which is preventing the device operating For example returning to the Apple iPod again in 2003 it was the subject of a short film which highlighted how the batteries in the early models failed after 18 months As a result of a 10 Wikipedia Planned obsolescence en wikipedia org wiki Planned_obsolescence 11 Wikipedia Firmware en wikipedia org wiki Firmware 12 The Neistat Brothers 2003 iPod s Dirty Secret www ipodsdirtysecret com Film available via YouTube www youtube com watch v F7ZsGIndF7E Figure 3 1 Carbon emissions from Apple products iPhone 4 iPod Classic 15 Macbook Pro Proportion of life cycle CO emitted during D Consumer use Device production subsequent court cases brought against Apple which showed that the design of the battery limited the life of the device Apple offered re placement batteries for the early iPods More recently claims have emerged about the latest design of Apple products in particular the use of tamper proof screws to hold the case togeth er It is argued that this makes it harder for people to carry out their own repairs servicing in order to extend the life of the device The iPod case and other e
29. d the primary storage or random access memory RAM Over the last decade or so memory chips have become extremely complex devices Depend ing upon the speed of the motherboard the mem ory modules must match the transfer speed of the front side bus or you ll get errors or more likely it ll refuse to work and the motherboard will signal a hardware error Confusingly there are different classes of memory DRAM SDRAM etc which operate at different data rates DDR DDR1 DDR2 etc and which come in different sized packages to fit different sized slots on the motherboard If you look at the Wikipedia page for DIMM dual in line memory module you can get a list of all 25 Wikipedia Computer data storage en wikipedia org wiki Primary_storage 26 Wikipedia Random access memory en wikipedia org wiki Random access_memory 27 Wikipedia DIMM en wikipedia org wiki DIMM a Bytes and magnitude Magnitude Size bytes 1 byte 1 1 kilobyte 1 megabyte 1 048 576 1 gigabyte 1 073 741 824 1 terabyte 1 099 511 627 776 1 125 899 906 842 624 1 petabyte the different types Look under the speeds sub section for a list of the different classifications of DIMM module Usually a motherboard has at least two memory slots Sometimes the board requires that they are used in a certain order and so problems arise when you use more than one memory module If the memory modules do
30. e DVI video port were often included but seldom used Irrespective of their popularity table 3 3 lists commonly occurring motherboard connec tors so that you know what s what To return to a point made earlier even if talking about it feels challenging hardware can not perform any useful function unless told to do so by a computer program Now to make the hardware into something useful we have to load an operating system onto the machine and that is an equally complex subject Hardware Putting the system together 23 Box 3 6 Purchasing and upgrade check list Upgrading is always better in the short term buy new for the long term Providing you can buy affordable components upgrading a system is often cheaper and less ecologically damag ing than buying a new system Most systems if cared for will last three to five years With some upgrading you could get that up to between five and seven years of useful life Unless you have to buy more powerful machine because you are required to use a certain op erating system there are a number of ways to increase the power of an existing system and prolong the life of its components Add more memory Adding memory allows more programs to be runin RAM rather than having data continually move to and from the hard disk Doubling the capacity of the RAM or better should make an appreciable difference to a slow computer Add a new hard disk For an existing system you
31. er system If you plug the monitor into the socket which powers the system you can measure the consumption of all the parts or you can isolate just one component the monitor printer or computer box to see how much power it consumes What is important to understand is that the power a PC system consumes varies all the time When idling it may consume only 15 of the maximum load if you re encoding video or some other power hungry exercise and using the speakers at full volume it will use much more Most power monitors will measure the supply volt age and the instantaneous power consumption What s more useful is to use the power meter function which measures the supplied power in kilo Watt hours kW h from when the unit is turned on This allows you to plug in the meter and measure consumption over an average day or week in order to get a more realistic value for the energy routinely consumed by the system Another important test these meters can perform is to measure the power factor The mains electricity supply is an oscillating wave When that waveform interacts with the electronics of the power supply most of it is used but not all of it In poorly made or damaged power supplies a large proportion of that power might be dumped back into the power grid unused you pay for the power but it s not used by the machine The difference between the amount of power supplied and the amount used by the equipment is called the power factor
32. ernal battery although finding the right memory module or drive can be difficult e Next there are desktop machines the large metal boxes that we traditionally associate with the term computer With the excep tion of Apple machines and some other pro prietary designs almost all of the components in a PC compatible desktop machine can be modified or upgraded This not only allows you to increase the power of the machine easily but the hardware itself is far easier to reuse recycle at the end of its life e Finally there are server machines These are like the plug in machines noted above but they re many times more powerful and for that Hardware Putting the system together 7 Box 3 1 Hardware buying check list Cheapest is not necessarily best Often you get what you pay for Devices which use non reusable or disposable goods such as the ink or toner in printers are often sold at cheap prices because the proprietary components they consumed are sold at a relatively higher price What you need to consider is the total cost of ownership how much over the likely life of the equipment you are going to spend on purchasing servicing consumables and power consumption Often paying more initially can reduce the costs later The warranty period is the best guide to the ex pected service life The longer the warranty period the greater the likelihood that the machine will have a long service life In
33. ext let s look at the front panel connectors 9 A PC has a power and reset switch a hard disc A PC card drive HDD and power light and recently a sleep light These all connect at a small group of ter minal posts usually in one corner of the mother board There s also an internal speaker that makes a beeping noise to warn of errors although some motherboards have the sounder fixed on the board and so don t need an external speaker The small button cell battery on the mother board 11 is there to keep power to the machines Basic Input Output System BIOS chip when the machine is switched off This stores all the configuration settings for the motherboard If removed after a few hours you ll lose these set tings which is a good way of clearing the access passwords on the motherboard Also if this bat tery runs down the BIOS settings might be lost or corrupted in which case you ll need to replace the button cell Most motherboards especially laptops where the battery is buried deep inside the machine have a pair of terminals which can instantly reset the contents of the BIOS memory if connected together To find them very useful to know for your laptop if you forget the user set up password you ll need to download the manual for the motherboard laptop and look up the BIOS settings information 3 3 9 Power supplies Next let s look at power supplies These days PCs only have one large power connector
34. f the chip is important the design of the other components in the system also has a big contribution to the overall speed The main difference when you buy a very expensive com puter isn t just the speed of the CPU or the size of the memory it s the quality of the other chips on the motherboard This increases the data transfer rate between the CPU the memory the disk drives and the accelerated graphics display The more expensive the motherboard the faster the chipset of the motherboard will function and so you ll squeeze more data through the system every second Even so and irrespective the sys tem specification of your computer you need to match what your hardware can provide to the de mands of the operating system see box 3 3 When you look at a motherboard the CPU ap pears to be the largest component on the board That s because it has to have a large fan fixed to the top of the chip to remove the heat it gen erates In older designs of CPU if the fan failed the chip would burn itself out Modern designs of chip are temperature controlled and will slow down as they heat up so if your computer ap pears to be working very slowly it s possible that the CPU fan has broken or it needs the dust cleared from the cooling fins to improve the rate of heat loss As the amount of heat that the CPU and motherboard generate increases with the CPU s power some manufacturers are even de veloping miniature refrigeration systems to
35. fit inside the computer s case For the large server farms and data centres which run the internet Hardware Putting the system together 11 Box 3 2 Processors and motherboards A PC motherboard is designed to take a specific type or range of x86 CPU chips There are two main manufactur ers of x86 CPUs Intel and AMD Each produces a range of chips with different specifications but there are two general differences between all CPU chips e 32 bit versus 64 bit The bits refer to the width of the data bus What this means is that a 64 bit chip will move twice as much data during each operation as a 32 bit chip For 64 bit chips you have to use a 64 bit operating system a 64 bit processor might work with a 32 bit operating system but you ll be wasting its processing power as none of its 64 bit features will be available Even if you use a 64 bit operating system some programs might not be able to use the extra power available from the chip and so for some tasks you re not going to be processing data much faster than on a 32 bit CPU e Number of cores A recent innovation As the com plexity of CPUs has grown we re reaching the physical limits of how big they can be The solution has been to include more than one CPU within the same chip allowing programs to be run in parallel The greater the number of cores in the CPU the more process ing power it has Multicore CPUs are available in 32 bit and 64 bit versions What ma
36. g the socket or both Damage to any of the essential sockets on the mother board might necessitate replacing the whole board All computer equipment needs good venti lation In a small or confined space the machine will very quickly raise the ambient temperature well above the human comfort zone and in a very small space it might be unhealthy for the machine too If you put any equipment inside a cupboard ensure that there are large ventila tion holes top and bottom either in the back or side of the cupboard to allow air to circulate If you install the computer unit the monitor or a Monitor Network RJ45 Switched surge protected socket Mouse Keyboard Hardware Putting the system together 21 laser printer in a small recess or under a shelf again make sure there is 15 20cm of free air space above and around the machine to ensure the free circulation of air And no matter how tempting it s never a good idea to leave pa pers books and files on top of computer units or monitors or in any position that obstructs the ventilation ducts of the equipment Not only does insufficient ventilation make the machine run hotter shortening the life of its components the thermal controls of the CPU and chipset will slow down the computer to re duce the heat load generated Next electrical power The electrical mains brings with it certain problems Electrical noise spikes from heavy industrial machines or loose elect
37. hat engages with the lug to stop the connector working loose Since the development of the Pentium IV the CPU now needs its own power supply and this is provided by the four pin connector 12 on more recent ATX power supplies it also has the lug hook ar rangement to stop it falling out Also before you turn the power on the large fan on top of the CPU needs a power supply Depending on the type of fan you ll find either a two or three pin connec tor 14 somewhere near the CPU where the fan can plug into the motherboard Sometimes the northbridge chip also has a fan in which case that should plug in somewhere nearby too al though some are directly wired into the mother board meaning they re a pain to remove if they fail and have to be replaced As computers have become more power ful so their power consumption has risen Early PC power supplies were rated at less than 200 watts Most PCs today have power supplies rated at 600 to 800 watts and some of the latest high performance PC used for video games and num ber crunching can have power supplies of over 1 000 watts with water cooling of the chips to increase the rate of heat removal On top of that the monitor might consume anywhere from 50 watts LCD to 250 watts plasma and printers speakers and other peripherals can consume an other 50 to 200 watts Put to gether a high pow ered PC can consume about the same as a small electric heater when running at full
38. hones and games consoles are not intended to be serviced or modified by their owners In many countries it s an offence under intellectual property law to try to modify the de sign of these devices in order to adapt or extend the way they operate This has come to a head re cently as the result of computer enthusiasts cir cumventing or removing the manufacturer s limi tations on the functions of machines removing blocks to certain types of activity or to allow the running of new or modified software In response the companies involved have brought court cas es against those responsible which has in turn made modding and jail breaking campaigning is sues amongst many digital rights activists For most PCs and similar hardware the restric tions on modification are not so strict Much of the PC hardware people use both laptop and desktop machines are to some extent designed to be mod ified On laptop machines you can in most cases change the memory modules and hard disk drive and replace the internal battery when it fails On desktop machines almost all the components can be modified or swapped allowing much greater freedom over the configuration of the system The reason for this relates to the way the first IBM compatible PC was created Rather than being designed as a wholly proprietary product the rush to get a PC into market meant that it was quickly cobbled together from a range of off the shelf components avail
39. ich group of computer users collectively has the greatest influence on the ecological footprint of IT then it s the ev eryday users of personal computers and com munications devices That s partly because their equipment does not function as efficiently as the highly managed computers of data centres and primarily because it s the mass of computer users at work and at home connecting to online services who are driving the demand both for new hardware and the greater network capacity required to support online services In this section we ll look first at the issue of open and closed hardware and using propri etary devices such as mobile phones or games consoles in contrast to more conventional per sonal computers Then we ll move on to look specifically at PCs and the factors which influ ence the way they work At each stage what we ll try to do is give an idea of the impact of these devices and how you can get involved in changing managing that impact 4 Wikipedia Personal computer hardware en wikipedia org wiki Personal_computer_hardware 4 A practical guide to sustainable IT 3 2 OPEN AND CLOSED HARDWARE he simplest way to consider what open and closed hardware is is to look at one recent trend which defines the difference between the two the jail breaking of Apple and Android phones and the modding of certain types of games console Closed proprietary equipment such as mobile p
40. icy makers are also included along with some practical tips for internet service providers Written by IT expert and environmentalist Paul Mobbs the purpose of the guideis to encourage ICT for development ICTD practitioners to begin using technology in an environmentally sound way But its usefulness extends beyond this to everyday consumers of technology whether in the home or office environment We can all play our part and the practice of sustainable computing will go a long way in helping to tackle the environmental crisis facing our planet This is also more than just a how to guide Mobbs brings his specific perspective to the topic of sustainable IT and the practical lessons learned here suggest a bigger picture of how we as humans need to live and interact in order to secure our future The guide is divided into 12 sections or units with each unit building thematically on the ones that have come before They can be read consecutively or separately The unit approach allows the sections to be updated over time extracted for use as resource guides in workshops or shared easily with colleagues and friends The guide has been developed on behalf of the Association for Progressive Communications APC with funding support from the International Development Research Centre www idrc ca It is part of a APC s GreeningIT initiative which looks to promote an environmental consciousness amongst civil society group
41. ide range of digital consumer electronics much of the energy and carbon impact and certainly much of the waste is created during the production of the device Therefore the majority of the impact that the device will have on the environment already ex ists on the day it is purchased our ongoing role as the user of the device powering it from the electricity grid is less significant For example let s look at Apple s products as shown in figure 3 1 Usefully Apple produces life cycle environmental reports for their prod ucts compiled under international standards for environmental reporting Apple should be praised for this and it is something that all manufacturers should be required to compile for their products Roughly a quarter of the life cycle carbon emissions of Apple products are the result of their use by the consumer around 8 The Story of Electronics Annie Leonard Free Range Stu dios 2010 www storyofelectronics org See also The Story of Stuff Annotated Script Annie Le onard Story of Stuff Project 2010 www storyofstuff org wp content uploads 2011 02 SoE_footnoted_script pdf 9 Apple Computer Apple and the Environment www apple com environment reports Hardware Putting the system together 5 a half or more are produced during the produc tion of the device the remainder is expended in transport and during materials reclamation One of the important variables in the calcula tion of these i
42. ifications you are bom barded with when you buy equipment 3 3 1 Types of PC hardware When we talk about computers we re conven tionally shown a large box with a screen and keyboard or a laptop which combines these el ements In fact computers come in all sorts of sizes and many don t have a screen or keyboard e At the smallest end are plug systems very small low power consumption computers such as the GuruPlug or SheevaPlug which plug into a mains plug socket and run your local network You access the machine over a network connection and the machine itself usually runs a Linux operating system 18 Ifixit Self Repair Manifesto www ifixit com Manifesto 19 Wikipedia Plug Computer en wikipedia org wiki Plug_computer e Next are mobile phones and palmtop ma chines and tablet pad computers and we should add games consoles and similar devic es into this category too As outlined earlier these are made from proprietary hardware components modules and are very difficult to modify Even the open mobile handsets which use the Android operating system are largely intended to allow users to change the software on the machine not the hardware itself e Next there are laptop and notepad comput ers Unlike wholly proprietary systems which are not intended to be modified by their users these allow limited scope for maintenance and upgrading Usually you have the option to change the memory hard drive and int
43. ined from studying the innards of a computer system is an under standing of the significance of system specifi cations and what those specifications relate to This should enable you to purchase or plan the upgrade of systems with a little more attention to the details which influence the power of the system and the energy consumed by the ma chine Box 3 6 contains a check list of points to consider when purchasing a system or deciding how to upgrade it Once you have a system you have to connect all the parts together With a laptop that s done already all you do is plug in the power and network connectors and perhaps an external speaker With desktop systems it s a little more difficult You have to connect many different cables to the main computer unit and there are Figure 3 8 Schematic of a desktop computer system speakers Router gateway Video 15 pin D or HDMI Sound Printer 2 5mm USB jack keyboard PS 2 or USB Computer some simple rules which can help protect and preserve the equipment Figure 3 8 shows a very simple desktop system as an example As a general rule you connect the thickest and heaviest cables first because if accidentally tugged they might snag and damage the other more delicate lightweight cables It s not dam age to the actual wire that s the problem If a lightweight connector is tugged hard at right angles to its connector it can be wrenched out damaging the plu
44. kes the greatest difference to the speed of a system apart from the CPU is the specification of the motherboard s chipset in particular the speed of the front side bus FSB The higher the FSB speed the faster the data can move between the CPU the mem ory and peripherals Another feature to look out for is the amount of cache memory that the CPU has usually called the Level 1 L1 or Level 2 L2 cache This speeds up the reading of data from the memory and the bigger the cache memory the faster the CPU can operate Different generations of chip use different sock ets or slots to connect the chip to the motherboard In practice choosing the correct CPU chip to fit to a moth erboard isn t an issue you re likely to deal with Usually your computer will arrive ready built or if you upgrade a computer you can buy a motherboard with the CPU and memory already fitted more cheaply than buying each separately The only time you need to worry about find ing the right processor for a motherboard is when the old one has failed in which case you must get the manual for the motherboard to find which CPUs it is able to ac commodate Every motherboard has a technical manual written for it if you can identify the design of the motherboard the maker s name is usually fairly prominent but find ing the code which identifies it can be more difficult then you can search online and find a copy of the manual The manual will tell you which CPU
45. mpacts is the length of product s service life For the Apple devices shown above they are expected to have a three year life span except for the Macbook which is expected to last four If you can make these devices work for lon ger than this then you will decrease the impact of the product overall Even though using the de vice for longer will mean that the user s propor tion of the total impact will rise because you use more power that fact the most of the impacts are created during production mean that you are unlikely to tip the balance the other way And in any case by delaying buying a new product you are delaying the creation of new pollution in order to replace it with a new one For example using an iPod or iPhone for four years instead of three will reduce the overall impact by almost a third The problem with trying to use many con sumer electronics goods for longer than their manufacturer s anticipated life span is that you run up against the issue of planned obsoles cence Analogue mechanical devices will work right up until individual components fail or wear out although it might be that the device has had its components engineered to last a certain period of time and then fail In contrast digital devices can have their service life programmed into them They are designed to work for acertain period of time and then irrespective of whether they are serviceable or not they will cease to function The only way to cir
46. ne complete freedom to vary or improve the design usually on the condition that all such changes are fed back into the community sharing the design Other groups such as iFixit through their Self Repair Manifesto and online repair guides are promoting the rights of owners to maintain and repair their hardware Reconfiguring computer hardware can be fairly simple once you ve got the hang on it as we ll see later In general the aims of the open hardware movement are to extend the scope of people s involvement with their equipment Its key ob jective is to develop the designs and skills that people can use to motivate their involvement and to extend these open principles to a far greater part of the engineered systems which support our lives 3 3 UNDERSTANDING COMPUTER HARDWARE or those who find it difficult to understand how to use computer programs the idea of taking the case off their machine and fiddling with the workings inside can be very daunting There s a great mystique surrounding the workings of com puter hardware although this isn t deserved be cause compared to most other consumer electron ics such as radios or washing machines the way computer hardware works is fairly simple Even if you don t bother to modify your system know ing how the insides of the machine function can be very helpful to finding faults with your system and it can be immensely useful to understand all the acronyms and spec
47. not have exactly the same speed data rate speci fication the board may have problems reading data because it can t synchronise the reading and writing cycles It s all very complicated and on older hardware where you might have problems finding large memory modules it can be quite annoying The general rule is to either use one large memory module big enough to provide the memory space you need or to find matched pairs of modules and always keep them together For all operating systems the amount of memory that the system has is one of the most critical limitations The table in box 3 3 lists a number of different operating systems and the absolute minimum system requirements to run them Although the system designers say that the system will run with these specs that doesn t mean that it will do so comfortably These are the bare minimum and so in practice it s best to dou ble or triple these figures e g if it states a Pen tium 2 processor use a Pentium 3 or 4 if it says 256MB of memory use at least 512MB or more In practice you re stuck with the processor that you have for the cost of buying a new processor on its own you can often buy a whole new mother board with a processor already attached However no matter what speed your processor runs at add ing more memory to the system will usually help Hardware Putting the system together 13 Box 3 3 System requirements Each operating system is usually ac
48. o be handled by purpose designed graphics card working separately from the CPU By making the AGP port an expansion slot you can fit the graph ics card of your choice into the motherboard Then instead of the CPU transferring data from the memory the video display is managed by the northbridge of the chipset without the CPU being involved All the CPU needs to do is update the display image held in the main memory On older machines without AGP the size and quality of the display is limited by the speed of the system With AGP and an accelerated graphics card the system can send far more data to the display and produce a much higher quality picture 3 3 7 The disk drive controller Next let s look at the southbridge and disk drive controller 3 The front side bus works at very high speeds to shift data from the memory to the CPU and AGP port That would be a waste of time when communicating with the hard disk and especially the keyboard because the data can t be supplied by the hardware at any thing near that rate If you can get hold of an old motherboard and look at the little copper wires on its surface you ll see that there s one set of wires linking the CPU the northbridge and the memory a second set links the northbridge and Hardware Putting the system together 15 the southbridge and a third links the south bridge to the disk drive connectors and PCI card slots The southbridge runs its own slow data bus
49. o the power ten 2 10 or 1 024 Table 3 1 shows the magnitude of the different prefixes applied to the size of data storage As the difference between each magnitude is a multiple of 1 024 this means a megabyte con tains 1 024 kilobytes a gigabyte contains 1 024 megabytes or 1 048 576 kilobytes etc Also what is a byte Today PCs use 32 or 64 bit processors A bit is one binary digit a single binary 0 or 1 When a CPU reads data from the memory it reads 32 or 64 bits at a time The greater the width of the data bus the more data the computer can read in one action and the faster the CPU processes data The first PCs had an eight bit data bus and eight bits were known as a byte As one byte eight bits is what you need to represent a single character of informa tion using the ASCII encoding system we came to associate one byte with one character of text However today s computers need to represent far more characters including those from lan guages other than English than are available us ing ASCII As a result ASCII has been superseded by Unicode which requires at least two bytes 16 bits or more to represent a single character 3 3 6 The video display Next let s look at the accelerated graphics port AGP 5 A modern video display is made up of points of data called pixels the more pixels and the more colours they use the finer the image your display can reproduce The first computer terminals didn t do
50. prevents the socket and its attached cables being dragged away Once all the mains cables are connected up and tidied away you can move on to the light er weight cables Again work from thickest to thinnest The next is probably the video cable then USB and network cables and finally the au dio cables Again leave loose coils in the cables which might get tugged especially the mouse keyboard and network cable or the phone line is you are using a modem to prevent acciden tal damage Web cams are usually fastened to the top of the monitor if you don t have a com patible bracket you can get Velcro pads stick ing one to the top of the monitor and the other to the bottom of the web cam to stick the two together Headsets and headphones also need to be carefully located to prevent the cable from being tugged You can buy small metal cable clamps with sticky foam backs stick them to the side of the case and then clamp the cable in the jaws to reduce the likelihood that it will be wrenched out Newer systems tend to have USB sockets on the front older ones do not If you regularly plug in MP3 players cameras or other devices get a short USB extension cable plug it in around the back and then trail it around the front of the computer This prevents continual rummaging behind the computer which will eventually cause cables to work loose or break Finally let s look at the dazzling array of port connectors which emerge from
51. r but only half of that figure 6 year is due to the computer box and its internal power supply Whether or not it s worth replacing the power supply depends upon the costs of replacement A high efficiency power supply might cost 50 Assuming a usable life of four years it will never repay the cost of the new supply Let s say that the power factor was 0 4 increasing to 0 7 would save almost 10 year which makes it almost worthwhile That s why the adequate power factor is 0 5 a result any higher is unlikely to merit changing the power supply unless you were able to do so at a negligible cost There are of course other ways to save energy and costs A laptop computer will generally use a tenth of the power of a desktop its monitor and speakers An LCD monitor will generally use around half to two thirds of the power of a plasma display Again these are the kind of decisions you need to take before you buy or obtain equipment changing components after the purchase is unlikely to pay for itself in the amount of power saved even if you re sell the unwanted parts 20 A practical guide to sustainable IT 3 4 PUTTING IT ALL TOGETHER y walking through the components which make up a desktop computer system you should hopefully have a better idea of what s in the box and what each of those parts does If you wish to take these ideas further we ll cover maintaining and assembling computers later Hopefully what you have ga
52. rical connections can accumulate damage to the components of the power supply and shorten its life In the worst case a prolonged power surge can disable the power supply and in the very worst case such as a lighten ing strike damage the motherboard as well The simplest solution to this is to plug all the mains plugs into a single switched and surge protected socket Surge protection minimises electrical noise and hopefully blocks the power surges More importantly having a single point to switch off the whole system means that with one switch it s possible to disconnect all the standby power drains of the computer unit printer and other power supplies Arguably assuming you always remember to switch off when the machine is not in use the electricity saved over the lifetime of the system will easily pay for the cost of your surge protected socket When laying out power cables always leave a little slack Ideally you place the switched sock et near or next to the computer partly so that it s always convenient to turn off but mainly so that you can plug in all the mains cables without leaving loops of cable which might get caught and pulled If you have a lot of cable left over you can coil the cable loosely and tie with a cable tie to keep it together If the power point for the machine is not nearby tie or fix the cable from the switched socket to the leg of the desk table In the event of the cable being pulled hard it
53. rving data to other machines rather than real people Even if we think of devices specifically intended to con nect people directly to information there are between five and six billion mobile phone ac counts in use around the world compared to around two billion personal computers And even when we talk of personal computers PCs many people accessing the internet and online services are doing so via video game consoles and set top TV boxes not just stand alone PC style computers That s why putting together a guide to sus tainable IT is so difficult the market is so diverse that it s difficult to give a concise guide which will cover all the possible means by which people might use computers and electronic networks 1 Wikipedia Embedded computer en wikipedia org wiki Embedded_computer 2 BBC News July 2010 Over 5 billion mobile phone connec tions worldwide www bbc co uk news 10569081 3 Wikipedia Personal computer en wikipedia org wiki Personal_computer Even when we talk of PC hardware there are many different types of machine in use which loosely fulfil the definition The managers of data centres made from thousands of micro processors and consuming perhaps thousands of kilo watt hours of electricity have a strong influ ence over the ecological footprint of IT The fact that most green IT reports address large com puter centres is a measure of their importance Even so if we weigh up wh
54. s hard drives or batteries it s worth shopping around as prices vary considerably Don t purchase on the processor speed alone both new systems and upgrades As noted earlier while the speed of the process is impor tant having a high quality chipset with a larger amount of cache memory and a fast front side bus will provide far more power overall especially when combined with a large memory capacity Buy the machine you need not what you are being sold Machines sold for the home market are increasingly be ing optimised for video gaming they have power hungry video cards and a large processor and memory capacity If you want a machine for browsing the internet and ba sic office tasks buying that extra power in not necessary Simple usage requires only a low end specification video gaming large quantities of video editing and graphic de sign require high spec machines Match the power of the machine to the operating system you wish to run Table 3 1 lists the bare minimum system specification quoted to run various operating systems Ideally you should double or triple these figures If you are buy ing second hand equipment and what you re buying is slightly under spec you could perform a motherboard processor upgrade to boost the power at a lower price than a new machine Beware when buying hardware for Linux always check for compatibility Always check compatibility before buying computers or peripherals for Linux L
55. s memory modules the board can work with 12 A practical guide to sustainable IT getting rid of the heat generated by the moth erboard is a major problem and they can use as much electricity pumping air to cool the ma chines as the motherboards consume directly For hot climates maintaining the CPU fan or perhaps buying a larger more efficient fan to cool the CPU is essential to keep the machine functioning normally You must also organise a good circulation of cool and relatively dry air humid air can corrode the workings to prevent overheating Overheating will if it takes place for long periods shorten the life of the compo nents on the motherboard What few people seem to realise is that all that extra heat and powering the fans or other technology to remove the heat from inside the case represents wasted energy Many desktop computers now burn hundreds of watts when operating at full power laptops are naturally less power hungry because of the need to maxi mise the battery life For those living off the pow er grid using small power generating systems like photovoltaic panels or wind to charge batteries the power consumption of IT equipment is be coming a pressing issue If you want to conserve power then you need to use a laptop and other battery operated mobile digital equipment as these are optimised to use a little power as pos sible 3 3 5 System memory Next let s look at the memory 4 also calle
56. s using ICTs and amongst the public generally Other publications and research reports completed as part of the GreeninglT initiative can be downloaded at greeningit apc org CZ NON APG 3 wc crDI
57. the motherboard through the back of the computer case It s very difficult to plug a connector into the wrong sock et as they are all constructed very differently More often the question arises as to whether the motherboard has the connector you require There is no standard set of ports on moth erboards although with more expensive boards you are often presented with a wider range of sockets Depending upon the design of the motherboard you ll have a variety of standard ports video USB and Ethernet but new moth erboards might not be compatible with older peripherals If you re in the situation where you need a port but there s none provided or if there are not enough provided then you ll need to in stall a PC card in one of the slots to provide the extra interface s required For very old ports such as the 9 pin serial connectors used by vari ous old types of technical equipment you can buy short adapter cables which will connect the serial cable to a USB socket although not all software may be able to work with this system Table 3 3 lists various ports and shows the design of their associated connectors the index numbers from figure 3 3 are also listed in curly brackets Over the last few years we ve seen some ports like the parallel printer port and 22 A practical guide to sustainable IT more recently the PS 2 keyboard and mouse ports fade away as the world has switched over to the ubiquitous USB Some like th
58. xamples where equipment has been engineered to have a short life and or be difficult to repair were highlighted recently in the documentary The Light Bulb Conspiracy 3 2 2 What is open hardware Today a new open hardware movement is beginning to take off pushing the boundaries of how people can share skills information and designs in order to adapt or modify different types of equipment Open hardware at its 13 BBC News 3rd June 2005 Apple deal for iPod battery cases news bbc co uk 1 hi technology 4606481 stm 14 Kahney Leander January 2011 Is Apple Guilty of Planned Obsolescence www cultofmac com 77814 is apple guilty of planned obsolescence 15 Dannoritzer Cosima 2010 The Light Bulb Conspiracy www facebook com TheLightBulbConspiracy View online at documentaryheaven com the lightbulb conspiracy 16 Wikipedia Open hardware en wikipedia org wiki Open_hardware 17 For example see www openhardware org or opensour ceecology org Watch a short video from Open Source Ecology on the principles of open hardware at vimeo com 30171620 6 A practical guide to sustainable IT most open allows the copying and complete modification of the hardware design While there has been little movement on this in the world of computing in the fields of intermediate technology and engineering there are a variety of projects now running around the globe which allow the owner or builder of a device or machi

Hardware: Putting the system together

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