01-04-2020-Oxford_English_for_Infomation_Technology (1171844), страница 19
Текст из файла (страница 19)
He's not completely certain.Compare these versions:1234It sounds as if you may have a driver fault.It sounds as if you have a driver fault.You probably have a driver fault.You must have a driver fault.In Unit 14, you studied these ways to advisesomeone to do something.Using an imperative:1Try to reinstall the sound drivers.Using the modal verb should:2 You should reinstall the sound drivers.Using recommend:3 / recommend reinstalling the sound drivers.Each statement is more certain than the onebefore. You can use the expressions studiedin Unit 16 to show how certain you are. Whenyou are sure you know the cause of theproblem, you can use must as in example 4.4Study this further extract:Or phrases such as:You could try to reinstall the sound drivers.6 The best thing to do is to reinstall the sounddrivers.Here David is giving advice.
Advice usuallyfollows diagnosis.You can also use:/ recommend that you reinstall the sounddrivers.5 / advise you to reinstall the sound drivers.Study these steps to take before you phone for technicalsupport. Rewrite each one using the clue given.12Reboot your PC to see if the problem recurs, (should)Use your PC's on-board diagnostic and repair tools.(recommend)3 Record the details of the problem so you can describe itaccurately.
(good idea)4Note your system's model name and serial number. (advise)5 Keep a record of hardware and software you've installed alongwith any changes you've made to settings. (stronglyrecommend)6 If you think hardware may be at fault, figure out how to openthe case. (should)7 Visit the vendor's website and check the FAQs.
(best thing)8 Avoid phoning in peak times. (never)9 Have your system up and running and be near it when you call.(good idea)10 When you reach a technician, tell him or her if you may havecaused the problem. (advise)UNIT 17 Computing Support119Diagnose these faults and provide advice on each problem.123456789101112My laser printer produces very faint copies.When I print, three or four sheets come through the printer atthe same time.My spreadsheet does not seem to add up correctly.Everything I type appears in capitals.My PC is switched on but the monitor screen is blank.I tried to print a document but nothing came out of the printer.My monitor picture is too narrow.My monitor screen flickers.My mouse responds erratically.The time display on my computer is one hour slow.When I print out a page, the first two lines are missing.My computer sometimes stops and reboots itself.
The lights dimat the same time.As a class, find out how many had problems with any of theseitems of hardware in the last twelve months. Calculate the percentagesand compare results with these findings from a national survey.% of users reporting problems in the last 12 monthsYour classOther usersHard disk17CD-ROM drive15Modem15Mouse13Monitor12Motherboard11Sound card7Cooling fan7Floppy disk drive7Battery7Keyboard6Power supply6Memory5Graphics/Video5CPU3120UNIT 17 Computing SupportSPEAKINGWork in pairs, A and B.
Advise your partner on his/hercomputing problem. Ask for advice on your computing problem.Complete this form for your partner's problem.Student A Your problems and advice are on page 187.Student B Your problems and advice are on page 193.Fig 2UNIT 17 Computing Support 121WRITINGStudy this brief report made from the completed form for Task3. Then write your own report of one of the Task 8 problems usingthe form you completed for that task. Your report should have thesesections:paragraph 1 user's hardware, software, network connections, etc.paragraph 2 description of the problem and the possible diagnosisparagraph 3 action takenJob No.
E83905The call was logged at 15. 22 on 26th June. The user hasan Apricot LS 550 with a Pentium III processor and 128MB of RAM. The operating system is Windows 2000. Themachine is networked - Windows NT. It is under warranty.The machine is not playing MIDI sound files. This may bedue to faulty sound drives.The client was advised to re-install the original sounddrivers. If this does not solve the problem, new sounddrivers will be sent. A visit is not required.122UNIT 17 Computing SupportSPECIALIST READINGFind the answers to these questions in thetext and table below.Give two reasons why server computersoften have connected hard drives.Why is RAID 0 particularly suited to imagingand scientific work?What is the advantage of using drivemirroring?To store data, RAID levels higher than 1require:a At least double the disk spaceb Up to about a third more disk spacec Less than half the disk spaceWhere is the backup data stored in a RAID 5system?Which levels of RAID can reconstruct datalost in failed drives from the backup dataspread across the remaining drives in thearray?Which level of RAID is the fastest?Server manufacturers connect hard drivesto ensure that data is adequately protectedand can be quickly accessed.
Computerengineers call such an arrangement aredundant array of inexpensive disks(RAID). By arranging drives in sets, usershope to take advantage of the higher seektimes of smaller drives. A special hard diskcontroller, called a RAID controller, ensuresthat the RAID array's individual drives areseen by the computer as one large diskdrive.RAID schemes are numbered, withhigher numbers indicating more elaboratemethods for ensuring data integrity andfault tolerance (or a computer's ability torecover from hardware errors).BRe-read the text and table to find theanswers to these questions.1 Match the terms in Table A with thestatements in Table B.Table AaRAIDb RAID controllercAn arraydStripingeMirroringfCheck data['Raid Technology Primer', PC Advisor, 4 January 1996;Windows Sources, April 1994]UNIT 17 Computing SupportFault tolerance?What does it do?What are theadvantages?What are thedisadvantages?RaidORaidlRaid 2-4RaidsNoYesYesYesCalled disk striping,RAID 0 breaks datainto blocks that arespread across alldrives rather thanfilling one beforewriting to the next.Called disk mirroring,RAID 1 uses twoidentical drives: datawritten to the first isduplicated on thesecond.RAID 2-4 are rarelyused and simplyenhance the stripingprovided by otherRAID levels.Called striping withparity, the popularRAID 5 writes errorcorrecting, or parity,data across availabledrives.Improved disk I/Othroughput - thefastest of all RAIDconfigurations as itdistributes read/writeoperations acrossmultiple drives.
Goodfor imaging andscientific work wherespeed is important.If either drive fails,the other continuesto provideuninterrupted accessto data.2 enhances 0 byusing additionaldrives to store paritydata. 3 enhances 2by requiring only oneerror-checking drive.4 builds on 3 byusing larger blocksizes, boostingperformance.If one drive fails, itscontents arerecovered byanalysing the data onthe remaining disksand comparing itwith the parity data.The failure of anysingle drive meansthe entire array islost.Inefficient use of diskspace.Uses dedicated disksto store the paritydata used toreconstruct drivecontents. Up to 30%more hard disk spaceneeded than 1.Not as fast as RAID 0.Table BiInformation which is used to restore dataif one of the RAID drives failii A process of spreading data across a setof disksiii Redundant array of inexpensive disksiv A setvA device for controlling a set of hard disksvi The technique of writing the sameinformation to more than one drive1232 Mark the following statements as True orFalse:aSmall disks tend to have lower seek timesthan large disks.b RAID controllers make one large hard diskact like a set of small disks.c In RAID systems, one disk is filled with databefore the next disk is used.d A higher numbered RAID array uses a moreelaborate system to protect the integrity ofdata.e RAID 0 provides good data recovery.f Small file servers do not usually use RAIDlevel 3.UNIT 18Data Security 1STARTERWhat stories do you think followed these headlines? Compareanswers within your group.123Love bug creates worldwide chaos.Hackers crack Microsoft software codes.Web phone scam.What other types of computer crime are there? Make a listwithin your group.READINGStudy this diagram which explains how one type of virusoperates.
Try to answer these questions.123What is the function of the Jump instruction?What are the main parts of the virus code?What is the last act of the virus?UNINFECTEDPROGRAMINFECTEDPROGRAMORIGINALstarting instructionJUMPinstructionMISDIRECTION routineREPRODUCTION routineTRIGGER routinePAYLOAD routineFig 1How a virus infects a programoriginal starting instruction,plus code to return control tothe program as originally writtenVIRUSCODEScan this text to check your answers to Task 3.
Ignore anyparts which do not help you with this task.THE ANATOMY OF A VIRUSA biological virus is a very small, simple organism thatinfects living cells, known as the host, by attachingitself to them and using them to reproduce itself. Thisoften causes harm to the host cells.Similarly, a computer virus is a very small programroutine that infects a computer system and uses itsresources to reproduce itself. It often does this bypatching the operating system to enable it to detectprogram files, such as COM or EXE files. It then copiesitself into those files.
This sometimes causes harm to thehost computer system.When the user runs an infected program, it is loadedinto memory carrying the virus. The virus uses acommon programming technique to stay resident inmemory. It can then use a reproduction routine to infectother programs. This process continues until thecomputer is switched off.The virus may also contain a payload that remainsdormant until a trigger event activates it, such as theuser pressing a particular key.
The payload can have avariety of forms. It might do something relativelyharmless such as displaying a message on the monitorscreen or it might do something more destructive suchas deleting files on the hard disk.When it infects a file, the virus replaces the firstinstruction in the host program with a command thatchanges the normal execution sequence. This type ofcommand is known as a JUMP command and causesthe virus instructions to be executed before the hostprogram. The virus then returns control to the hostprogram which then continues with its normal sequenceof instructions and is executed in the normal way.To be a virus, a program only needs to have areproduction routine that enables it to infect otherprograms. Viruses can, however, have four main parts.A misdirection routine that enables it to hide itself; areproduction routine that allows it to copy itself toother programs; a trigger that causes the payload to beactivated at a particular time or when a particular eventtakes place; and a payload that may be a fairly harmlessjoke or may be very destructive.
![](https://s.studizba.com/z.php?f=/templates/si/i/noavatar.png&w=100&h=100&t=1"){kind=avatar}
