Vocabulary

time lag (1ine 26-27) - time delay

Spitting Image (1ine 51) - satirical British TV programme, using computer-controlled animated puppets

bobsleigh (1ine 57) - large vehicle, moving on strips of wood, for travelling fast over ice and snow

Task 1 Answer the following questions about the text:

1. Where does the term 'virtual reality' come from?

2. Which country leads the field in VR research?

3. Why are robots controlled via mounted video cameras less effective than the VR solution?

4. How does Robert Stone's system allow the user to 'feel' objects?

5. What application of VR is expected to be the commonest to start with?

Task 2 Using the line reference given, look back in the text and find the reference for the words in italics.

2. one that comes closer to real life (line 3)

3. which see it as a technology for the next century (line 17)

4. without taking them out of the office (line 21-22)

5. it is not a natural system (line 25)

6. to record where it is pointing (line 32-33)

7. and displays it on the screen (line 34)

8. to give the illusion of carrying it (line39)

9. while a robot would move through the real thing (line 46-47)

Task 3 Using the line references given, look back in the text and find words or phrases meaning:

1. whenever and however they like (lines 1-5)

2. qualities (lines 5-10)

3. large amounts of money (lines 15-20)

4. immerse (lines 20-25)

5. twisting (lines 20-25)

6. small pockets filled with air (lines 40-45)

7. filled with air (lines 50-55)

8. released on to the market (lines 50-55)

9. imitate (lines 55-60)

10. war plane (lines 60-65)

Task 4 Choose the appropriate form of the word to fit the meaning of the sentence. Make sure you understand the different forms of the word and their meanings. Use your dictionary to find this information.

1 Correct, correctly, correction, corrective, correctness

a If an error occurs, it is important to take __________________________ action immediately.

b The 'spell check' facility checks the _____________________________ of your spelling.

c The data was entered ________________________ , so the result must be accurate.

2 Detect, detection, detectable, detective

a There were ____________________________ traces of radiation in the water sample.

b The analyst could not ________________________ any errors in the system.

c She tried to escape ___________________________ by disguising herself.

3 Sense, sensor, sensation, sensitive

a An infra-red __________________________ detects the presence of intruders in the building.

b The probe is _________________________ to heat and light.

c The new system caused a ______________________ when it was launched last month.

Task 5 Translate three paragraphs (beginning ' The problem with guiding a robot ...' lines 23 - 39) into your own language.

UNIT SEVEN: HOW COMPUTER VIRUSES WORK

Task 1 Before reading the text, match the words and definitions listed below.

1 a detonator

2 an infector

3 to boot

4 to trigger

5 to erase

6 pirated

7 a shield

8 to detect

a a protective device

b to remove all traces of something

c a device used to set off an explosion or other destructive process

d to discover or recognize that something is present

e to set a process in motion

f something which transmits a disease or virus

g stolen, obtained without the owner's consent

h to load the operating system into memor

A computer virus - an unwanted program that has entered your system without you knowing about it - has two parts, which I'll call the infector and the detonator. They have two very different jobs. One of the features of a computer virus that separates it from other

5 kinds of computer program is that it replicates itself, so that it can spread (via floppies transported from computer to computer, or networks) to other computers.

After the infector has copied the virus elsewhere, the detonator performs the virus's main work. Generally, that work is either

10 damaging data on your disks, altering what you see on your computer display, or doing something else that interferes with the normal use of your computer.

Here's an example of a simple virus, the Lehigh virus. The infector portion of Lehigh replicates by attaching a copy of itself to

15 COMMAND.COM (an important part of DOS), enlarging it by about 1000 bytes.

So let's say you put a floppy containing COMMAND.COM into an infected PC at your office -that is, a PC that is running the Lehigh program. The infector portion of Lehigh looks over DOS's

20 shoulder, monitoring all floppy accesses. The first time you tell the infected PC to access your floppy drive, the Lehigh infector notices the copy of COMMAND.COM on the floppy and adds a copy of itself to that file.

Then you take the floppy home to your PC and boot from the

25 floppy. (In this case, you've got to boot from the floppy in order for the virus to take effect, since you may have many copies of COMMAND.COM on your hard and floppy disks, but DOS only uses the COMMAND.COM on the boot drive.)

Now the virus has silently and instantly been installed in your

30 PC's memory. Every time you access a hard disk subdirectory or a floppy disk containing COMMAND.COM, the virus sees that file and infects it, in the hope that this particular COMMAND.COM will be used on a boot disk on some computer someday.

Meanwhile, Lehigh keeps a count of infections. Once it has

35 infected four copies of COMMAND.COM, the detonator is triggered. The detonator in Lehigh is a simple one. It erases a vital part of your hard disk, making the files on that part of the disk no longer accessible. You grumble and set about rebuilding your work, unaware that Lehigh is waiting to infect other unsuspecting

40 computers if you boot from one of those four infected floppies.

Don't worry too much about viruses. You may never see one. There are just a few ways to become infected that you should be aware of. The sources seem to be service people, pirated games, putting floppies in publicly available PCs without write-protect tabs,

45 commercial software (rarely), and software distributed over computer bulletin board systems (also quite rarely, despite media misinformation).

Many viruses have spread through pirated - illegally copied or broken - games. This is easy to avoid. Pay for your games, fair and

50 square. If you use a shared PC or a PC that has public access, such as one in a college PC lab or a library, be very careful about putting floppies into that PC's drives without a write-protect tab. Carry a virus-checking program and scan the PC before letting it write data onto floppies.

55 Despite the low incidence of actual viruses, it can't hurt to run a virus checking program now and then. There are actually two kinds of antivirus programs: virus shields, which detect viruses as they are infecting your PC, and virus scanners, which detect viruses once they've infected you.

60 Viruses are something to worry about, but not a lot. A little common sense and the occasional virus scan will keep you virus-free.

Remember these four points:

• Viruses can't infect a data or text file.

65 • Before running an antivirus program, be sure to cold-boot from a write-protected floppy.

• Don't boot from floppies except reliable DOS disks or your original production disks.

• Stay away from pirated software.