Computers are electronic machines which can accept data in a certain form, process data and give the results of the processing.
There are three basic steps in the process: first, you feed data into the computer’s memory. Then, the computer performs a set of instructions and processes the data. Finally, you can see the results (the output) on the screen or in the printed form.
We know information in the form of data and programs as software, and the electronic and mechanical parts that make up a computer system as hardware. A standard computer system consists of three main sections: the Central Processing Unit (CPU), the main memory and the peripherals.
Perhaps the most influential component is the CPU. Its function is to execute program instruction and coordinate the activities of all the other units. In a way, it is the ‘brain’ of the computer. The main memory holds the instructions and data. The peripherals are the physical units attached to the computer. They include storage devices and input/output devices.
Storage devices (floppy or hard disks) provide a permanent storage of both data and programs. Disk drives handle one or more floppy disks. Input devices enable data to go into the computer’s memory. The most common input devices are the mouse and the keyboard. Output devices enable us to extract the finished product from the system. For example, the computer shows the output on the monitor or prints the results onto paper by means of a printer.
On the rear panel of the computer there are several ports into which we can plug a wide range of peripherals – modems, fax machines and scanners.
History of computers.
Let us take a look at the history of the computers that we know today. The very first calculating device was the ten fingers of a man’s hands. That is why today we still count in tens and multiplies of tens. Then people invented the abacus. They went on using some forms of abacus well into the 16th century. During the 17th and 18th centuries many people tried to find easy ways of calculating, but the first real calculating machine appeared in 1820 as the result of several people’s experiments. This type of machine saves a great deal of time and reduces the possibility of making mistakes. In 1830 Charles Babbage, an Englishman, designed a machine that he called “the Analytical Engine”. He never finished his work, but many of his ideas were the basis for building the today’s computers. In 1930 Vannevar Bush, an American, built the first analog computer. People used it in the World War II to help aim guns. In 1944 professor Howard Aiken and some people from IBM completed the first digital computer. This was the first machine that could figure out long lists of mathematical problems, all at a very fast rate. In 1946 two engineers at the University of Pennsylvania, J.Ecert and J. Mauchly, built the first digital computer using parts called vacuum tubes. They named their invention ENIAC. Another important advancement in computers came in 1947 when John von Newman developed the idea of keeping instructions for the computer inside the computer’s memory.
The first generation of computers, which used vacuum tubes, came out in 1950. Univac I is an example of these computers, which could perform thousands calculations per second. In 1960 people began to use transistors instead of the vacuum tubes. These computers could perform work ten times faster than their predecessors. Second-generation computers were smaller, faster and more dependable than the first-generation computers. The third –generation computers appeared on the marketing 1965. These computers could do a million calculations a second, which is a thousand times faster than the first-generation computers. Unlike second-generation computers, they used integrated circuits, which are consequently smaller and more dependable. Fourth-generation computers have now arrived, and people have greatly reduced the integrated circuits in size. This is due to microminiaturization, which means that the circuits are much smaller than before; as many as 1000 tiny circuits now fit onto a single chip. Fourth-generation computers are 50 times faster than third-generation computers and can complete approximately 1 000 000 instructions per hour.
SOFTWARE – Programs which can be used on a particular computer system
OUTPUT – Results produced by a computer
HARDWARE – Hardware equipment attached to the computer
INPUT – The information which is presented to the computer
Central Processing Unit – The brain of the computer is
Monitor – Visual display unit
PORT – Any socket or channel in a computer system into which an input/output device may be connected
Peripheral devices – Physical parts that make up a computer system
Floppy disk – Small devices used to store information. Same as 'diskette'
Kompyuter nima ?
Kompyuter – bu qandaydir hajmdagi ma’lumotlarni qabul qilib, ularni ishlab va qayta ishlov natijalarini taqdim etuvchi elektron mashina hisoblanadi.
Jarayonda 3 ta bosqich bajariladi: avvalambor, siz kompyuter xotirasiga ma’lumotni kiritasiz. Shunda kompyuter qo’llanmalar ketma ketligini bajaradi va ma’lumotlarni qayta ishlaydi. Nihoyat natijani siz ekranda yoki qog’ozga bosma tarzda ko’rishingiz mumkin.
Biz axborotni ma’lumot va dastur ta’minotidagi dastur sifatida hamda kompyuter tizimini tashkil etuvchi elektron va mexanik qismlarni qattiqdik sifatida bilamiz. Standart kompyuterning tizimi 3 ta asosiy seksiyadan iborat: Markaziy protsessor, asosiy xotira va axborot kirituvchi qurilma.
Kompyuter - kuchli ta’sir etuvchi komponent bo’lishi mumkin. Uning vazifasi – boshqa barcha birliklarni koordinatsiyalash va dastur qo’llanmalarini bajarishi shart. Bu komyuterning “miya”si hisoblanadi. Axborot kirituvchi qurilma – kompyuterga ulangan, fizik birliklarni kirituvchi qurilma. Ular saqlash va kiritish-chiqarish qurilmalarini o’z ichiga oladi.
Saqlash qurilmalari (qattiq va yumshoq disk) ma’lumot va dasturlarni doimiy xotirada saqlashni ta’minlaydi. Disk yurituvchi - bir yoki undan ko’p disketalarni aylantiradi. Kiritish qurilmalari ma’lumotlarni kompyuter xotirasiga kiritish imkoniyatini beradi. Ko’pincha kiritish sichqoncha va klaviatura yordamida amalga oshiriladi. Chiqarish qurilmasi bizga tayyor ma’lumotni tizimdan chiqarishga yordam beradi. Masalan, kompyuter chiqish signalini monitorda ko’rsatadi yoki printer orqali natijani qog’ozga bosi chiqaradi.
Keng diapazondagi periferiyalar –modem, faks mashinasi va skanerlarni kompyuter orqasida joylashgan bir necha portlarga ulash mumkin.
Keling biz hozirgi kunda biladigan kompyuter tarixiga nazar tashlaymiz. Eng birinchi hisoblash moslamasi bu inson qo’lining 10 ta barmog’i hisoblanagan. Aynan shuning uchun biz hali ham o’nliklarda hisoblaymiz va o’nliklarda ko’paytiriamiz. Shunda odamlar hisoblagichni kashf etishdi. Ular XVI asrda ham hisoblagichning bir necha turlaridan yaxshi foydalandilar. XVII – XVIII asrlar davomida ko’pgina odamlar hisoblashning oson yo’llarini topishga harakat qilib ko’rishdi, lekin birinchi haqiqiy hisoblash mashinasi 1820-yilda bir necha xalqlarning tajribasi natijasida paydo bo’ldi. Mashinaning bu turi ko’p vaqtni tejaydi va kam xato qilish imkoniyatini beradi. 1830 – yilda angliyalik Charlz Babbag “Analitik dvigatel” nomli mashina ishlab chiqdi. U o’z ishini hech tugatolmadi, lekin uning ko’pgina g’oyalari bugungi kompyuterlar qurilishida asos bo’ldi. 1930 – yilda amerikalik Vannever Bush birinchi analogli kompyuter qurdi. Odamlar undan II jahon urushida foydalanishdi. 1944-yil Govard Aiken va IBMning ba’zi odamlari birinchi EHM ishini tugatishdi. Bu uzun matematik masalalar to’plamini tez yecha oladigan birinchi mashina edi. 1946 – yilda Pensilvaniya shtati universitetidagi 2 injener Esert va Mauchly birinchi marta vaakumli nay ishlatilgan EHMni kashf etishdi. Ular uni ENIAC ixtirosi deb nomladilar. 1947 –yilda Jon von Neyman kompyuter uchun saqlash qurilmasini kompyuter ichki xotirasida bo’lish g’oyasini taqdim etganda kompyuterning boshqa muhim rivoji bo’ldi.
Vaakum nayli kompyuterning birinchi avlodi 1950 – yilda chiqdi. Shular misolidagi Univac sekundiga minglab hisoblashlarni amalga oshira olardi. 1960 –yilda odamlar vaakum naylari o’rniga tranzistorlarni qo’llay boshladilar. Bu kompyuterlar ulardan oldingilariga qaraganda ishini 10 barobar tez bajara olardi. Ikkinchi avlod kompyuteri birinchisiga nisbatan ixchamroq, tezroq va ishonchliroq bo’lgan. Kompyuterning uchinchi avlodi bozorda 1965 –yilda paydo bo’ldi. Bu kompyuterlar birinchi avlod kompyuterlariga nisbatan ming marta tezroq ishlab, ya’ni sekundiga million hisoblashni amalga oshira oladi. Ikkinchi avlod kompyuteridan farqli ravishda ular ixchamroq va ishonchliroq bo’lgan integralli mikrosxemani ishlatdi. Endi to’rtinchi avlod kompyuterlari foyda keltirdi va odamlar integral mikrosxemaning hajmini kichraytirdilar. Bu microminiaturizatsiyalar, ya’ni elektrosxemalrning ancha kichrayganligi tufayli bo’ldi, ya’ni endi mingta elektrosxemalar yagona chipga to’g’ri keladi. To’rtinchi avlod kompyuterlari uchinchi avlod kompyuterlariga nisbatan 50 marta tezroq va soatiga taxminan 1000000 amallarni bajara oladi.
Modal auxiliary verbs WillShallMay and MightWouldCan and CouldMustShouldOught to
What are "modal auxiliary verbs"?
They are verbs which 'help' other verbs to express a meaning: it is important to realise that "modal verbs" have no meaning by themselves. A modal verb such as would has several varying functions; it can be used, for example, to help verbs express ideas about the past, the present and the future. It is therefore wrong to simply believe that "would is the past of will": it is many other things.
A few basic grammatical rules applying to modal verbs
Modal verbs are NEVER used with other auxiliary verbs such as do, does, did etc. The negative is formed simply by adding "not" after the verb; questions are formed by inversion of the verb and subject:
You should not do that.
Could you pick me up when I've finished?
Modal verbs NEVER change form: you can never add an "-s" or "-ed", for example.
Modal verbs are NEVER followed by to, with the exception of ought to.
What sort of meanings do modals give to other verbs?
The meaning are usually connected with ideas of DOUBT, CERTAINTY, POSSIBILITY and PROBABILITY, OBLIGATION and PERMISSION (or lack of these). You will see that they are not used to talk about things that definitely exist, or events that definitely happened. These meanings are sometimes divided into two groups:
DEGREES OF CERTAINTY: certainty; probability; possibility; impossibility
OBLIGATION/FREEDOM TO ACT: permission,lack of permission; ability; obligation.
Let's look at each modal verb separately, and the functions they help to express:
Will Making personal predictions
I don't think the Queen will ever abdicate.
I doubt if I'll stay here much longer.
Talking about the present with certainty (making deductions)
I'm sure you will understand that there is nothing the Department can do
There's a letter for you. It'll be from the bank: they said they'd be writing.
Talking about the future with certainty
I won't be in the office until 11; I've got a meeting.
Don't bother ringing: they'll have left for their 10 o'clock lecture.
I'm sure you will have noticed that attendance has fallen sharply.
Don't worry! You'll settle down quickly, I'm sure.
It'll be all right! You won't have to speak by yourself.
Making a decision
For the main course I'll have grilled tuna.
I'm very tired. I think I'll stay at home tonight.
Making a semi-formal request
Will you open the window, please? It's very hot in here.
Sign this, will you?
Offering to do something
You stay there! I'll fetch the drinks.
Insistence; habitual behaviour
I'm not surprised you don't know what to do! You will keep talking in class.
Damn! My car won't start. I'll have to call the garage.
Making a promise or a threat
You can count on me! I'll be there at 8 o'clock sharp.
If you don't finish your dinner off, you'll go straight to bed!
Shall Shall is a form of will, used mostly in the first person. Its use, however, is decreasing, and in any case in spoken English it would be contracted to "-ll" and be indistinguishable from will.
The only time you do need to use it is in questions, when:
Shall I fetch you another glass of wine?
Shall we go to the cinema tonight?
May and Might May and might sometimes have virtually the same meaning; they are used to talk about possibilities in the past, present or future. ("Could" is also sometimes used).
May is sometimes a little bit "more sure" (50% chance); whereas might expresses more doubt (maybe only a 30% chance).
May and might are used, then, for:
Talking about the present or future with uncertainty
She may be back in her office: the lecture finished ten minutes ago.
I may go shopping tonight, I haven't decided yet.
England might win the World Cup, you never know.
Talking about the past with uncertainty
I'm surprised he failed. I suppose he might have been ill on the day of the exam.
They can also sometimes be used for talking about permission, but usually only in formal situations. Instead of saying May I open a window? we would say Is it all right/OK if I open a window? or Can I open a window? for example. You might, however, see:
Students may not borrow equipment without written permission.
Talking about things that can happen in certain situations
If the monitors are used in poorly lit places, some users may experience headaches.
Each nurse may be responsible for up to twenty patients.
With a similar meaning to although
The experiment may have been a success, but there is still a lot of work to be done. (= Although it was a success, there is still ...)
Saying that something was possible, but did not actually happen
You saw me standing at the bus stop! You might have stopped and given me a lift!
Would As the past of will, for example in indirect speech
"The next meeting will be in a month's time" becomes
He said the next meeting would be in a month's time.
Polite requests and offers (a 'softer' form of will)
Would you like another cup of tea?
Would you give me a ring after lunch?
I'd like the roast duck, please.
In conditionals, to indicate 'distance from reality': imagined, unreal, impossible situations
If I ruled the world, every day would be the first day of Spring.
It would have been better if you'd word processed your assignment.
After 'wish', to show regret or irritation over someone (or something's) refusal or insistence on doing something (present or future)
I wish you wouldn't keep interrupting me.
I wish it would snow.
(This is a complicated area! Check in a good grammar book for full details!)
Talking about past habits (similiar meaning to used to)
When I was small, we would always visit relatives on Christmas Day.
Future in the past
The assassination would become one of the key events of the century.
Can and Could
Talking about ability
Can you speak Mandarin? (present) She could play the piano when she was five. (past)
Can you give me a ring at about 10?
Could you speak up a bit please? (slightly more formal, polite or 'softer')
Can I ask you a question?
Could I ask you a personal question? (more formal, polite or indirect)
Reported speech Could is used as the past of can.
He asked me if I could pick him up after work.
You can drive when you're 17. (present)
Women couldn't vote until just after the First World War.
Choice and opportunities
If you want some help with your writing, you can come to classes, or you can get some 1:1 help.
Future probability Could (NOT can) is sometimes used in the same way as might or may, often indicating something less definite.
When I leave university I might travel around a bit, I might do an MA or I suppose I could even get a job.
I think you could be right you know. (NOT can)
That can't be the right answer, it just doesn't make sense.
If I'd known the lecture had been cancelled, I could have stayed in bed longer.
Examples here refer to British English; there is some variation in American English.
Necessity and obligation Must isoften used to indicate 'personal' obligation; what you think you yourself or other people/things must do. If the obligation comes from outside (eg a rule or law), then have to is often (but not always) preferred:
I really must get some exercise.
People must try to be more tolerant of each other.
You musn't look - promise?
If you own a car, you have to pay an annual road tax.
Strong advice and invitations
I think you really must make more of an effort.
You must go and see the film - it's brilliant.
You must come and see me next time you're in town.
Saying you think something is certain
This must be the place - there's a white car parked outside.
You must be mad.
What a suntan! You must have had great weather.