A) Read the text without a dictionary.A little over some decades ago computers were large, not very reliable and slow in operation. Since then, several generations of complex electronic computing machines have been developed. The use of advanced components of hardware provides modern generation of computers with super-high speed of operation (billions operations per second). In our country computers development began with the MESM machine, conceived and constructed by academician Lebedev in Kiev. This machine was the first sequence-controlled electronic computer developed in continental Europe. Some years later digital computers BESM, URAL, RASDAH, KIEV, EM series and many others were constructed by Soviet scientists. All these digital computers have the same basic units: input-output units, storage or memory unit, arithmetic unit and control unit. Research and development of all these computer units continue and tend to make them the smaller and the cheaper the better. b) Make up dialogues using the information of Unit 3. 3.24 Make a timeline (временная последовательность) map.
Dialogues 3.25 Role-play the dialogues. a) The Stored Program Concept - Do you know the computer's ability to call in instructions and follow them is known as the stored program concept? - Really? How does it work? - Instructions are copied into memory from a disk, tape or other source before any data can be processed. The computer is directed to start with the first instruction in the program. It copies the instruction from memory into its control unit circuit and matches it against its built-in set of instructions. - What for? - If the instruction is valid, the processor carries it out. If not, the computer comes to an abnormal end (abend, crash). The computer executes instructions sequentially until it finds a GOTO instruction. - What kind of instruction is it? - The GOTO instruction tells it to go to a different place in the program. It can execute millions of instructions per second tracing the logic of the program over and over again on each new set of data it brings in. - So fast! - As computers get faster, operations can be made to overlap1. - How can the computer manage to carry out several tasks at a time? - While one program is waiting for input from one user, the operating system (master control program) directs the computer to process data in another program. - You mean there exist any computers that are able to process the data of several users at a time? - Sure, large computers are designed to allow inputs and outputs to occur simultaneously with processing. While one user's data is being processed, data from the next user can be retrieved into the computer. It can take hundreds of thousands of discrete machine steps to perform very routine tasks. Your computer could easily execute a million instructions to put a requested record on screen for you. - That’s incredible! And how big a computer can be? - computers come in many sizes. Computers are as small as a chip or as large as a truck. The difference is in the amount of work they do within the same time frame. Its power is based on many factors, including word size and the speed of its CPU, memory and peripherals. NB: 1 overlap - заходить (один на другой); (частично) совпадать.
b) Computers step by step - I know that first-generation computers, starting with the UNIVAC I in 1951, used vacuum tubes, and their memories were made of thin tubes of liquid mercury and magnetic drums. And what do you know about second-generation computers? - Second-generation systems in the late 1950s replaced tubes with transistors and used magnetic cores for memories For example, IBM 1401, Honeywell 800. Their size was reduced and reliability was significantly improved. - As far as I remember, the third-generation computers, beginning in the mid 1960s, used the first integrated circuits. - Yes, they were such machines as IBM 360, CDC 6400, the first operating systems, and DBMSs. Online systems were widely developed, although most processing was still batch oriented using punched cards and magnetic tapes. - I don’t know the term ‘ batch processing’. What does it mean? - ‘Batch processing’ is processing a group of transactions at one time. Transactions are collected and processed against the master files at the end of the day or some other time period. This term is used in contrast with ‘transaction processing’ that means processing transactions as they are received by the computer. Also called online or realtime systems, transaction processing means that master files are updated as soon as transactions are entered at terminals or received over communications lines. Information systems typically use both batch and transaction processing methods. - Thanks for your explanations. - Starting in the mid 1970s, the fourth generation brought us computers made entirely of chips. It spawned1 the microprocessor and personal computer. It introduced distributed processing and office automation. Query languages, report writers and spreadsheets put large numbers of people in touch with the computer for the first time. By the way, do you know exactly what does the term ‘ query language ’ mean? - No, I’m afraid I don’t. Do you? - Yes,‘ query language’ is a generalized language that allows a user to select records from a database. It uses a command language, menu-driven method or a Query By Example (QBE) format for expressing the matching condition. - I see. And what generation computers are being designed nowadays? And what are their distinguishing features? - The fifth generation ought to become visible by the mid 1990s with the more widespread use of voice recognition, natural and foreign language translation, optical disks and fiber optic networks. Higher-speed machines combined with more sophisticated software will enable the average computer to talk to us with reasonable intelligence by the early years of the 21st century. - I believe the game isn't over. More surprises are in store. - You are undoubtedly right. NB: 1spawn - плодить, порождать.
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