Computer World. Матросова Т.А. - 43 стр.

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42
about a million times as fast as accessing a disk. Each byte in a RAM chip can be
independently stored and retrieved without affecting other bytes, by providing the
unique memory address belonging to the byte you want.
The CPU (also called the …) is the active component in the computer. It is also
made of millions of microscopic transistors on a chip. The CPU executes programs
consisting of instructions stored in RAM, using data also stored in RAM. However,
the CPU is so fast that even the typical RAM … … of 10 nanoseconds is a
bottleneck; therefore, computer manufacturers have added both … … and… … which
are faster types of memory used to reduce the amount of time that the CPU has to
wait. The internal cache resides on the same chip as the CPU and can be accessed
without delay. … sits between the CPU and the regular RAM; it's faster than the
latter, but not as fast as the internal cache. Finally, a very small part of the on-chip
memory is organized as …which can be accessed within the normal cycle time of the
CPU, thus allowing the fastest possible processing.
TEXT 4
Look through the text and define its theme. What two characteristics are
discussed? What is the real reason for C problems?
It may sound odd to describe computers as providing grand scope for creative
activities: Aren’t they monotonous, dull, unintelligent, and extremely limited? Yes,
they are. However, they have redeeming virtues that make them ideal as the canvas of
invention: they are extraordinarily fast and spectacularly reliable. These
characteristics allow the creator of a program to weave intricate chains of thought and
have a fantastic number of steps carried out without fail.
The most impressive attribute of modern computers, of course, is their speed; as
we have already seen, this is measured in MIPS (millions of instructions per second).
Of course, raw speed is not very valuable if we can't rely on the results we get.
ENIAC, one of the first electronic computers, had a failure every few hours, on the
average; since the problems it was solving took about that long to run, the likelihood
that the results w ere c orrec t w asn't very high. Partic ularly c rit ic al c alc ulations w ere
often ran several times, and if the users got the same answer twice, they figured it
was probably correct. By contrast, modern computers are almost incomprehensibly
reliable. With almost any other machine, a failure rate of one in every million
operations would be considered phenomenally low, but a computer with such a
failure rate would make thousands of errors per second.
On the other hand, if computers are so reliable, why are they blamed for so
much that goes wrong with modern life? Who among us has not been the victim of an
erroneous credit report, or a bill sent to the wrong address, or been put on hold for a
long time because «the computer is down»? The answer is fairly simple: It's almost
certainly not the computer. More precisely, it's very unlikely that the CPU was at
fault; it may be the software, other equipment such as telephone lines, tape or disk
drives, or any of the myriad «peripheral devices» that the computer uses to store and
retrieve information and interact with the outside world. Usually, it's the software;

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