3. Make a summary of the text using the words from Vocabulary Exercises. B. Vocabulary

4. Give English-Russian equivalents of the following words and ex- pressions:

efficiency; вычитать; smart; fail; разгружать; gate; шина; cache; адрес ячейки памяти; режим, состояние; internally; требование; access; вентиль; abstraction layer; внешний; latch; bottleneck; за- паздывание, задержка; density; величина, количество; pipelining; потребляемая мощность; throughput; clock speed; задержка (обработки) прерывания; hence; быстродействие, эффектив- ность; wire; архитектурный план (кристалла микропроцессора); firmware; эффективность, производительность; interrupt latency; критический элемент/ параметр; off-load; недействительность, неправильность, ошибочность; central processing unit (CPU); иметь доступ, получить доступ (к чему-л.); регистр; memory address; instruction set; встроенная программа; amount; скорость передачи данных; blueprint; производительность (вычисли- тельной системы); benchmarking; контакт, штырек; external; invalidation; разумный, интеллектуальный, изящный (напр., о программе); floor plan; провод, сеть; защелка; requirement; набор команд (процессора); data rate; performance; проведение сопоставительных (оценочных) испытаний; pin; subtract; цен- тральный процессор; программа, образец; mode; плотность, концентрация, интенсивность.

5. Find the word not belonging to the given synonymic group. Explain your choice.

1. Smart, sharp, brainy, bright, intelligent, tricky, clever;

2. density, intensity, concentration, mass, crux, bulk;

3. access, get into, retrieve, open;

4. performance, implementation, execution, palmtop, carrying out, operation, running, working;

5. blueprint, outline, design, plan, bus, pattern, scheme;

6. hence, therefore, for this reason, thus, so, ultimately;

7. subtract, take away, add, take off;

8. wire, pipelining, cable, rope, line, chain;

9. external, outside, outer, exterior, outdoor, peripheral, inter- nal;

10. invalidation, unavailability, inoperativeness, indicative, inef- ficiency, ineffectiveness;

11. amount, timeline, sum, total, number;

12. fail, reduce, stop working, break down, crash;

13. requirement, obligation, condition, kernel, necessity, con- straint;

14. latch, handle, bolt, key, fastener;

15. mode, status, condition, operation, state, treatment, con- : ^; sole.

С Reading and Discussion

6. Study the words given at the bottom and explain their meanings. Read the text. Determine the interdependence of code density and the type of computer architecture. Give brief characteristics of each Computer type, pointing out its benefits and disadvantages. Summarize the text.

Code Density

In early computers program memory was expensive, so mini- mizing the size of a program to make sure it would fit in the limited memory was often central. Thus the combined size of all the instruc- tions needed to perform a particular task, the code density was an important characteristic of any instruction set. Computers with high code density also often had (and have) complex instructions for proce- dure entry, parameterized returns, loops, etc. (therefore retroactively named Complex Instruction Set Computers, CISC). However, more typical, or frequent, «CISC» instructions merely combine a basic ALU operation, such as «add», with the access of one or more operands in memory (using addressing modes such as direct, indirect, indexed etc). Certain architectures may allow two or tiiree operands (including the result) directly in memory or may be able to perform functions such as automatic pointer increment, etc. Software-implemented instruction sets may have even more complex and powerful instructions.

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Reduced instruction-set computers, RISC, were first widely im- plemented during a period of rapidly-growing memory subsystems and sacrifice code density in order to simplify implementation circuitry and thereby try to increase performance via higher clock frequencies and more registers. RISC instructions typically perform only a single operation, such as an «add» of registers or a «load» from a memory location into a register; they also normally use a fixed instruction width, whereas a typical CISC instruction set has many instructions shorter than this fixed length. Fixed-width instructions are less com- plicated to handle than variable-width instructions for several reasons (not having to check whether an instruction straddles a cache line or virtual memory page boundary, for instance), and are therefore somewhat easier to optimize for speed. However, as RISC computers normally require more and often longer instructions to implement a given task, they inherently make less optimal use of bus bandwidth and cache memories.

Minimal instruction set computers (MISC) are a form of stack machine, where there are few separate instructions (16-64), so that multiple instructions can be fit into a single machine word. This type of cores often takes little silicon to implement, so they can be easily realized in an FPGA or in a multi-core form. Code density is similar to RISC; the increased instruction density is offset by requiring more of me primitive instructions to do a task.

A complex instruction set computer (CISC, pronounced like «sisk») is a microprocessor instruction set architecture (ISA) in which each instruction can execute several low-level operations, such as a load from memory, an arithmetic operation, and a memory store, all in a single instruction. The term was retroactively coined in contrast to reduced instruction set computer (RISC).

Before the RISC philosophy became prominent, many computer architects tried to bridge the so called semantic gap, i.e. to design instruction sets that directly supported high-level programming con- structs such as procedure calls, loop control, and complex addressing modes, allowing data structure and array accesses to be combined into single instructions. The compact nature of such instruction sets results in smaller program sizes and fewer calls to main memory, which at the time (early 1960s and onwards) resulted in a tremendous savings on the cost of computer memory and disc storage. It also meant good programming productivity even in assembly language, as high level

languages such as Fortran or Algol, were not always available or appropriate.

v In computer science, ZISC stands for zero instruction set compu- ter, which refers to a chip technology based on pure pattern matching and absence of (microinstructions in the classical sense. The ZISC acronym alludes to the previously developed RISC (Reduced Instruc- tion Set Computer) technology. Practical uses of ZISC/CogniMem technology focus on pattern recognition, information retrieval (data mining), security and similar tasks.

loop, operand, increment, circuitry, width, stack, FPGA (Field Programmable Gate Array), offset, array, acronym, allude, data mining

7. Read the text and answer the questions: 1) What computer design can be referred to as von Neumann ? 2) What are the drawbacks of the von Neumann architecture? 3) How can Harvard architecture com- puter be characterized? 4) What distinctions of Harvard architecture machines from von Neumann ones are there?