Chapters 3.1, 3.2 & 3.3

(Year 11 to Year 13)

1 Name three different types of bus in a processor and state what each is used for. [6] (MJ/11/P32/Q1)

2 (a) Explain the relationship between assembly languages and machine code. [2]

(b) Describe how an assembler produces machine code from assembly language. [2]

(c) The address part of a low-level instruction can be the address of the data to be used.

This is a direct address.

Describe the following types of addressing:

(i) Indirect addressing (ii) Indexed addressing (iii) Relative addressing [6] (MJ/11/P32/Q2)

3 (a) Describe what is meant by the spooling of files. [2]

(b) (i) State why files which are sent to a shared printer on a local network will be

spooled.

(ii) Explain how this spooling is carried out. [T5] (MJ/11/P32/Q5)

4 (a) Describe the differences between interpretation and compilation of a high-level

language program. [3]

(b) When a program is run the processor uses special purpose registers. Describe how the contents of

each of the following registers changes during the fetch-execute cycle:

(i) Memory Address Register (MAR) (ii) Memory Data Register (MDR) [T4] (MJ/11/P32/Q11)

5) On Page 6 & 7 (MJ/12/P32/Q5)

6) In a multiprogramming environment the operating system includes a scheduler.

(a) Explain the purpose of the scheduler. [2]

(b) A process will at any time be in one of three states.

(i) Name and describe each possible state. [6]

(ii) How will the operating system keep details about the state of all processes? [1]

(c) Any process can be described as either ‘processor bound’ or ‘input/output bound’.

(i) Explain what is meant by these terms and give a typical application of each.

(A) Processor bound (B)Application which is processor bound

(C) Input/Output bound (D)Application which is I/O bound [4]

(ii) A particular scheduler allocates a priority to each process for the use of the

processor.

State which type of process – processor bound or I/O bound – would be given

higher priority for the use of the processor. Explain why. [2] (MJ/12/P32/Q6)

7) On page 8, 9, 10 & 11 (MJ/13/P32/Q3

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8) The following are the first few lines of a source code program written in high-level language

XYZ which is about to be translated by the language compiler.

(a) During the lexical analysis stage the compiler will use a keyword table and a symbol

table.

(i) Describe what information is contained in these tables.

(A)Keyword table (B) Symbol table [2]

(ii) Explain how the table contents are used to translate the source code. [2]

(iii) Describe one other task done at the lexical analysis stage which does not involve

the use of the keyword table or symbol table. [1]

(b) The final stage of compilation is code optimisation.

(i) Explain what is meant by code optimisation. [2]

(ii) Give one practical example of code which would benefit from optimising. [1] (MJ/13/P32/Q5)

9) A multiprogramming, multi-user operating system organises the available memory into two

fixed sized partitions.

• Partition 1 – size 30 Gb – is used only for batch processing

• Partition 2 – size 40 Gb – is used only for interactive processing at a terminal

A program, once loaded, occupies the same memory locations until its execution is

complete.

(a) Explain what is meant by:

(i) Batch processing [3]

(ii) Interactive processing [1]

(b) The diagram shows the current contents of main memory with a list of programs

waiting to be scheduled.

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Currently waiting to be loaded are:

• PROG16 (batch processing requiring 25 Gb)

• PROG17 (interactive processing requiring 8 Gb)

• PROG44 (interactive processing requiring 9 Gb)

• PROG45 (interactive processing requiring 8 Gb)

• PROG23 (batch processing requiring 15 Gb)

(i) If PROG6 completes execution, which programs (if any) can be loaded next? [1]

(ii) If PROG8 completes execution, which programs (if any) can be loaded next? [1]

(iii) Describe two variations on this use of partitions which may make more efficient

use of memory. [2]

(c) 10 Gb of the main memory is labelled OTHER and will not be used for the execution of

application programs.

Name two possible items of software this memory will be used for. [2]

(d) Any program loaded is always in one of three possible states. One is the ‘running’ state

meaning the job currently has use of the processor.

Name and describe the two other states. [4] (MJ/13/P32/Q6)

10) (a) State what is meant by spooling and why it is used. [2]

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(b) A network of computers has a single printer. Each of the computers can send a job for

printing at any time. Explain how a print spooler can be used to control the printing of jobs on the

network. [4] (ON/11/P32/Q1)

11(a) Describe the use of the following special purpose registers and how they change

during the fetch-execute cycle.

(i) Memory Address Register (MAR) [3] (ii) Index Register (IR) [3]

(b) Explain how the address bus and the data bus are used in a computer. [3] (ON/11/P32/Q2)

12) Explain how scheduling manages job throughput in a computer. [6] (ON/11/P32/Q6)

13) (a) (i) Describe what happens during the syntax analysis phase of compilation. [4]

(ii) Explain how syntax errors are identified during compilation. [3]

(b) (i) Give two advantages of using a compiler rather than an interpreter to translate a

high-level language program. [2]

(ii) Describe an advantage of using an interpreter rather than a compiler to translate a

high-level language program. [2] (ON/11/P32/Q9)

14) (a) The sequence of operations below show - in register transfer notation - the fetch stage

of the fetch-execute cycle.

Note:

• [register] denotes the contents of the specified register

• Step 1 above is read as ‘The contents of the Program Counter are copied to the

Memory Address Register’.

(i) Describe what is happening at step 4. [1]

(ii) Explain how the data bus is used at step 3. [1]

(iii) Explain how the address bus is used at step 3. [1]

(b) A programmer writing low-level code has the choice of using either machine code or

assembly language.

(i) Describe two advantages of using assembly language. [2]

(ii) Describe three specific tasks done by the assembler software. [3]

(c) A low-level language contains instructions for direct addressing and relative

addressing.

Explain these terms. You may wish to illustrate your answers with a diagram.

(i) Direct addressing [2]

(ii) Relative addressing [2] (ON/12/P32/Q3)

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15) The two types of software which are used to translate high-level language programs are a

compiler and an interpreter.

(a) A source code program is compiled for the first time.

State two outputs that could be produced by the compiler. [2]

(b) Describe two benefits of using a compiler (rather than an interpreter). [2]

(c) Explain what is meant by code optimisation. [3]

(d) Explain why the following system software may be required to produce the final

executable file.

(i) Linker [1] (ii) Loader [1] (ON/12/P32/Q4)

16) (a) Multiprogramming is the ability to have more than one program loaded in the main

memory at the same time.

The operating system for a computer which supports multiprogramming must contain a

program module for management of the main memory.

Describe two strategies for memory management. [4]

(b) In a multiprogramming computer system, describe two possible strategies for

scheduling the use of the processor. [4]

(c) (i) Describe what is meant by an interrupt. [2]

(ii) State two different sources of an interrupt and give a reason for each interrupt. [4] (ON/12/P32/Q6)

17) On page 12, 13 & 14 (ON/13/P32/Q3)

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