9608_s16_qp_12 - revisedeck

9608_s16_qp_12

A paper of Computer Science, 9608

Questions:

9

Year:

2016

Paper:

1

Variant:

2

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1

Three examples of language translators and four definitions are shown below. Draw lines to link each language translator to the correct one or more definitions. Definition Language translator The software reads the source code and reports all errors. The software produces an executable file. The software reads each statement and checks it before running it. The software halts when it encounters a syntax error. The software translates a high-level language program into machine code for the processor to execute. The software translates low-level statements into machine code for the processor to execute. Compiler Assembler Interpreter

1. Theory Fundamentals → 1.5. System software

2. Fundamental Problem-solving and Programming Skills → 2.4. Software development

3. Advanced Theory → 3.4. System software

Open

2

Convert the following denary integer into 8-bit binary. Convert the following Binary Coded Decimal (BCD) number into denary. Convert the following denary integer into 8-bit two’s complement. -102 Convert the following hexadecimal number into denary. 4E

1. Theory Fundamentals → 1.1. Information representation

3. Advanced Theory → 3.1. Data representation

Open

3

Describe how special purpose registers are used in the fetch stage of the fetch-execute cycle. Use the statements A, B, C and D to complete the description of how the fetch-execute cycle handles an interrupt. A the address of the Interrupt Service Routine (ISR) is loaded to the Program Counter (PC). B the processor checks if there is an interrupt. C when the ISR completes, the processor restores the register contents. D the register contents are saved. At the end of the cycle for the current instruction . If the interrupt flag is set, , and . The interrupted program continues its execution.

1. Theory Fundamentals → 1.4. Processor fundamentals

Open

4

A group of students broadcast a school radio station on a website. They record their sound clips in advance and email them to the producer. Describe how sampling is used to record the sound clips. The students use software to compress the sound clips before emailing them. Circle your chosen method of compression and justify your choice. Lossy / Lossless Justification: Students also email images to the radio station for use on its website. These are compressed before sending using run-length encoding (RLE). Explain what is meant by run-length encoding. The following diagrams show: • the denary colour code that represents each colour • the first three rows of a bitmap image Colour symbol Colour code B W B B B B B B B B B B W W W B B B B B B B B B B B B W W W W W W B B B B B B B B W W W W W W W W W … Show how RLE will compress the first three rows of this image. Row 1: Row 2: Row 3:

1. Theory Fundamentals → 1.1. Information representation

Open

5

Three types of software licensing and four descriptions are shown in the table below. Put a tick (✓) in each row to match each description to the appropriate type of software licensing. Type of software Description Open source Shareware Commercial Software is purchased before it can be used Source code comes with the software Software is provided free on a trial basis The software can be modified by the user

1. Theory Fundamentals → 1.7. Ethics and ownership

1. Theory Fundamentals → 1.5. System software

Open

6

A team of software engineers is developing a new e-commerce program for a client. State three of the principles of the ACM/IEEE Software Engineering Code of Ethics. Illustrate each one, with an example, describing how it will influence their working practices.

1. Theory Fundamentals → 1.7. Ethics and ownership

Open

7

Access to World Wide Web content uses IP addressing. State what IP stands for. The following table shows four possible IP addresses. Indicate for each IP address whether it is valid or invalid and give a reason. Address Denary / Hexadecimal Valid or Invalid Reason 3.2A.6AA.BBBB Hexadecimal 2.0.255.1 Denary 6.0.257.6 Denary A.78.F4.J8 Hexadecimal Describe two differences between public and private IP addresses.

1. Theory Fundamentals → 1.2. Communication and Internet technologies

Open

8

A school stores a large amount of data. This includes student attendance, qualification, and contact details. The school’s software uses a file-based approach to store this data. The school is considering changing to a DBMS. State what DBMS stands for. Describe two ways in which the Database Administrator (DBA) could use the DBMS software to ensure the security of the student data. A feature of the DBMS software is a query processor. Describe how the school secretary could use this software. The DBMS has replaced software that used a file-based approach with a relational database. Describe how using a relational database has overcome the previous problems associated with a file-based approach. The database design has three tables to store the classes that students attend. STUDENT(StudentID, FirstName, LastName, Year, TutorGroup) CLASS(ClassID, Subject) CLASS-GROUP(StudentID, ClassID) Primary keys are not shown. There is a one-to-many relationship between CLASS and CLASS–GROUP. Describe how this relationship is implemented. Describe the relationship between CLASS-GROUP and STUDENT. Write an SQL script to display the StudentID and FirstName of all students who are in the tutor group 10B. Display the list in alphabetical order of LastName. Write an SQL script to display the LastName of all students who attend the class whose ClassID is CS1.

1. Theory Fundamentals → 1.8. Database and data modelling

Open

9

The table shows assembly language instructions for a processor which has one general purpose register, the Accumulator (ACC) and an index register (. Instruction Explanation Op code Operand LDD Direct addressing. Load the contents of the given address to ACC. LDX Indexed addressing. Form the address from + the contents of the index register. Copy the contents of this calculated address to ACC. STO Store contents of ACC at the given address. ADD Add the contents of the given address to ACC. INC Add 1 to the contents of the register (ACC or . DEC Subtract 1 from the contents of the register (ACC or . CMP Compare contents of ACC with contents of . JPE Following a compare instruction, jump to if the compare was True. JPN Following a compare instruction, jump to if the compare was False. JMP Jump to the given address. OUT Output to screen the character whose ASCII value is stored in ACC. END Return control to the operating system. The diagram shows the current contents of a section of main memory and the index register: 0011 0010 0101 1101 0000 0100 1111 1001 0101 0101 1101 1111 0000 1101 0100 1101 0100 0101 0100 0011 0110 1001 Index register: 0 Show the contents of the Accumulator after the execution of the instruction: LDX 60 Accumulator: Show how you obtained your answer. Show the contents of the index register after the execution of the instruction: DEC IX Index register: Complete the trace table on the opposite page for the following assembly language program. LDD 100 ADD 102 STO 103 LDX 100 ADD 100 CMP 101 JPE 58 JPN 59 OUT INC IX LDX 98 ADD 101 OUT END IX (Index Register) Selected values from the ASCII character set: ASCII Code Character v w x y z { | }

1. Theory Fundamentals → 1.4. Processor fundamentals

Open