9608_w16_qp_13
A paper of Computer Science, 9608
Questions:
8
Year:
2016
Paper:
1
Variant:
3
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1
Five descriptions and seven relational database terms are shown below. Draw a line to link each description to its correct database term. Description Database term Any object, person or thing about which it is possible to store data Dataset organised in rows and columns; the columns form the structure and the rows form the content Any attribute or combination of attributes that can act as a unique key Attributein a table that link to the primary key in another table to form a relationship Attribute or combination of attributes that is used to uniquely identify a record Secondary key Candidate key Entity Foreign key Primary key Table Tuple Explain what is meant by referential integrity.
1. Theory Fundamentals  →  1.8. Database and data modelling
Open
3
Convert the denary number 46 to an 8-bit binary integer. Convert the denary integer – 46 to an 8-bit two’s complement form. Convert the denary number 46 into hexadecimal. Binary Coded Decimal (BCD) is another way of representing numbers. Describe how denary integers larger than 9 can be converted into BCD. Give an example in your answer. Describe how an 8-bit BCD representation can be converted into a denary integer. Give an example in your answer.
1. Theory Fundamentals  →  1.1. Information representation
3. Advanced Theory  →  3.1. Data representation
Open
5
A motor is controlled by a logic circuit. The circuit has inputs (0 or 1) from three sensors R, T and W. The motor is switched off when the output from the logic circuit is 1. The following table shows the three sensors and the conditions being monitored. Sensor Description Binary value Condition R rotation rotation = 4000 rpm T temperature temperature >= 90 °C temperature = 50 litre/min water flow rate = 90 °C and rotation >= 4000 rpm or temperature = 50 litre/min Draw a corresponding logic circuit. R T X W Give a logic statement corresponding to the logic circuit in part . Complete the truth table for this system. INPUT Workspace OUTPUT X R T W
3. Advanced Theory  →  3.3. Hardware
1. Theory Fundamentals  →  1.3. Hardware
Open
7
A small company produces scientific magazines. The owner buys some new desktop computers. The computers are used to store thousands of colour images (diagrams and photographs). All the computers have Internet access. Name three utility programs the company would use on all their computers. Describe what each program does. Description Description Description The images contained in the magazines are produced using either bitmap or vector graphics software. Give four differences between bitmap and vector graphics. Employees using the new computers receive training. At the end of the training, each employee completes a series of questions. Three answers given by an employee are shown below. Explain why each answer is incorrect. “Encryption prevents hackers breaking into the company’s computers.” “Data validation is used to make sure that data keyed in are the same as the original data supplied.” “The use of passwords will always prevent unauthorised access to the data stored on the computers.”
1. Theory Fundamentals  →  1.6. Security, privacy and data integrity
1. Theory Fundamentals  →  1.2. Communication and Internet technologies
Open
8
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. 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 the screen the character whose ASCII value is stored in ACC. END Return control to the operating system. The diagram shows the contents of the main memory: Main memory 0110 0100 0111 1100 1001 0111 0111 0011 1001 0000 0011 1111 0000 1110 1110 1000 1000 1110 1100 0010 : : 1011 0101 Show the contents of the Accumulator after execution of the instruction: LDD 802 Accumulator: Show the contents of the Accumulator after execution of the instruction: LDX 800 Index Register: Accumulator: Explain how you arrived at your answer. Complete the trace table below for the following assembly language program. This program contains denary values. LDD 800 ADD 801 STO 802 LDD 803 CMP 802 JPE 107 JPN 110 STO 802 OUT JMP 112 LDD 801 OUT END : : Selected values from the ASCII character set: ASCII code Character ( P Z d Trace table: ACC Memory address OUTPUT There is a redundant instruction in the code in part . State the address of this instruction. The program used the ASCII coding system for character codes. An alternative coding system is Unicode. Give two disadvantages of using ASCII code. Describe how Unicode is designed to overcome the disadvantages of ASCII.
1. Theory Fundamentals  →  1.4. Processor fundamentals
Open