9618_s22_qp_13
A paper of Computer Science, 9618
Questions:
8
Year:
2022
Paper:
1
Variant:
3
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1
Text and numbers are examples of data stored in a computer. A character set is used to represent characters in a computer. Describe what is meant by a character set. Identify two character sets and state one difference between them. Character set 1 Character set 2 Difference Describe how lossless compression can be used to reduce the file size of a text file. Explain why lossy compression should not be used on a text file. A computer can represent numerical data in different forms. Complete the table by writing the answer to each statement. Statement Answer The hexadecimal value 11 represented in denary The smallest denary number that can be represented by an unsigned 8-bit binary integer The denary number 87 represented in Binary Coded Decimal (BCD) The denary number 240 represented in hexadecimal The denary number –20 represented in 8-bit two’s complement binary Working space
1. Information representation  →  1.1. Data Representation
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3
The table shows part of the instruction set for a processor. The processor has one general purpose register, the Accumulator (ACC). Instruction Explanation Opcode Operand LDM #n Immediate addressing. Load the number n to ACC LDD Direct addressing. Load the contents of the location at the given address to ACC LDI Indirect addressing. The address to be used is at the given address. Load the contents of this second address to ACC can be an absolute or symbolic address # denotes a denary number, e.g. #123 The current contents of main memory are: Address Complete the table by writing the value stored in the accumulator after the execution of each instruction. Instruction Accumulator LDM #103 LDD 102 LDI 103 The instructions in part are examples of the data movement group. Describe two other instruction groups. The table shows part of the instruction set for a processor. The processor has one general purpose register, the Accumulator (ACC). Instruction Explanation Opcode Operand AND Bn Bitwise AND operation of the contents of ACC with the operand XOR Bn Bitwise XOR operation of the contents of ACC with the operand OR Bn Bitwise OR operation of the contents of ACC with the operand B denotes a binary number, e.g. B01001010 The binary value 00111101 is stored in the memory address 200. Each instruction in the diagram is performed on the data in memory address 200. Draw one line from each instruction to its correct result. Instruction Result XOR B11110000 OR B01010101 AND B11111111
4. Processor Fundamentals  →  4.2. Assembly Language
4. Processor Fundamentals  →  4.1. Central Processing Unit (CPU) Architecture
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5
A company wants to store data about its employees in a computer system. The owner of the company wants to ensure the security and integrity of the data. State why data needs to be kept secure. One way the data stored in a computer can be kept secure is by using back-up software. Give two other ways the data stored in a computer can be kept secure. The data about the employees is currently stored on paper. The data needs to be transferred into the computer system. Data validation and verification are used to help maintain the integrity of the data. Identify and describe one method of data verification that can be used when transferring the data from paper to the computer. Method Description The company needs to transfer the date of birth of each employee into the computer system. Give one example of how each of the following data validation rules can be used to validate the date of birth when it is entered into the system. Range check Presence check Length check Explain why the data in the system may not be correct even after validating and verifying the data.
6. Security, privacy and data integrity  →  6.2. Data Integrity
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6
A relational database, TECHNOLOGY, stores data about the staff in a company and the computer devices used by the staff. The database has the following tables: STAFF(StaffID, FirstName, LastName, DateOfBirth, JobTitle) DEVICE(DeviceID, Type, DatePurchased, StaffID) Describe the relationship between the two tables. Refer to the primary and foreign keys in your answer. The database uses a Data Definition Language (DDL) and Data Manipulation Language (DML). Complete the SQL script to return the number of devices stored in the database for the staff member with the first name ‘Ali’ and last name ‘Khan’. SELECT (STAFF.StaffID) FROM INNER JOIN DEVICE STAFF.StaffID = DEVICE.StaffID WHERE STAFF.FirstName = 'Ali' STAFF.LastName = 'Khan'; The table DEVICE needs a new attribute to store whether the device has been returned by the staff member, or not. Write a Structured Query Language (SQL) script to insert the new attribute into the table DEVICE. The database is in Third Normal Form (3NF). Complete the table by describing the three normal forms. Normal Form Description First Normal Form (1NF) Second Normal Form (2NF) Third Normal Form (3NF)
8. Databases  →  8.3. Data Definition Language (DDL) and Data Manipulation Language (DML)
8. Databases  →  8.1. Database Concepts
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