1. The processor performs the fetch-decode-execute (FDE) cycle.
(i) The first register used in the FDE cycle stores the location in random access memory (RAM) of the next instruction.
Identify the name of this register.

• Program counter // PC
•  Memory Address register // MAR

(ii) Describe the actions that take place in the decode stage of the FDE cycle.

• The instruction is sent/copied to the current instruction register/CIR/control unit/CU // The CIR/CU receives the instruction // The CIR stores/holds the instruction from the memory data register/MDR
• The control unit/CU decodes the instruction
•  An instruction set is used (to decode the instruction)
• The instruction is decoded/converted into the Opcode and Operand

(iii) Give the name of one component that is used in the execute stage of the FDE cycle.

• Arithmetic logic unit // ALU
• Accumulator // ACC
• Control unit // CU
• (Data/address/control) bus
• Memory data register // MDR
• Memory address register // MAR
• Program counter // PC
• Random access memory // RAM

Explain the advantages of the smartphone having a quad-core processor instead of a dual-core processor

• It can execute more instructions/FDE/FE/clock cycles simultaneously
•  four instructions/FDE/FE/clock cycles can be executed simultaneously rather than two
•  It can execute more instructions/FDE/FE/clock cycles per second as it has double the number of cores // It has twice as many cores // It has more cores // It has 4 cores instead of 2 cores

The smartphone has built-in input and output devices.
(i) Identify two input devices that could be built into the smartphone.

• Touchscreen
• Microphone
• Keyboard/keypad
• Button
• Sensor
• (Digital) camera

(ii) Identify two output devices that could be built into the smartphone.

• Screen // touchscreen
• Speaker
• LED // light
• Actuator

An optical mouse is connected to a computer using a universal serial bus (USB) cable.
(a) State the purpose of the optical mouse.

• To input data // interact with/navigate the computer/interface
• To control/move the cursor on the screen
• To act as a pointing device/pointer
• To allow the user to click/select/choose/drag (items on the screen) 
• To scroll through different pages/a page

(b) The USB cable transmits data using the serial half-duplex data transmission method. Describe how the serial half-duplex data transmission method transmits the data.

• (Serial) transmits the data one bit at a time down a single wire/channel/line
• (Half-duplex) transmits the data (between the computer and the mouse) in both directions/ways but only one direction/way at a time

(c) One benefit of using the USB cable to connect the optical mouse to the computer is that bits of data are less likely to arrive out of order.

Give two other benefits of using the USB cable to connect the optical mouse to the computer.

• Cannot plug the cable in the wrong way round
• Different data transmission speeds are supported
• High/adequate speed of data transmission
• Universal connection/standard
• Connection is backwards compatible
• It will power the mouse // It will charge the mouse (if it has wireless capabilities)
• The mouse will be automatically detected // Mouse drivers will be
• automatically downloaded // plug and play
• Unlikely to have interference/crosstalk

Complete the table with the missing functions and roles of an operating system.

Providing an interface

• To allow a user to communicate/interact with the computer/device/system

Managing memory

• It makes sure that two processes do not access the same memory location at the same time

Managing interrupts 

• Checks the source of the interrupt
• assigns/checks interrupt priority // Finds highest priority interrupt // Decides which interrupts to action
• Controls/checks the interrupt queue
• Calls/uses the interrupt service routine/ISR

Managing (user) accounts // providing/managing
(system) security

• It allows the user to set a username and password