Chapter 5 (Abi) Flashcards
(85 cards)
What is the CPU?
The Central Processing Unit which has the main role of processing programs and data.
What is the fetch-execute cycle?
The repeated process where the CPU fetches the instruction from the memory and carries it out.
What are the 3 main components of the CPU?
The Control Unit, Arithmetic and Logic Unit, Immediate Access Store
What is the control unit?
The Control Unit is a part of the CPU which manages the execution of instructions in the fetch-execute cycle, mainly one at a time in some form of order. It decides which instruction to carry out next and fetch it from the memory, decode the instruction & to execute the instruction.
What is the ALU?
The Arithmetic Logic Unit is the part of the CPU which processes data which requires arithmetic calculations, e.g. addition and division. It also performs logical comparisons using logical operators AND, OR and NOT.
What is the IAS?
The Immediate Access Store is the part of the CPU which is also referred to as the main memory. It stores all programs and data temporarily while they are in use. During the fetch-execute cycle, all instructions are fetched from their specific location in the IAS using an address.
What are CPU registers?
High speed memory locations which are all used for a specific purpose and all have a crucial role in the fetch-execute cycle.
What is the PC?
The Program Counter is the CPU register which stores the address (memory location reference) of the next instruction to be fetched. As many program instructions are ordered in sequence, the program counter is automatically incremented by one every time an instruction is fetched.
What is the MAR?
The Memory Address Register temporarily stores the address of the current instruction or data being executed.
What is the MDR?
The Memory Data Register temporarily stores data being fetched from or written to the main memory. All data transferred from the main memory to the CPU goes via the MDR.
What is the IR?
The Instruction Register temporarily stores the current instruction to be decoded and then executed after it has been fetched from the main memory.
What is the Accumulator?
The Accumulator is part of the Arithmetic and Logic Unit. When calculations take place, all results are temporarily stored in the accumulator before being transferred to and stored in the main memory. It is the default location to store any calculations performed by the ALU.
How does clock speed influence the speed of processing?
Clock speed is an indicator of what speed at which the CPU can work at. It is commonly measured GHz (gigahertz); this is a representation of how many billion instruction cycles the CPU can complete per second. In terms of the speed of processing, a greater clock speed allows for faster execution of tasks and improves system responsiveness. However, this is pointless without hardware which is of a greater speed capability.
How does cache influence the speed of processing?
Cache memory is a small capacity of memory which is situated between the processor and the RAM. This can be costly but using it can increase processor speed as it can temporarily store frequently used instructions and data. This means that the control unit of the CPU can automatically check the cache memory first when fetching an instruction. As this is quicker than checking the RAM (cache is significantly smaller), the processor speed will increase.
How do processor cores influence the speed of processing?
A core can be defined as a single processing unit which has its own control unit, ALU and registers. More advanced CPUs contain more than one core (e.g. dual core processor) which will increase their ability to run several programs at once which will therefore enhance the overall processing speed.
What is a microphone?
A microphone is an input device which records voice and sound to allow it to be inputted to the computer. A voice recognition system converts sound to text or accepts spoken commands. Microphones are also used to record music in analogue format and store it in digital format. They are also used in applications like Skype where users use VOIP (Voice Over Internet Protocol) to speak to each other.
Give 2 advantages of a microphone:
- Faster to use voice to text rather than type out everything with a keyboard.
- It is hands free which allows users to multitask.
Give 2 disadvantages of a microphone:
1.The recognition rate of spoken words can be low if there is background noise.
2. Sound files require greater storage capacity than text.
What is a mouse?
A mouse is a device which includes 3 buttons. Typically, the left button is used to make selections (e.g. selecting an option from a menu); the right button is used display a pop-up menu at the position of the cursor and the middle button is used to scroll. When moved. the pointer is repositioned on a VDU (visual display unit), using sensors to detect movement.
What is an advantage of using a mouse?
Easy to use and requires little or no training
How does using a mouse compare to using a keyboard for selecting menus?
Quicker to select menus and icons compared to using a keyboard
What is a disadvantage of using a mouse for experienced users?
Slow compared to using ‘hot keys’
What do experienced users prefer over using a mouse for printing?
Pressing ctrl + P
What surface is required for a mouse to function properly?
A flat surface
