1651697
| Question | Answer |
| what are the two main components of the CPU and what do they do? | - the CU (control unit) which controls the hardware and software devices and performs the fetch, decode, execute cycle -the AUL (Arithmetic and Logic Unit) which performs arithmetic and logical operations |
| explain what happens in the fetch, decode, execute cycle | FETCH - The CPU receives its instruction in binary bit pattern. DECODE - These instructions are written in machine code and enable the CPU to perform calculations. The result of these calculations is stored in the CPU’s main memory, referred to as the IAS (Immediate Access Storage). EXECUTE - The results then inform the CPU what instructions to relay to the input and output devices. |
| What is the CU (control unit) responsible for doing? | the control unit is responsible for informing the system that to do so that instructions are executed. |
| What does the CU (control unit) manage? | The CU manages all of the computers programs by directing the flow of data between the CPU and other devices. It also controls an instruction register that can transfer instructions or data and perform arithmetic and logical comparisons at high speed. |
| What are registers used by the CU for? | Registers are used by the CU as temporary, convenient places to store the information necessary to decode and execute |
| What does the AUL (Arithmetic logic unit) do? | The arithmetic logic unit receives coded instructions from the control unit to complete the required calculations or operations - like a powerful calculator. The result of these calculations are stored in an output register. Some of the calculations ALU carries out: -comparisons : use relational operators (=, <, >) to determine the relationship between values - logical operations: use the logic gates AND , OR and NOT |
| How is data encoded? | When a calculation is complete, the data is encoded as bit patterns using the binary number system. These bit patterns are stored in memory addresses. |
| What do memory addresses do? | Memory addresses identify locations in a computers storage memory. Every memory address is numbered consecutively and stores each part of the instruction in the correct order |
| What is clock speed? | The CPU's speed is also known as the clock speed. The clock speed measures the frequency at which the CPU completes and instruction. Clock speed is measured in hertz (Hz) |
| Explain Moore's Law | Moore’s law is an observation that the number of transistors on integrated circuits doubles approximately every two years. Moore’s law is used in the computer industry in long-term planning |
| What is a transistor? | A transistor is a component which can be switched on or off to amplify signal. More transistors means more complex calculations can be carried out. This means that processor speed increases. |
| what are mini processors? | Mini processors called cores are built within the CPU. Modern CPU’s are dual or quad core. This allows multitasking as each core can process a programs instructions without slowing down the overall performance of the computer. |
| What is cache memory? | The cache memory is a special high speed memory that can be accessed quickly. Frequently used software instructions are stored in the cache and are recalled when required. As a result, the overall processing time is much quicker. |
| What happens when the CPU requests data from the cache memory? | The CPU requests data from the cache. If available, the data is sent. If the data is unavailable, it is requested from the RAM (memory). Data is then transferred to the cache and then on to the CPU |
| Explain RAM | RAM stands for Random Access Memory – it stores all the current instructions that a piece of software requires to run and temporarily stores data being processed by the CPU. |
| Explain ROM | ROM stands for Read Only Memory. The contents of ROM are programmed by the manufacturer and can only be read. ROM contains all the information required for the computer to boot up |
| How does RAM determine the value of a memory address | It uses electrical charge to determine the value of a memory address, if the address has a charge, the value is 1. if it has no charge the value is 0. this soon builds a sequence of binary code, which the CPU then converts into a set of instructions. |
| What can RAM be referred to as? | RAM can be referred to a temporary or volatile memory because data as an electrical charge can be wiped if the power supply is cut |
| Explain the memory space in RAM | When loading and using software, program instructions are loaded into the RAM. If more software is loaded, more memory space is used. After a while the memory space will run out and the RAM must overwrite previous addresses. RAM is measured in megabytes (MB) or gigabytes (GB). The larger the number, the faster the program will run. Increasing the amount of ram will increase the computers overall speed |
| How is data saved in ROM? | Instructions are permanently saved in ROM and are present even when the power is turned off (non-volatile memory). The contents are programmed by the manufacturer and cannot be deleted. The transistors in the ROM chip are connected in a particular way so that even when the computer is turned off or there is a power failure, data is not lost |
| Give an example of ROM | An example of ROM is BIOS (Basic Input Output System) a chip found in most computers that contains all the instructions necessary to boot up |
| What is Flash Memory? | Flash memory is a non-volatile computer storage memory that can be electronically erased and rewritten. Flash memory’s formal name is EEPROM (Electrically Erasable Programmable Read-only Memory) Flash memory is used in SD cards, USB drives and solid-state drives. It was developed in the 1980s as a type of re-writeable ROM. It used a ‘flash’ of electric current to erase all or part of its contents. Flash memory devices are easy to manufacture, can hold large amounts of data and have no moving parts. They are also faster, smaller and more durable than CD ROMs. |
| What is Virtual Memory? | Virtual memory is located on the hard disk and is used as storage for program/software instructions that will not fit into the RAM. If the RAM is full, content can be temporarily written to the hard disk and retrieved when required. This prevents the computer from slowing down. |
| TRUE OR FALSE? calculations are performed by the ALU | TRUE |
| TRUE OR FALSE? the IAS is the only memory used by the CPU | FALSE |
| TRUE OR FALSE? RAM has an impact on a computers overall speed | TRUE |
| TRUE OR FALSE? most computer processors have one core | FALSE |
| TRUE OR FALSE? volatile memory means that data is wiped id the power supply is lost | TRUE |
| TRUE OR FALSE? non-volatile memory means that the data is stored permanently | TRUE |
| TRUE OR FALSE? the CU controls the memory | FALSE |
| TRUE OR FALSE? clock speed determines where the instructions are sent | FALSE |
| TRUE OR FALSE? memory addresses turn calculations into code | FALSE |
| TRUE OR FALSE? flash memory is a type of programmable read-only memory | TRUE |
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