CS: memory and storage and CPU components Flashcards
(24 cards)
What is secondary storage? Why is it necessary?
Secondary storage is a non-volatile, long term, external way of storing data on a computer.
What is the purpose of RAM?
Random Access Memory - a volatile way to store data and instructions that are currently running, for the CPU to directly access.
What is virtual memory? What are the benefits and drawbacks?
Virtual memory is the technique of using secondary storage like RAM when the RAM cannot hold all running programs. Programs that are running but not currently being used can be placed into secondary storage, and switched back into RAM when they are being used (because RAM is faster to access data from).
It means you can run more programs at once than your RAM supports. However, slows down your computer significantly, and can also wear down the hard drive due to the constant use.
What is magnetic storage? Give examples.
A way of storing binary data using magnetic north and south for 1 and 0. Examples include a hard disk drive and magnetic tape.
What is optical storage? Give examples.
A way of storing binary data by using pits and lands, which respectively allow light to be reflected off them and don’t. Examples include CD-RW, DVD-RW and Blue-Ray.
What is solid state storage? Give examples.
Storing data electronically, with delocalised electrons as 1 and trapped electrons as 0. Examples include memory sticks, flash memory cards and a solid state drive.
What is magnetic storage suitable for?
Anything with high capacity or low cost data requirements. Cloud storage on server farms.
What is solid state storage suitable for?
Because it’s light and durable, anything small and mobile, like a phone or camera. It’s also power efficient, which makes it useful for low power embedded systems. It’s has fast data access speeds, which is useful for devices without the best connection.
What is optical storage suitable for?
Long, serially read data or large scale, read only data to be distributed. High resolution video or audio players.
What does primary memory consist of? Are these components volatile?
RAM, ROM, registers, cache. All are volatile except ROM.
What is the purpose of ROM?
Read Only Memory. A non-volatile form of primary storage that holds start-up programs for the computer.
Discuss the differences between buying a physical copy vs online copy of a video game.
Online is more convenient, without the need to insert a disk; the game also cannot be damaged. Physical allows you to swap and share; it can be cheaper second hand.
Rank the 3 types of storage for speed
Solid state > magnetic > optical
Rank the 3 types of storage for capacity and price/GB
Magnetic > solid state > optical
Rank the 3 types of storage for durability
Solid state > magnetic > optical
Which storage types give you detectable anomalies before failure?
Magnetic does; solid state fail without warning.
Compare RAM and ROM.
Both are forms of primary storage that the CPU reads data from.
RAM is volatile, ROM is not. ROM is read only, with RAM you can read and write.
What does the program counter (PC) do?
Holds the address of the instruction the processor will execute next.
What does the current instruction register (CIR) do?
Holds the address of the instruction that the processor is currently executing
What does the memory address register (MAR) do?
Holds the address of the memory location the CPU needs to access next
What does the memory data register (MDR) do?
Holds data that will be passed onto the data bus, or has just been received from the data bus
What does the accumulator do?
Holds the results of calculations
What does the ALU do?
Does arithmetic calculations, logical operations and binary shifts (halving and doubling)
What does the control unit do?
Coordinates the execution of instructions. Sends signals to control the flow of data throughout the CPU.
