A451 – Memory

This post contains information regarding memory in computing hardware, including:

  • The difference between RAM AND ROM
  • Explaining why we need ROM
  • Describing the purpose of RAM
  • How the amount of RAM affects the performance of a PC
  • Why we need Virtual Memory
  • Describing Cache and Flash memory
  • Discussing how changes in memory technologies are leading to innovative computer designs



What is the difference between RAM and ROM?

RAM stands for Random Access Memory
ROM stands for Read-Only Memory

A ROM chip is non-volatile storage and doesn’t need a constant source of power to keep information stored on it. When power is turned off, a ROM chip will keep the information on it. However, a RAM chip is volatile and needs a constant source of power to keep information. When power is lost or turned off, a RAM chip will lose the information stored on it.

  • A ROM chip is mainly used in the start up process of a computer and a RAM chip is used for normal operations after the computer has started up and has loaded up the operating system.
  • Writing data to a ROM chip takes a longer amount of time than writing data to a RAM chip.
  • A RAM chip can store up to 16 GB of data unlike the ROM chip that can store from 4MB and more per chip.
rom chip ROM chip      ram chipRAM chip


Why do we need ROM in a computer system?

ROM is a special kind of memory which stores the instructions which the computer uses when it boots up. It is needed as the computer needs instructions as soon as it’s switched on and it needs to know basic things about the hardware, for example the configuration settings.

rom chip 2ROM chip


Describing the purpose of RAM

RAM is your computers short term memory, it temporarily stores data while the computer is online. The CPU can access parts of the memory randomly, without having to go through the entire thing. RAM is controlled and organized in a way that allows data to be stored and retrieved from specific locations, meaning that the process is fast and efficient.

ram chip 2Ram chip


How does the amount of RAM affect the performance of a PC?

RAM does not make the computer processor run faster and does not increase the performance of the computer processor.

The computer processor searches for the instructions in the RAM memory in order for programs to run. If these instructions are not in the RAM, they have to be transferred from where they are (the hard drive, CD-ROMS and any other storage system) to the RAM memory, this process is the loading of a program.

This means that a larger amount of RAM means that more instructions can be fit into the memory and therefore larger programs can loaded all at once. Computers allow us to multitask and have multiple programs loaded at the same time. If the computer does not have enough RAM then the computer may not be able to support running them at the same time.

Simply put, the more RAM you have the more programs you can have loaded at the same time.


Why do we need Virtual Memory?

If your computer lacks the RAM to run a certain process or program, your computer will use Virtual Memory to compensate.

Virtual memory is when your computer combines your computers RAM with temporary space of your hard drive.

Virtual memory is written onto a file in the hard drive, and it is often a “page file” or a “swap file”.

If we didn’t have Virtual Memory then we would not be able to run programs that we do not have enough RAM to support.

virtual memoryVirtual memory settings on windows 7


Describing Cache and Flash memory

Flash memory

Flash memory is non-volatile and therefore stores data without there being any power.

Flash uses electrical effects to store data. It is a ‘solid state’ technology because it is based on a silicon crystal slice and metal layers, there are no moving parts included in Flash Memory.

Data can only be stored in chunks, around 512 to 2048 bytes at a time, this makes it good as secondary storage, however it is not suitable to be main memory like RAM and ROM.

Flash memory is used in: memory sticks, jump drives, camera memory cards, and solid state hard drives.

memory stickMemory stick


Cache Memory

Cache is a type of memory that is quite small, but it can be accessed quickly. It stores information that is likely to be used again.

Web browsers use cache to make webpages load faster by storing a copy of the webpage locally, this is called a web cache.

Cache is also used in other parts of the computer system, most importantly the CPU Cache.

On the CPU (Central processing unit) chip, designers have place a small form of memory directly on the chip itself called the CPU Cache. It is much smaller, however can be accessed a lot faster than the main memory. The CPU cache stores the most frequently used information so it can be retrieved quicker.

cpu chipCPU chip


Discussing how changes in memory technologies are leading to innovative computer designs

Changes in memory technology means that storage in computer systems can be a lot smaller, especially in portable devices. Faster reading and writing times allows technology to become more efficient.

With memory chips being smaller, less power is consumed, meaning that less electricity is used and the battery life on portable devices last longer.

Lower cost allows a significantly better amount of RAM to be installed on basic computer systems.

Overall these improvements to technology allows devices to become more efficient and less expensive.




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