Computer Memory

Computer memory consists of a linear array of addressable storage cells.

Word (Memory)

The storage cells of memory are of a regular and fixed size known as a word. In exams, take a word to be $16\text{ bits}$.

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• Word-addressable memory

  Memory is commonly word-addressable: processor identifies a particular [[Word (Memory)|word]] when it needs to read and write data

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• Byte-addressable memory

  Memory can be byte-addressable: processor is able to address different sizes of memory compared to the word size

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• Modern PC architectures have a word size of 32-bit or 64-bit.

Random Access Memory

Random Access Memory (RAM) stores actively running programs and any data currently in use.

RAM chips are often referred to in terms of length $\times$ width.

• If the word size is $16\text{ bits}$, then a $4\text{M}\times 16$ RAM chip gives us $4\times 2^{20}$ 16-bit memory locations.

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