1.2.1.2 Memory

Since a processor cannot store much data, it is up to another component to do so during the execution of a program. The size of memory is often measured in MB (megabytes) . One mega byte is roughtly one million (1,000,000) bytes. To be more exact, one mega byte is actually 1,048,576 bytes. A byte is the size of the smallest individual addressable location in memory. A byte contains eight bits . ``Bit'' is derived from ``binary digit''.

The physical form of a piece of memory is a small printed circuit board (PCB) . Most memory modules are called DIMMs for ``dual-inline memory module''. Notebook computers use SODIMMs, which stands for ``small outline dual-inline memory module''.

The processor and memory of a computer are separate components inside a computer. Due to the physics of electricity, data cannot flow from a processor to/from memory as quickly as the processor can handle. Memory modules are rated based on how quickly they can interact with a processor. For example, a PC2100 400MHz DDR memory module can handle up to 400,000,000 interactions with the processor per second. DDR stands for ``double data rate'', which is a method that allows more data transfer between memory and processor compared to pre-DDR memory modules.