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| Memory | stores the instructions and data. It's one of the most important components of personal computer hardware. |
| RAM | Random Access Memory. RAM holds information only while the computer is on. It’s volatile or temporary memory as it is cleared when the computer is turned off. |
| SDRAM | Synchronous Dynamic Random Access Memory. This allows faster access to data by synchronizing with the clock speed of the computer’s system bus. |
| Memory capacity | The amount of data a computer can handle at any given time. Usually measured in gigabytes. |
| Cache memory | Special, high speed memory located on or near the microprocessor itself. Sometimes called RAM cache or CPU cache. Stores frequently accessed and recently accessed data and commands. |
| Virtual memory | Space on the computer’s storage devices (usually the hard disk drive) that simulates additional RAM. It enables programs to run like your computer has more RAM, but it is slower than RAM. |
| ROM | Read only memory or firmware. This is the chip on the motherboard that permanently stores the BIOS. It never changes, and you keep it when the computer is turned off, so it is known as nonvolatile or permanent memory. |
| BIOS | Basic input/output system. The BIOS is activated when you turn on the computer; it initializes the motherboard, recognizes any devices connected to your computer, and starts the boot process. |
| Boot process; Booting up | Includes loading the operating system software (like Windows) and preparing the computer so you can begin working. |
| Firmware update | Some computers allow ROM to be reprogrammed via a firmware update, which allows a manufacturer to fix bugs and add features. |
| CMOS memory | Complementary metal oxide semiconductor memory – a chip on the motherboard that stores the date, time, and system parameters. It is often referred to as semipermanent memory. |
