Megabit	Amount of memory equal to 1,048,576 bits of information. (Abbreviated Mb.)
Megabyte	Amount of memory equal to 1,048,576 bytes of information. (Abbreviated MB.)
Megahertz	A measurement of clock cycles in millions of cycles per second.
Memory Configuration	The amount of memory in an IC and how it is accessed.
Memory Controller	The logic chip used to handle the I/O (input/output) of data going to and from memory. See Chipset.
Memory Cycle Time	Minimum amount of time required for a memory to complete a cycle such as read, write, read/write, or read/modify/write.
Memory Types	Cache: static random access memory containing recently used information DRAM: dynamic random access memory. SDRAM: single data rate synchronous dynamic random access memory. DDR SDRAM: double data rate synchronous dynamic random access memory. Usually referred to as DDR. SLDRAM: synchronous link dynamic random access memory. RDRAM: Rambus dynamic random access memory. RAM: random access memory. ROM: read only memory (permanent memory that cannot be changed). SRAM: static random access memory.
MHz	See Megahertz
Micron	1. A unit of measure equivalent to one-millionth of a meter; synonymous with micrometer. 2. Also the company name of one of the largest memory producers in the world and the parent company of Crucial Technology.
MIPS	Millions of instructions per second. This measurement is generally used when describing the speed of computer systems.
Motherboard	The main printed circuit board in a computer that carries the system buses. It is equipped with sockets to which all processors, memory modules, plug-in cards, daughterboards, or peripheral devices are connected.
MTBF	Mean time between failures.
MU	Memory unit. Usually a printed circuit board assembly populated with memory chips that stores a certain quantity of memory. Intel term for one of the types of cards in a memory system card set.
Nanometer (nm)	One billionth of a meter.
Nanosecond(ns)	One billionth of a second; used to measure the speed of the parts.
Nibble	Usually 4 bits (half a byte).
Nonvolatile Memory	A memory that retains information if power is removed and then reapplied. SRAM and flash are examples of nonvolatile memory.
Operating system	Software controlling the overall operation of a multipurpose computer system, including such tasks as memory allocation, input and output distribution, interrupt processing, and job scheduling.
Page	The number of bits that can be accessed from one row address. This is also sometimes referred to as a row.
Page Mode	Mode in which if RAS is kept low and the DRAM is given a column address without being given a new row-address, the chip will remember which row it was on the last time and automatically stay on that row. It is like saying that all the bits along one row are all on the same page, and the part will assume the same page is intended until a different page is specified.
Parity	A bit added to a group of bits to detect the presence of an error. The parity bit looks at the other 8 bits and determines if they are even or odd and correspondingly is a 0 or 1. The system compares the 8 bits with the parity bit. If they both are even or odd, the data is assumed to be correct. If one is even and one is odd, there is an error, and typically the system will fail.
Passive Device	A device incapable of current gain or switching, such as a resistor or capacitor.
PC100	The PC100 specification defines the requirements for SDRAM modules used on 100MHz FSB motherboards.
PC133	The PC133 specification details the requirements for SDRAM modules used on 133MHz FSB motherboards. PC133 SDRAM can be used on 100MHz FSB motherboards but will not yield a performance advantage over PC100 memory at 100MHz.
PCB	Printed circuit board. Board that contains layers of circuitry that is used to connect components to a system.
PCMCIA	Personal Computer Memory Card International Association. An industry organization that helps to set standards for flash cards.
PD	See Presence Detect.
Pin	1. The metal extensions from an IC package or discrete component that connects the component to the PCB. 2. Another term for the Edge Contacts on a Memory Module.
Populated Board	A PCB with components.
Power Down	To turn the system's power OFF.
Power up	To turn the system's power ON.
Presence Detect	Circuitry on certain memory modules that provides information to the system.
Processor	The primary chip of the system that oversees all the other components of the system.
Pull-up	A device or method used to keep the output voltage of a device at a high level, often a resistor network connected to a positive supply voltage.
Quad Flat Pack (QFP)	A flat, rectangular, integrated circuit with its leads projecting from all four sides of the package without radius.
RAM	Random access memory. A data storage device for which the order of access to different locations does not affect the speed of access, except for bursts. Data is typically stored in RAM temporarily for use by the process or while the computer is operating. FPM, EDO, SDRAM, DDR, etc. are all types of RAM.
RAS	Row address strobe. The signal that tells the DRAM to accept the given address as a row address. Used with CAS and a column address to select a bit within the DRAM.
RDRAM	Rambus DRAM is a revolutionary type of DRAM that uses a 16-18 bit data path and is designed to operate with FSB speed of 800MHz, producing a burst transfer rate of 1.6 gigahertz.
Read Time	The amount of time required for the output data to become valid once the read and address inputs have been enabled. Generally called access time.
Refresh	The process used to restore the charge in DRAM cells at specific intervals.
Refresh Rate	A count of the number of rows (in thousands) refreshed at a time in a refresh cycle. Common refresh rates are 1K, 2K, 4K, and 8K.
Registered Memory	Registers delay memory information for one clock cycle to ensure all communication from the chipset is collected by the clock edge, providing a controlled delay on heavily loaded memories.
RIMM™	Rambus inline memory modules used for Rambus DRAM.
Row	Part of the RAM array; a bit can be stored where a column and a row intersect. Sometimes also referred to as a page.