RAM, RAM, who's got the RAM? We all know how frustrating it is to keep up with growing and changing PC technologies, so we thought we'd give you a break. When it comes to RAM, come here to learn all you need to know about memory terms... both old and new.

RAM Acronyms
RAM Chip Terms
Cache Memory Terms
General Memory Terms

RAM Acronyms
DRAM Dynamic Random Access Memory	RAM that requires external refresh circuitry and a minimum clock speed to retain its state. If dynamic RAM loses power, all its little capacitors discharge and it forgets everything.
EDO RAM Extended Data Oout Random Access Memory	A newer, faster type of asynchronous computer memory that holds its last-requested data in a cache after releasing it.
MDRAM Multibank Dynamic Random Access Memory	Memory normally used in video boards that boasts extended performance with high bandwidth and short access times. The MDRAM chip can access several memory banks at a time.
NVRAM Non- Volatile Random Access Memory	Uses either a permanently connected battery or takes advantage of non-volatile cache to store data indefinitely in the event of a power failure.
RAM Random Access Memory	Computer memory used to temporarily hold programs and data. RAM is stored in ICs that plug into the system board or into an expansion card which in turn plugs into slots on the system board.
RDRAM Rambus Dynamic Access Memory	A type of memory targeted at the video card market. It uses a proprietary RAM bus channel and boasts high data transfer rates (up to 500MBps sustained). It excels at such tasks as video streaming but lacks in the more intensive tasks like random access.
ROM Read Only Memory	Computer memory used to permanently store parts of the computer's or expansion card's operating system. ROM chips can contain instructions and data. Informally means any storage which can be read but not changed.
SDRAM Synchronous Dynamic Random Access Memory	Fast memory capable of transmitting data on every clock cycle, skipping the wait states and improving system performance.
SGRAM Synchronous Graphics Random Access Memory	Provides high bandwidth at a low cost and has support for masked write (reduces need for read-modify-write memory operations) and block write (accelerated foreground/background fills such as color expansion for text).
SRAM Static Random Access Memory	Requires less power than DRAM and will retain values as long as the computer has power. It is usually faster, but costs more, and is most often utilized for speed critical areas of the computer, like cache.
VRAM Video Random Access Memory	Utilizes a dual port design, allowing the accelerator chip and RAMDAC to access the frame buffer simultaneously. In other words, it's cooler than DRAM but not as cool as WRAM.
WRAM Window Random Access Memory	Ultra high performance memory for video with high bandwidth and a dual ported design (can move data in and out simultaneously) More memory is also concentrated on a single chip, allowing maufacturers to use one where other types of video memory may need two.
RAM Chip Terms
DIMM Dual Inline Memory Module	Circuit board with pins connecting to different memory chips on both sides of the board, which allows for wider and faster data transfer (128-bit). Thought to eventually replace the SIMM as the market standard.
SIMM Single Inline Memory Module	A way of packaging RAM chips that combines several compact chips on a small circuit board. SIMM pins have a 64-bit data path and are located on both sides of the circuit board, but they connect to only one memory chip, while DIMMs can connect to multiple chips.
Cache Memory Terms
Asynchronous Cache	The slowest, most inexpensive type of secondary SRAM cache, running at speeds of 15 to 20 ns.
Cache	A special block of fast memory used for temporary storage of data for quick retrieval. (Think of cache as a temporary holding place for one device.).
Disk Cache	RAM that holds data that is frequently read from or written to a disk. This is faster than getting the data from the disk. Some hard disk controller cards are equipped with their own on-board cache.
L2 Cache	Refers to "level 2 or secondary" cache. A type of cache that resides on the motherboard except when referring to a Pentium Pro machine, where it resides on the processor.
Pipeline Burst Cache	Secondary synchronous SRAM cache with speeds as fast as 9ns. It uses "burst" data transfers rather than a steady stream in order to take advantage of the faster bus cycles and CPU's available on today's systems. Data is moved through the SRAM core in an assembly line fashion -- as if going through a "pipe".
RAM Cache Random Access Memory Cache	A method of storing frequently-accessed data in static RAM that is much faster than the system's main memory, resulting in a significant increase in system speed.
Secondary Write-Back Cache Random Access Memory Cache	The "secondary" refers to this type being a slower, intermediate level cache between the primary cache and the main memory. The "write-back" refers to the cache architecture, where data is only written to the main memory after it is forced out of the cache.
SRAM Cache Static Random Access Memory Cache	Requires less power than DRAM and will retain values as long as the computer has power.
Synchronous Cache	A popular type of secondary SRAM cache used in most Pentium systems. Very fast, running at speeds of up to 9ns.
Write-Back Cache	A cache architechture where data is only written to main memory after it is forced out of the cache.
Write-Through Cache	A cache architechture where data is wrtten to main memory at the same time as it is being cached.
General Memory Terms
Base Memory	The first 640K of computer memory.
Conventional Memory	Random access memory (RAM) with addresses below 640KB; DOS can only directly address conventional memory.
Core Memory	An old term for main memory. From when RAM was physical frameworks of donut-shaped magnets called cores.
ECC Memory Error Checking & Correcting Memory	Advanced type of memory that can find and correct certain types of single-bit memory errors, providing greater data integrity. Advanced ECC can correct some double-bit errors.
EEMS Enhanced Extended Memory Specification	An improved version of EMS. The improvements are now part of EMS version 4.0.
EMS Expanded Memory Specification	A method for accessing memory beyond the 640K DOS limit.
Expanded Memory	RAM above 1MB accessed on an alternating basis (using bank switching) so that addresses appear to be below 1MB. Software must be written for compatibility with EMS in order to use expanded memory. Applications running under OS/2 cannot access expanded memory. They use extended memory.
Extended Memory	RAM above 1MB, with addresses above 1MB that some applications can address directly. 80286 processors can access this memory when running in protected mode, and 80386 and 80486 can access it when running in virtual real mode. However, DOS programs cannot generally use these modes. Extended memory can be used to emulate expanded memory. Applications running under OS/2 can access extended memory.
High Memory	Addresses in main memory between 640K and 1MB.
Interleaved Memory	An option on some system boards that increases processing speed by assigning memory locations on an alternating basis to two banks of RAM. The computer has to wait one cycle between accesses to a single bank of memory, but it can access a different bank without having to wait.
Low Memory	The first MB of RAM in a DOS computer. Also known as standard memory, main memory, and primary storage.
Memory	A place in computer circuitry that stores data.
MMU Memory Management Unit	Circuitry that manages the swapping of blocks of memory.
Non-Parity Memory	Newer than parity and does not include the extra "error-detecting" chip.
Nonvolatile Memory	Does not disappear when the power is shut off.
Parity Memory	Contains an extra chip used to detect errors.
Virtual Memory	Memory addresses and data that appear to the CPU to be in RAM but actually are on a hard disk. Special software manages this memory and gives the CPU access to it.
Volatile Memory	Information disappears when the power is shut off.

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