| Term |
Definition |
| Cache Controller |
The circuit in control of the interface between the CPU, cache and DRAM (main memory). |
| Cache memory |
Cache RAM is high-speed memory (usually SRAM) which is dedicated to storing frequently requested data. If the CPU needs data, it will check in the high-speed cache memory first before looking in the slower main memory. Cache memory may be three to five times faster than system DRAM. Most computers have two separate memory caches; L1 cache, located on the CPU, and L2 cache, located between the CPU and DRAM. L1 cache is faster than L2, and is the first place the CPU looks for its data. If data is not found in L1 cache, the search continues with L2 cache, and then on to DRAM. |
| Card Memory |
A type of memory typically used in laptop and notebook computers. Credit card memory features a small for factor and is named for its similarity to the size of credit card. |
| CAS |
(Column Address Select/or Strobe)--A control pin on a DRAM used to and activate a column address. The column selected on a DRAM is determined by the data present at the address pins when CAS becomes active |
| CAS Latency |
The ratio between column access time and clock cycle time. CAS Latency 2 (CL2) offers a slight performance increase over CAS Latency 3 (CL3).
|
| CBR |
(CAS Before RAS)- a fast refresh technique in which the DRAM keeps track of the next row it needs to refresh, thus simplifying what a system would have to do to refresh the part. |
| Check Bits |
Extra data bits provided by a DRAM module to support ECC function. For a 4-byte bus, 7 or 8 check bits are needed to implement ECC, resulting in a total bus width of 39 or 40 bits. On an 8-byte bus, 8 additional bits are required, resulting in a bus width of 72 bits. |
| Checkboard |
A detail test pattern designed to exercise each individual cell in the memory and find possible shorts between adjacent columns and data buses |
| Clock |
An electrical current that alternates between high and low voltages. The speed of the clock is measured in Megahertz (MHz) |
| Clock speed |
The rate at which a computer's internal system clock operates. The clock is used to synchronize operations between the components within the clock. |
| CMOS |
Complementary Metal Oxide Semiconductor: a process that uses both N- and P-channel devices in a complimentary fashion to achieve small geometries and low power consumption. |
| Column |
Part of the memory array. A bit can be stored where a column and a row intersect. |
| Compact Flash Memory |
A fast, postage stamp size RAM that is removable. The CF Card weighs half an ounce, with roughly one-fourth the volume and one-half the thickness of a PCMCIA Type II Card. The CF Card fits into a CF PC Card Adapter making it compatible with a standard PCMCIA Type II slot on any notebook or desktop computer. This allows the easy transfer of stored digital information from the CF Card to a computer or printer. Currently, the most readily available application for the CompactFlash Card is the digital still camera. |
| CPU |
(Central Processing Unit)--The chip in a computer that has primary responsibility for interpreting commands and running programs. The CPU is the most vital component of a computer system. The speed of the CPU has a significant impact on overall system performance, but the CPU doesn't act alone. If slower memory is paired with a fast processor, the processor will be forced to wait for the memory to respond. When the speed mismatch is extreme, the user will see numerous memory errors and even complete system failure. |
