What are the common terminology of memory

A detailed analysis of common memory terms:

Bank:bank refers to the memory slot of the unit of calculation (also known as memory), which is the computer system and memory between the basic operating unit of data convergence.

Memory speed: The speed of memory is calculated by the amount of time spent in data processing between each CPU and memory, in the cycle (NS) unit for Bus loops (buses).

Memory Module (Memory module): Refers to the memory module is a printed circuit board has a mosaic of several memory chip chips, and this memory chip is usually a DRAM chip, but the recent system design also has the use of cache chip embedded in the memory module is installed on the PC The number of DRAM chips (chips) embedded on the module and the capacity of individual chips (chips) are the main factors that determine the design of the memory module on the host board's dedicated slot (Slot).

Simms (single In-line Memory Module): The circuit board is welded with a number of different memory IC, can be divided into the following 2 types of patterns:

72pin:72-sided Memory module is used to support 32-bit data processing volume.

30PIN:30-sided Memory module is used to support 8-bit data processing volume.

DIMM (Dual in-line Memory Module): (168PIN) used to support 64-bit or wider bus, and only 3.3 volts, usually on 64-bit desktop computers or servers.

The Rimm:rimm module is one of the main specifications for the next generation of memory modules, a memory module supported by Intel's chipset in 1999, with bandwidth up to 1.6gbyte/sec.

So-dimm (Small Outline Dual in-line Memory module) (144PIN): This is an improved DIMM module that is smaller than a typical DIMM module and is used for notebook computers, list machines, fax machines, or various terminals.

PLL: For the phase-locked loop, it is used to unify the pulse signal so that the memory can access the data correctly.

Rambus Memory Module (184PIN): Using direct Rdram memory module, called Rimm module, the module has 184pin feet, the data output mode is serial, and the existing DIMM module 168pin, parallel output structure is very different.

6-Layer and 4-layer Board (6 layers v.s. 4 layers): Refers to the Circuit printing board PCB printed circuit Board with 6 or 4 layer of glass fiber, usually SDRAM will use 6 layer board, although will increase the cost of PCB but can be exempted from noise interference, While the 4-layer board can reduce the cost of PCB but poor performance.

Register: Is the meaning of the buffer, its function is to be able to achieve synchronization at high speed purposes.

SPD: for serial Presence detect abbreviation, it is burned in the EEPROM code, the BIOS must detect the previous boot memory, but with the SPD do not have to do the detection of the action, and by the BIOS directly read the SPD access to the memory of the relevant information.

Comparison between parity and ECC: the same-bit check code (parity check codes) is widely used on the debug code (Error detection codes), they add a check bit to each data character (or byte), and can detect all the odd (even The same bit of error, but parity has a disadvantage, when the computer found a byte error, and can not determine the error in which bit, you can not fix the error.

Buffer and no buffer (buffer v.s. Unbuffer): A buffer DIMM is a way to improve the timing (timing) problem. A buffer-free DIMM can be designed for use on the system, but it can support only four DIMMs. If the buffer-free DIMM is used on the 100Mhz motherboard, there will be poor access. DIMMs with buffers can use more than four memory, but if the buffer speed is not fast enough, it will affect the performance. In other words, a buffer has the risk of slowing the speed of the DIMM, but it can support the use of more DIMMs.

Self-Charging (Self-refresh): DRAM internal independent and built-in charging circuit for a certain period of time to do self recharge, usually used in notebook computers or portable computers, such as the high demand for computers.

Pre-charging time (CAS latency): Usually referred to as CL. For example, Cl=3, which indicates that the computer system's autonomous memory reads the first data, the required preparation time is 3 external time vessels (System clock). The difference between CL2 and CL3 is only the preparation time for the first reading of the data, the difference of one time pulse has no significant effect on the efficiency of the whole system.

Clock signal (Clock): The clock signal is provided for synchronous memory to do signal synchronization, synchronous memory of the access action must be synchronized with the clock signal.