10.3DynamicRAM(1)10.3.1 IntroductionRandom access memory(RAM) is the best known form ofcomputer memory. RAM isconsidered"random access"becauseyou can access anymemory cell directly if you knowthe row and column that intersectat that cell.相交，交叉
Return Next Random access memory (RAM) is the best known form of computer memory. RAM is considered "random access" because you can access any memory cell directly if you know the row and column that intersect at that cell. 10.3.1 Introduction 10.3 Dynamic RAM(1) 相交, 交叉
10.3 DynamicRAM(2)10.2.2 DRAMIn the most common form of computermemory, dynamic random accessmemory (DRAM), a transistor and acapacitor are paired to create a memorycell, which represents a single bit of data.The capacitor holds the bit of information --a 0 or a 1. The transistor acts as a switchthat lets the control circuitry on the memorychip read the capacitor or change its state
10.2.2 DRAM Return Back Next In the most common form of computer memory, dynamic random access memory (DRAM), a transistor and a capacitor are paired to create a memory cell, which represents a single bit of data. The capacitor holds the bit of information - a 0 or a 1. The transistor acts as a switch that lets the control circuitry on the memory chip read the capacitor or change its state. 10.3 Dynamic RAM(2)
10.3DynamicRAM(3)桶A capacitor is like a small bucket that is ableto store electrons. To store a 1 in the memorycell, the bucket is filled with electrons. To store aO, it is emptied. The problem with the capacitor'sbucket is that it has a leak. In a matter of a fewmilliseconds a full bucket becomes emptyTherefore, for dynamic memory to work, eitherthe CPU or the memory controller has to comealong and recharge all of the capacitors holding a1 before they discharge. To do this, the memorycontroller reads the memory and then writes itright back. This refresh operation happensautomaticallythousandsoftimes persecond
A capacitor is like a small bucket that is able to store electrons. To store a 1 in the memory cell, the bucket is filled with electrons. To store a 0, it is emptied. The problem with the capacitor's bucket is that it has a leak. In a matter of a few milliseconds a full bucket becomes empty. Therefore, for dynamic memory to work, either the CPU or the memory controller has to come along and recharge all of the capacitors holding a 1 before they discharge. To do this, the memory controller reads the memory and then writes it right back. This refresh operation happens automatically thousands of times per second. 10.3 Dynamic RAM(3) 桶
10.3DynamicRAM(4)The capacitor in a dynamic RAM memory cellislikea leaky bucket. It needs to be refreshedperiodically or it willdischarge to 0
10.3 Dynamic RAM(4) The capacitor in a dynamic RAM memory cell is like a leaky bucket. It needs to be refreshed periodically or it will discharge to 0
10.3DynamicRAM(5)This refresh operation is where dynamicRAM gets its name. Dynamic RAM has to bedynamically refreshed all of the time or itforgets what it is holding. The downside of allof this refreshing is that it takes time andslows down the memory.被侵蚀的，被蚀刻的晶片Memory cells are etched onto a siliconwafer in an array of columns (bitlines) androws (wordlines). The intersection of a bitlineand wordlineconstitutes the address ofthememory cell.字线位线
This refresh operation is where dynamic RAM gets its name. Dynamic RAM has to be dynamically refreshed all of the time or it forgets what it is holding. The downside of all of this refreshing is that it takes time and slows down the memory. Memory cells are etched onto a silicon wafer in an array of columns (bitlines) and rows (wordlines). The intersection of a bitline and wordline constitutes the address of the memory cell. 10.3 Dynamic RAM(5) 被侵蚀的, 被蚀刻的 晶片 字线 位线