VIII.
SDRAM, 1990 . , SDR SDRAM (Single Data Rate SDRAM ). 2000 SDR SDRAM DDR SDRAM (Dual Data Rate SDRAM SDRAM ), . DDR2 SDRAM, , 2007 , , , DDR3 SDRAM.
, 90- , RDRAM (Rambus DRAM), - .
, .
, . , .. , , .
64 (, 1 , .. ), .VIII.1. 16 : 8 , RAS (Row Address Strobe) , 8 , CAS (Column Address Strobe) . (Clock) () CAS. () W (Write) WE (Write Enable), () .
.VIII.1
64 .
, - . VIII.2.
, , / 14- , 16 384 , . 512 . , , 4,8,16, 32 .
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SDRAM-, , . VIII.3. , . , . , ( ) . .
. VIII.2 - .
.VIII.3
, ( ), . , , , (Sense Amplifier), , .
, , , , . . , , .. , .
, ( , BAi). , .
(, , , , ).
. , , , , .. . . , . , , , .
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.VIII.4 , , , 8192 1024 . , 8192×1024×8=213×210×23= =226=64 , .. 8 . CS (Chip Select) () . , . .
BA (Bank Address) - BA0 BA1. . : 00,01,10,11 .
, , (, ) CS (Chip Select).
WE ( ) . , , CAS RAS . D0D7 , .
.VIII.4
8 8 .
.
(),
() .
.
4,8,16 32 .
, ..
( ), ,
.
. , 1024 128×8, .. 128 8 . 64×16 32×32, .. 64 32 , , 16 32 .
, . , ( 64-), .
, , . , , , , , () . , 64 . , 512 64 : (512×220×23) / 26 = 64×220 = 64.
() , , SIMM (Single In-line Memory Module ) DIMM (Dual In-line Memory Module ). , . SIMM , 30- 72-, 8 2 . DIMM 64- . 168 184 - 13 .
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SIMM DIMM VIII.5 . VIII.6.
. VIII.5 SIMM c 72
RIMM (Rambus In-line Memory Module), Rambus . RIMM DIMM, , , .
. VIII.6. DIMM:
) DIMM-168;
) ;
) ;
) DIMM-184.
, SIMM, DIMM RIMM, () , , , (). 64, 128, 256 512 . , , , .
(, ), () .
.
,
.
. , , . , . 64 (8 ), , , 800 , 6,4 / (800 × 8 ). .VIII.7.
RAS. ACTivation (). , , .
, () , , . , . .
CAS. AS, Clock, , , WE , ( READ) , WE .
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, PREcharge ( ), . .
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.VIII.7
.
VIII.1.
VIII.1.
, .
CS | RAS | CAS | WE | |
Low | High | High | High | |
Low | Low | High | High | |
Low | High | Low | High | |
Low | High | Low | Low | |
Precharge | Low | Low | High | Low |
, . . , .. , , . , . .
. VIII.7, , tRCD, RAS CAS (RAS-to-CAS Delay), .. ( ) .
tCL, (CAS Latancy), () () ( ). , , , . ( 4 ). SDRAM , . (Burst Length BL). 2, 4 8.
tRAS (Active-to-Precharge Delay), RAS PRE, .. , Prechage. (tRAS) , tRAS > tRCD + tCL. , tRAS , , .
.
tRP (RAS Precharge), PRECHARGE . . VIII.8.
, CS# (Command Rate ). (. .VIII.9).
, , .
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, , , , : tCLtRCDtRPtRASCommand Rate. , , PC3200 : 2345(1). , CAS Latency (tCL) 2 , RAS to CAS Delay (tRCD) 3 , RAS Precharge (tRP) 4 , ACTIVE to precharge delay (tRAS) 5 Command Rate 1 . , : tCL tRCD tRP.
. VIII.8 RAS Precharge
.VIII.9 Command Rate
SDRAM (Synchronous Dynamic RAM) . SDR SDRAM (Single Data Rate ), .
SDR SDRAM, .VIII.10a, : /. , /. , / , . SDRAM . , .. . , .
1999 DDR SDRAM (Double Data Rate SDRAM SDRAM ). , , , , , /, .
.VIII.10 DDR SDRAM. DDR / 64, 128 . - , , 64 128 64 , .. , .
/, . , /, , , .
. VIII.10 SDRAM
, / 64 128 , / 64 . , , , .. . DDR .
.VIII.10 DDR2 SDRAM. , -, , -, 4 64 , 256 . - , 64 , , . , 64 , , DDR2 4 . DDR2 , 1 2 .
2008 DDR3, 2009 2010 , . (. VIII.11).
VIII.11 DDR3 SDRAM
DDR3 / 64 , , 512 . DDR3 - ( ) . - 64 , DDR3 , . , , DDR3 , . DDR- 2,5 , DDR2 1,8 , DDR3- 1,5 .
, , Samsung DDR4, ( 2133 4266 ) (1,2 ). 2013 .
, DDR, DDR2, DDR3 DDR4 , , .
, , DDRDDR3 . : DDR3-800 DDR3 ( 64 ), 800 . , , , PC3-6400, .. DDR3 6,4 /.