英语翻译Inmostmoderncomputersmainmemoryisvolatilewhichmeansthatitloosesitsmemorywhenthepowerisremoved.Memoryisdividedintomanyidenticalstoragecells.Eachcellcontainsafixednumberofbits.Eightbitcellsarecalledbyte

　　英语翻译

　　Inmostmoderncomputersmainmemoryisvolatilewhichmeansthatitloosesitsmemorywhenthepowerisremoved.

　　Memoryisdividedintomanyidenticalstoragecells.

　　Eachcellcontainsafixednumberofbits.

　　Eightbitcellsarecalledbytes.

　　Eachstoragecellisgivenauniqueaddress,whichiscalledthecell'slocation

　　ACPUonlyhastwowaystoaccessamemorylocation,suchasReadandWrite.

　　TheI/OSubsystemprovidesaconsistentlinktothemanyI/Odevicesattachedtothecomputersystem

　　ACPUaccessesdevicesviaI/Oports.

　　TherearetwocomputerdesigntechniquesusedforaccessingI/Oports:

　　Accesstheportasamemoryaddress.CPUsthatimplementthistechniquereserveaspecialrangeofmemoryaddressesforI/Oports.

　　Useaseparateaddressingmechanism.CPUsthatreserveaseparateaddressspaceforI/Oportsmustusespecialinstructionsforaccessingtheports.

　　谢谢两位的诚恳回答