Labels:box | bulletin board | diskette | sky OCR: The 8088 Fxecution Unit Bus Interface Unit Prefetch queue PC bus Memory systom RAM ROM Devices (disks, keyboard display memory) display adapters timers speaker DMA channels Data and so on) Machine rlanguage code FIGURE 3.4 This view of the PC's resources reflects the true na ture of code as data stored in system memory Codle stored in memory so i must be fetched by the bus terface unit (BIU) just as data must consequently any cycle eaters present between system memory and the BIU affect the 8088's code fetching speed as well its data fetching speed In addition all memory accesses must pass through the BIU byte at a time at rate no faster than 1.2 bytes 'microsecond 1 byte per cycles), and se rious boulenecks can develop since code and data fetch ing can demand dta transfer rates as high as ...
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