The functions performed by the control unit vary greatly by the internal
architecture of the CPU, since the control unit really implements this
architecture. On a regular processor that executes x86 instructions natively the
control unit performs the tasks of fetching, decoding, managing execution and
then storing results. On a x86 processor with a
RISCC core, the control unit has significantly more work to do. It manages
the translation of x86 instructions to RISC micro-instructions, manages
scheduling the micro-instructions between the various execution units, and
juggles the output from these units to make sure they end up where they are
supposed to go. On one of these processors the control unit may be broken into
other units (such as a scheduling unit to handle scheduling and a retirement
unit to deal with results coming from the pipeline) due to the complexity of the
job it must perform.
Dealers of North America conference. ComputerLand dealers
placed orders for nearly 250,000 computers that day. On
August 12, 1981 IBM took orders for almost 250,000 more Personal
Computers. IBM's planners have not been correct since.
At the same meeting the target environment
for the PC was described. Here are some of the assumptions
Small business would buy most PCs.
Large business would stick with mainframes and dumb
A few departments in large businesses would use PCs for
local, non-connected work.
The PC would be used for one task only. Not just one task at
a time, but a single task all day long. This might be a
spreadsheet, or word processing, or accounting, but no more
than one task would be performed all day