The Central Processing Unit
of the computer system collects the raw data from the input devices and converts
it to useful information which can then be used by the output devices. On
some computers, the CPU can be a single microchip. On bigger systems, the
CPU can be formed from a number of chips working together.
The CPU is made up of three main parts:
Data that is held in the Immediate Access Store (IAS) can be
used immediately by the Arithmetic Logic Unit (ALU), if the data is held in
the backing store then it may take a little longer for the CPU to find it
and copy it into memory. In 2002 a powerful microcomputer has 256 Mb (megabytes)
of memory ... that is 256 million bytes.
The Control Unit is connected to a clock (a piece of crystal that 'ticks'
very fast) and it issues a command at each 'tick' of the clock. If your
computer has a very fast clock it means that the control unit is able
to issue a lot of commands in a short time. So the computer carries
out its jobs in a shorter time: it is faster.
In 2002 a fast microcomputer has a clock speed of 1.8
GHz (gigahertz) - this means that the control unit can issue about 1.8
billion instructions in a second ... every second.
Answer these questions:
out of 5 on that test