The Evaluation of the Microprocessor.

The microprocessor has changed a lot over the years, says (Michael W.
Davidson, Microprocessor technology
is progressing so rapidly that even experts in the field are having trouble
keeping up with current advances. As more competition develops in this $150
billion a year business, power and speed of the microprocessor is expanding at
an almost explosive rate. The changes have been most evident over the last
decade. The microprocessor has changed the way computers work by making them
faster. The microprocessor is often called the brain of the C.P.U.(or the
central processing unit)and without the microprocessor the computer is more or
less useless. Motorola and Intel have invented most of the microprocessors over
the last decade. Over the years their has been a constant battle over cutting
edge technology. In the 80\'s Motorola won the battle, but now in the 90\'s it
looks as Intel has won the war.

The microprocessor 68000 is the original microprocessor(Encarta 95). It was
invented by Motorola in the early 80\'s. The 68000 also had two very distinct
qualities like 24-bit physical addressing and a 16-bit data bus. The original
Apple Macintosh ,released in 1984, had the 8-MHz found at the core of it. It
was also found in the Macintosh Plus, the original Macintosh SE, the Apple
Laser-Writer IISC, and the Hewlett-Packard\'s LaserJet printer family. The
68000 was very efficient for its time for example it could address 16 megabytes
of memory, that is 16 more times the memory than the Intel 8088 which was found
in the IBM PC. Also the 68000 has a linear addressing architecture which was
better than the 8088\'s segmented memory architecture because it made making
large applications more straightforward.

The 68020 was invented by Motorola in the mid-80\'s(Encarta 95). The 68020 is
about two times as powerful as the 68000. The 68020 has 32-bit addressing and a
32-bit data bus and is available in various speeds like 16MHz, 20MHz, 25MHz, and
33MHz. The microprocessor 68020 is found in the original Macintosh II and in the
LaserWriter IINT both of which are from Apple.

The 68030 microprocessor was invented by Motorola about a year after the 68020
was released(Encarta 95). The 68030 has 32-bit addressing and a 32-bit data bus
just like it\'s previous model, but it has paged memory management built into it,
delaying the need for additional chips to provide that function. A 16-MHz
version was used in the Macintosh IIx, IIcx, and SE/30. A 25-MHz model was used
in the Mac IIci and the NeXT computer. The 68030 is produced in various
versions like the 20-MHz, 33MHz, 40-MHz, and 50MHz.

The microprocessor 68040 was invented by Motorola(Encarta 95). The 68040 has a
32-bit addressing and a 32-bit data bus just like the previous two
microprocessors. But unlike the two previous microprocessors this one runs at
25MHz and includes a built-in floating point unit and memory management units
which includes 4-KB instruction and data coaches. Which just happens to
eliminate the need additional chips to provide these functions. Also the 68040
is capable of parallel instruction execution by means of multiple independent
instruction pipelines, multiple internal buses, and separate caches for both
data and instructions.

The microprocessor 68881 was invented by Motorola for the use with both
microprocessor 68000 and the 68020(Encarta 95). Math coprocessors, if supported
by the application software, would speed up any function that is math-based.
The microprocessor 68881 does this by additional set of instructions for high-
proformance floating point arithmetic, a set of floating-point data registers,
and 22 built-inconstants including p and powers of 10. The microprocessor 68881
conforms to the ANSI/IEEE 754-1985 standard for binary floating-point
arithmetic. When making the Macintosh II, Apple noticed that when they added a
68881, the improvement in performance of the interface, and thus the apparent
performance was changed dramatically. Apple then decided to add it as standard

The microprocessor 80286, also called the 286was invented by Motorola in
1982(Encarta 95). The 286 was included in the IBM PC/AT and compatible
computers in 1984. The 286 has a 16-bit resister, transfers information over
the data bus 16 bits at a time, and use 24 bits to address memory location. The
286 was able to operate in two modes real (which is compatible with MS-DOS and
limits the 8086 and 8088 chips) and protected ( which increases the
microprocessor\'s functionality). Real mode limits the amount of memory the
microprocessor can address to one megabyte; in protected mode, however the
addressing access is increased and is capable of accessing up to 16 megabytes of
memory directly. Also, an 286 microprocessor in protected mode protects the
operating system from mis-behaved applications that could