The document provides information about processors and CPU terminology. It defines terms like data bus, address bus, registers, instruction set, and cache. It describes how CPUs work using transistors and how manufacturers like Intel and AMD make CPUs. It outlines the components of CPUs like execution cores, arithmetic logic units, and memory controllers. The document provides a timeline of CPUs from the 1970s to recent years to show advances in processing power and core counts.
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Module 1 unit 3
1. Module 1 / unit 3
Processors
By Kenneth Ayebazibwe
256774185458 / 256702555890
kynaye@gmail.com
2. Objectives
• On completion of this unit, you will be able to:
• Define the following processor terminology;
– Data bus and address bus
– Registers
– Manufacturing process
– Packaging
– Instruction set
– Cache
– Clock speed, throttling and overclocking
• Understand technologies for improving performance, such as
multitasking, multi processing, superscalar design and dual core
• Describe features of Intel and AMD desktop and mobile CPUs
• Describe characteristics and CPU compatibility of processor sockets
• Describe different CPU cooling solutions
3. Central Processing Unit (CPU)
• The Central Processing Unit (CPU) is the "brain" of the computer--it is the 'compute'
in computer. Without the CPU, you have no computer. Computer CPU's (processors)
are composed of thin layers of thousands of transistors. Transistors are tiny, nearly
microscopic bits of material that will block electricity when the electricity is only a
weak charge, but will allow the electricity pass through when the electricity is strong
enough. The transistors transition from being a non-conductor (resist the electricity) to
a conductor (they conduct electricity) when the electrical change is strong enough. The
material the transistor is made of loses its resistance to electricity and becomes a
conductor when the electricity gets strong enough. The ability of these materials
(called semi-conductors) to transition from a non-conducting to a conducting state
allows them to take two electrical inputs and produce a different output only when one
or both inputs are switched on. A computer CPU is composed of millions (and soon
billions) of transistors. Because CPU's are so small, they are often referred to as
microprocessors. So, the terms processor, microprocessor and CPU are
interchangeable. AMD, IBM, Intel, Motorola, SGI and Sun are just a few of the
companies that make most of the CPU's used for various kinds of computers
including home desktops, office computers, mainframes and supercomputers.
4. • Modern CPU's are what are called 'integrated chips'. The idea behind an
integrated chip is that several types of components are integrated into a single
piece of silicon (a single CPU), such as one or more execution
cores, arithmetic logic unit (ALU) or 'floating point'
processor, registers, instruction memory, cache memory and the input/output
controller (bus controller).
• Each transistor is a receives a set of inputs and produces output. When one
or more of the inputs receive electricity, the combined charge changes the
state of the transistor internally and you get a result out the other side. This
simple effect of the transistor is what makes it possible for the computer to
count and perform logical operations, all of which we call processing.
• A modern computer's CPU usually contains an execution core with two or
more instruction pipelines, a data and address bus, a dedicated arithmetic
logic unit (ALU, also called the math co-processor), and in some cases special
high-speed memory for caching program instructions from RAM.
5. • The CPU's in most PC's and servers are general purpose integrated chips
composed of several smaller dedicated-purpose components which together
create the processing capabilities of the modern computer.
• For example, Intel makes a Pentium, while AMD makes the Athlon, and
Duron (no memory cache).
6. • CPU manufacturers engineer new ways to do processing that requires some
significant re-engineering of the current chip design. When they create this
new design that changes the number of bits the chip can handle, or some
other major way in which the chip performs its job, they are creating a new
generation of processors.
7. CPU Components
• A lot of components go into building a modern computer processor
and just what goes in changes with every generation as engineers and
scientists find new, more efficient ways to do old tasks.
– Execution Core(s)
– Data Bus
– Address Bus
– Math Co-processor
– Instruction sets / Microcode
– Multimedia extensions
– Registers
– Flags
– Pipelining
– Memory Controller
– Cache Memory (L1, L2 and L3)
8. Measuring Speed: Bits, Cycles and
Execution Cores
Bit Width
– The first way of describing a processor is to say how many bits it processes in a
single instruction or transports across the processor's internal bus in a single cycle
(not exactly correct, but close enough). The number of bits used in the CPU's
instructions and registers and how many bits the buses can transfer simultaneously
is usually expressed in multiples of 8 bits. It is possible for the registers and the
bus to have different sizes. Current chip designs are 64 bit chips (as of 2008).
– More bits usually means more processing capability and more speed.
Clock Cycles
– The second way of describing a processor is to say how many cycles per second
the chip operates at. This is how many times per second a charge of electricity
passes through the chip. The more cycles, the faster the processor.
Currently, chips operate in the billions of cycles per second range. When you're
talking about billions of anything in computer terms, you're talking about 'giga'
something. When you're talking about how many cycles per second, your talking
about 'hertz'. Putting the two together, you get gigahertz.
– More clock cycles usually means more processing capability and more speed.
9. • Execution Cores
– The third way of describing a processor is to say how many execution
cores are in the chip. The most advanced chips today have eight execution
cores. More execution cores means you can get more work done at the
same time, but it doesn't necessarily mean a single program will run faster.
To put it another way, a processor with one execution core might be able
to run your MP3 music, your web browser, a graphics program and that's
about where it starts to slow down enough, it's not worth it running more
programs. A system with a processor with 8 cores could run all that plus
ten more applications without even seeming to slow down (of course, this
assumes you have enough RAM to load all of this software at the same
time).
– More execution cores means more processing capability, but not
necessarily more speed.
– The most advanced processors available are 64-bit processors with 8
cores, running as fast as 3-4 gigahertz. Intel has released quad-core 64-bit
chips as has AMD.
10. • Multi-Processor Computers
– And if you're still needing more processing power, some computers are designed to run
more than one processor chip at the same time. Many companies that manufacture servers
make models that accept two, four, eight, sixteen even thirty two processors in a single
chassis. The biggest supercomputers are running hundreds of thousands of quad-core
processors in parallel to do major calculations for such applications as thermonuclear
weapons simulations, radioactive decay simulations, weather simulations, high energy physics
calculations and more.
11. CPU Speed Measurements
• The main measurement quoted by manufacturers as a supposed indication of
processing speed, is the clock speed of the chip measured in hertz. The
theory goes that the higher the number of mega or gigahertz, the faster the
processor.
• However comparing raw speeds is not always a good comparison between
chips. Counting how many instructions are processed per second
(MIPS, BIPS, TIPS for millions, billions and trillions of instructions per
second) is a better measurement. Still others use the number of mathematical
calculations per second to rate the speed of a processor.
• Of course, what measurement is most important and most helpful to you
depends on what you use a computer for. If you primarily do intensive math
calculations, measuring the number of calculations per second is most
important. If you are measuring how fast the computer runs an
application, then instructions per second are most important.
12. Processor Manufacturers
• American Micro Devices (AMD)
• Intel
• IBM
• Motorola
• Cyrix
• Texas Instruments
– AMD and Intel have pretty much dominated the market. AMD and Intel are for IBM
compatible machines. Motorola chips are made for MacIntoshes. Cyrix (another IBM
compatible chip maker) runs a distant fourth place in terms of number of chips sold.
– Today all chip manufacturers produce chips whose input and output are identical, though the
internal architecture may be different. This means that though they may not be built the
same way, they DO all run the same software.
– The CPU is built using logic gates, and contains a small number of programs called
'microcode' built into the chip to perform certain basic processes (like reading data from the
bus and writing to a device). Current chips use a 'reduced instruction set' or RISC
architectures. Chips can also be measured in terms of instructions processed per second
(MIPS).
13. Symbols, Instructions and Microcode
• Symbols
– Symbols represent binary values. Symbols are the simplest representation of the relationship
between computer binary values and the information that computers process. A symbol
might be a particular tone your modem screeches that represents a series of bits (zeroes and
ones). A symbol also might be a specific electrical voltage on the phone line that represents a
pattern of bits.
• Instructions
– Instructions are basic commands composed of one or more symbols that when passed to a
processor as input, produce a specific output pattern. Functions an instruction can perform
include adding two numbers, subtracting two numbers, reading a byte from input, writing a
byte to output and more.
– At the lowest level, computer processors execute instructions. Computers must be given
information and then told what to do with it. Binary data is the information and instructions
are the 'what to do'. The computer's clock cycles in a regular pattern between zero and
one, releasing pulses of electricity into the rest of the computer's circuitry. Each pulse is
called a 'clock cycle'. During each clock cycle, the computer executes part or all of an
instruction. Some instructions take more than one clock cycle, others take only part of a
clock cycle.
14. • Microcode
– Microcode is a logically organized set of instructions that allows the computer to perform a
basic task such as writing information to video memory, reading a keystroke from the
keyboard buffer, or performing a math calculation each of which is embedded in the design
of the transistors in an integrated chip and forms the basis of a CPU instruction set.