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M Miller, 2007-08 Inside the Computer 2
Introduction
Computers are used by people around the world for various purposes
To most, the computer is merely a keyboard, mouse, monitor and tower connected together by many cables
Although the average user can tell you the function of each device above, few can tell you what is inside the tower and how the components inside work
We will devote this class to learning the components within a tower and how they interact with one another
M Miller, 2007-08 Inside the Computer 3
Preparing to Build
Tools Hardware vs. Software Hardware Tools
Do NOT use a Magnetic Screwdriver! Power Screwdriver is fine Multi-head Screwdrivers are great, provided they’re NOT
magnetic Flat Head Screwdriver (do NOT pry with them!) Philips Screwdriver (usually No. 2 – smaller for
notebooks)
M Miller, 2007-08 Inside the Computer 4
Hardware Tools Continued
Torx Screwdriver usually sizes T-10 and T-15 (especially for Compaq and Apple computers) You may need smaller ones for laptop computers
Needle-Nose Pliers Flashlight Dental Mirror A container to put screws in so you don’t lose them Compressed Air
More useful for cleaning older systems, but a good thing to have around
M Miller, 2007-08 Inside the Computer 5
Software Tools
Boot Device To “Boot” means to start up a computer
Cold boot – start from power off Warm boot – re-start from power on
A Boot device is any medium (Floppy Disk, CDROM, DVD, USB drive) that the computer can get its starting instructions from
Will hold on it the “kernel” of an operating system The kernel of an operating system is the minimum set of
instructions needed to get a computer to start up, recognize its different parts and perform minimal but key tasks Tasks include
Formatting a hard drive Writing more start-up instructions Running programs from other devices (i.e. CD’s)
Check in the BIOS what type of devices the motherboard can use to boot from
M Miller, 2007-08 Inside the Computer 6
Software Tools Continued
Bootable Floppy Disk Typically Windows 98 SE so it can handle large drives
Make sure it has a CD ROM driver loaded Data reading/recovery utilities
Network capable floppy a good idea Bootable CD ROM
Many systems no longer include floppies (especially laptops) Same features as for a Floppy Don’t just rely on an OS install CD, you most likely one that will
allow you some data access A “Live CD” (e.g. Knoppix – Linux and free, BartPE – Windows
needs a Windows license, etc) Bootable USB Drive
Not all motherboards will have a setting to boot from USB, so this is not as good an idea
M Miller, 2007-08 Inside the Computer 7
Software Tools Continued
There are many software packages that will examine the hardware, report its configuration and identify any errors they find CheckIt Pro QAPlus Microsoft’s MSD (Microsoft Diagnostics) http://www.majorgeeks.com has MANY tools that are both
general and hardware/software specific that you may want to look at (ALWAYS beware of Internet downloads, especially ones designed to dig into a system’s hardware and software! Why?)
M Miller, 2007-08 Inside the Computer 8
Preventative Measures
Both you and the computer contain components that can easily be damaged, always be careful and keep safety in mind! Don’t have loose cords lying around Always put parts entirely on flat and stable
surfaces, not stacked on each other! Keep liquids and foods well away from all
components
M Miller, 2007-08 Inside the Computer 9
Preventative Measures Continued
Don’t let yourself get distracted Have a plan BEFORE you start to work Tuck in or remove loose or hanging clothing (e.g.
a tie) or hair Be aware that there are MANY sharp edges and
soldering bumps that can cut and nick your hands and fingers
Before you power a system on that you’ve worked on make sure all parts are “Seated” securely by gently and evenly pressing on all connectors and parts evenly into their sockets
M Miller, 2007-08 Inside the Computer 10
Electrostatic Discharge (ESD) ESD occurs when two objects of dissimilar charge
come in contact with one another CPU and memory chips are extremely sensitive to ESD 100 volts is enough to damage computer parts You can generate 100 volts by just sitting in a chair You can generate 3000 volts by shuffling your feet across a
carpeted floor You can SEE 10 000 volts get transferred
M Miller, 2007-08 Inside the Computer 11
Avoiding/Minimizing ESD
Try to avoid “dry” rooms Keep relative humidity to around 50% where possible
Anti-static Wrist Straps Plug into the round part of a wall plug or clip onto the round poll of an
extension cord Anti-static Mats
Drains excess charge away from any item coming in contact with it Keep parts you are not using in Static Bags Use an anti-static spray
Or, a spray with one part liquid fabric softener and one part water Vendors will ship goods with anti-static foam, keep that around and use
on the table-top While working, keep part of your skin touching (grounded to) the metal
case of the power supply that is plugged into a grounded outlet
M Miller, 2007-08 Inside the Computer 12
Components and Connectors
You will need to have an idea of what pieces you have, where they go in the system and what their purpose is
You will need to know how they connect and thus communicate with each other
M Miller, 2007-08 Inside the Computer 13
Case
Today, towers come in many cool shapes and designs
The basic purpose of the tower is to contain and protect the computers hardware components
Hardware components are mounted by plastic clips or by screws
The front of the tower contains panels that can be removed, thus exposing the “bays”
These bays are slots that hold devices such DVD/CD-ROM drives, floppy drives and other devices that need to have external access
M Miller, 2007-08 Inside the Computer 14
Motherboard
A motherboard allows all the parts of your computer to receive power and communicate with one another
The first motherboards held very few actual components and had only a processor and card slots
Today, motherboards boast a wide variety of built-in features, and they directly affect a computer's capabilities and potential for upgrades
M Miller, 2007-08 Inside the Computer 15
Motherboard (cont’d)
Most people physically interact with a motherboard on a daily basis and don’t even know it
If you have ever plugged in a printer, mouse, memory stick, joystick or any other device to your computer, chances are you plugged it into the motherboard
This is known as the “back” of the motherboard
Every place that you can plug a device into is called a port
M Miller, 2007-08 Inside the Computer 16
Motherboard (cont’d) The inside of a motherboard
controls all the hardware on your system
key motherboard components: Bus Processor Socket Memory Socket IDE/SCSI/RAID/SATA PCI/AGP or Expansion Slots
This is where you plug in Expansion Cards which can give your computer extra functionality E.g. game controller cards,
Network cards, advanced video cards etc.
BIOS Chip
M Miller, 2007-08 Inside the Computer 17
Bus
The power and speed of computer components has increased at a steady rate since desktop computers were first developed decades ago
However, there is one element that often escapes notice - the bus
The bus is a channel or pathway between the components in a computer (i.e. CPU, RAM, Sound Card, … etc)
The best analogy for this is that if you have a 1000HP engine and a cheap transmission, you can't get all that power to the wheels
Today, the processors run so fast that most computers have two or more buses
It is important to know the bus speed when purchasing a motherboard
M Miller, 2007-08 Inside the Computer 18
BIOS Chip
On virtually every computer, the BIOS makes sure all the other chips, hard drives, ports and CPU function together
The BIOS software’s most important role is to load the operating system, since there are no instructions to the CPU at start-up
The BIOS provides these instructions Some of the other common tasks that the BIOS
performs include: A power-on self-test (POST) for all of the
different hardware components in the system to make sure everything is working properly
Activating other BIOS chips on different cards installed in the computer
Managing a collection of settings for the hard drives, clock, … etc
Whenever you turn on your computer, the first thing you see is the BIOS software doing its thing
On many machines, the BIOS displays text describing things like the amount of memory installed in your computer, the type of hard drive and so on
M Miller, 2007-08 Inside the Computer 19
BIOS Chip (cont’d)
To enter the BIOS Setup, you must press a certain key during the initial start-up sequence, usually Del or F1 key
Once in there, you may see some of the following options: System Time/Date Boot Sequence Plug and Play Mouse/Keyboard Drive Configuration Memory Security Power Management Exit
Be very careful when making changes to setup as incorrect settings may keep your computer from booting
M Miller, 2007-08 Inside the Computer 20
Power Supply Of course any piece of electronics
needs electricity The computer gets its power via the
power supply which converts 120V/220V AC to lower DC voltages, such as 3.3V, 5V and 12V
The 3.3V and 5V are typically used by digital circuits, while the 12V is used to run motors in disk drives and fans
Power supplies are measured in Watts
They also can get can get very hot so they come with a built-in fan
Motherboard
Power
Hard Drive & CD-ROM Power
Floppy Drive Power
M Miller, 2007-08 Inside the Computer 21
Power RequiredPC Item Watts
Video Card 20 to 30W
PCI card 5W
Floppy Drive 5W
Network Card 4W
CD-ROM drive 10 to 25W
Memory 10W/ 128M
Hard Drive 5 to 11W
Motherboard 20 to 30W
733MHz Pentium 3 23.5W
600MHz AMD Athlon 45W
M Miller, 2007-08 Inside the Computer 22
CPU The CPU, or microprocessor as it is
also called, is the heart of any desktop computer, server or laptop
A computer may be using a Intel, AMD or G5 CPU, but they all do approximately the same thing in approximately the same way
The first microprocessor, introduced in 1971, was the Intel 4004 and it could only add and subtract 4-bit numbers
The first microprocessor to make it into a home computer, introduced in 1974, was the Intel 8080, and it could only add and subtract 8-bit numbers
Today’s microprocessor can process 64-bits at a time and are thousands of times faster
A CPU contains millions of transistors – think of them as switches that simply go on and off
The human hair is 100 Microns in width
Intel 4004Intel 4004 Intel 8080Intel 8080
Name Date Transistors MicronsClock Speed
Data Width
8080 1974 6,000 6 2MHz 8 bits
8088 1979 29,000 3 5MHz 16 bits
80286 1982 134,000 1.5 6MHz 16 bits
80386 1985 275,000 1.5 16MHz 32 bits
80486 1989 1,200,000 1 25MHz 32 bits
Pentium 1993 3,100,000 0.8 60MHz 32 bits
Pentium II 1997 7,500,000 0.35 233MHz 32 bits
Pentium III 1999 9,500,000 0.25 450MHz 32 bits
Pentium 4 2005 125,000,000 0.09 3.6GHz 64 bits
M Miller, 2007-08 Inside the Computer 23
CPU (cont’d)
CPUs today are incredibly small but very complex in design
The CPUs job is to fetch, decode and execute instructions
Every CPU has a set of instructions that it can perform
Each instruction has a different meaning when loaded into the instruction register
A set of short words are defined to represent the different instructions
This collection of words is called the assembly language of the processor
M Miller, 2007-08 Inside the Computer 24
Processor Socket
In the early days of PC computers, all processors had the same set of pins that would connect the CPU to the motherboard, called the Pin Grid Array (PGA) so that any processor would fit into any motherboard
As CPUs advance, they need more and more pins, both to handle new features and to provide more and more power to the chip
Anyone who has a specific CPU in mind should select a motherboard based on that CPU, otherwise it will not fit
M Miller, 2007-08 Inside the Computer 26
Processor Socket (cont’d)
The processor socket serves two purposes: Holds the CPU Holds the CPU heat sink/fan
As the CPU executes commands, it can get extremely hot As a result, a heat sink/fan is required to keep it cool Failure to attach the heat sink/fan will cause the chip to go up
in smoke, literally DON’T separate the heat sink from the CPU unless you have the
conductive silicon
M Miller, 2007-08 Inside the Computer 27
Memory
There are many types of memory: RAM ROM Cache Dynamic RAM Static RAM Flash memory Memory Sticks Virtual memory Video memory BIOS
Random access memory (RAM) is the most common form of computer memory
Technically any form of electronic storage is memory, but it is often used to describe temporary forms of storage
M Miller, 2007-08 Inside the Computer 28
Memory (cont’d)
RAM modules come in various sizes (pins), capacities (MB/GB), speeds (MHz) and types
Here are a few types of RAM used today: SDRAM (Old and slow) DDR SDRAM (Most common
and fast) RDRAM (Rare and very fast)
RAM is very fast since it is composed entirely of circuitry, unlike hard drives which are mechanical
Remember, RAM is temporary storage
M Miller, 2007-08 Inside the Computer 29
Memory Socket
Memory sockets hold and connect RAM modules to the motherboard
They provide a link to the bus so that the memory can communicate with other components on the motherboard
Today, motherboards have three or more memory sockets, thus allowing various configurations of RAM
M Miller, 2007-08 Inside the Computer 30
Memory Socket (cont’d)
Installing RAM is very easy, but a delicate affair Before adding RAM to a motherboard, make sure it is the
right size, capacity, speed and type Often, adding more RAM to a computer can increase its
performance
M Miller, 2007-08 Inside the Computer 31
Hard Drive Nearly every computer and server contains
one or more hard drives, while mainframes and supercomputers normally use hundreds of them
Hard drives magnetically store changing digital information into relatively permanent files, thus allowing computers the ability to remember things when the power goes out
A typical hard drive has a capacity between 80 and 320GB
There are two ways to measure the performance of a hard drive: Data rate - The data rate is the number of
bytes per second that the drive can deliver to the CPU (Normally between 5 and 40MB/s)
Seek time - The seek time is the amount of time between when the CPU requests a file and when the first byte of the file is sent to the CPU (Normally between 10 and 20 milliseconds)
The other important parameter is the capacity of the drive, which is the number of bytes it can hold
M Miller, 2007-08 Inside the Computer 32
Hard Drive (cont’d) A hard drive is a sealed aluminium box with
controller electronics attached to one side The electronics control the read/write
mechanism and the motor that spins the platters
The mechanical aspects of the drive are as follows: The motor – Spins between 3600 to
7200rpm The platters - Are manufactured to
amazing tolerances and are mirror-smooth
The arm - Holds the read/write heads and is controlled by the mechanism in the upper-left corner
The mechanism that holds the arms can move the heads from the hub to the edge of the drive about 50 times per second
In order to increase the amount of information the drive can store, most hard drives have multiple platters and read/write heads
M Miller, 2007-08 Inside the Computer 33
Hard Drive (cont’d)
Data is stored on the surface of a platter in sectors and tracks
Tracks are concentric circles (yellow), and sectors (blue) are pie-shaped wedges on a track
A sector contains a fixed number of bytes Sectors are often grouped together into
clusters The process of low-level formatting a drive
establishes the tracks and starting/ending sectors on the platter
This process prepares the drive to hold blocks of bytes
High-level formatting then writes the file-storage structures, like the file-allocation table, into the sectors
This process prepares the drive to hold files
M Miller, 2007-08 Inside the Computer 34
IDE/SCSI/RAID/SATA Most computers have one or more
of the following storage devices: Floppy drive Hard drive CD-ROM drive
Usually, these devices connect to the computer through an Integrated Drive Electronics (IDE) interface
These devices are connected via IDE cables
However, IDE is an old technology and there have been advancements to better its performance
M Miller, 2007-08 Inside the Computer 35
IDE/SCSI/RAID/SATA (cont’d) The following are some
technology enhancements that have been made: SCSI – Faster and
reliable RAID – Allows for two
hard drives to be connected in synch
SATA – Latest technology and is very fast
The above each have their own special cables, except RAID which still uses IDE
M Miller, 2007-08 Inside the Computer 36
Ribbon Cables
Each of IDE/SCSI/SATA have their own cables to fit into the connectors on the drives and the motherboards
These cables are called ribbon cables because of the way they look
Be careful when detaching and re-attaching the cables because pulling or pushing on an angle could bend or break pins on the motherboard and/or drive
Use tabs provided on the cables for pulling the cables out
Make sure the connectors are lined up flat to the controller on the motherboard before you push them into place
There are generally two numbered slots/controllers on the motherboard to plug these cables into
If you only need one cable make sure it is plugged into the slot with the lowest number
M Miller, 2007-08 Inside the Computer 37
Jumpers
When you have multiple IDE type devices that connect to the motherboard using the same cable you may have to set what are called “jumpers” one each drive to tell the motherboard which drive should take what “priority” on that cable.
There are 3 basic settings: Master – the most important drive, if
this cable is connected to the first connector on the motherboard then the Master drive is the one the computer will want to boot from. This is also called the Primary drive.
Slave – the less important drive, called the Secondary drive
Cable Select – indicates that the drive plugged in at the end of the cable is the Primary drive and that the drive plugged into the connector part way down the cable is the Secondary cable.
M Miller, 2007-08 Inside the Computer 38
Video Card The images you see on your monitor are
made of tiny dots called pixels At most common resolution settings, a
screen displays over a million pixels, and the computer has to decide what to do with every one in order to create an image
To do this, it needs a translator - something to take binary data from the CPU and turn it into a picture you can see
This translation takes place on the video card
A video card's job is demanding and complex, but its principles and components are easy to understand
To make a 3-D image, the video card first creates a wire frame out of straight lines and then fills in the remaining pixels
It also adds lighting, texture and color For fast-paced games, the computer has
to go through this process about sixty times per second
M Miller, 2007-08 Inside the Computer 39
Video Card (cont’d)
Like a motherboard, a video card houses a processor, RAM and BIOS chip
A video card's processor, called a Graphics Processing Unit (GPU), is similar to a computer's CPU except it is designed specifically for performing the complex mathematical and geometric calculations that are necessary for graphics rendering
Some of the fastest GPUs have more transistors than the average CPU and produces a lot of heat, so it is usually located under a heat sink or a fan
ATI and NVIDIA produce the vast majority of GPUs on the market, and both companies have developed their own enhancements for GPU performance
To improve image quality, the processors use: Full scene anti aliasing (FSAA), which
smoothes the edges of 3-D objects Anisotropic filtering (AF), which makes
images look crisper
OpenGL Rendering (Doom 3)OpenGL Rendering (Doom 3)
DirectX Rendering (Far Cry)DirectX Rendering (Far Cry)
M Miller, 2007-08 Inside the Computer 40
PCI/AGP Slots
PCI slots are what connect your network card, sound card, … etc to the PCI bus
They are easy to install and support “Plug & Play”
Most motherboards provide four or more of these slots for any additional devices you may want to add
M Miller, 2007-08 Inside the Computer 41
PCI/AGP Slots (cont’d)
Today, computer software is very complex and demanding
This is especially true when dealing with graphical applications such as videos and gaming
As a result, the video card is used quite intensely and requires quick access to system resources
Video cards used to be connected to PCI slots, but are now connected to an Accelerated Graphics Port (AGP) slot
The AGP slot is given a special link to the CPU, thus bypassing most of the PCI bus
This slot is located by itself, above the PCI slots