the visible pc lecture 2: a look at the brains of the computer, the motherboard, and its associated...
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THE VISIBLE PC
Lecture 2: A look at the brains of the computer, the motherboard, and its associated components.
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Outline
1. Inside a PC2. The Motherboard3. Motherboard Power Connector (P1) 4. RAM5. ROM6. CMOS Memory7. The CPU8. Expansion Slots9. Chipsets10. External Connections
types of memory
the 'brains'
the processor
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The complete PC
All of the processing and storage takes place in the system unit
All other parts of the PC – the printer, the keyboard, the monitor – connect to the system unit and are known as peripherals.
The system unit’s case protects the internal components from the environment
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Typical PC case
Power supplyCD-ROM drive
Floppy disk drive
Hard disk drive
Wires andribbon cables
Sound/networkcards
Motherboard
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Motherboard
Is a thin, flat piece of circuit board, usually green or gold, and often slightly larger than a typical piece of notebook paper.
It holds: The processor chip Memory chips Special sockets Multipurpose expansion slots onboard connector (I/O)
Some chips are soldered onto the motherboard(permanent), and some are removable (so they can be upgraded).
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Motherboard (Cont.)
Expansion slots
RAM
CPU
Onboard connector
Sockets
Video card
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Motherboard Power Connector (P1)
The motherboard would do nothing without power going through it.
(P1) Power Connector connects between the power outlet on your wall and the computer components.
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Motherboard Power Connector (P1)
(P1) Power Connector powers the objects
on the motherboard like CPU and memory
It does not power the hard-drive, CD-ROM
or floppy drive so they need their own
power connectors
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RAM
Random Access Memory (RAM).
RAM is used to hold programs while they are
being executed, and data while it is being
processed.
Measured in units called bytes
RAM is volatile, meaning that information written
to RAM will disappear when the computer is
turned off.
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RAM (Cont.)
RAM contents can be accessed in any (i.e. random) order.
Each piece of RAM is called stick on common type of stick called a dual
inline memory module (DIMM) You can install extra RAM.(same type)
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RAM (Cont.)
Each RAM locationhas an address and holds one byte of data (eight bits).
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RAM (Cont.)
Virtual memory uses part of the hard
disk to simulate more memory (RAM)
than actually exists.
It allows a computer to run more
programs at the same time.
Virtual memory is slower than
RAM.
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ROM
Read-Only Memory can
be read but not changed.
It is non-volatile storage: it remembers
its contents even when the power is
turned off.
ROM chips are used to store the
instructions a computer needs during
start-up, called firmware.
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ROM (Cont.)
Every motherboard comes with a small
code that enables the CPU to connect
with other devices
This program is called Basic Input/Output
System (BIOS)
The BIOS is stored inside a Flash ROM
(system ROM)
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CMOS Memory
Separate memory chip called the complementary metal oxide semiconductor (CMOS)
Stores the information that describes specific device parameters
This data read by BIOS to complete the programs needed to talk to changeable hardware
It also acts as clock to keep the current date and time
the battery
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Date and Time Battery
This battery is not the source of your
computer power
It enables your computer to retain the
accurate time and date
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CPU
The central processing unit (CPU), also called the microprocessor or processor
performs all the calculations that take place inside a PC.
CPUs come in a variety of shapes and sizes.
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CPU (Cont.)
a cooling fan and heat sink assembly to avoid overheating
A heat sink is a big slab of copper or aluminum that helps draw heat away from the processor.
The fan then blows the heat out into the case.
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CPU (Cont.)
The two most common makers of CPUs
used in PCs are AMD and Intel.
Some of the more common models made
over the last few years have names such
as Celeron, Athlon, Sempron, Pentium III,
Pentium 4 , I3, I5 and I7.
CPUs come in different packages.
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Expansion Slots
Expansion slots allows you to customize your computer by adding components through them.
Common expansion cards: graphics card (for connecting to a monitor) network card (for transmitting data over a
network) sound card (for connecting to a microphone and
speakers)
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Expansion Slots (Cont.)
Most PCs offer 4-8 expansion slots.
There are several different types of expansion slot:
ISA: (Industry Standard Architecture) older
technology, for modems and slow devices
PCI: (Peripheral Component Interconnect) for
graphics, sound, video, modem or network cards
AGP: (Accelerated Graphics Port) for graphics cards
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Expansion Slots (Cont.)
Most expansion cardscontain a port.
A connector cable plugsinto the port, and leads to a peripheral.
Expansion slot containing an expansion card.
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Chipset
There are 2 chipset chips to facilitate
communication between the CPU and
other devices :
Northbridge and Southbridge
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Chipset (Cont.)
The Northbridge helps the CPU connect
with RAM, It deals with high speed
interfaces
The Southbridge connects the CPU with
the expansion devices and storage drives
like Hard-drive and floppy-disk-drive, It
works mainly with lower speed devices
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External connections
A Plug is a part with some type of
projection that goes into a port
A port is a part that has some type of
matching hole or slot that accepts the
plug
The jack is used as an alternative to port
The connector describes either a port or
a plug
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External connections (Cont.)1. Mini-DIN Connectors: The original DIN connector was replaced
by mini-DIN Older style keyboards and mice plug into
mini-DIN ports
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External connections (Cont.)2. USB Connectors Universal serial bus (USB) The most common general-purpose
connection for PCs. Many different devices, such as mice,
keyboards, scanners, cameras, and printers. USB connections come in three different
sizes: A (very common), B, and mini-B (less
common).
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USB Connectors (Cont.)
The USB A connector’s distinctive rectangular shape makes it easily recognizable (as shown in Figure)
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USB B connectors are for the other end of the USB cable where it attaches to the USB device (as shown in Figure).
The smaller mini-B-style connector (as shown in figure)
For small devices such as camera
USB B connectors Mini-USB Connectors
USB Connectors (Cont.)
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USB Connectors (Cont.)
USB has a number of features that make it particularly popular on PCs.
1. USB devices are hot-swappable, which
means you can insert or remove them
without restarting your PC.
2. many USB devices get their electrical
power through the USB connection
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External connections (Cont.)3. FireWire Connectors Moves data at incredibly high speeds,
making it the perfect connection for highly specialized
applications, such as streaming video from a digital video camera onto a hard drive
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FireWire Connectors (Cont.)
FireWire consists of a special 6-wire connector, as shown in Figure.
There’s also a smaller, 4-pin version, usually seen on peripherals.
Like USB, FireWire devices are hot-swappable.
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External connections (Cont.)4. DB Connectors Over the years, DB connectors have
been used for almost any type of peripheral you can think of, with the exception of keyboards.
They have a slight D shape, which allows only one proper way to insert a plug into the socket.
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DB Connectors (Cont.)
DB connectors in the PC world can have from 9 to 37 pins or sockets, although you rarely see a DB connector with more than 25 pins or sockets.
DB-type connectors are some of the oldest and most common connectors used in the back of PCs.
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External connections (Cont.)
5. RJ Connectors The little plastic plug used to connect your
telephone cord to the jack is a classic example of an RJ plug.
Modern PCs use only two types of RJ jacks: the RJ-11 and the RJ-45.
The phone jack is an RJ-11. It is used almost exclusively for modems.
The slightly wider RJ-45 jack is used for your network connection.
Figure shows an RJ-11 jack (bottom) and an RJ-45 jack (top).
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External connections (Cont.)6. Audio Connectors Speakers and microphones connect to
audio jacks on the system unit. The most common type of sound
connector in popular use is the mini-audio connector.