THE VISIBLE PC Lecture 2: A look at the brains of the computer, the motherboard, and its associated components. Networks and Communication Department 1

Outline Networks and Communication Department 1. Inside a PC 2. The Motherboard 3. Motherboard Power Connector (P1) 4. RAM 5. ROM 6. CMOS Memory 7. The CPU 8. Expansion Slots 9. Chipsets 10. External Connections types of memory the 'brains' the processor

The complete PC Networks and Communication Department  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

Typical PC case Networks and Communication Department Power supply CD-ROM drive Floppy disk drive Hard disk drive Wires and ribbon cables Wires and ribbon cables Sound/network cards Sound/network cards Motherboard

Inside the System Unit Networks and Communication Department

Motherboard Networks and Communication Department 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).

Motherboard (Cont.) Networks and Communication Department Expansion slots RAM CPU Onboard connector Sockets Video card

Networks and Communication Department

Motherboard Power Connector (P1) Networks and Communication Department  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.

Motherboard Power Connector (P1) Networks and Communication Department  (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

RAM Networks and Communication Department  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.

RAM (Cont.) Networks and Communication Department  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)

RAM (Cont.) Networks and Communication Department Each RAM location has an address and holds one byte of data (eight bits). Each RAM location has an address and holds one byte of data (eight bits).

RAM (Cont.) Networks and Communication Department

RAM (Cont.) Networks and Communication Department  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.

ROM Networks and Communication Department  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.

ROM (Cont.) Networks and Communication Department  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)

CMOS Memory Networks and Communication Department  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

Date and Time Battery Networks and Communication Department  This battery is not the source of your computer power  It enables your computer to retain the accurate time and date

CPU Networks and Communication Department  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.

CPU (Cont.) Networks and Communication Department  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.

CPU (Cont.) Networks and Communication Department  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.

Expansion Slots Networks and Communication Department 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)

Expansion Slots (Cont.) Networks and Communication Department 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

Expansion Slots (Cont.) Networks and Communication Department Most expansion cards contain a port. Most expansion cards contain a port. A connector cable plugs into the port, and leads to a peripheral. A connector cable plugs into the port, and leads to a peripheral. Expansion slot containing an expansion card. Expansion slot containing an expansion card.

Chipset Networks and Communication Department  There are 2 chipset chips to facilitate communication between the CPU and other devices : Northbridge and Southbridge

Networks and Communication Department

Chipset (Cont.) Networks and Communication Department  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

External Connections Networks and Communication Department

External connections Networks and Communication Department  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

External connections (Cont.) Networks and Communication Department 1. Mini-DIN Connectors:  The original DIN connector was replaced by mini- DIN  Older style keyboards and mice plug into mini-DIN ports

External connections (Cont.) Networks and Communication Department 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).

USB Connectors (Cont.) Networks and Communication Department  The USB A connector’s distinctive rectangular shape makes it easily recognizable (as shown in Figure)

 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  The smaller mini-B- style connector (as shown in figure)  For small devices such as camera Networks and Communication Department USB B connectors Mini-USB Connectors USB Connectors (Cont.)

Networks and Communication Department  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

External connections (Cont.) Networks and Communication Department 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

FireWire Connectors (Cont.) Networks and Communication Department  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.

External connections (Cont.) Networks and Communication Department 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.

DB Connectors (Cont.) Networks and Communication Department  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.

External connections (Cont.) Networks and Communication Department 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).

External connections (Cont.) Networks and Communication Department 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.

Networks and Communication Department 42 Any Questions ?

References Networks and Communication Department  Mike Meyers, “CompTIA A+ Certification, all-in- one”, sixth edition, chapter 2, p. 30 – 53  Mike Meyers, “Introduction to PC Hardware and Troubleshooting”, first edition, chapter 4, p. 84 – 93.