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1. Motherboard &
System Software

2.  This lesson will show you how
motherboards work, how to identify various
kinds of motherboards, the importance of
chipsets, and how to install and
troubleshoot motherboards. By the end of
this lesson, you should be able to do the
following:
 Explain how motherboards work
 Identify the types of motherboards and
chipsets
 Upgrade and install motherboards
 Troubleshoot motherboard problems

3. Motherboard and It’s Classification
What is Motherboard?
 Motherboard is the main component of the CPU
 Backbone of the Computer
Functions of Motherboard
 It integrates all Hardware components into one system
 Allows all parts of your computer to receive power and
communicate with one another.

4. Computing Systems Week 2 -
Hardware 4
CPU Socket
USB
Audio
Keyboard &
Mouse
(PS/2)
Expansion
Slots (PCI
or PCI
Express)
Expansion
Slot (AGP or
PCI Express)
Disk drive
connectors
Power
supply
connector
RAM slots
Serial Port
Parallel
Port

5. Motherboard and It’s Classification
 Speed
 Upgrade Capabilities
 Size and shape (form Factor)
Specifications

6. Motherboard and It’s Classification
Processor
socket
Memory
slot
PCI slots
ATX Power
connector
PCIe slot
SATA
connector
PATA/IDE
connector
Components of Motherboard

7. Motherboard and It’s Classification
CMOS
Battery
ISA
Slot
AGP
Slot
Components of Motherboard

8. Motherboard and It’s Classification
I/O Ports
PS/2
Port
VGA
Port
Serial
Port
Audio
Port
Parallel
Port
USB
Port
Ethernet
Port
I/O Ports

9. Motherboard and It’s Classification
Classification of Motherboard
Integrated Motherboard Non-Integrated Motherboard

10. Motherboard and It’s Classification
Integrated Motherboard
 Components are in built in the
motherboard.
 Designed for simplicity.
Draw backs
 When one component in the
board is broken or stops
working you have to replace
the whole board
 Cheaper to produce but more
expensive to repair.

11. Motherboard and It’s Classification
Non-Integrated Motherboard
 The major assemblies like Video
circuitry, disk controllers, and
accessories are installed on the
Computer as expansion cards.
 Can easily Identify the
Non-integrated motherboards
by their expansion slots usually
occupied by one of the components.
Expansion card

12.  A. Three primary characteristics
 1. Form factor determines size of the
motherboard and general location of the
parts.
 2. Chipset defines the type of processor
and RAM supported.
 3. Built-in components determine
functionality and expandability of the
system.
 B. The motherboard contains traces or
wires through which the data and
commands flow. Motherboards typically
have traces on multiple layers of the
board.

13.  C. Form factors
1 What is a form factor?
a)Industry standardized shapes and layouts
b)Allows standardization of cases and power supplies. Cases
are designed so that when the motherboard is properly
mounted, motherboard connectors are available externally.
2. AT motherboards are old-style form factors and currently
obsolete. Each features a large keyboard plug and two
connectors called P8 and P9 from the power supply.
3. AT motherboard (about 12×13 inches in size) was followed by
the Baby AT (about 8.5×13 inches in size).
4. A number of different form factors appeared and quickly
disappeared, including the Slimline LPX (sometimes referred
to as Low-Profile Extensions) and the NLX.
a)The LPX features a case height of about 4 inches and has a
limited number of expansion slots mounted on a central riser
card.
b)The LPX, also small, provides better support for CPUs, AGP
video, USB, and large amounts of RAM.
NLX: New Low Profile eXtended LPX: Low Profile eXtension

14.  6. The ATX form factor
 a) In 1995, Intel introduced a new form factor called
ATX. Roughly the same size as the Baby AT, it mounted
at a 90-degree angle relative to the computer’s case. It
featured a rear panel with all necessary ports built in. It
had a mini-DIN or PS/2 keyboard and mouse port. The
position of the power supply allowed for better cooling.
The CPU and RAM were more accessible.
 b) RAM was closer to the Northbridge and the CPU
than on AT boards, allowing the clock speed to be
doubled or quadrupled.
 c) It incorporates “soft power” features, allowing the
operating system software to turn the PC on and off.
Instead of a large power cord from the power supply to
the on/off switch, the ATX board runs the power
through the motherboard itself and uses only a pair of
small wires from the motherboard to the on/off switch.
 d) It has only a single 20-pin connector, called P1,
from the power supply to the motherboard.
 e) A number of variations of the ATX have been
produced, including the microATX and the FlexATX.

15. 7. BTX form factor designed to be cooler
than other boards.
a) BTX designed to replace ATX
b) MicroBTX designed to replace
microATX
c) PicoBTX designed to replace FlexATX
8. Some manufacturers produced
proprietary motherboards.
a) Didn’t follow standards
b) Difficult to support
BTX: Balanced Technology eXtended

16.  Chipset varieties
1. The chipset defines many aspects of the
motherboard, including the processor type, the
type and capacity of RAM, and the kinds of
internal and external devices it can support.
2. Modern chipsets consist of two primary
chips, the Northbridge and the Southbridge, plus
a Super I/O chip to provide legacy support.
a) The Northbridge chip on Intel-based
motherboards connects the CPU with RAM. On
AMD-based motherboards, the Northbridge
provides the communication with the video card,
but the CPU has an onboard MCC (memory chip
controller) chip that communicates with RAM.
Northbridge is called memory controller hub
(MCH) on some Intel-based systems.

17.  The PC has become so complex that even
the most recent, powerful processors can 't
do the entire job of managing the flow of
data by themselves.
 The CPU has been given help in the form of
the chip set, located nearby on the
motherboard.
 The chip set consists of two microchips,
often referred to as the North Bridge and
the South Bridge, that act as the
administrators to the CPU, or chief
executive.
 The chip set bridges logical and physical
gaps between the CPU and other chips, all
the time watching and controlling the input
and output of specific components.

18. Many processor
architectures have moved
the Northbridge into the
CPU package or chip itself
Advanced Configuration and Power Interface

19.  The exact function of the chip set is constantly
changing. But in all cases, the bridges
determine what kinds of memory, processors,
and other components can work with that
particular motherboard.
 There is an unfortunate trend to replace the
names North Bridge and South Bridge with less
elegant terms such as Graphics Memory
Controller Hub (GMCH) and the I/O
Controller Hub (ICH), even though their basic
purpose is the same.

20.  The North Bridge and South Bridge together form
the computer's chip set, secondary only to the
processor in determining the performance and
capabilities of a Pc.
 The North Bridge chip either provides or controls
the computer's graphics, RAM, and the front side
bus, the main highway for data connecting
graphics and memory to the CPU.
 A crucial mechanism in the North Bridge is the
memory controller, which constantly renews the
memory modules (RAM). Each memory cell with
an electrical charge represents a 1 bit. Because
the charge begins to dissipate as soon as it's
created, the bridge's memory controller endlessly,
thousands of times a second, reads each of the
millions of cells and writes back the values it
read.

21.  When the CPU needs data from RAM, it
sends a request to the North Bridge
memory controller. The controller, in turn,
sends the request along to memory and
tells the CPU how long the processor must
wait to read the memory over a speedy
connection called the front side bus (FSB).
 The North Bridge is also the liaison with
the other component for which speed is
crucial: the video card. (Some chip sets
have video, sound, or other functions built
into them, but on chip video is not as fast
as a dedicated expansion card).

22.  The other half of the PC chip set, the South
Bridge is in charge of input/output with the
disk drives, audio, networking and universal
serial port.
 The South Bridge primarily handles the routing
of traffic between the various input/output
(I/O) devices on the system for which speed is
not vital to the total performance, such as the
disk drives, optical drives, PCI-Express devices,
the older PCI bus, and the USB, Ethernet, and
audio ports.
 It is also responsible for less prominent
input/output, such as the real-time clock,
interrupt controller, and power management.
 Some South Bridge chips incorporate audio
capabilities good enough to support Dolby
Digital and THX multimedia audio.

23. PC's Hypothalamus
CPU’s brain

24.  When you first turn on your PC
◦ Your PC requires information
 to detect PC components
 To find the operating system(floppy disk, hard drive,
or a CD-ROM)
◦ This information is stored in the BIOS

26.  When a computer is turned on, the microprocessor has no
idea what to do next as there is nothing at all in the
memory to execute, it tries to execute its first instruction
and it has to get the instruction from somewhere.
 BIOS provides those instructions and it is stored in a BIOS
ROM.
 The instruction typically located at memory location FFFF0h,
or right at the end of the system memory
 This process is known as booting, or booting up, which is
short for bootstrapping
 The whole process is hidden because the only thing
displayed by the monitor is the logo of the machine
manufacturer or the logo of the bios company.

27. Power-on Self Test ( POST ) - Takes place right after you
power on. It will test computer hardware, ensuring
hardware is properly functioning before starting
process of loading operating system. If the POST is
successful, the BIOS calls INT 19 (Interrupt 19) and
then proceeds to look for devices attached to the
motherboard.
Bootstrap Loader - Process of locating the operating
system. If capable operating system located, BIOS will
pass the control to it.

28. 1. Tests the system and prepares the computer for
operation based on CMOS settings (installed hardware
and the configuration settings from the manufacturer
and user)
2. Load the interrupt handlers and device drivers
Interrupt handlers - Small pieces of software that act as a
translator between the hardware components and the operating
system.
Device drivers – other pieces of software that identify the base
hardware components such as keyboard, mouse, hard drive or
floppy drive.
3. Initialize registers and power management

29.  Once finished, it begins searching for a drive to boot an
operating system → the boot order or sequence
 Depending on the BIOS setting, the procedure may try
to access (in a predefined, customizable order) the first
sector (boot sector) of any floppy disk, any hard disk,
and any CD-ROM in the system.
 BIOS will try to initiate the boot sequence from the first
device.
 If it does not find the proper files in the device, the
startup process will halt and an error message is
displayed.

30.  Most are set to first look for a bootable floppy
disk, and if one is not found then proceed to a
hard disk, which is usually the C: drive.
 Once the drive is identified, it looks for boot
information to start the operating system boot
process.
 If it is searching a hard disk, it looks for a master
boot record (MBR) at cylinder 0, head 0, ‘sector
zero’, the first sector on the disk.
 If a Master Boot Record is found, it is read into
memory at location 0000:7c00 and INT 19 jumps
to memory location 0000:7c00.
 At this point, the BIOS attempts to move control
of the computer from the BIOS to the actual
operating system.

31. Configuring BIOS - CMOS Setup
 During the initial start up or the boot sequence, you
will notice a sentence
Press ____ to Enter Setup. Most system use Esc, Del,
F1, F2 or combination of keys to enter Setup menu.
 This will cause the boot process to be diverted into
the CMOS configuration. CMOS contains stored
configuration regarding how the system is to be
booted.

32.  It is configuration program that allows you to
configure hardware settings including system
settings such as boot sequence, computer
passwords, time and date.

34. AN EXAMPLE OF A CMOS SETUP

36. • BIOS program continually checks the CPU
temperature and voltages, the cooling fans RPM,
etc.
• If over heating occurs, the PC will shut down
automatically.
• The PC can also be turned on by for example
modem signals, since the power supply is
controlled by the motherboard.
• The on/off button will turn the PC "down"
without turning it completely off.

37. • Some BIOSes contain a "tattoo", a digital signature
placed inside the BIOS by the manufacturer, for
example Dell.
• Computer manufacturers that distribute original
equipment manufactured (OEM) versions of Microsoft
Windows and Microsoft application software can use
the tattoo to authenticate licensing to the OEM
Windows Installation disk and/or system recovery
disc containing Windows software.
• Dell systems having tattoos do not require entry of
the Product Key (the Product Key on the label in fact
being invalid), and they bypass Windows Product
Activation (a convenience to the user and to
Microsoft).

38. • Apple Macintosh, where the system software
originally relied heavily on the ToolBox—a set of
drivers and other useful routines stored in ROM
based on Motorola's 680x0 CPUs.
• These Apple ROMs were replaced by Open
Firmware in the PowerPC Macintosh, then EFI
(Extensible Firmware Interface) in Intel Macintosh
computers.

39. 1. Large hard drive support. Older BIOS's couldn't see drives larger
than 37GB due the 48bit problem.
2. New video card technology such as AGP 8X support, or in older
machines 2X to 4X. This includes SLI.
3. Advanced Configuration and Power Interface (ACPI ) compatibility
4. CPU support. BIOS companies often release new CPU microcode
updates to the motherboard companies who in turn add them to
their BIOS's to support newer CPU's
5. Fix problems. A common problem is USB compatibility. There are
so many USB devices nowadays and many of them try to use the
same interrupt request (IRQ). Hence, as the system BIOS is loading,
IRQ conflicts can cause USB devices to not be found.
6. Memory support. Newer faster memory can have issues on your
motherboard. Might be larger than what was originally tested or
approved. A tweak from the motherboard company can fix that.

41.  Every desktop computer
uses an operating system.
 The operating system
forms a platform for other
system software and
application software
 The most popular
operating systems in use
today are:
 Windows from Microsoft
 Mac OS from Apple
 UNIX / LINUX

42. There are three basic elements that make up
the major design components of any operating
system:
 User interface
 Kernel
 File management system

43.  A user interacts with the operating system through the user
interface.
 The user interface is the part of the operating system that can be
used to issue commands by either typing them at a command
prompt or pointing and clicking the mouse on a graphical user
interface (GUI).
 Older operating systems integrated the GUI into the kernel but the
modern ones have the user interface separating the graphics
subsystem from the kernel (like in Linux and Mac OSX).
 Many operating systems allow the user to install or create any
user interface they desire.
 The X Window System in conjunction with GNOME or KDE is a
commonly found setup on most Unix and Unix derivative systems.
 Graphical user interfaces evolve over time

44.  This is the core of the operating system.
 The kernel is responsible for loading and
operating programs or processes, and
managing input and output.

45.  Kernel act as a bridge between applications
and the actual data processing done at the
hardware level
Resources

46.  The file management system is what the operating system
uses to organize and manage files.
 A file is a collection of data.
 Virtually all of the information that a computer stores is in
the form of a file.
 There are many types of files, including program files, data
files, and text files.
 The way an operating system organizes information into
files is called the file system.
 Most operating systems use a hierarchical file system, which
organizes files into directories under a tree structure.
 The beginning of the directory system is called the root
directory.

47.  Multiuser: when two or more users can work with
programs and share peripheral devices (printer,
scanner, fax)
 Multitasking: multiple applications operated at the
same time
 Multiprocessing: more than one CPUs that can be
shared
 Multithreading: smaller parts of a program are
loaded when needed by OS
 Real-Time Operating System (RTOS): designed to
allow computers to process and respond to the
consistent input of information without delay

48.  File and folder management
 An operating system creates a file structure on the computer
hard drive where the data can be stored and retrieved
 Applications management
 Whenever a program is requested the operating system locates
it and loads into the primary memory or RAM.
 Support for built-in utility programs
 The operating system comes with tools for maintenance and
repairs. They identify the problem, they find lost files, repair
the damaged ones and do backups for your data.
 Computer hardware control
 Operating systems facilitates the access of programs to the
computer hardware through the BIOS and through device
drivers.

49. At the simplest level, an operating system does
two things:
 It manages the hardware and software resources
of the system. In a desktop computer, these
resources include such things as the processor,
memory, disk space, etc.
 The operating system plays the role of the good
parent, making sure that each application gets the
necessary resources while playing nicely with all
the other applications
It provides a stable, consistent way for
applications to deal with the hardware without
having to know all the details of the hardware

50.  One of the task under Application
Management
 The heart of managing the processor comes
down to two related issues:
◦ Ensuring that each process and application
receives enough of the processor's time to
function properly.
◦ Using as many processor cycles for real work
as possible.
 Uses interrupts as an efficient way to
communicate with its environments

51.  This is a signal to a processor indicating that
an asynchronous event has occurred.
 Here the current sequence of instructions is
temporarily suspended, and a sequence
appropriate to the interruption is started in
its place.
 Its purpose is to alert the operating system
when any special event occurs so that it can
suspend its current activity and deal
appropriately with the new situation

52.  Usually an interrupt gives a signal from a device attached
to a computer or from a program within the computer that
causes the main program that operates the computer (the
operating system) to stop and figure out what to do next.
 Almost all personal (or larger) computers today are
interrupt-driven - that is, they start down the list of
computer instructions in one program (perhaps an
application such as a word processor) and keep running
the instructions until either
 (A) they can't go any further or
 (B) an interrupt signal is sensed.
 After the interrupt signal is sensed, the computer either
resumes running the program it was running or begins
running another program.

53.  Basically, a single computer can perform only one
computer instruction at a time. But, because it can be
interrupted, it can take turns in which programs or sets of
instructions that it performs.
 This is known as multitasking. It allows the user to do a
number of different things at the same time.
 The computer simply takes turns managing the programs
that the user effectively starts. Of course, the computer
operates at speeds that make it seem as though all of the
user's tasks are being performed at the same time.

54.  A code in operating system that prioritizes
the interrupts and saves them in a queue if
more than one is waiting to be handled.
 The operating system has another little
program, sometimes called a scheduler,
which figures out which program to give
control to next.

55.  In general, there are hardware interrupts and
software interrupts.
 A hardware interrupt occurs, for example,
when an I/O operation is completed such as
reading some data into the computer from a
tape drive.
 A software interrupt occurs when an
application program terminates or requests
certain services from the operating system.

56.  Interrupts alter a program’s flow of control
 Interrupt causes transfer of control to an
interrupt service routine (ISR)
◦ ISR is also called a handler
 When the ISR is completed, the original
program resumes execution
◦ Hence, interrupts provide an efficient way to handle
unanticipated events

57. When an operating system manages the
computer's memory, there are two broad tasks to
be accomplished:
 Each process must have enough memory in
which to execute, and it can neither run into
the memory space of another process nor be
run into by another process.
 The different types of memory in the system
must be used properly so that each process
can run most effectively.

58.  The path between the operating system and
virtually all hardware/device that are not on the
computer's motherboard goes through a special
program called a driver.
 Much of a driver's function is to be the translator
between the electrical signals of the hardware
subsystems and the high-level programming
languages of the operating system and
application programs.
 Drivers take data that the operating system has
defined as a file and translate them into streams
of bits placed in specific locations on storage
devices, or a series of laser pulses in a printer.

59. Windows
Linux
(UNIX)
Mac

60.  Single-user, multi-tasking
 Similar to Windows since it is the same type of OS
 However, when comparison is performed between them in
terms of:
 Application
 Power
 Files and Folders
 GUI and etc
 Result: MAC obtains a slightly better score than Windows
 Comparison Website
 It is also possible to have BOTH operating systems on the
same PC. However, it requires
 lots of free hard disk space
 emulation software that duplicates (provide an emulation
of) the functions of one system with a different system
 a faster machine for faster installation time