Transcript module 5.ppt

MODULE 5
Main Components of
Motherboard

CPU Socket & Memory Slots

ISA, PCI & AGP Expansion Slots

CMOS Battery

Power Connectors

Memory Slots

Chipset

Serial/ Parallel/ USB etc ports.
Industry Standard
Architecture (ISA)
ISA Contd…

First open system bus architecture.

IBM introduced this 8-bit bus architecture in 1981. It had transfer rate of 4
MB/sec.

in 1984, with the release of the 286 data processor which used a 16-bit
data path, the ISA bus was expanded to 16 bits, with data rate 8MB/Sec.

A major disadvantage of this bus was that IRQs had be manually defined
through jumpers .
Peripheral Component
Interconnect (PCI Slots)
PCI Contd..

Introduced by Intel in 1992. Widely in use today.

Requires an additional bridge chip to connect to the I/O
of the CPU.

Operates on 33MHz, & capable of transferring data at
132 MB/sec.
PCI Contd..

Important feature of PCI is the model for the PNP (Plugn-Play) specification, which means that PCI cards could
be configured via software, rather than through
jumpers as was the case with ISA cards.
Accelerated Graphics Port
(AGP)
AGP Contd..

The AGP port is a dedicated graphics port based on PCI.

It’s a dedicated point-to-point channel that enables the graphics
controller to access main memory, bypassing the bottleneck of the PCI
bus.

It allows textures to be stored in main memory rather than video memory.
AGP Contd..
• The AGP channel is 32 bits wide and
• Runs at 66 MHz, giving a bandwidth of
266 MB/sec.
• AGP also supports two optional faster
modes, giving throughputs of 533 MB/sec
and 1.07 GB/sec.
Random Access Memory
(RAM)
Old 72-pin SIMM-type memory sockets
168-pin DIMM-type memory sockets
RAM CHIPS
Single In-line Memory
Module (SIMM)

A SIMM is a small circuit board designed to hold a set of
RAM chips.

Two types of SIMM's have been in general use. 30-pin
SIMM's and 72-pin SIMM's.

30-bit SIMM's have 8-bit data buses; 72-pin SIMM's have
32-bit data buses.
Dual Inline Memory
Module (DIMM)

DIMMs have separate electrical contacts on each side of the module.

DIMMs have a 64-bit data path.
Enhanced Integrated Drive
Electronics (EIDE slot)
EIDE Contd..

Enhanced (sometimes "Expanded") IDE is a standard electronic interface
between your computer and its mass storage drives.

Makes it possible to address a hard disk larger than 528 Mbytes.

EIDE also provides faster access to the hard drive, support for Direct
Memory Access (DMA), and additional drives, including CD-ROM
Analog Audio Input
Connectors
Analog Audio Input
Connectors
These are typically used for CD ROM drives. Since the CD ROM drive can

deliver audio via the 40-pin IDE connection, the analog audio connectors
are not generally needed. If you have a video capture card, you may need
to use the analog audio input to get the sound into the computer.
front panel switches and LEDs
front panel switches and LEDs

There are typically 4 connections (hard drive LED,
power/message LED, power switch and reset switch).

The LED connections are polarity sensitive (if connected
in reverse, the LEDs will not work).

The colored wire is generally positive and the
white/black wire is negative.
I/O Ports
Mouse & Keyboard
Connectors
AT motherboard Power Supply
ATX Power
ATX Power
Chipset

A chipset or chip set refers to a group of integrated circuits, or chips, that
are designed to work together.

The chipset is the heart of the computer and is the hub for all data
transfer. It determines how fast components like the processor, memory,
keyboard and various plug-ins can function in relation to each other
Chipset
Northbridge

The actual function of a chipset is to communicate
between all components of the modern PC.

The Northbridge usually contains the CPU interface and
the memory controller, sometimes the graphics unit is
also on the Northbridge.
Southbridge

The southbridge mainly deals with Input Output devces.

The Southbridge contains at least a PCI controller,
floppy/ IDE/ hard disk controllers, serial and parallel
ports, USB support and power management functions.
BIOS
BIOS

A BIOS (Basic Input/Output System) is an electronic set of instructions that
a computer uses to successfully start operating.

A main function of the BIOS is to give instructions for the power-on self
test (POST).

It gives the computer basic information about how to interact with some
critical components, such as drives and memory
ZIF Socket
ZIF Contd..

ZIF is an acronym for zero insertion force, a concept
used in the design of IC sockets, invented to avoid
problems caused by applying force upon insertion and
extraction.
ZIF Contd..
ZIF Contd..
CPU Fan Connector
CPU Fan Connector
Hard Disk Storage
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Objectives

In this chapter, you will:

Understand how hard drives read and write data

Know the difference between tracks, sectors, and
cylinders

Understand the difference between high-level and
low-level formatting

Identify the major internal components and
understand the workings of a typical hard drive

Identify cables and connectors used with hard drives
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Definition

A hard disk drive is a
sealed unit that a PC
uses for nonvolatile
data storage.

A hard disk drive
contains rigid, diskshaped platters, usually
constructed of
aluminum or glass
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Drive Operation

The basic physical construction of a hard disk drive consists of
spinning disks with heads that move over the disks and store
data in tracks and sectors.

The heads read and write data in concentric rings called
tracks, which are divided up into segments called sectors,
which normally store 512 bytes each.
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Drive Operation

One side of a platter is
called a “head”.

Hard drives can have
different numbers of
platters, depending on
their design and storage
capacity.

On the heads, you will see
concentric rings (tracks)
and pieces of rings
(sectors) just like on the
floppy disks.
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Drive Operation

Many hard drives today use a
technology called “zone bit
recording”

Which enables the hard drive to have
more sectors on the outer tracks,
where there is more room than on
the inner tracks.

Original
This allows more room for storage
Zone Bit
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Drive Operation

Another logical unit of a
hard drive is the
cylinder.

Let’s say we have a disk
drive with three
platters. Imagine
passing a cylinder down
through both sides of
each platter (6 tracks).

These 6 tracks make up
a logical cylinder on the
disk.
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Computer Data Storage

The read/write head on the drive moves very close to the
spinning disk as it goes by and writes to specific concentric rings
on the disk, called tracks.

The electrical particles on the disk are arranged according to the
charge given to them by the head.

The head can read the magnetic data as it passes by, or write to
it by using an electrical charge.

Preparing a disk drive for data
storage involves three steps:

Low-Level formatting (LLF)

Partitioning

High-level formatting (HLF)
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Low Level Formatting
Sector
 Low
level formatting
marks the tracks and
sectors of the disk.
A
sector is a small
section of a track that
stores 512 Bytes of
information
Track
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Partitioning



Partitioning a disk is the act of defining
areas of the disk for an operating
system to use.
Partitioning is required because a hard
disk is designed to be used with more
than one operating system.
Partitioning enables a single hard disk
drive to run more than one type of
operating system (dual boot), or it can
enable a single operating system to use
the disk as several volumes or logical
drives.
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Partitioning

You decide you want to break the 10GB space into
three logical partitions: one with 5GB of space,
one with 3GB, and one with 2GB.

The operating systems will logically view these
three partitions as three separate drives and gives
them separate drive letters C:, D:, and E:.

Physically all you have is one hard drive with three
logical drives.

Hard drive partitions must always begin at C:;
because the A: and B: drives are reserved for
floppies.
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High Level Formatting

A part of the system area is called the “Master boot
sector”.


This is the process of creating the disk's logical structures such
as the file allocation table and root directory.
The Master boot sector is:

Always the first sector (sector 0) of the first track (track 0) of
the first cylinder (cylinder 0) disk.

512 bytes long, just like any other sector

Contains information on all logical drives, regardless of
whether they are bootable.
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High Level Formatting

Formatting also creates the root
directory. (C:\)

If the disk is to be made bootable,
COMMAND.COM and two system files
(io.sys and msdos.sys) must be in the
root directory of the bootable drive.
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Components

The basic components of a
typical hard disk drive are as
follows:

Disk platters

Read/write heads

Head actuator mechanismSpindle motor (inside platter
hub)

Logic board (controller or
Printed Circuit Board)

Cables and connectors

Configuration items (such as
jumpers or switches)
The platters, spindle motor,
heads, and head actuator
mechanisms usually are
contained in a sealed
chamber called the Head
Disk Assembly (HDA).
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Platters

A hard disk drive has one or more platters, or disks.

Most hard disk drives have two or more platters, the number of
platters a drive can have is limited by the drive's vertical
physical size.

Platters have traditionally been made from an
aluminum/magnesium alloy, which provides both strength and
light weight. However, manufacturers' desire for higher and
higher densities and smaller drives has led to the use of platters
made of glass.
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Recording Media

No matter which substrate is used, the platters are covered
with a thin layer of a magnetically retentive substance, called
the medium, on which magnetic information is stored. Two
popular types of magnetic media are used on hard disk
platters:
-Oxide medium
-Thin-film medium
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Drive Operation: magnetization

HDDs record data by magnetizing ferromagnetic material
directionally, to represent either a 0 or a 1 binary digit.

The Co-based alloy thin films are polycrystalline and the size of
grains has an order of 10 nm.

In practice, a group of grains (about 100) are magnetized as one bit.

The read-and-write head is used to detect and modify the
magnetization of the material immediately under it. There is one
head for each magnetic platter surface on the spindle, mounted on
a common arm.
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Read Write Heads

A hard disk drive usually has one read/write head for each platter
surface These heads are connected, or ganged, on a single
movement mechanism.
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Air Filters

Nearly all hard disk drives
have two air filters.

One filter is called the
recirculating filter, and the
other is called either a
barometric or breather filter.

These filters are permanently
sealed inside the drive and
are designed never to be
changed for the life of the
drive.
HD heads are kept from contacting the platter surface by the
air that is extremely close to the platter; that air moves at, or
close to, the platter speed.
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Spindle Motors

The motor that spins the platters is called the
spindle motor because it is connected to the spindle
around which the platters revolve. Spindle motors in
hard disk drives are always connected directly; no
belts or gears are involved.

The spindle motor also must be precisely controlled
for speed. The platters in hard disk drives revolve at
speeds ranging from 3,600 rpm to 15,000 rpm or
more.
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Logic Boards

All hard disk drives have one or more logic boards mounted on
them.

The logic boards contain the electronics that control the
drive's spindle and head actuator systems and present data to
the controller in some agreed-upon form.

On ATA drives, the boards include the controller itself,
whereas SCSI drives include the controller and the SCSI bus
adapter circuit.
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Cables and Connectors

Hard disk drives typically have several connectors for interfacing
to the computer, receiving power, and sometimes grounding to
the system chassis. Most drives have at least these three types of
connectors:
-Interface connector(s)
-Power connector
-Optional ground connector (tab)

The interface connectors are the most
important because they carry the data
and command signals between the
system and the drive.

The power connector is usually the same four-pin type that is
used in floppy disk drives, and the same power-supply connector
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plugs into it.
Configurations Items

To configure a hard disk drive
for installation in a system,
you usually must set several
jumpers (and, possibly,
terminating resistors)
properly.

Master, Slave, and Cable
Select are different
configurations you can select
with jumpers
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IDE Hard Drive
Originally hard drives required a separate plug-in
controller to connect the drive to the rest of the
system.
 IDE: Integrated Device Electronics.




Today’s hard drives have the controller built onto the drive rather
than using a separate controller. This shortens the distance between
the controller and the hard drive and eliminates the interference
problem inherent with older drives.

It is the most widely-used hard drive interface on the market.

The fancy name refers to how the IDE technology "integrates" the
electronics controller into the drive itself.
The IDE interface, which could only support drives up
to 540 MB has been replaced by the superior EIDE
(Enhanced-IDE) technology which supports over 50 GB
and allows for over twice as fast data transfer rates.
The other most common hard drive interface is SCSI,
which is faster than EIDE, but usually costs more.
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ATAPI Devices


ATA: AT Attachment.

The specification, formulated in the 1980s by a consortium of
hardware and software manufacturers, that defines the IDE
drive interface.

AT refers to the IBM PC/AT personal computer and its bus
architecture. IDE drives are sometimes referred to as ATA
drives or AT bus drives.
Shortly after the introduction of the IDE drive, CD ROM
drives were being added to the system to add multimedia capabilities.

With the new ATAPI (Advanced Technology Attachment Packet
Interface) standard devices like CD ROM drives, Tape Drives,
Zip Drives, and DVD Drives could share the same IDE hard
drive cable.
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SATA Drives

Serial ATA was designed to replace the older ATA (AT
Attachment) standard (also known as EIDE).

It is able to use the same low level commands, but serial ATA
host-adapters and devices communicate via a high-speed
serial cable over two pairs of conductors.

Serial ATA has distinct key advantages over its predecessor.
Cables are very thin with small 7-pin connectors. They can
be up to 3 feet (1 meter) in length, and are easily routed to
stay out of the way allowing maximum airflow inside the
case.

ATA cables limited to 18 inches (46 cm) in length often made connections
difficult and also clogged cases blocking airflow, while cooling has become
crucial.

SATA also has a far lower power requirement of just 250 mV
compared to PATA's 5-volt requirement, and with chip core
voltages declining, this speaks well of SATA's future.

First generation SATA has a maximum transfer rate of 150
MBps, and second generation SATA delivers 300 MBps. A third
generation SATA set for 2009, "SATA 6Gb/s" will deliver
roughly twice the speed of the previous SATA iteration.
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SATA Drives
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Floppy



8-inch, 5¼-inch, and 3½inch floppy disks
A floppy disk is a data storage
medium that is composed of a
disk of thin, flexible ("floppy")
magnetic storage medium
encased in a square or
rectangular plastic shell.
Invented by IBM, floppy disks in
8-inch (200 mm), 5¼-inch
(133.35 mm), and 3½-inch
(90 mm) formats enjoyed many
years as a popular and ubiquitous
form of data storage and
exchange, from the mid-1970s to
the late 1990s.
They have now been largely
superseded by USB flash drives
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Floppy
Disk format
8-inch - IBM 23FD (read-only)
8-inch - SSSD
IBM 33FD / Shugart 901
8-inch - DSSD
IBM 43FD / Shugart 850
8-inch DSDD
IBM 53FD / Shugart 850
5¼-inch DD
3½-inch
HP single sided
Year introduced
Formatted
Storage capacity
in KB (1024 bytes) if not stated
Marketed
capacity¹
1971
79.7
?
1973
237.25
3.1 Mbits unformatted
1976
500.5
6.2 Mbits unformatted
1978
980
- 1200 (MS-DOS FAT)
360 or 800
360 KB
1982
280
264 kB
3-inch
1982
360
125 kB
3½-inch (DD at release)
1984
720 (400 SS, 800 DS on Macintosh,
880 DS on Amiga)
1 MB
1,182,720 bytes
1.2 MB
?
?
?
1.44 MB (2.0 MB
unformatted)
2.88 MB
21 MB
120 MB
240 MB
150/200 MB
5¼-inch HD
1977
1982 YE Data YD380
3-inch DD
2-inch
5¼-inch Perpendicular
1984
1985
1986
720
720
100 MB
3½-inch HD
1987
1440
3½-inch ED
3½-inch Floptical (LS)
3½-inch LS-120
3½-inch LS-240
3½-inch HiFD
1987
1991
1996
1997
1998/99
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21000
120.375 MB
240.75 MB
150/200 MB
75
1.2 MB
Floppy

The A: and B: drives on a desktop
computer are reserved in the
BIOS for floppy disk drives.

As most computers only come with one
floppy disk drive only the A: drive will be
visible in file explorer.

If a second floppy disk drive is fitted
then both A: and B: drives will be visible.
Ribbon cable used
to connect floppy.
To indicate which
end of the cable is
pin 1 on a drive
cable, a stripe is
drawn on the edge
of the cable.
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