This document provides an overview of portable computers including notebooks and their components. It discusses how notebooks differ from desktop PCs in being smaller, more portable devices powered by batteries. The key components of notebooks are similar to desktops but miniaturized for mobility, including processors, memory, expansion cards, power supplies, batteries, and integrated video controllers. Notebooks come in various sizes from ultra-portables to desktop replacements.

1. Portable computers
Module 2 /unit 1
By Kenneth Ayebazibwe
256774185458 / 256702555890
kynaye@gmail.com

2. OBJECTIVES
• On completion of this unit,
– Distinguish different types of portable devices from
desktop computers
– Describe typical components and functions of different
notebook computers
– Install and upgrade memory and peripheral devices on a
notebook
– Describe the operation of AC adaptors, batteries and
power management
– Identify a tablet pc and describe its uses
– Identify key features of handheld devices (PDAs and
smartphones)

3. Portable and Desktop Computers
• A portable computer is a personal computer that is
designed to be easily transported and relocated, but
is larger and less convenient to transport than a
notebook computer. The earliest PCs designed for
easy transport were called portables. As the size and
weight of most portables decreased, they became
known as laptop computer and later as notebook
computer. Today, larger transportable computers
continue to be called portable computers. Most of
these are special-purpose computers - for example,
those for use in industrial environments where they
need to be moved about frequently.

4. • The term "desktop computer" comes from an age
when it was considered chic for a computer to be
small enough to fit on top of a desk and the term
"personal computer" was coming into use, in the
late 70's and early 80's. The term desktop computer
is used interchangeably with "personal computer",
but there are other kinds of computers that are also
called "personal computers". At one time, any
computer with reasonable processing power was
large, heavy, loud, bolted down to the floor and
roughly the size of a refridgerator.

5. • As computer hardware has become ever smaller and more integrated, a
desktop computer is now considered a large, clunky system compared
to today's sleek, slim laptops, efficient notebooks and highly portable
tablet PC's (the Apple iPad, Samsung Galaxy, HP Touch and others).
Today's desktop computers are the upper range of computing power
most home and office users have access to directly at their desk. These
computers are on utility power, not a battery, so they have the
electricity to run faster processors, more memory and disks and
operate at higher speeds. As a general rule, a brand new desktop
computer will be more powerful and have more storage than any
smaller computer such as a laptop, ultrabook, notebook or tablet PC.
As a general rule, a desktop computer will get you more computing
power for your dollar. Making electronics smaller and portable means
greater expense, and lower electrical power usage means slower
electronics.

6. Notebook computer
• A notebook computer is a battery- or AC-powered personal computer
generally smaller than a briefcase that can easily be transported and
conveniently used in temporary spaces such as on airplanes, in libraries,
temporary offices, and at meetings. A notebook computer, sometimes
called a laptop computer, typically weighs less than 5 pounds and is 3
inches or less in thickness. Among the best-known makers of
notebook and laptop computers are IBM, Apple, Compaq, Dell,
Toshiba, and Hewlett-Packard.
• Notebook computers generally cost more than desktop computers
with the same capabilities because they are more difficult to design and
manufacture. A notebook can effectively be turned into a desktop
computer with a docking station, a hardware frame that supplies
connections for peripheral input/output devices such as a printer or
larger monitor. The less capable port replicator allows you to connect a
notebook to a number of peripherals through a single plug.

7. Types of Note Book computers
• Notebooks can be divided into a number of types
depending upon its size and functions. Listed below
are some types of notebooks.
– Ultra portables- having a screen size of 12 inches and a
weight less than 2 kg.
– Thin and lights- having a screen size of 12 to 14 inches
and weight ranging from 1.8 to 2.8 kg.
– Medium sized laptops- with a screen size of 14 to 15.4
inches and a weight ranging from 3 to 3.5 kg.
– Desktop replacement computers- having a screen size
varying from 17 to 20 inches and a weight ranging from
4 to 6 kg.

8. Note Book components
• The basic components of laptops are similar in function
to their desktop counterparts, but are miniaturized,
adapted to mobile use, and designed for low power
consumption. Because of the additional requirements,
laptop components are usually slower compared to
similarly priced desktop parts. Furthermore, the design
bounds on power, size, and cooling of laptops limit the
maximum performance of laptop parts compared to that
of desktop components.
• The following list summarizes the differences and
distinguishing features of laptop components in
comparison to desktop personal computer parts.

9. • Central processing unit (CPU): Laptop CPUs have advanced power-
saving features and produce less heat than desktop processors, but are
not as power full. There is a wide range of CPUs designed for laptops
available from Intel (Pentium M, Celeron M, Intel Core and Core 2
Duo), AMD (Athlon, Turion 64, and Sempron), VIA Technologies,
Transmeta and others. On the non-x86 architectures, Motorola and
IBM produced the chips for the former PowerPC-based Apple laptops
(iBook and PowerBook). Most laptops have removable CPUs,
although some support by the motherboard may be restricted to the
specific models. Some laptops use a desktop processor instead of the
laptop version. Those laptops have high performance at the cost of
being likely to have overheating problems, and having less battery life.
In other laptops the CPU is soldered on the motherboard and is non-
replaceable.

10. • Memory (RAM): SO-DIMM memory modules
that are usually found in laptops are about half the
size of desktop DIMMs.They may be accessible
from the bottom of the laptop for ease of
upgrading, or placed in locations not intended for
user replacement such as between the keyboard and
the motherboard. Currently, most midrange laptops
are factory equipped with 3–4 GB of DDR2 RAM,
while some higher end notebooks feature up to 32
GB of DDR3 memory. Netbooks however, are
commonly equipped with only 1 GB of RAM to
keep manufacturing costs low.

11. • Expansion cards: A PC Card (formerly PCMCIA)
or ExpressCard bay for expansion cards is often
present on laptops to allow adding and removing
functionality, even when the laptop is powered on.
Some subsystems (such as Ethernet, Wi-Fi, or a
cellular modem) can be implemented as replaceable
internal expansion cards, usually accessible under an
access cover on the bottom of the laptop. Two
popular standards for such cards are MiniPCI and
its successor, the PCI Express Mini.

12. • Power supply: Laptops are typically powered by an
internal rechargeable battery that is charged using
an external power supply, which outputs a DC
voltage typically in the range of 7.2– 24 volts. The
power supply is usually external, and connected to
the laptop through a AC connector cable. It can
charge the battery and power the laptop
simultaneously; when the battery is fully charged,
the laptop continues to run on power supplied by
the external power supply. The charger adds about
400 grams (1 lb) to the overall "transport weight" of
the notebook.

13. • Battery: Current laptops utilize lithium ion batteries, with more recent
models using the new lithium polymer technology. These two technologies
have largely replaced the older nickel metal-hydride batteries. Typical battery
life for standard laptops is two to five hours of light-duty use, but may drop
to as little as one hour when doing power-intensive tasks. A battery's
performance gradually decreases with time, leading to an eventual
replacement in one to three years, depending on the charging and discharging
pattern. This large-capacity main battery should not be confused with the
much smaller battery nearly all computers use to run the real-time clock and
to store the BIOS configuration in the CMOS memory when the computer is
off. Lithium-ion batteries do not have a memory effect as older batteries may
have. The memory effect happens when one does not use a battery to its
fullest extent, then recharges the battery. Innovations in laptops and batteries
have seen new possible matchings which can provide up to a full 24 hours of
continued operation, assuming average power consumption levels. An
example of this is the HP EliteBook 6930p when used with its ultra-capacity
battery.

14. • Video display controller: On standard laptops the video controller is
usually integrated into the chipset to conserve power. This tends to
limit the use of laptops for gaming and entertainment, two fields which
have constantly escalating hardware demands, and because the
integrated chipset is very difficult to upgrade for a standard user,
laptops may grow obsolete quickly for use in gaming and
entertainment. Higher-end laptops and desktop replacements in
particular often come with dedicated graphics processors on the
motherboard or as an internal expansion card. These mobile graphics
processors are comparable in performance to mainstream desktop
graphic accelerator boards. A few notebooks have switchable graphics
with both an integrated and discrete card installed. The user can
choose between using integrated graphics when battery life is
important and dedicated graphics when demanding applications call for
it. This allows for greater flexibility and also conserves power when not
required.

15. • Display: Most modern laptops feature 13 inches (33 cm)
or larger color active matrix displays based on CCFL or
LED lighting with resolutions of 1280×800 (16:10) or
1366 × 768 (16:9) pixels and above. Some models use
screens with resolutions common in desktop PCs (for
example, 1440×900, 1600×900 and 1680×1050.) Models
with LED-based lighting offer lesser power consumption,
and often higher brightness. Netbooks with a 10 inches
(25 cm) or smaller screen typically use a resolution of
1024×600, while netbooks and subnotebooks with a 11.6
inches (29 cm) or 12 inches (30 cm) screen use standard
notebook resolutions.

16. • Removable media drives: A DVD/CD
reader/writer drive is nearly universal on full-
sized models, and is common on thin-and-light
models; it is uncommon on subnotebooks and
unknown on netbooks. CD drives are becoming
rare, while Blu-ray is becoming more common
on notebooks

17. • Internal storage: Laptop hard disks are physically
smaller—2.5 inches (64 mm) or 1.8 inches (46 mm) —
compared to desktop 3.5 inches (89 mm) drives. Some
newer laptops (usually ultra portables) employ more
expensive, but faster, lighter and power-efficient flash
memory-based SSDs instead. Currently, 250 to 500 GB
sizes are common for laptop hard disks (64 to 512 GB
for SSDs).
• Input: A pointing stick, touchpad or both are used to
control the position of the cursor on the screen, and an
integrated keyboard is used for typing. An external
keyboard and/or mouse may be connected using USB or
PS/2 port, or Bluetooth (if present).

18. • Ports: several USB ports, an external monitor
port (VGA, DVI, mini-DisplayPort or HDMI),
audio in/out, and an Ethernet network port are
found on most laptops. Less common are legacy
ports such as a PS/2 keyboard/mouse port,
serial port or a parallel port. S-video or
composite video ports are more common on
consumer-oriented notebooks.

19. • Cooling: Waste heat from operation is difficult to remove in
the compact internal space of a laptop. Early laptops used heat
sinks placed directly on the components to be cooled, but
when these hot components are deep inside the device, a large
space-wasting air duct is needed to exhaust the heat. Modern
laptops instead rely on heat pipes to rapidly move waste heat
towards the edges of the device, to allow for a much smaller
and compact fan and heat sink cooling system. Waste heat is
usually exhausted away from the device operator, towards the
rear or sides of the device. Multiple air intake paths are used,
because some intakes can be blocked, such as when the device
is placed on a soft conforming surface such as a chair cushion.

20. • Review Questions on the face Book page!