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PORTABLE COMPUTERS

Identify the fundamental principles of using laptops and portable devices

Portable Computers

Laptop

In this fast-changing technological world, sometimes you are faced with some difficult choices. For instance, your current laptop has matured to the ripe old age of 5 months and has been deemed obsolete. Now it's time to purchase a new laptop and the question is, "What kind of laptop?"

Of course, the main benefit of a laptop is the mobility. This can be a huge benefit, allowing you to take your computer to and from work, on airplanes, on nice tropical beaches, and practically anywhere else. Along with this benefit comes a large drawback. It is just as easy for someone else to walk off with it as it is for you. Laptops are stolen at an alarming rate, because they are just so easy to steal. And when that laptop is stolen, not only do you lose the value of the laptop, but also all of your valuable data.

Laptops should be viewed as a purchase that should only be made when necessary. You would not purchase a car with 4-wheel drive (no matter how fun it looked) unless you actually had use of that feature, because otherwise it wouldn’t justify the added cost. The same is true of laptops.

Different Types of Portable Computers

Notebooks

They are not the notebooks that you used to write in when you were little bambino, but simply a rather new name for laptops. Earlier, when the laptops were introduced in 1983, the term 'laptop' was used to describe them. Notebooks are nothing but laptops with a new name. However, they are smaller models than laptops. Now days, laptops and notebooks are both common terms as all the brands are coming up with small, compact, and portable PCs that weigh anywhere between one to three kilograms. Just like PCs, laptops are capable of performing the same tasks but they can be less powerful than a PC.

Ultra-portables

They are the smallest one of the laptop family. These are use almost exclusively by the business traveler set.

Thin-and Light Notebooks

They are somewhat larger than Ultra-portables and supports a larger screen with more functionality that Ultra-portables.

Desktop Replacements

These are perhaps the largest of the notebook families. These are more powerful than the previous counterparts we talked about but provide space for more powerful components and the largest screen. Desktop replacement has a much shorter battery life span than any other laptop computers.

Palmtops

Palmtops are also known as a Handheld PC or then H/PC for short. This term has been coined by Microsoft, which suggests that palmtops are essentially smaller than the standard notebooks or PCs. The features that define a palmtop are as follows;
• A palmtop must run Microsoft’s Window CE.
• A palmtop must include a keyboard, a Compact Flash Slot, a PCMCIA Slot, and an infrared (IrDA) port.
• It should also provide USB connectivity or/and wired serial.
NEC MobilePro 780 and HP Jornada 720 are examples of some of the palmtops.

PDAs

PDAs or Personal Digital Assistants are basically devices that are handheld. They were originally designed as personal organizers but as the years went by their uses increased to a great extent and are usually characterized with the presence of a touch screen. The PDAs are typically used for calculating, playing computer games, sending and receiving e-mails, video recording, used as an address book, clock, calendar, radio or a stereo, and a spreadsheet, accessing the Internet, recording notes and GPS. The newer version of PDAs can be used as mobile phones or smart phones as they are commonly called. They have audio capabilities and color screens and is able to access the Internet, intranets and extranets via the Wi-Fi or Wireless Wide-Area Networks. Some of the popular PDAs are Sony CLIÉ, Fujitsu Siemens, Palm Pilot, and BlackBerry.

Tablet PCs

A tablet PC is basically a slate-shaped notebook with a digitizing tablet technology or touch screen that enables the operator to use a digital pen or stylus instead of a mouse or a keyboard. Tablet PCs are generally used when the normal notebooks are not practical and bulky to use. The different form of tablet PCs are slates, thin-client slates, convertibles and hybrids. There are many advantages of using a tablet PC. Since you will be using a digital pen to operate it, it is convenient to take down handwritten notes and diagrams at a conference or a class. With its handwriting recognition in place, you are even able to make an automatic search for the notes.

Now that you have a rough idea about the different types of laptops, it will help you in deciding the one that you really require.

What to look for when purchasing a laptop?

Function and Durability
Weight and Size
Style
Screen size
Processor/Motherboard
Storage Devices
Memory
Battery Life Support
PC card support
Price

Laptop Case
A laptop case is made of a plastic cover that surrounds the components and provides protection from the elements.

Laptop Display
Laptops today use LCD (Liquid Crystal Display) technology to view information

Two major types of LCD exist:

Passive and Active Matrix

Passive-matrix LCDs use a simple grid to supply the charge to a particular pixel on the display. Creating the grid is quite a process! It starts with two glass layers called substrates. One substrate is given columns and the other is given rows made from a transparent conductive material. This is usually indium-tin oxide. The rows or columns are connected to integrated circuits that control when a charge is sent down a particular column or row. The liquid crystal material is sandwiched between the two glass substrates, and a polarizing film is added to the outer side of each substrate. To turn on a pixel, the integrated circuit sends a charge down the correct column of one substrate and a ground activated on the correct row of the other. The row and column intersect at the designated pixel, and that delivers the voltage to untwist the liquid crystals at that pixel.

The simplicity of the passive-matrix system is beautiful, but it has significant drawbacks, notably slow response time and imprecise voltage control. Response time refers to the LCD's ability to refresh the image displayed. The easiest way to observe slow response time in a passive-matrix LCD is to move the mouse pointer quickly from one side of the screen to the other. You will notice a series of "ghosts" following the pointer. Imprecise voltage control hinders the passive matrix's ability to influence only one pixel at a time. When voltage is applied to untwist one pixel, the pixels around it also partially untwist, which makes images appear fuzzy and lacking in contrast.

Active-matrix LCDs depend on thin film transistors (TFT). Basically, TFTs are tiny switching transistors and capacitors. They are arranged in a matrix on a glass substrate. To address a particular pixel, the proper row is switched on, and then a charge is sent down the correct column. Since all of the other rows that the column intersects are turned off, only the capacitor at the designated pixel receives a charge. The capacitor is able to hold the charge until the next refresh cycle. And if we carefully control the amount of voltage supplied to a crystal, we can make it untwist only enough to allow some light through.

LCD Video Standards for laptops

Name Resolution Ratio

XGA Extended Graphics Array 800 x 600 4:3 or 1024 x 768 4:3
SXGA Super XGA 1400 x 1050 4:3
UXGA Ultra XGA 1600 x 1200 4:3
WUXGA Widescreen Ultra XGA 1920 x 1200 16:10

Laptop Motherboard and Processors
A laptop motherboard is much smaller that it’s desktop predecessor and therefore proprietary.
A laptop processor is integrated to the motherboard and it’s much more compact.

Pentium CPUs with an M rating and AMD Turion are some examples of laptop’s CPU
There are perhaps a couple of features in a laptop that distinguished them from their desktop counterparts.
CPU Throttling – This is essential in laptop and mobile PCs. This allows mobile devices to cut down on the amount of time, energy, and heat expended in computer operations.

Power management – This is a must in laptop operations

WiFi – The number one priority of laptop devices is mobility. This feature must be built in so that your laptop can access Internet anywhere and anytime.

Laptop Memory

Memory use by laptops

Most laptop memory use the SO DIMM or the Micro DIMM Packages
(72, 144, 200) SO-DIMM

SO-DIMM Short for Small Outline DIMM, a small version of a DIMM used commonly in notebook computers. 72 supports 32bit and 144 and 200 SO-DIMM pins support a full 64-bit transfer.
(144, 172) Micro-DIMM

Micro-DIMM Short for Micro Dual Inline Memory Module, a competing memory used on laptops mostly supports 144 and 172 pins.

Storage devices
Nearly all laptops have a hard drive and some form of CD or DVD ROM device that you can easily pull out of the laptop.

If you want to add more storage capabilities you can use either a flash drive, USB or a Firewire hard drive.
Input Devices
Portable computers take advantage of a wide variety of input devices. Due in part to their mobility, input devices for laptops, PDAs, palmtops, etc. tend to focus on producing enhanced functionality while keeping the footprint of the system small.

Different ways to move around a laptop

Fn Key and Num Pad keyboard
Touch Pad
Eraser or Pointer Stick (very popular with IBM/Lenovo computers)
Trackball
Traditional USB, PS/2 and Serial Mouse
Wireless Mouse: Infrared or Bluetooth
Stylus or Digitizer

Batteries
Mobility is one of the key features of a having a portable computer. Which mean when an AC outlet is not around you're going to need batteries to run your laptop? Here are some of the different types of batteries your laptop would use.

Nickel Cadmium Ni-CD first battery ever used in mobile PC no smart recharging must wait before PC is drained before you can recharge (memory effect) also battery did not last as long and when removing must clean corrosion in order for new battery to work.

Nickel Metal Hydride Ni-MH a little better than the Ni-CD but has the same problems stated above as NiMH

Lithium Ion are completely immune to memory problems can recharge on the fly and lasts longer will not explode if overcharge this should be the battery you will need for your laptop

Note * Typical Laptop batteries should last around 2-4 hours

If you want to add capabilities to your laptop you can connect to a docking station or a port replicator

Docking Stations - A docking station lets you connect many peripheral devices to a portable laptop at once

Port Replicator – A device use by a laptop to replicate peripheral ports

Expansion Capabilities for a laptop

PCMCIA Cards or PC Card (16 or 32bit)

Types of PC Cards Thickness Width Length Use

Type I 3.3mm 54.0mm 85.6mm Flash Memory
Type II 5.0mm 54.0mm 85.6mm NIC/Modem/USB/Firewire Devices
Type III 10.5mm 54.0mm 85.6mm Hard Drives

The newest bus for a laptop is called an Express Bus which is much more compact that a PCMCIA Card

Centrino – a platform-marketing initiative from Intel covers a particular combination of CPU, motherboard chipset and wireless network interface in the design of a laptop computer. Intel claimed that systems equipped with these technologies should deliver better performance, longer battery life and broad wireless network interoperability.

2.2 Install configure, optimize, and upgrade laptops and portable devices

Battery Upgrade
Laptop or notebook computers usually come with around a 2-3 hour battery and your requirements may demand a higher capacity battery. Many notebook manufacturers sell extended life batteries to replace your primary battery or an extended battery which fits in one of the laptop expansion slots.

Hard Drive Upgrade
Typically, a notebook computer has only one hard drive slot containing a 2.5” EIDE drive. You can either upgrade this hard drive, or there are some other choices in upgrading your storage space.
An alternative is to purchase a hard drive adapter for your expansion bay, if your computer has one. Or, alternatively, you can purchase a Type III PCMCIA hard drive which occupies two Type II PCMCIA expansion slots.

Additionally, you may be able to purchase an external portable hard drive which operates off your USB, Firewire, or Parallel ports.

Adding a Docking Station
A docking station allows your laptop to replicate its ports so you can leave the network, an external monitor, keyboard, mouse, expansion cards, etc. plugged in and just remove and insert your laptop or notebook computer as needed.

Expanding Laptop Memory
Typically, laptop memory is a bit more expensive than desktop memory and you are more limited in the number of memory chips you can fit on the notebook motherboard.
Typically, laptops either have a access panel which can be unscrewed to add additional (or replace) memory, or it is accessible under the keyboard. On Compaq Armada notebook computers, there are several tabs you slide down to open the keyboard and insert the memory under the keyboard.

Adding Additional PCMCIA Cards
A typical laptop has two Type II PCMCIA slots, though on most sub-notebooks, there is only one slot available.

There is a wide range of devices available which fit the Type II PCMCIA slots such as IEEE1394 expansion cards, Type III hard drives, NIC cards, cellular modems, GPS units, and more.
Adding these devices is relatively simple. PCMCIA cards are hot swappable so you can add a device while the computer is turned on (though my experience has been to add a new card before the computer comes on, makes installation and discovery easier).


Laptop Power Management

ACPI (Advanced Configuration and Power Interface) is an open industry specification co-developed by Hewlett-Packard, Intel, Microsoft, Phoenix, and Toshiba.
ACPI establishes industry-standard interfaces enabling OS-directed configuration, power management, and thermal management of mobile, desktop, and server platforms.
When first published in 1999, ACPI evolved an existing collection of power management BIOS code, Advanced Power Management (APM) application programming interfaces (APIs), PNPBIOS APIs, and Multiprocessor Specification (MPS) tables into a well-defined power management and configuration interface specification.
The specification enables new power management technologies to evolve independently in operating systems and hardware while ensuring that they continue to work together.

Hardware Profiles

How to Configure the Hardware Profiles
Hardware profiles are especially useful if you have a portable computer. Most portable computers are used in a variety of locations, and hardware profiles let you change which devices your computer uses when you move it from location to location. For example, you may have one profile named Docking Station Configuration for using your portable computer at a docking station with hardware components such as a CD-ROM drive and a network adapter. You may have a second profile named Undocked Configuration for using your portable computer in a hotel or on an airplane, when you are not using a network adapter or a CD-ROM, but you are using a modem.

If there is more than one hardware profile on your computer, you can designate a default profile that is used every time you start your computer. You can also have Windows prompt you for which profile to use when you start your computer. After you create a hardware profile, you can use Device Manager to disable and enable devices that are in the profile. When you disable a device in a hardware profile, the device drivers for the device are not loaded when you start your computer with that profile.

Hardware Profile in Windows XP

Hardware Removal
Hot-Swappable Devices
In the taskbar click on the Safely Remove Hardware dialog box to disconnect your laptop devices.

2.3 Identify tools, basic diagnostic procedures and troubleshooting techniques for laptops and portable devices

Diagnosing Laptop Problems

Power Concerns
Understanding how laptop power works can be very useful in determining what the problem is. I will first explain how it works, and then I will explain how we can troubleshoot.

AC power adapter

How the AC adapter works
The most common type of AC power adapter involves a small box, with one wire to go to the computer and another wire to go to the wall. There is usually an LED light on it, to tell you that it is on. (Is it lit on yours?) By the way, Laptop power adapters often have an LED that is actually built into the side of the computer, not into the adapter box, so obviously it won't light up when it's not connected to the computer.
The power adapter box does several things. It lowers the voltage from the wall's 120 volts AC to typically 19 volts DC (it will be labeled with the exact voltage). It includes some power noise filtering. It often includes an automatic circuit breaker or overload detection. If this gets tripped, you can generally reset it if you unplug it from everything for a few minutes.
You can measure the voltages on your AC adapter with a multi-meter. When it is unplugged from the computer but still plugged in to the wall, it is normal to find that the voltage may be 1 to 3 volts higher than the printed output rating. Troubleshooting: AC Power adapter LED is off when you plug the adapter into the wall but not into the computer
Has it been overloaded? Is the power strip turned on / is the outlet working? Is the cord from the adapter to the wall fully plugged in on both ends (try wiggling)? Your adapter may be fried- try borrowing an identical adapter from a friend and seeing if that one will work in its place (but do not plug it in to your computer, or you might fry your friend's adapter).

Troubleshooting: Check output voltages with a multi-meter device
For those of you with circular connectors, your task is easy. Measure the voltage between the inside and the outside. A diagram on the adapter's label will tell you which should be positive and negative
Power distribution inside the laptop

How laptop power distribution works
Okay, the power comes into the plug on the back of the computer. This connects it to metal traces inside the motherboard of the computer. These will be connected to voltage regulators which often output 5 volts, 12 volts, 3.3 volts, and the CPU voltage
These will be connected to cylindrical capacitors distributed throughout the motherboard. Capacitors act like tiny, fast batteries, supplying extra power where needed to maintain a steady voltage during high demand.
Finally, power goes to all the devices that need it.
Power for the LCD display is usually done separately. Generally, LCD backlights require high voltage to operate. A component that might be called a power inverter will step the voltage up to what is needed for the backlight. Sometimes this inverter is a discrete and replaceable component, and sometimes just a chip on your motherboard. It is also involved in the brightness control.
The battery is an important part. It supplies power to the input-side of the voltage regulators, just like the power from the AC adapter. Additionally, there is a charging circuit, which uses the power from the AC adapter prior to the voltage regulators, to charge the battery. (By the way, this is why the AC adapter voltage is always rated higher than the battery's rated voltage-- you need higher voltage for charging.)
There is a separate page exclusively for Laptop battery power.

Short circuits
Anywhere in your laptop, physical or electrical damage can cause a short circuit. A short circuit will consume all available power, causing your laptop to not turn on. If your power adapter LED comes on when you plug it into the wall, but then goes off when you plug in the laptop, you probably have a short circuit.

Troubleshooting short circuits
An ohm-meter / multi-meter will read less than ~3 ohms when you measure the resistance between sides of power going into a short circuit. When measuring between then power pins going into the back of your computer, consider the 2 pins where you expect voltage to be applied by the AC adapter. If the resistance indicates a short circuit, this is bad.
A common trick to help isolate possible problems is to try to removing anything that might be a short circuit. Take out the battery, the hard drive, the DVD/CD drive, the floppy drive, PCMCIA cards, USB devices, mini-PCI cards. See if the computer will then turn on.
You might have luck with a thermal imager (see story below) to find a hot spot caused by the short circuit.
Computer turns off randomly
Your computer can turn off due to: power overload in the AC adapter, overheated processor / clogged fan, overheated battery, pushing the power button, Windows telling it to, the BIOS telling it to, loose wires (especially the power cord), or intermittent short circuits.
The most common problem is cooling. Try going somewhere air conditioned. Notice if the fan is broken or clogged with dust (common older HP problem).

Video Issues
Here are some tips and tricks for troubleshooting and fixing laptop video problems. Video issues are very common within portable computers and with the following tips you should be able to detect and eliminate basic laptop video problems.

LCD screen is faint

Look at the LCD screen very closely and check if you can see a faint image on the screen. It’s possible that the LCD lid close switch stuck in the “closed” position and the backlight stays off even when you open the LCD screen or turn on the laptop. The switch turns off the backlight when you close the LCD display to save the laptop battery power. Check the LCD lid close switch. Usually it is a small plastic pin located close to the LCD hinges. Try to tap on the switch a few times to turn on the backlight. If after tapping on the LCD lid close switch the backlight stays on, you fixed the problem.
It is also possible that after tapping on the LCD lid close switch the backlight works fine, you see a normal video on the screen for some time and then the backlight turns itself off again. In this case I would blame the FL inverter board. Try to reseat cables on both end of the FL inverter to make a better contact between the cables and the FL inverter board. If it doesn’t help I would try to replace the FL inverter board.
Laptop LCD screen is solid white color.

Most likely it is just a bad connection between the LCD display and the system board. I would try to reseat the video connector on the back of the LCD screen first and check if it fixes the problem. After that I would try to reseat the video cable connector on the system board. I would also reseat cables if there is no video on the LCD screen at all.
The video on the LCD screen is garbage.

Try to connect the LCD screen to an external monitor. If the external video is fine, you have a problem with the LCD screen or the LCD video cable. You can try to fix the problem by reseating the video cable on the back of the LCD and on the system board.
If you see the same garbage video output on the external monitor most likely it is not the LCD screen problem. In this case the system board (with onboard video) is bad or the video card is bad.

There is no video on the LCD screen
The laptop started without any video on the LCD screen, but the backlight lighted the screen. When you have a problem like this, always try to connect the laptop to an external monitor. If the external video is fine, then most likely the system board or the video board in the laptop are fine and the problem is somewhere between the LCD screen and the system board. I connected the laptop to an external monitor and got a normal video output. To find the problem, I opened up the laptop display assembly and found that the video cable on the back of the LCD screen was half way out. After I reseated the display video cable, the laptop started with the internal video.
Input Problems

If any of the integrated port are damage like the USB, VGA, DVI, Firewire it’s most likely you have to replace the motherboard or get a PC Card with those connectors as a temporarily solution.

Networking Troubles

If built-in wireless networking is not working make sure your LEDs on your network card is functioning.
If wireless capability is dependent on a PC card, ensure that the card is properly seated in the slot and that the drivers are installed.

Check the antennas are not broken on some of the wireless devices on a laptop

Ensure that the laptop is within range of the wireless access point. Check the configuration of your wireless network and ensure that you have the proper SSID and key in order to connect to your wireless access point

Check for conflicts and make sure the network component has the driver installed

2.4 Perform preventative maintenance on laptops and portable devices

Environment Issues
Cleaning Materials – clean your laptop keyboard with compress air
LCD screens should be wiped off regularly with either a damp cloth or some specialized LCD cleaning material. NOTE never use windex or other glass cleaner for this purpose
Always recycle laptop battery when you are ready to discard it.

Cooling mechanism for a laptop

Laptop Cooling Mechanism
Is the stock fan on your laptop making strange noise? Is it even working? Are you getting Blue screens, VXD errors, system freeze ups? The main reason you are getting these symptoms may be because your laptop is overheating! Picture your laptop like the engine in your car and picture this laptop cooler like a high performance radiator that keeps your engine cool. After extreme usage your laptop often "heats" up to high temperatures. In some cases, temperatures so hot that the stock fan in your laptop is just not good enough to cool down your laptop. Which will result of course in? OVERHEATING, system lock-ups, blue screens, memory dump errors and in extreme cases the whole laptop goes bad.

Storage and Shipping

Make sure when not in used, laptops should be kept in hardened case. When shipping, get the right box and use Styrofoam to protect your laptop from being damaged.
Always buy extra warranty
I am really not a proponent of this but if your laptop breaks it is much cheaper to replace it than to fix it.