Portable PC’s

Chapter 18

History/Background

Problems with making PC’s mobile– Not enough power in batteries

Early PC’s only had plugs, no batteries

– Ensure reliability PC parts were not designed to be bumped around Some of the first mobile PC’s had shock absorbers

– Functionality How could you use a mouse, other parts of the PC that

weren’t so easy to use with a mobile PC

Luggables

The first portable PC’s were “suitcase luggable”– Weighed up to 40 pounds– No batteries, could only be plugged in

First luggable was the Osborne One, but wasn’t considered a PC, because it was not compatible with IBM’s BIOS

Compaq came out with the first true portable PC

Laptops

2 separate technologies that allowed PCs to become truly portable– Nickel-Cadmium batteries

provided constant voltage

– Liquid Crystal Display (LCD) You could only have a 4” to 6” CRT because of the tubes

and the weight. STN (super twist nematic) allowed LCD to become quicker

and keep up with the demands of the PC

Laptops/Notebooks

Zenith first combined a Ni-Cad battery and LCD display with a mobile computer. – Picture on 1078

When the laptop was made even smaller to fit into briefcases it was then that they got the name “notebooks”

Personal Digital Assistants

This is the actual term for what most people no as Palm Pilots, or handhelds.

PDA’s used to have a little keyboard, but now use “pen-based computing”

Batteries

Nickel Cadmium (Ni-Cad)– First batteries commonly used in mobile PCs– One problem was with “battery memory”, the

tendency for it to lose a significant amount of its rechargeability it was recharged completely without being totally discharged

– Would last for a max of about 1000 charges– Very susceptible to heat– Be careful when disposing of them

Batteries

Nickel Metal Hydride (Ni-MH)– The answer to Ni-Cad’s problems– Are still quite common today– Can tolerate overheating, last longer between

recharges, and take more recharges

Batteries

Lithium Ion (Li-Ion)– Most common type of battery used today– Completely immune to memory problems and last at

least twice as long as comparable Ni-MH batteries on one charge.

– They can’t handle as many charges as Ni-MH though.

– Can’t be used as replacement batteries

Batteries

Smart batteries– A new type of battery that tells the computer when

they need to be charged, conditioned, or replaced.

Batteries

Always store batteries in a cool place Condition your Ni-Cad and Ni-MH batteries Keep battery contacts clean with a little alcohol

or a dry cloth Never handle a ruptured or broken battery Always recycle old batteries

PC Cards

Used to be known as PCMCIA Know the 3 sizes

– Type I – 3.3mm - Memory– Type II - 5 mm - NICS and Modems– Type III - 10.5 - Hard drives

Type II are by far the most common, so most laptops will have 2 type II slots

PC Cards

There are two levels of software drivers to support PC cards– Socket services – device drivers that support the PC

card socket; I/O, IRQ– Card services – recognizes the function of a

particular PC card There is something called CardBus that is out

now that has several advantages over normal PC cards (1088)

USB

In theory up to 127 devices may use a single USB port

In reality its throughput of 12 Mb/s limit it to about 3 or 4 devices

They run at 2 speeds: 1.5 Mb/s or 12 Mb/s Allows for a maximum cable length of 5

meters; you can use a USB hub to extend the distance

USB Configuration

Follow these steps when configuring– Be sure that the CMOS provides for an IRQ for the

USB ports– Ensure that your OS supports USB– Always install the device driver for a new device

BEFORE you plug it in

Basic Parts

RAM– Every decent laptop has upgradeable RAM slots.

SO-DIMMs 72 or 144 pin.

Hard drives– ATA drives in the 2.5 inch drive format are most

common in laptops

Video cards– Not very standard, but are becoming more

popular

Power Management

The process of cooperation between the hardware, the BIOS, and the OS to reduce power use.

APM/ACPI – Standards that allow a specialized BIOS and OS to

perform power management (1094-97)