Upgrading & Fixing Laptops DUMmIES

and sometimes problematic connection to certain external hard drives

(including a few using the parallel port), what was needed was a high-speed

link to advanced devices.

The first solution was the introduction of PC Cards (which when introduced

were called by the unmemorable name PCMCIA Cards and then the slightly

less forgettable CardBus). PC Cardsallow extension of the computer’s internal

bus to a new device; these tightly packed credit card-sized cards plug in to

sockets in the side of a laptop.

Today PC Cards are used for communication devices including modems, net-

work interface cards (NICs), and WiFi cards. You can also purchase flash

memory cards with capacities of a few gigabytes (see Chapter 7) and tiny

hard drives.

But the biggest breakthrough for input and output on modern computers and

especially laptops was the development of the Universal Serial Bus (USB),

which pumped up the old serial concept to amazing speeds and allows use

of a wide range of external devices at speeds little different from those con-

nected internally.

Although it has not caught on to the same extent as USB, FireWire is another

modern high-speed serial standard. FireWire is more commonly used in the

Mac world.

Picking a card, any PC Card ..............................................................

PC Cards attach to 68-pin sockets that branch off a computer’s internal PCI bus,

mini versions of the slots within a desktop computer.

Modern laptops have one or two PC Card sockets and accept 16- or 32-bit

cards; you’ll be hard pressed to find any of the slower cards on the market. If

you have a choice, don’t work with a slower card instead of a faster one. PC

242 Part IV: Failing to Communicate

PCMCIAs are wild

When PCMCIA Cards were first introduced they

were limited to 16-bit data paths; the later

CardBus standard expanded the path to 32 bits.

(Think of a bus as a superhighway carrying 0s

and 1s of information; a 32-bit path is twice as

wide and potentially twice as efficient in deliv-

ering data as a 16-bit channel. CardBus devices

also run at a faster bus speed. The original

PCMCIA was capable of a slow throughput of

about 20 MBps at a bus speed of 10 MHz,

devouring 5 volts of power in doing so; CardBus

devices worked at a bus speed of 33 MHz and

deliver about 133 MBps of data, consuming just

3.3 volts.)