Oct 31 2006

Understanding Technology By Dissecting The Inner Workings Of Computers

Think computers are complicated? They are--until you examine them piece by piece. Then they are much easier to understand.

The computers in our schools and homes—and in our backpacks and our pockets—are remarkably multitalented devices. They still perform the classic computer tasks, such as running word processing and spreadsheet applications, as well as handling Internet applications, such as e-mail, Web browsers and calendars.

During the past several years, audio, video and multimedia capabilities have been added. And these graphic-rich applications play an increasingly important role in the education environment.

Yet these miracles of modern computing still work in much the same way as the first electronic computers did more than half a century ago.

At their heart, all computers perform the same inner functions, manipulating sequences of zeros and ones (OFF and ON), also known as bits. Bits are grouped into bytes (eight bits equal one byte), and these are used to represent things like instructions, numerical values, characters and memory locations.

Computers are a combination of hardware—the components you see (and some that are too small to see)—and software—the programs containing instructions that tell the computer what to do.

Computer languages like C++, Perl and Java enable developers to create computer programs using instructions that look somewhat like English (compared to strings of zeros and ones, that is). Operating systems, such as Microsoft Windows, let individuals use a mouse or keyboard to give the computer commands, enter text and display the results on a screen.

Taking a Peek Inside

Engineers used vacuum tubes to build the early, immensely huge computers of the mid-20th century. It took the invention of the transistor, by scientists at Bell Laboratories, to start bringing computers down to a more manageable size.

The invention of the integrated circuit, or chip, combined large numbers of transistors and additional electronic components into an apparently single, solid, postage-stamp-size device, often called a microprocessor. This led to the next revolution in computing: powerful, affordable machines small enough to fit on our desks, then in our briefcases and backpacks and now in our pockets. Today, these chips are part of cell phones, MP3 players, digital cameras, DVD recorders and other high-tech gadgets.

The microprocessor is the heart, or central processing unit (CPU), of every computer, but it’s only one of the many components that go into your desktop or notebook machine.

“The computer includes a number of key subsystems,” explains Stephen Bigelow, the author of PC Hardware Annoyances: How to Fix the Most Annoying Things About Your Computer Hardware. “Drives—hard drives, CD/DVDs, floppy drives, etc.—provide a place to store software and files.”

All of the other key processing components, Bigelow says, are on the motherboard, which is “one main board bolted to the chassis. The motherboard is where you’ll find the CPU and the main set of chips that define the various capabilities of the computer.”

The motherboard includes slots for memory, known as dynamic random access memory (DRAM), which provides temporary space—like a very fast blackboard—for instructions and data being created or processed by the computer.

“The motherboard handles all the interfaces to your keyboard, mouse, USB [Universal Serial Bus] and Fire Wire ports for external devices and network connections,” Bigelow explains. “It also provides bus card slots—places where additional functions can be plugged in, like sound cards or high-performance graphics cards for your monitor.”

To connect and house all of these components, Bigelow adds, “you’ve got the box (chassis), which includes the enclosure and the racks that the motherboard and drives are mounted on. The box also has ventilation holes, filters, buttons, switches, lights and places for the USB ports, earphone and microphone jacks, and so on. In addition, there are cables to connect the components, fans to help with air circulation for cooling, and a few other odds and ends.”

Peripheral Devices

There are also a variety of devices outside the computer chassis. These include peripherals (such as monitors, keyboards, a mouse, printers, external wireless network adapters, external hard drives, scanners and memory card readers), as well as portable devices (such as personal digital assistants, digital cameras and cell phones) that are periodically docked to the computer to exchange data.

Your computer runs by executing software files on your drives. It takes input from you through the mouse and keyboard, works on files from your drives, and displays information on your monitor. The computer may also send it to your printer or to a CD or DVD. In addition, the basic input/output system (BIOS) oversees all communication and ensures that hardware and software are operating in harmony to achieve maximum performance.

All thanks to a lot of zeros and ones.

Daniel P. Dern is a freelance technology writer based in the Boston area.

Why Does My Computer Crash?

Any number of things can cause your computer to crash or fail to work properly. “Hardware, surprisingly, is not the most frequent culprit,” says Stephen Bigelow, author of PC Hardware Annoyances: How to Fix the Most Annoying Things About Your Computer Hardware. “The two main roots [are] bugs [mistakes in the software] and hardware compatibility issues in software upgrades.”

However, he adds that there are numerous hardware-level occurrences that can lead to crashes or other problems. These include cabling errors and cooling problems. “A lot of people tuck computers under desks or into cubbyholes that don’t have enough air circulation,” Bigelow points out. “It’s also important to periodically clean out the dust and debris that accumulate in the ventilation holes and the filters under them.”

“The biggest post-installation problems occur with viruses and other malware like spyware and browser attachments,” adds Tom Henderson, managing director of ExtremeLabs, a computer testing and research firm in Indianapolis. “The second biggest problem occurs when users play with settings in their software. Most settings can be changed, but most shouldn’t [be].”

One suggestion from Henderson: “In Windows XP, it’s possible to lock down settings so that they can’t be easily changed.”

Electrostatic discharge is another common source of problems, says Jason McKinney, a system administrator for a Washington state agency, who has built and fixed his share of computers and networks. Other problematic events include “hard drives and video cards cooking themselves,” he says, “and fans throwing bearings or clogging with dust and slowly grinding to a halt.”

The other components inside the computer case, as well as the wires and utilities connecting to the case, can also be the source of computer-crashing problems, according to author Bigelow.

“There’s damage due to electrical shocks, power glitches, dropping the machine, overheating, overclocking, wiring errors, loose components or cabling,” Bigelow says. “Just like your car, a computer has all sorts of parts you may not think about. But, if they don’t work, the computer fails.”

To help avoid computer crashes, use an uninterruptible power supply; run firewall, antivirus and antispyware software; update software regularly; and perform regular daily or weekly backups of your data to CD, DVD, tape or an external hard drive.

And remember: If rebooting the computer solves the problem, it wasn’t really a problem.