your computer is like and unlike your brain

1) monitor

Also known as the display, an apt name since it doesn't in fact "do" anything except project images as instructed by the computer, the way the printer does on paper.

2) motherboard

A big circuit board that communicates between the various components of the computer, described below, via a data conduit called (for some reason) the system bus. I guess the idea being that the data is riding a bus from one component to another?

3) central processing unit, aka processor or CPU

The computer's 'brain' where all the 'thinking' happens. Except computers that computers can't 'think' in any meaningful sense (not yet, anyway.) What computers can do is addition, multiplication and a few simple logical operations on a list of numbers, then another, then another, according to instructions from all the software it has running. The miraculous-seeming 'thinking' is an illusion produced by the terrific speed at which modern computers can do these things. The one I'm typing on can do one billion eight hundred million plus operations every second. Current computers are fast but stupid. They can only add, multiply, move numbers from one memory location to another, and not much else.

Those spiky things sticking out of the CPU are for cooling, as is the noisy fan in the back, since high-speed processing generates a lot of heat.

4) memory, aka Random Access Memory or RAM

Short-term memory, a scratch pad where the computer temporarily stores information pertaining to whatever it's doing at any given moment. This includes whatever programs are running, whatever you've got going on in the various windows, the song currently playing in iTunes, the picture on your desktop, and all the many invisible programs running in the background making it all possible. The CPU can access memory so rapidly as to make it seem instantaneous to the user. The more memory the computer has, the faster it runs, because calling up information from the hard drive or a CD is much slower than getting it from memory. Also, more memory means you can have more programs running at the same time. The rub is that memory is quite expensive and is thus limited. We're locked in a sort of arms race, where memory is getting rapidly less expensive, but new and better computer programs demand more and more of it.

There's a strong analogy here to your own short-term memory. You can hold between five and nine distinct pieces of information "at the tip of your tongue" at any one time. There's a vastly larger amount of information stored in your long-term memory, but that takes more time to access. Your name is stored where you can access it quickly, whereas it's going to take some chin-scratching to call up the name of your fourth-grade teacher. You and your computer share this narrow bottleneck in your mental abilities. The scarceness of instanteously accessible short-term memory limits the number of different processes you can have going at the same time; it places a limit on your ability to multitask. When you have too many programs running at once on the computer, it starts getting crashy, sluggish, disorganized-seeming, much the same way humans do when similarly overwhelmed.

5) expansion cards

Each of the plugs and ports in the back of the computer connects to a big microchip-encrusted card plugged into the motherboard. There's a video card that sends pictures to the display, a card that lets USB devices talk to the motherboard, a sound card that converts data into analog signal and sends it off to the speakers, an Ethernet card that connects the machine to the Internet or the office network, etc. These used to be more important to the user in the olden days, when you routinely needed to plug and unplug cards whenever you got a scanner or something. Now that we're blessed with USB and Firewire, you can go your whole computer-using life ignoring your expansion card slots.

6) power supply

Distributes extremely precise voltages to the various components of the computer. Every so often, the power supply might go bad, especially if your building has faulty wiring or gets hit by lightning a lot. If this happens, the computer won't turn on at all, which makes it appear as though the machine is dead. No fear, though, it's actually not a big deal to replace a power supply.

7) optical drive

Here you put your CDs and DVDs in, and a laser reads data off microscopic pits in the thin spiral groove carved into the disk, the way a record-player needle reads grooves in vinyl. Optical disks are slower than memory, but still pretty darn fast. Equally breathtaking is the speed at which the laser can burn data into blank CDs. (This is a rare computer slang term that actually makes sense - the laser is literally burning holes in the plastic.) People take this particular technological miracle for granted, but a single twenty-five cent CD-R from Officemax stores more data than four hundred eighty-five floppy disks, with a much longer shelf life. The one problem with storing data on CDs is that once you've burned the holes in the plastic, it's hard to unburn them, so you can't rewrite or erase. Now that CD-Rs are so cheap, I don't consider this a big deal anymore and don't bother with the rewriteables, which are too delicate for my comfort level.

Other optical drives include CD and DVD players, as well as Playstations and other video game machines. That's why you can watch movies on computers and the newer game consoles. The only reason you can't play XBox games on your computer or burn commercial DVDs is that there are security measures encoded into the disks; it isn't anything fundamental to the technology. All thin, shiny plastic disks that spins around and are read by lasers are basically just the same kind of computer data storage medium. The only difference between a CD and a DVD is that the DVD holds six and a half times as much info. The various formats are evolving rapidly, and not all formats work on all equipment, so read the labels carefully.

8) hard disk/hard drive

Long-term data storage, not just for your own documents, mp3s, etc, but for all of the programs your computer can run, including the operating system. When you install a program from a disk or the Internet, you're really copying it onto your hard disk. When you save something like a Word document, you similarly copy it from memory onto the hard disk. IPods and video game consoles have hard drives too. Big spacious hard disks are much slower than memory, but they have the advantage of being way, way, cheaper, and getting cheaper all the time.

The name 'hard disk' is in contrast to the floppy disk of yore. You don't remember the floppy disk as being floppy because the delicate magnetic media itself was in a protective plastic casing. Hard disks are, well, hard. They're also vastly more capacious and vastly faster than their floppy predecessors. This is another technological miracle that we blithely take for granted. The hard disk on this laptop can store around fifty-eight gigabytes of data. That's enough to store fifty-eight million pages of plain written text. When you factor in the Internet connection, I'm basically carrying around a device capable of storing and retrieving all of verbalized human knowledge. This is an interesting evolutionary turn of events, to say the tiniest least.

9) keyboard

Take a break from typing every so often to avoid expensive trips to the orthopedic surgeon.

10) mouse

Another major culprit in repetitive stress disorders. I narrowly averted carpal tunnel a few years back by getting a trackball, much easier on the right wrist.

The mouse and accompanying concept of the graphical user interface (with pictures and menus and dragging and dropping and so on) was famously invented by engineers at Xerox in the seventies, but their bosses didn't really see a commercial application for it. The Apple and Microsoft people certainly did, when they got their eyes on it.

11) not pictured but extremely important: the operating system

Speaking of Apple and Microsoft. Residing on the hard disk, and occupying a substantial portion of memory whenever the computer is on, is the operating system, a vast assemblage of programs and instructions that enable the computer to do anything at all: run programs, respond to the mouse and keyboard, show graphics on the screen, communicate with the various peripherals like printers and networks, and many other such behind-the-scenes operations. The very first thing the computer does when you turn it on, after its automatic assessment of its own well-being, is to copy the operating system from the hard disk into memory. As you may have noticed, this can take a while, especially for Windows users.

There are a great many operating systems in the world, but at present, there are only two you're likely to come in contact with personally: the various flavors of Windows and Mac OS X. Neil Stephenson, author of many fine paranoid technothrillers, wrote an amusing essay in 1999 called In the Beginning...Was The Command Line, which takes an anthropological approach to that year's four major operating system contenders: Windows 98, Mac OS 9, Linux and BeOS. He makes a hilarious analogy to cars: Windows 98 is a clunky beige station wagon riddled with mechanical problems. Mac OS 9 is a fine European luxury car with its hood welded shut. Linux is a free tank that you have to assemble yourself. BeOS is the Batmobile. (Since the essay's publication, the Linux-based Mac OS X appeared, which Neal S swiftly embraced. BeOS went the way of the dodo.)

I say this often, and I'll say it again: Windows is a dreadful mess under the hood, and until Microsoft has a strong financial incentive to redesign it completely from scratch, it's not going to get any better. MS makes their money from big companies and institutions, where the first priority is backwards compatibility with all their existing stuff, and where there are full-time tech support staffs to plug the gaps. My advice to the individual home or small-business user is to get a Mac. OS X has plenty of technical flaws of its own, but it crashes one quarter as often as Windows, the visual design is a pleasure for the eyes, and the menus are laid out in a way that makes somewhat more intuitive sense.

If you find computers bewildering, here are some ways to make them less so.

every program has a File menu

Save As...	You'll be asked two things: what you want the file to be named and (just as important) where in the computer's vast hard disk you want the file to be stored. It used to be that you only hadeight letters to name your file, but now you get 242, including spaces and some punctuation. Use descriptive file names.
Save	This saves the document with the same name and in the same location as wherever you saved it last. The keyboard shortcut is Ctrl-S in Windows and Apple-S on the Mac. If you use it every time you pause to think, you can save yourself much heartache when the crash inevitably arrives.
Open	Remember what I said about descriptive file naming? Here's where it comes in handy.
Print	Hidden in this dialog is the useful option to save your document as a PDF document, which can then be opened and read by just about any computer anywhere. Why this isn't an option under Save As is beyond me.

just about every program has an Edit menu

Undo	When you make a mistake, don't panic. Just take a deep breath and undo.
Cut	Temporarily removes selected text and places it in a special memory region called the Clipboard for later pasting (see below.)
Copy	Copies selected text and places it on the Clipboard.
Paste	Inserts the contents of the Clipboard into your document. In MS Office you have the choice to do Paste Special -> Paste As Link, which is a fabulously useful way to include pie charts and other illustrations in your document.
Find/Replace	Did you use the wrong word or name a hundred times throughout your long document? Let the computer fix it for you.

So how does all of this work?

Computers are basically just gargantuan assemblies of tiny transistors, electrical switches like the ones you turn the lights on and off with. The difference is that transistors can be flipped with electricity, making it possible to wire together vast networks of simple automated information-sorting and storing operations, networks that can rewire themselves as necessary.

In case you're curious, here's what a hugely magnified silicon chip looks like:

I said above that computers only understand numbers, and every word or sound or picture in the computer has been translated into a series of numbers.

Text formats

.txt	Plain text, letters and numbers with no formatting. Most e-mail is plain text.
.rtf	Rich Text Format; plain text plus basic formatting. Nearly all computers can read and create Rich Text.
.doc	Microsoft Word document. Word embeds all kinds of hidden code into its documents, which sometimes appears as computer gibberish when you try to open or paste the text into other programs, e-mail messages, etc.
.html	Hypertext Markup Language, the format of pages on the World Wide Web and some e-mail messages. HTML includes text, images and hyperlinks.
.pdf	Postscript Document Format, formatted text plus images, readable by any computer with Adobe's free Acrobat Reader program.
.xls	Excel spreadsheet, readable only by Excel.

Image Formats

.tif	Tagged Image File Format. TIFFs are readable by pretty much every computer program, so it's a good format for high-quality images.
.psd	Photoshop Document, readable only by Photoshop.
.jpg	JPEG, named by its inventors, the Joint Photographic Experts Group, after themselves. Most photos you see on the Web and nearly all photos taken by digital cameras are JPEGs. This format uses lossy compression, which means that you can sacrifice image quality to make the file size smaller. TIFF and PSD are lossless - they don't sacrifice any quality, but the files are larger.
.gif	GIF, another lossy compression scheme, most commonly used on the Web for line art.

Audio Formats

.wav	The Windows format for CD-quality audio encoding. WAVs are big files, around 10 MB/minute.
.aif	The Mac equivalent of WAV.
.mp3	MPEG layer 3, readable by just about every audio program. Like the JPEG format, MP3s use lossy compression, sacrificing sound quality to bring the file size down to around one MB/minute.
.wma	Windows Media, about which I know nothing whatsoever.
.aac	Apple Audio Compression, Apple's version of MP4, which as the name suggests is a more advanced form of the MP3 format, allowing somewhat better sound quality.

Some handy information theory

Computer data is measured in bytes. Each byte is a group of eight zeros and ones, or equivalently, the on-off positions of eight tiny switches.

1 Byte	a single character
10 Bytes	a word or two
100 Bytes	a sentence or two
1 kB	a kilobyte, a thousand bytes; a page of text
100 kB	a medium-resolution photograph
1 MB	a megabyte, a million bytes; a short novel
10 MB	Two copies of the complete works of Shakespeare
100 MB	one meter of shelved books
1 GB	a gigabyte, a billion bytes; a pickup truck filled with pages of text
10 TB	ten terabytes, ten trillion bytes; the printed collection of the US Library of Congress

How the computer is like your brain

You both have separate, complimentary short and long-term memory systems.

You can both do logic, sorting and grouping information in meaningful ways.

You both create a 'user illusion.' The operating system creates an intelligible metaphor for the bewildering mathematical interactions going on under the hood. Your mind creates an intelligible metaphor for itself.

You can both encode a wide variety of different media. It's possible to translate images, text, sound, video, simulations of reality and so on as computer data and as webs of connected neurons in your head.

Emotions predate brains in evolution. Antonio Damasio defines an emotion as a preprogrammed hardware-level routine that helps the body maintain homeostasis. Think reflexes, but more complicated; a reflex is a simple automatic survival response, while an emotion is a coordinated system of such responses.

How the computer is unlike your brain

Logic is effortful for humans; even when we can do it, we're slow and unreliable. The computer can do logic extremely fast with perfect correctness, but it can't do anything else.

Computer memory and knowledge are non-ambiguous, quantized. Human memory and knowledge are diffuse, sacrificing precision for rich associative novelty.

The computer is serial, performing one set of calculations at a time only. The brain is parallel, massively multiply parallel, with countless processing unfolding simultaneously and all of the complex mutual interactions that entails.

An insect's brain is much more like a computer than yours is. Another way to put that: it's easy to build a robot that behaves remarkably like an insect, but robots that behave like humans are a long, long technological ways off.

© ethan hein 2007 | back to memebase | back to top