
                    KEYBOARDS
  The usual way to communicate with the computer is to type 
messages on the computer's keyboard.

                Famous keyboards
  These pages show pictures of famous keyboards:
Keyboard      Page
the ideal keyboard324
IBM PC 83-key keyboard422
IBM PC 101-key keyboard422
Mac keyboard  427
Apple 2 keyboard431
Commodore keyboard438
Tandy model 4 keyboard443
Tandy Color keyboard445

                     IBM PC
  The IBM PC's keyboard can print all the letters of the alphabet 
(from A to Z), all the digits (from 0 to 9), and these symbols:
SymbolOfficial nameNicknames used by computer enthusiasts
    . period    dot, decimal point, point, full stop
    , comma     cedilla

    : colon     dots, double stop
    ; semicolon semi

    ! exclamation pointbang, shriek
    ? question markques, query, what, huh, wildchar

    " quotation markquote, double quote, dieresis, rabbit ears
    ' apostrophesingle quote, acute accent, prime
    ` grave accentleft single quote, open single quote, open 
quote, backquote

    ^ circumflexcaret, hat
    ~ tilde     squiggle, twiddle, not

    = equals    is, gets, takes
    + plus      add
    - minus     dash, hyphen
    _ underline underscore, under

    * asterisk  star, splat, wildcard, Nathan Hale
    & ampersand amper, amp, and, pretzel
    @ at sign   at, whorl, strudel
    $ dollar signdollar, buck, string
    # number signpound sign, pound, tic-tac-toe
    % percent signpercent, grapes, James Bond

    / slash     forward slash, rising slash, slant, stroke
    \ backslash reverse slash, falling slash, backwhack
    | vertical linevertical bar, bar, pipe, enlarged colon

    ( )parenthesesopen parenthesis & close parenthesis, left 
paren & right paren
    [ ]brackets open bracket & close bracket, square brackets
    { }braces   curly brackets, curly braces, squiggly braces, 
left tit & right tit
    <>brockets  angle brackets, less than & greater than, from & 
to, suck & blow
  For example, the symbol * is officially called an ``asterisk''. 
More briefly, it's called a ``star''. It's also called a 
``splat'', since it looks like a squashed bug. In some programs, 
an asterisk means ``match anything'', as in a card game where the 
Joker is a ``wildcard'' that matches any other card. The asterisk 
is also called a ``Nathan Hale'', since he was the American 
patriot who during the Revolutionary War declared this final 
thought before being hanged by the British: ``I regret that I 
have just one ass to risk for my country.''
                                                     The % sign 
is called a ``James Bond'' because it looks like that spy's code 
number: 007.
                                                     The IBM PC's 
keyboard also contains special keys that help you do special 
activities, such as move around the screen while you type:
Key                                                      Usual 
purpose
                                                        move up, 
to the line above
                                                        move 
down, to the line below
                                                        move 
left, to the previous character
                                                        move 
right, to the next character

Home                                                     move 
back to the beginning
End                                                      move 
ahead to the end
Page Up                                                  move 
back to the previous page
Page Down                                                move 
ahead to the next page

Tab                                                      hop to 
next field or far to the right
Enter                                                    finish a 
command or paragraph
Pause                                                    pause 
until you press Enter
Print Scrn                                               copy 
from the screen to paper

Shift                                                    
capitalize a letter
Caps Lock                                                
capitalize a whole phrase
Num Lock                                                 use 
numbers on keyboard's right side
Scroll Lock                                              change 
how text moves up & down

Insert                                                   insert 
new character in middle of text
Delete                                                   delete 
the current character
Backspace                                                delete 
the previous character
Esc                                                      escape 
from a mistake

F1                                                       get help 
from the computer
F2, F3, etc.                                             do 
special activities
Ctrl                                                     do 
special activities
Alt                                                      do 
special activities
Many programs make those keys serve different purposes instead. 
Be safe: avoid those keys until you read the details in later 
chapters.

       GRAPHICS-INPUT DEVICES
  If you feed the computer a picture (such as a photograph, 
drawing, or diagram), the computer will analyze the picture and 
even help you improve it. To feed the computer a picture, you can 
use three methods. . . . 
  Method 1: point a video camera at what you want to take a 
picture of, while the video camera is wired to a box called 
Computer Eyes, which is wired to the computer.
  Method 2: draw the picture on paper, then put that paper 
underneath an optical scanner wired to the computer.
  Method 3: draw the picture by using a pen wired to the 
computer. The six popular kinds of computerized pens are light 
pens, touch screens, graphics tablets, mice, trackballs, and 
joysticks.

             Light pens
  A light pen is a computerized pen that you point at the screen 
of your TV or monitor. To draw, you move the pen across the 
screen.
  Light pens are cheap: prices begin at $20. But light pens are 
less reliable, less convenient, and less popular than other 
graphics-input devices.

            Touch screens
  A touch screen is a special overlay that covers the screen and 
lets you draw with your finger instead of with a light pen.

          Graphics tablets
  A graphics tablet is a computerized board that lies flat on 
your desk. To draw, you move either a pen or your finger across 
the board.
  The cheapest graphics tablet is the Koala pad. Koala makes 
versions of it for all the popular computers by IBM, Apple, 
Commodore, and Radio Shack.
  Fancier tablets for the IBM PC are made by Wacom.
                                                       Mice
                                         A mouse is a 
computerized box that's about as big as a pack of cigarettes. To 
draw, you slide the mouse across your desk, as if it were a fat 
pen.
                                         When you slide the 
typical mouse, a ball in its belly rolls on the table. The 
computer senses how many times the ball rotated and in what 
direction.
                                         The mouse was invented 
at Xerox's Palo Alto Research Center (PARC). The first company to 
provide mice to the general public was Apple, which provided a 
free mouse with every Lisa and Mac computer. Now every Mac, 
Commodore Amiga, and Atari ST computer comes with a free mouse 
___ and so do many IBM computers and clones.
                                         Microsoft Mouse The 
nicest mouse for the IBM PC is the Microsoft Mouse.
                                         Its first version was 
boring. Then came an improved version, nicknamed ``The Dove Bar'' 
because it was shaped like a bar of Dove soap. It felt great in 
your hand; but trying to draw a picture by using that mouse ___ 
or any mouse ___ was as clumsy as drawing with a bar of soap.
                                         The newest version of 
the Microsoft Mouse is nicknamed ``The Dog's Paw'' because it's 
shaped like a dog's lower leg: it's long with an asymmetrical 
bump (paw) at the end. It feels even better than The Dove Bar, 
unless your hand is too small to wrap around it. Discount dealers 
sell it for $59.
                                         Cheaper mice If you're 
nearly broke, buy a cheaper brand of mouse. Prices start at just 
$10.

                                                    Trackballs
                                         A trackball is a box 
that has a ball sticking out the top of it. To draw, just put 
your fingers on the ball and rotate it.
                                         Most notebook computers 
have a trackball built into the keyboard.
                                         Technologically, a 
trackball is the same as a typical mouse: each is a box 
containing a ball. For a trackball, the ball sticks up from the 
box and you finger it directly; for a mouse, the ball hides 
underneath and gets rotated when you move the box.
                                         The mouse feels more 
natural (somewhat like gripping a pen) but requires lots of desk 
space (so you can move the box).
                                         The trackball was 
invented first. The mouse came later.

                                                     Joysticks
                                         A joystick is a box with 
a stick coming out of its top. To draw, you move the stick in any 
direction (left, right, forward, back, or diagonally) as if you 
were the pilot of a small airplane.
                                         The most popular 
joysticks are made by Atari and Kraft.
                                         Atari joysticks work 
just on Atari and Commodore computers. Kraft joysticks are nicer, 
more expensive, and work on all popular computers by IBM, Apple, 
Commodore, and Radio Shack.

        SPEAKERS
  To produce sounds, the typical computer uses a speaker (similar 
to the speakers in your stereo system, but smaller).
  The speaker is typically inside the system unit. Some computers 
use the speaker in your TV or monitor instead. By using the 
speaker, the computer beeps at you whenever you make an error.
  Aesthetic computers, such as the Mac, can make the speaker play 
nice music. The IBM PC is a boring business computer that 
produces just harsh beeps, unless you make the IBM PC sound as 
good as a Mac by inserting a sound card (such as the Sound 
Blaster).
  The fanciest computers can speak words, by attaching the 
speaker to a speech synthesizer.
  The newest Mac computers come with a microphone. (You can also 
add a microphone to other computers.) By using the microphone, 
you can make the computer record sounds. For example, you can 
make the computer record the sound of your voice and imitate it, 
so the computer sounds just like you!

                     MODEMS
                             You can connect your computer to a 
telephone line so your computer can chat with other computers 
around the world! Here's how. . . . 
                             To let your computer chat with a 
computer that's far away, attach each computer to telephone lines 
by using a ``special device'' that turns computer signals into 
telephone signals, and turns telephone signals back into computer 
signals.
                             Turning a computer signal into a 
telephone signal is called modulating the signal. Turning a 
telephone signal back into a computer signal is called 
demodulating the signal. Since the ``special device'' can 
modulate and also demodulate signals, the device is called a 
modulator/demodulator (or modem, which is pronounced ``mode 
em'').

                                    Acoustic versus direct-connect
                             You can buy two kinds of modems.
                             The old-fashioned kind is a black 
box that has big ears on top, so that it can listen to the 
telephone. Because of its big ears, it's called a Mickey Mouse 
modem or an acoustic coupler. It usually costs $120.
                             The newer kind of modem plugs 
directly into the phone system, as if it were an answering 
machine. It doesn't have any ears: it has telephone wires 
instead. It's called a direct-connect modem. It usually costs 
under $100, and it's cheaper and more reliable than a Mickey 
Mouse modem. It's more popular than a Mickey Mouse modem because 
it's better than a Mickey Mouse modem in every way, except that 
you can't attach it to pay phones or to phones in hotel rooms.

                                    Kinds of direct-connect modems
                             A direct-connect modem can be either 
external or internal. If it's external, it's a box that sits next 
to your computer. If it's internal, it's a printed-circuit card 
that hides inside your computer. Regardless of whether it's 
external or internal, a wire runs from it to the phone system.
                             Internal modems are more popular 
than external ones, because external modems typically cost more 
and require that you buy a cable to run from the modem to the 
computer. But external modems have the advantage of being easier 
to control, since they give you push-buttons and blinking lights.
                             Many notebook computers include 
internal modems at no extra charge. So do some desktop computers.
                             Most direct-connect modems have 
fancy features, such as auto-dial (which means the modem can 
memorize the other computer's phone number and dial it for you) 
and auto-answer (which means the modem automatically answers the 
phone whenever the other computer calls). A direct-connect modem 
having many such fancy features is called smart. Nearly all 
modems sold today are smart.

                                         10 bits per character
                             To transmit a character, the modem 
usually transmits a 10-bit number, like this: 1001011101.
                             The first bit (which is always a 1) 
is called the start bit; it means ``hey, wake up, and get ready 
to receive the data I'm going to send you''. The last bit (which 
is always a 1) is called the stop bit; it means ``hey, I'm done, 
you can go back to sleep until I send you more data''. The eight 
middle bits (such as 00101110) are usually called the data bits: 
they're a code that represents 1 byte of information (1 
character). So to transmit 1 character, the modem transmits 10 
bits.

                                                 Speed
                             The typical modem transmits 2400 
bits per second (2400 bps). That speed is also called 2400 baud. 
Since 10 bits make a character, that kind of modem transmits 240 
characters per second. That speed is quite fast: it's about as 
fast as the average person can read.
                             Faster modems can transmit 9600 bits 
per second (which is 9600 bps, 9600 baud, 960 characters per 
second). That's faster than you can read, but it's great for 
transmitting documents that you want to skim, programs that you 
want to run, and graphics.
  Even faster modems can transmit 14400 bits per second. Since 
1000 bits is called a kilobit, 14400 bits per second is called 
14.4 kilobits per second (or 14.4 kbps or 14.4 kilobaud).
  Some computerists still use old modems transmitting just 1200 
bits per second (1200 baud) or 300 bits per second.
  If you buy a fast modem, you can tell it to go slower. For 
example, if you buy a 9600-baud modem, you can tell it to go at 
five popular speeds: fast (9600 baud), medium (2400 baud), slow 
(1200 baud), and super-slow (300 baud).
  To communicate with a friend's computer, your modem must go at 
the same speed as your friend's. For example, if you buy a 9600 
baud modem but your friend has just a 300-baud modem, your 
modem's software will detect the slowness of your friend's modem 
and automatically downshift (slow down) to 300 baud.

              Standards
  Standards for modem communication have been invented by AT&T 
and a French-speaking international committee called the Comit 
Consultatif International Tlgraphique et Tlphonique (CCITT). 
Here's what they call their standards:
  SpeedCCITT standardAT&T standard
  300 bpsV.21     Bell 103

 1200 bpsV.22     Bell 212a
 2400 bpsV.22bis

 9600 bpsV.32
14400 bpsV.32bis
19200 bpsV.32terbo

28800 bpsV.34 (or V.fast)
  For example, if you see an ad for a V.22-compatible modem or a 
Bell 212a modem, the ad is trying to sell you a 1200 bps modem.
  Notice that the second version of V.22 is called V.22bis, 
because bis is a French word that means ``2nd version''. Notice 
that the third version of V.32 is called V.32terbo, because terbo 
is an international word that combines the French ``ter'' (which 
means 3) with the English word ``turbo'' (which means ``fast'').
  Find all those terms confusing? That's why computerists say 
that ``CCITT'' really stands for ``Committee for Confusing 
International Telecommunications Terms''.

          Data compression
  Modems sometimes use a shorthand notation that lets data to be 
expressed in fewer bits than normal, so more data can be 
transmitted per second. The shorthand notation is called a 
data-compression technique.
  The most popular data-compression techniques are Microcom's MNP 
level 5 (which compresses data to half as many bits as normal), 
Microcom's MNP level 7 (which compresses data to a third as many 
bits as normal), and CCITT's V.42bis (which compresses data to a 
fourth as many bits as normal). For example, if you see an ad for 
a 2400-baud modem with MNP level 5, that modem will transmit 
about as much data per second as a plain 4800-baud modem.

                 Fax
  You can send messages from your computer to fax machines around 
the world, if you buy a fax/modem, which is a modem that can also 
send faxes. If the fax/modem is
fancy, it can also receive faxes and print them on your printer.
                                         The typical fax/modem 
transmits modem information (to other computers) at 2400 baud. It 
transmits faxes (to fax machines) at 9600 baud. It's called a 
2400/9600-baud fax/modem. (Most ads list the modem speed first, 
then the fax speed, because the modem speed is more important.) 
More briefly, it's called a 2496 fax/modem. Warning: though every 
2496 fax/modem can send faxes at 9600 baud, the cheapest 2496 
fax/modems receive faxes at just 4800 baud ___ or can't receive 
faxes at all!
                                         Faster fax/modems can 
transmit 14400 baud (14.4 kilobaud) for faxes and modem data.

                                                      Brands
                                         The most famous modems 
are made by Hayes, which charges high prices. Other companies 
make cheaper modems that imitate Hayes' and are called 
Hayes-compatible. Nearly all modems sold today are 
Hayes-compatible.
                                         For example, 
high-quality Hayes-compatible modems have been built by Everex 
and Practical Peripherals. To avoid competition from those 
companies, Hayes sued Everex and bought Practical Peripherals. So 
Everex had to pay Hayes a royalty (and eventually stopped selling 
modems), and Practical Peripherals become owned by Hayes.
                                         To pay less for a 
Hayes-compatible modem, get the ones made by Zoom.
                                         You can get another 
brand, Infotel, at even lower prices. For example, you can get a 
14400-baud Infotel fax/modem for just $85 internal, $99 external, 
from a discount dealers such as Midwest Micro (in Ohio at 
800-972-8822).
                                         If even $85 is beyond 
your budget, spend just $40, which gets you an internal fax/modem 
handling modem data at 2400 baud, sending faxes at 9600 baud, and 
receiving faxes at 4800 baud. That's the price for the cheapest 
Best Data modem at Staples (a chain of office-supply stores); 
it's also the price for the cheapest Boca Research modem at USA 
Flex (an Illinois discount dealer at 800-944-5599 or 
708-582-6206).

                                                 COM1 versus COM2
                                         A modem is an example of 
a serial device. You might own another serial device also, such 
as a serial mouse or a serial printer.
                                         The IBM PC can handle 
two serial devices simultaneously. The first serial device is 
called communication device #1 (COM1). The second serial device 
is called COM2.
                                         If you add a modem to 
your IBM PC or clone, you must decide whether to call the modem 
COM1 or COM2.
                                         Most hardware and 
software assume the modem is COM2. To avoid headaches, make the 
modem be COM2. Here's how.
                                         If the modem is 
external, run its cable to your computer's COM2 port. (If your 
computer doesn't have a COM2 port yet, buy a serial interface 
card containing it.)
                                         If the modem is 
internal, make sure the switch or jumper on the modem is set to 
the COM2 position; and make sure no other hardware in your 
computer system is called COM2. For example, if your computer 
contains a serial interface card having a COM2 port on it, you 
must disable the serial interface card's COM2 port (by moving a 
jumper or switch on it).
                                         Avoid using COM3 or 
COM4, since the computer has trouble handling COM3 and COM4 
reliably. (COM3 often conflicts with COM1, and COM4 often 
conflicts with COM2.)

                TAPES
  Like a disk, a magnetic tape consists of magnetized rust. Just 
as you put a disk into a disk drive, you put a tape into a tape 
drive.
  Tape drives are slower than disk drives. To skip from the 
disk's beginning to the disk's end, the disk drive's arm simply 
hops from the outermost track to the innermost track. But to skip 
from the beginning of a tape to the end of a tape, you must wait 
for the tape drive to wind the entire tape.

  Cassettes for primitive computers
  The cheapest kind of tape drive is an audio cassette tape 
recorder ___ the same kind you use for listening to music, at the 
beach or in your car. You can attach that kind of tape recorder 
to an old Radio Shack computer (such as the Radio Shack TRS-80 
model 1, 3, or 4 or the Radio Shack Color Computer). Wires run 
from the tape recorder to the computer, and the computer sings a 
song into the tape recorder; the song is a code that represents 
the data.
  Unfortunately, audio cassette tape recorders aren't very 
reliable. If you're using one of those old Radio Shack computers, 
you can improve the reliability somewhat by getting Radio Shack's 
own tape recorder, which is specially designed to work well with 
computers and automatically controls the tape's volume. But since 
a tape recorder is so much slower than a disk drive, I recommend 
that you not buy Radio Shack's tape recorder, and instead keep 
saving your pennies until someday you can afford a disk drive. 
Once you've experienced the thrilling speed, convenience, and 
pleasure of a disk drive, you'll never want to use a tape 
recorder ever again!
  Commodore & Atari Old computers by Commodore and Atari (such as 
the Commodore Vic, Commodore 64, Commodore 128, and Atari 800) do 
not attach to ordinary audio cassette tape recorders; you must 
buy special cassette tape recorders sold by Commodore and Atari 
or ___ better yet ___ buy a disk drive instead, if you can afford 
it.
  Coleco The Coleco Adam computer comes with a built-in cassette 
tape recorder, at no extra charge. Coleco's tape recorder is 
high-speed and requires specially lubricated tapes, sold by 
Coleco. Since it handles just tapes that contain computer 
information and cannot play ordinary musical tapes, it's called a 
digital cassette tape drive instead of an audio cassette 
recorder. But even though Coleco's tape recorder is 
``high-speed'' and handles computer data rather well, it's still 
not nearly as fast or convenient as a disk drive.
                                               Modern microcomputers
                                         Most people who buy 
modern computers (such as the Mac, Commodore Amiga, IBM PC, and 
clones) buy disk drives and don't bother using tapes at all.
                                         If you buy a hard disk, 
how do you make a backup copy of that hard disk, and where do you 
put the backup? You could put the backup copy onto a second hard 
disk or onto a pile of about 50 floppy disks. Another possibility 
is to put the backup copy onto a special super-fast digital 
cassette tape drive that holds super-long cassette tapes that can 
contain backups.
                                         Colorado The most 
popular such tape drives are the Jumbo 120 and the Jumbo 250, 
both built by Colorado Memory Systems (which used to be an 
independent company but is now owned by Hewlett-Packard). Those 
Jumbo drives work with the IBM PC and clones.
                                         The Jumbo 120 can back 
up a 120-megabyte hard disk by taking the hard disk's data, 
compressing it into a shorthand notation, and then storing the 
compressed data on a 60-megabyte tape. Because of that scheme, 
the Jumbo 120 is called a 60/120M tape drive.
                                         The Jumbo 250 can back 
up a 250-megabyte hard disk by compressing the hard disk's data 
onto a 120-megabyte tape. It's called a 120/250M tape drive.
                                         The Jumbo 120 uses the 
same blank tape as the Jumbo 250. The Jumbo 120 formats that tape 
to hold 60 megabytes of data (from a 120-megabyte drive), whereas 
the Jumbo 250 takes the same tape but formats it differently, to 
hold 120 megabytes of data (from a 250-megabyte drive).
                                         To buy those drives 
cheaply, phone discount dealers such as USA Flex (800-USA-FLEX) 
and Insight (800-755-3874). Here's what they'll charge you:
Item                                                   Price
Jumbo 120 drive                                         $99
Jumbo 250 drive                                        $165

tape, unformatted                                       $15 each 
(if you buy 5)
tape, formatted for Jumbo 250                           $16 each 
(if you buy 5)
                                         Each Jumbo drive is 
internal: it goes inside your computer. It uses the same 
controller card that controls your floppy disk drives. If you 
want to put the drive outside the computer, put the drive in an 
external case that costs $80.
                                         Alternatives Instead of 
buying a tape drive, the typical computerist uses a pile of 
floppy disks or buys a second hard drive.

                                            Big reels for big computers
                                         Maxicomputers and 
minicomputers use big reels of tape for three purposes: to backup 
big disks, to send data by mail, and to store the archives (old 
files that are used rarely if ever).
                                         The reel's diameter is 
10 inches. If you unwind the tape, you'll find the tape is half 
an inch wide and almost half a mile long! The exact length is 
2400 feet.
                                         To use a reel of tape, 
you put the reel into a reel-to-reel tape drive, which typically 
costs about $5000 and writes 1600 bytes per inch, so that the 
entire tape holds 43 megabytes. Super-fancy drives, used only on 
the largest maxicomputers, squeeze 6250 bytes onto every inch 
(instead of 1600), so that they squeeze 171 megabytes onto a 
single reel of tape.
                                         IBM's fanciest drive not 
only writes 6250 bytes per inch but also does the writing 
amazingly quickly. It moves the tape at 200 inches per second, so 
that it transfers about 1.2 megabytes per second.

                CASES
  The motherboard and other main circuitry are enclosed in a box. 
The box and the circuitry inside it are called the system unit. 
The box itself ___ without its contents ___ is called the case.

            Interference
  The computer thinks at about the same speed (number of cycles 
per second) as radio & TV waves. If you put your computer next to 
a radio or TV, the computer's electromagnetic ``thought waves'' 
cause static on the radio or TV. To decrease that interference, 
move the computer away from the radio or TV (or change the 
position of the radio or TV's antenna).
  The Federal Communications Commission (FCC) prohibits you from 
owning any device (such as a computer) that interferes with your 
neighbors' radio and TV. The FCC requires all computers to pass 
the FCC class A non-interference test. Any computer used in a 
residential area must also pass the FCC class B non-interference 
test, which is harder to pass than the class A test.
  To help the computer pass the class A and class B tests, 
manufacturers line the insides of cases with metal that breaks up 
the electromagnetic waves.
  When you buy a computer, ask whether it's FCC class B approved. 
If it's not ___ if it's just FCC class A approved ___ you cannot 
legally use it in a residential area.

          SURGE SUPPRESSORS
                                         Instead of plugging your 
computer into the wall, you can plug it into a surge suppressor, 
which is a special extension cord that protects your computer 
against surges in electrical power.
                                         Unless you live in a 
neighborhood or building that has extremely poor electricity, 
don't bother buying a surge suppressor. The typical computer has 
some surge protection built into it already.
                                         If you're worried about 
thunderstorms sending surges to your computer, just unplug your 
computer during storms! If your air conditioner or electric 
heater consumes too much electricity and causes a brownout (so 
your computer acts unreliably), use a plain extension cord to 
plug your computer into a different outlet, so that the 
computer's not on the same circuit as the power-hungry appliance.
                                         During the summer, most 
computer errors are caused by temperatures over 95, not by power 
surges.