This is more
than a child's question.
The answer is fundamental towards
developing a relationship with the machine.
Philosophically, a
computer has two facets-
An Idiot Genius, and a Tool for the Mind.
Idiot Genius
As an idiot genius, the computer can absolutely and devastatingly
apply itself to any task that you can define in its terms. Work
that can be composed so the computer can apply its unique talent
is often completed with blinding speed. This makes the computer
a fearful device to workers who depend on repetitive, low-skill,
clerical tasks for their livelihood, and to skilled workers whose
abilities rely either on expensive custom equipment that can
be duplicated by the machine (such as typesetting), or rote memorization
of large amounts of specialized information (such as 'information
desk' workers, lawyers, accountants, and the like.) In one box,
the computer can grant the skilled user the talents and virtues
of a thousand careers; give them the benefits of a hundred years
of experience; and also plays Solitaire and Doom. This potential,
however, implies the ability to use it. This is the great challenge
declared by the machine, and programmers around the world strive
to meet it with a constant stream of innovative software- Long
lists of instructions on how the hardware can complete established
tasks.
Tool
for the Mind
The second facet of a computer complements the first- It is a
tool for the mind. All of recorded history is filled with tools
for hands, tools for societies, tools for culture- But there
have been very few tools for the mind as clever as a computer.
Corporations, Governments, Universities, and libraries have all
been designed as systems to augment the power of one human mind.
Until now, these were great clumsy tools; the computer is the
first real chance for the "Common" person to wield
such a lever for the intellect. Again, we are early in the evolution
of the computer in this role. It remains awkward for the user
to turn their will into work, their thoughts into threads. But
the tool does exist, and you can use it.
The
Parts List
The machine that we know as a "computer" consists of
a number of component parts, referred to collectively as 'hardware'.
There is a Monitor (or "display") where the computer
shows data to the user. A board covered with keys (keyboard)
or a sort of upside-down trackball (mouse) is how the user communicates
back to the machine. A printer will produce printed pages (hard
copy), and a scanner reads in information as graphics (pictures)
or text (Optical Character Recognition, or OCR) from the outside
world. Hard disks and floppy drives provide for data storage,
where the computer keeps chunks of computer code stored as patterns
of magnetism on strips of iron oxide. Tapes store huge amounts
of information on little tape cartridges. CD's hold information
as pits in a mirrored surface, and a CD-R drive can create CD's.
But all these are mere "peripherals", or outside devices.
These devices must connect to the computer itself, the part we
rarely see- the Central Processing Unit, or CPU.
The CPU is the place where the actual "work" of the
computer takes place. Although the large central processing chip
normally takes top billing (Intel Pentium III, Celeron, AMD K-6,
etc.), the CPU is more than a single chip. It is the processing
center without which the peripherals would never function. It
features a motherboard, with many different chips for many different
functions. There are BIOS chips, which hold low-level operating
instructions for the hardware so the computer can boot, or start
itself up. Clocks keeps time, both for the user and for the relationships
between each chip and chip array. Memory stores information being
fed to the central CPU. Specialized chips handle specialized
tasks, such as supporting Universal Serial Bus (USB), floppy
drive, and hard disk connections. There are typically expansion
slots, for a variety of cards to add new (peripheral) functions
to the CPU.
A
Collection of Chips
The computer in its bare
form is a collection of chips, controlled by highly accurate
and fast clocks, that form a huge group of switches. Similar
to a telephone exchange with big banks of relay switches managing
the flow of calls, a computer is basically a complex mass of
on-off positions. This could also be compared to the switches
in a train yard. There are millions of these switches in a computer,
and they switch VERY fast. Their speed is measured in a frequency
of millions of changes per second - Megahertz, or 'Mhz'.
In order for a mass of switches to "process"
information, it must get data in some sort of organized pattern.
The earliest computers got their information in a line across
of eight switch positions. With each switch known as a "Bit",
this is known as an "8-bit" machine. Later, a line
across of sixteen, and now thirty two switch positions are fed
into the machine at once. The latest computer chips process by
rows of sixty four and even one hundred and twenty eight switches.
Binary
Numbers
These switch positions,
organizing on-off "bits", are the only method a computer
has to deal with the world. A special form of math was worked
out that can be expressed in on-off bits, known as 'Binary'.
Binary code, and binary math, is simple but beyond the scope
of this document to explain. Still, a basic understanding of
how binary works is important. Binary is a system of using on
and off switches to represent numbers.
Each switch position has a value. With two on-off switches, you
would assign the value of one to the first switch, and two to
the second switch. We can now show numbers zero to three, or
four separate numbers. With both switches down, the number zero
is expressed. With the first switch up, one is set. With only
the second switch up, two is expressed. With the first and second
switches up, Three is expressed. The four "numbers"
are Off/Off; On/Off; Off/On; and On/On. (Simple, right?) Add
more switches, and the numbers that can be shown become much
higher.
With four switches, you can express 16 numbers.
Eight switches gives you 256. Now the raw power of 16-bit (65,536
numbers), 32-bit (4,294,967,296), and 64-bit based processors
(the number is too large!) becomes evident.
You may see a link between the above explanation
and the "bit depth" of computer monitors. This is because
a computer monitor, with its mass of on-off "pixels",
is a visual analog to the interior workings of a computer.
Good
Software
The ability to move and
manage massive amounts of data, by throwing millions of switches,
is the sort of stunning power that quality software must harness
with novel-length sets of instructions. Without good software,
the best hardware in the world might serve as an excellent flower
pot. It is in the integration of hardware with a rich software
environment that the computer demonstrates its true value.
Bit
Tricks
How does the computer
'compute' with these bits? A computer does the most fundamental
binary math procedure- it ADDS them. You can calculate a subtraction
by doing a clever form of addition. To multiply, the computer
does- Addition! VERY fast! One thousand times a thousand? It
adds one thousand to one thousand- one thousand times! A logical
device known as an "ADDer" is the fundamental building
block of the computer's processing functions. (Of course, with
special math processors, mathematics on computers is now more
sophisticated than this basic model.)
Do
You Remember?
Memory in a computer
is vital. This is where the results from the CPU's work are stored
to be assembled into larger results, and where lists of instructions
(the program) for the CPU to follow are stored for quick access.
RAM Memory (Random Access Memory) is a giant grid of on-off spaces,
that are either filled or turned off by instructions from the
processor. This gigantic grid can be expanded by the addition
of more memory chips to increase performance. RAM Memory is a
very fast way for the processor to retrieve or save data, as
it reacts almost as quickly as the processor itself. Hard disk
memory storage, intended for long-term use, is thousands of times
slower than RAM memory.
Computer Memory is expressed in BYTES; a thousand
bytes is a Kilobyte (or 'K') and a million bytes is a Megabyte.
(Called a 'Meg', or 'Mb'.) Dating from the early days of computing,
a BYTE is eight BITS. The byte is the user's fundamental measurement
of file size, generally shown by 'K'.
Please be aware that communication speeds,
such as Baud Rate or the speed of your modem, are measured in
Bits- not Bytes. Does your modem now seem eight times slower
than before?
Today's
Memory- Tommorow's History
There are many types
of computer memory. This is because there is a frantic race between
the memory manufacturers, memory engineers, and computer processor
engineers. The processor engineers always seem to win, creating
faster and faster processing chips. Memory must evolve to try
to keep up. Memory engineers keep designing faster and faster
memory. Then the memory must be manufactured, often in huge quantities.
This may require the building or rebuilding of entire factories.
Once the memory has been designed, and manufactured in quantity,
a computer manufacturer may decide to use it in their new computer
system- until a faster type of memory comes along!
Memory is sold as chips attached to a type
of circuit card, and is very specific for your computer. To add
memory, you must know the exact type your machine requires. Is
it a 66Mhz 72-pin SIMM (with a notch in the middle)? Is it EDO
memory, with special Extended Data Out modules? Is it Parity
memory, with an extra chip to check that the memory is valid?
(Most memory sold today is non-parity). Is it PC-100 SRAM, PC-133
SRAM, or a DIMM module? Confused? (So are we.)
Putting
It Together
A series of bits are
placed in the computer by the keyboard or mouse, or are sent
to memory from a hard disk or floppy. These bits are organized
by clocks, flow thru the Central Processing Unit in a method
governed by software, and are ADDed to produce results. The results
are assembled and stored in memory. After flowing past more chips,
the result may be shown on the Monitor or Printer.
Therefore, a modern computer is much more than
simply a processing chip. It is the combination, first and foremost,
of both hardware and software, combined with essential peripheral
units, that makes this device supreme at performing specific
and pre-defined work tasks. Your ability to perform work on this
machine is limited only by your ability to give instruction in
what you want it to do.
Conclusion
The keyboard of the future
may hold one button- a "Do What I Want" button. For
now, we must make do with what we have. (And what we have is
pretty impressive…)
The nature of the computer as a "mass
of switches" is an important concept to remember -and use.
When you take an "action" on the computer, such as
choosing a menu item or clicking on a button, you have Thrown
A Switch. It is this 'On-Off', 'Do-Ignore' type of interaction
that is the core of the machine's function. Want to perform an
action? Find the correct switch to throw. If you look hard enough,
there is a "Do What I Want" button in there somewhere... |
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