For the past
five years, the SonyPlayStation (PSX) has been the dominant video game
system. Although challenged by the incredible technical
features of the Nintendo64 and the next generation SegaDreamcast, the PlayStation is so popular that Sony
estimates one out of every four households in the United
States has one!
The PlayStation console has been the biggest
seller among video game systems.
In this edition of HowStuffWorks,
you will learn about the development of the PSX, what's inside
the box and how it all works together. You will also learn
about the controller, including the popular Dual Shock
History In 1988, Sony entered into an
agreement with Nintendo to develop a CD-ROM attachment, known
as the Super Disc, for the soon-to-be released Super
Nintendo. Due to many contractual and licensing problems,
the Super Disc was never released. Instead, a modified version
was introduced by Sony in 1991, in a system called the Play
A look at the back of the
The original Play Station read these Super Discs,
special interactive CDs based on technology developed by Sony
and Phillips called CD-ROM/XA. This extension of the
CD-ROM format allowed audio, video and computer data to be
accessed simultaneously by the processor.
The Play Station also read audio CDs, and had a
cartridge port for accepting Super Nintendo game cartridges.
The Play Station was envisioned as the core of a home
multimedia center. Sony only manufactured about 200 of them
before deciding to retool the design.
The new design, dubbed the PlayStation X, or PSX,
dropped the Super Nintendo cartridge port and focused solely
on CD-ROM-based games. The component hardware inside the
console was revamped as well, to ensure an immersing and
responsive gaming experience. Launched in Japan in December of
1994, and in the United States and Europe in September of
1995, the PlayStation quickly became the most popular system
Console Let's take a look at the components
inside a PlayStation, and what their capabilities are. [Be
sure to check out How Video
Game Consoles Work first for a general introduction to
When you look inside a PlayStation, you can
see the processor and memory chips.
Transfer speed: 150 KB per second normal, 300 KB per
second double speed
Audio CD support
Memory buffer: 32K
The CPU in the PSX
is a RISC processor. RISC stands for reduced
instruction set computer, and means that the instructions
and computations performed by the processor are simpler and
fewer. Also, RISC chips are superscalar -- they can
perform multiple instructions at the same time. This
combination of capabilities, performing multiple instructions
simultaneously and completing each instruction faster because
it is simpler, allows the CPU to perform better than many
chips with a much faster clock speed.
To lower production costs, the CPU, graphics and audio
processors are combined into a single application specific
integrated circuit, or ASIC. Simply put, the ASIC
is a customized chip created to manage all of the components
that would otherwise be handled by three separate chips.
The PlayStation reads games from a CD-ROM/XA
disc with a laser.
The games come on proprietary CD-ROM/XA discs that are read
by laser, just like regular CDs. When a
game is put in the console, the following happens:
You turn the power on.
The disc spins up to speed.
While the disc is spinning up, the console loads
portions of the operating system from ROM into RAM.
The game initialization sequence is loaded into RAM.
You interact with the game via the controller.
As each specific part of the game is requested, the
application code and hardware-render geometry are loaded
into RAM, while the video and audio portions are usually
streamed directly from the CD.
The CPU coordinates everything. It receives the input
from the controller, pulls the data from RAM and directs the
graphics and audio processing.
You are finally beaten by the game and turn it off.
Since all information is flushed from RAM when the power is
turned off, you will lose any personal game data. But you can
save it by using one of the special Flash
memory cards. The card is inserted into one of the two
slots on the front of the PSX, above the port for the
PlayStation loses all game data when you turn
the power off, but you can use a Flash memory card to
The Sony PlayStation console
The controller is the primary user interface for the
PlayStation. And just as the gamepad that came with the
original Nintendo Entertainment System was a radical departure
from previous controllers, the PSX controller changed the
rules again. With its winged shape and abundance of
well-positioned buttons, it is user-friendly and yet powerful.
The innovative PlayStation controller
attracted attention with its winged shape and its
The standard PSX controller has 14 buttons! They include:
four buttons arranged as a directional pad on the top
Start and Select buttons in the top middle
four action buttons on the top right
two action buttons on the front left
two action buttons on the front right
each button can be configured to perform a specific and
distinctive action, they all work on the same principle. In
essence, each button is a switch that completes a circuit when
it is pressed. A small metal disk beneath the button is pushed
into contact with two strips of conductive material on the
circuit board inside the controller. While the metal disk is
in contact, it conducts electricity between the two strips.
The controller senses that the circuit is closed and sends
that data to the PSX. The CPU compares that data with the
instructions in the game software for that button, and
triggers the appropriate response. There is also a metal disk
under each arm of the directional pad. If you're playing a
game in which pushing down on the directional pad causes the
character to crouch, a similar string of connections is made
from the time you push down on the pad to when the character
Newer Dual Shock PSX controllers have analog
joysticks on them, as well as the standard buttons. These
joysticks work in a completely different way from the buttons
described above. Two potentiometers (variable
resistors) are positioned at right angles to each other below
the joystick. Current flows constantly through each one, but
the amount of current is determined by the amount of
resistance. Resistance is increased or decreased based on the
position of the joystick. By monitoring the output of each
potentiometer, the PSX can determine the exact angle at which
the joystick is being held, and trigger the appropriate
response based on that angle. In games that support them,
analog features like these allow for amazing control over
Another feature of the Dual Shock controller, actually the
reason for its name, is force feedback. This feature
provides a tactile stimulation to certain actions in a game.
For example, in a racing game, you might feel a jarring
vibration as your car
slams into the wall.
The Dual Shock controller uses force feedback
to simulate the action in the game.
Force feedback is actually accomplished through the use of
a very common device, a simple electric motor. In
the Dual Shock controller, two motors are used, one housed in
each handgrip. The shaft of each motor holds an unbalanced
weight. When power is supplied to the motor, it spins the
weight. Because the weight is unbalanced, the motor tries to
wobble. But since the motor is securely mounted inside the
controller, the wobble translates into a shuddering vibration
of the controller itself. Now let's take a closer look at how
the controller talks to the PSX.
Here's what each pin does:
DATA - This pin carries the signal that the controller
sends to the PSX each time a button is pressed. It is an
8-bit serial transmission.
COMMAND - This pin is used by the PSX to send
information to the controller. Such information might
trigger the motors in a Dual Shock controller at the proper
moment. It also uses an 8-bit serial transmission.
POWER - This pin supplies 5 volts to the controller from
SELECT - This pin is used by the PSX to notify the
controller of incoming data.
CLOCK - This pin carries a synchronizing signal sent
from the PSX to the controller.
ACKNOWLEDGE - This pin sends a signal to the PSX from
the controller after each command that is received on Pin 2.
Games The games on the PSX are CD-ROM-based,
so they are limited to a maximum size of 650 Mb. But this is a
lot of space. In fact, most games do not use more than a
fraction of it for the actual game. What can eat up the space
are the incredible full motion video intros and intermissions
that PlayStation games are known for.
There is a noticeable delay while the game is loaded from
the CD, which you do not get in cartridge-based
games. Of course, the trade-off for faster loading is a
significantly smaller amount of storage on the cartridge.
Because they are black instead of the traditional silver,
PSX CDs are very distinctive. But don't let that fool you. The
CDs are just as susceptible to scratches and intense heat as
normal audio CDs -- even more so in fact, since a scratch on a
game CD can make it totally unusable.
The games available for the PlayStation cover all of the
categories. It has, by far, the largest game library of any of
the consoles on the market today. Game prices range from under
$10, for certain preplayed titles, to over $50 for some of the
hottest new games.