Download Chapter Two - Computer Basics

Police Technology
Chapter Two
Computer Basics
Copyright 2005 - 2009: Hi Tech Criminal
Justice, Raymond E. Foster
Learning Objectives



Understand the basic hardware and
software components of a Desk Top
Personal Computer (PC).
The difference between Operating
Systems and Applications software.
The difference between and Flat File and
Relational Database
Copyright 2005 - 2009: Hi Tech Criminal
Justice, Raymond E. Foster
Binary Number System
A mathematical counting scheme
that has only two digits – zero
(0) and one (1) which are
combined to represent our tendigit counting scheme.
Today’s computers use this
off/on scheme to represent
the binary digits, commonly
referred to as bits, 1 and 0.
Copyright 2005 - 2009: Hi Tech Criminal
Justice, Raymond E. Foster
Binary Number System
It is simple for computers to translate binary
digits into a sixteen digit-based code called
hexadecimal. This coding system is a
compromise between our abilities and the
computer that allows us to interface.
Copyright 2005 - 2009: Hi Tech Criminal
Justice, Raymond E. Foster
ASCII
The standard computer code configuration
that works with computer bits is called the
American Standard Code for Information
Interchange (ASCII).
Binary digits
Byte
A byte is eight bits,
or a series of eight ones
and zeros.
ASCII
Words you can read!
Copyright 2005 - 2009: Hi Tech Criminal
Justice, Raymond E. Foster
Interface Means to Interact

User interface is
how we interact
with the computer,
e.g. the keyboard
and mouse are
user interface
inputs and the
monitor is the
computer’s user
interface output
Copyright 2005 - 2009: Hi Tech Criminal
Justice, Raymond E. Foster
Your Computer as a System
A computer system can considered as
three broad categories of components:
 Hardware
 Software
 Firmware
Copyright 2005 - 2009: Hi Tech Criminal
Justice, Raymond E. Foster
Your Computer as a System
The user is a human being.
The input devices are the
computer keyboard, mouse,
and microphone.
The output devices are the
monitor, speakers, printer,
and various storage media.
Copyright 2005 - 2009: Hi Tech Criminal
Justice, Raymond E. Foster
Hardware
Input/output devices are
referred to as peripheral
devices. Think of a
peripheral device as any
device not inside the
computer case.
They communicate with the
main part of the computer
using ports.
Copyright 2005 - 2009: Hi Tech Criminal
Justice, Raymond E. Foster
Hardware
In addition to receiving information directly from
human users via input devices, computers can
receive information from other computers. This
is done via a network, e.g. the Internet.
Network information can come to the computers
through:

Hard lines (standard telephone line)

Wireless (via radio signals)
Copyright 2005 - 2009: Hi Tech Criminal
Justice, Raymond E. Foster
Hardware
Computers have the
ability to store
information:

Floppy Disks

Compact Discs
(CDs)

Digital Video Discs
(DVDs)
Copyright 2005 - 2009: Hi Tech Criminal
Justice, Raymond E. Foster
Inside your Computer
The systems board,
or motherboard, is
the brain of the
computer. The
motherboard
contains a series of
micro chips that are
connected together
by circuitry.
Copyright 2005 - 2009: Hi Tech Criminal
Justice, Raymond E. Foster
Inside your Computer
Circuits, like wires or cables, transmit
electrical signals containing binary
data between the various microchips.
The microchips in the computer can
detect the presence or absence of
electronic impulses.
Copyright 2005 - 2009: Hi Tech Criminal
Justice, Raymond E. Foster
Inside The Computer
The Motherboard contains three types
of memory chips:
 The Central Processing Unit (CPU)
 The Read-only Memory (ROM)
 The Random Access Memory (RAM)
Copyright 2005 - 2009: Hi Tech Criminal
Justice, Raymond E. Foster
Inside your Computer
The CPU has three core sets of
instructions that it carries out:



Mathematical computations (addition,
subtraction, division);
Moving data or information from one
memory location to another; and,
Making decisions and moving to a
different set of instructions based upon
those decisions.
Copyright 2005 - 2009: Hi Tech Criminal
Justice, Raymond E. Foster
Inside your Computer
Random Access Memory (RAM)
chips contain information only
when your computer is on. When
you turn off the computer, the
memory in the RAM disappears.
Also known as
Volatile storage!
Copyright 2005 - 2009: Hi Tech Criminal
Justice, Raymond E. Foster
Inside your Computer



Read Only Memory (ROM) Contains the basic
set of instructions that are required to start the
computer.
Memory was installed during the
manufacturing process.
ROM (BIOS instructions) is a permanent part
of the chip.
Also known as
Non- Volatile storage!
Copyright 2005 - 2009: Hi Tech Criminal
Justice, Raymond E. Foster
Inside your Computer

The Motherboard contains…..




A Complementary Metal Oxide Semiconductor (CMOS) configuration chip.
A system clock.
Expansions slots.
RAM memory.
Copyright 2005 - 2009: Hi Tech Criminal
Justice, Raymond E. Foster
Inside your Computer

The CMOS Chip:



Responsible for remembering what
hardware is in your computer.
Necessary for your computer to initially
organize itself. If you added a new drive,
card, or peripheral device, your CMOS
information would change.
Volatile (information can be lost) so it has its
own battery with constant power
Copyright 2005 - 2009: Hi Tech Criminal
Justice, Raymond E. Foster
Inside your Computer

Random Access Memory (RAM) ………….



Contains information your computer is
working with now (What is on the screen).
Has to be limited in the amount of
information it can contain.
Once you are finished using the RAM and
move on to another project, what was in
RAM is dumped.
Copyright 2005 - 2009: Hi Tech Criminal
Justice, Raymond E. Foster
Inside your Computer
Cache Memory contains memory
your computer anticipates you
might need, similar to the human
brain. It makes assumptions about
what information you might need
based on certain programming.
Copyright 2005 - 2009: Hi Tech Criminal
Justice, Raymond E. Foster
Inside your Computer



A BUS Contains the
electrical pathways and
directions for use of those
pathways that the
information uses while
inside a computer.
The small metal tracings in
the circuit board take the
place of wires to conduct
electricity.
The bus is these traces and
the instructions for their
use.
Copyright 2005 - 2009: Hi Tech Criminal
Justice, Raymond E. Foster
Inside your Computer
CMOS Chips Continually hold the
information on the configuration of your
computer. When you turn on the computer,
the startup process is called a booting.
When a computer is booted from the poweroff condition, it is called a “hard boot.” If
you push the reset button, you are
performing a “soft boot.”
Copyright 2005 - 2009: Hi Tech Criminal
Justice, Raymond E. Foster
Inside your Computer
The Random Access Memory (ROM) contains a
set of permanent instructions known as the
basic input/output system (BIOS). Sometimes
referred to as the ROM BIOS or Flash BIOS.
ROM chips are a hybrid of both hardware and
software. It is a physical component with
embedded software. ROM chips are
sometimes referred to as firmware.
Copyright 2005 - 2009: Hi Tech Criminal
Justice, Raymond E. Foster
Inside Your Computer
Information on the Motherboard, except
the ROM chip, is volatile.
Long term or secondary
storage are non-volatile:

Hard disks;

Zip disks;

Floppy disks; Cassette
tapes;

CD-ROMs; and,

DVDs.
Copyright 2005 - 2009: Hi Tech Criminal
Justice, Raymond E. Foster
Software


Instructions that tell
hardware what to
do; or,
A set of instructions
written in a
language that the
computer can
understand.
Two broad classifications
of software:


Operating Systems (also
called platform)
Applications
Copyright 2005 - 2009: Hi Tech Criminal
Justice, Raymond E. Foster
Operating Systems


Tells the computer
what to do.
The computer
software that controls
and coordinates the
interaction among the
hardware elements
and between the
hardware and the
application programs.
Copyright 2005 - 2009: Hi Tech Criminal
Justice, Raymond E. Foster
The operating
system is the
computer’s
traffic cop.
Operating Systems
After your computer has booted and CMOS
hands your computer over to the operating
system the operating system has two
primary functions:

Managing the hardware and software.

It provides application program interface
(API).
Copyright 2005 - 2009: Hi Tech Criminal
Justice, Raymond E. Foster
Disc Operating System
DOS is probably the most common operating system.
Users interface with a DOS in one of three ways:

A command driven interface;

A menu-driven interface; or,

An icon-driven interface.
Most police employees work with an icon-driven
interface that is also called a graphical user
interface (GUI).
Copyright 2005 - 2009: Hi Tech Criminal
Justice, Raymond E. Foster
Applications
Applications
software allows the
user to work with
information in the
computer.
Applications are
specific programs
that allow the user
to do specific tasks
such as word
processing.
Copyright 2005 - 2009: Hi Tech Criminal
Justice, Raymond E. Foster
Databases
A collection of organized information
that is centrally located and designed
to meet the needs of users. There are
two classifications of databases:
 Flat file
 Relational Database
Copyright 2005 - 2009: Hi Tech Criminal
Justice, Raymond E. Foster
Forced Choice Formats
Many state and local police
agencies use software that allows
them to configure data entries to
match their specific data
dictionary.
Screen capture provided by Crimestar Corporation
Through the use of forced-choice
formats, GUI software restricts
data entries to previously
determined attributes, properties
or characteristics.
Copyright 2005 - 2009: Hi Tech Criminal
Justice, Raymond E. Foster
Useful Terms

Multi-media is the different forms of media being
used by any particular application.



Multimedia applications can include graphics, animation, sound, and
video elements
A scalable system can be adapted and expanded
to meet increased needs.
Most legacy systems are proprietary.


The system manufacturer (either hardware, software,
or both) will not reveal the systems specifications so
that other firms may not duplicate the product.
Also known as a closed architecture.
Copyright 2005 - 2009: Hi Tech Criminal
Justice, Raymond E. Foster
Police Technology
Discuss criminal justice issues
www.criminaljustice-online.com
Copyright 2005 - 2009: Hi Tech Criminal
Justice, Raymond E. Foster