Java Software Solutions
1. Computer Processing
is made up of
: Chips, keyboards, disks, wires, etc.
: Programs and the data those programs use.
Key Components of a Computer System
central processing unit (CPU)
input/output (I/O) devices
secondary memory devices
Programs and data are held in storage devices called
which fall into
Main Memory (“primary memory,” “central memory”…)
The storage device (e.g., chips on the mother board) that holds the
their data (software) while the programs are
Devices such as hard disks that store software in a relatively
We save our software on
software are brought into
Copies = data and programs
We will be concerned with two categories of software.
Provides a user interface that allows us to interact with the
machine (enter input and view output).
Manages computer resources such as the CPU and main
Provides protection, and much more.
Generic term for just about any software other than the
Word processors, spreadsheets (office tools), web browsers,
games, hosts of search engines, twitter, facebook, …etc.
Scientific applications; business / commercial applications…
focus of this course
is development of
application programs to be used in business / commercial
What This Means to Us
We will be learning to create application
programs using the Java programming
We will be using an IDE called NetBeans.
Current version of NetBeans is 6.7 but 5.0 and 5.5
should both be sufficient also.
IDE stands for
. (Know this)
There are many IDEs ‘out there.’
More: What this means to us
You will download and install the J2SE
Standard Edition and Development Kit JDK
and NetBeans 6.7 (bundled together) from
links on my web page.
See: Link to Download NetBean and Java.
See the link on my web page and instructions
to download and install NetBeans 6.7 and the
See NetBeans Tutorial and Project0 Details are
See also the tutorial on how to use NetBeans
6.7 to develop and submit Project0.
Analog versus Digital Signals
and/or signals are
varying in direct proportion to the source of the
like the amplitude of a wave may vary
with volume. It’s period may vary with frequency…
(Hz (frequency) measured in cycles per second; Period is
seconds per cycle)
breaks information into
and represents the pieces as numbers.
Music on a CD is stored digitally, as a series of numbers.
The music is sampled about 40,000 times per second and
each number represents the voltage level of one specific
instance of the recording.
An Analog Signal
versus a Digital Signal
1 0 1 0 0 1 …
A digital computer stores information as
numbers: ones and zeroes.
These numbers represent ‘state’
On/off; one/zero, etc.
All information in a computer is stored and
nary number system has only two digits,
is called a
Converting Binary Numbers
to Decimal Numbers
Starting with the
in a binary number,
each position represents a
power of 2
, with the
rightmost bit position representing
which is decimal
, the next bit position representing
the next representing
0 * 2
1 * 2
2 + 1 *
which adds up to
decimal (base 10).
CAN YOU DO THIS???? Yes, you need to know this!
bits can represent
Computers typically manipulate sequences of
sequence of 8 bits referred to as a
2. Hardware Components
We use the term
of a computer are put together.
The Central Processing Units (CPU) reads one program
instruction from main memory and executes it.
If an instruction needs data, such as the amount in a bank
account, the CPU will acquire that information from central
memory (which may require the access of data in secondary
memory to be brought into memory first).
The process repeats until the program ends.
in a computer other than
the CPU and main memory are called
are devices that coordinate the
activities of specific peripherals.
A unit with several disks attached will have a disk
controller for timing, contention, data access, …
devices like disks and other
devices (Jump drives,
etc.)are considered peripherals.
We won’t pay much attention to them.
For our purposes, the primary I/O devices will be the
Output on a monitor is achieved by breaking the screen
picture into small pieces called
The pixels are represented in the computer as numbers (as
is everything else) and each pixel has a specific ‘screen
A typical monitor can display a number of ‘
’ such as 640x480, 800x720, 1280 x 1024
These numbers represent the number of pixels used to
display the screen information.
Main Memory and Secondary
Main memory is made up of a series of consecutive
memory locations called
Associated with each memory location is a
On many computers, each memory location consists of 8
bits, or one
of a device such as main
memory is the total number of bytes it can hold.
Larger units are a megabyte (MB), a gigabyte (GB), and a
It is usually easier to think about these capacities by
rounding them off.
Characteristics of Main Memory
When data is stored in a main memory
(thus destroying) any
information that was previously stored there.
Main memory is said to be
The information stored in it will be lost if its power
is lost. (meaning of volatile in this context)
You should frequently
your work onto a
secondary memory device (such as a disk).
Secondary Memory Devices
since the read/write head moves quickly to the information needed.
In the prerequisite to this course, you have seen pictures of disks and
how they operate.
Disk is both a
direct access device
and can be accessed
just like a tape unit.
/ rewound / or fast
forwarded to get to the desired information.
A tape is thus a considered a
While tapes were the medium of choice when disks were expensive and
access was controlled to
those types of applications
disks, tapes now are almost exclusively used for
Very inexpensive and can store
Two More Terms
Random Access Memory (RAM)
interchangeable. Sometimes called
RAM should probably be called
data can be both written to it and read from it.
Only Memory (ROM)
After information is stored on ROM, it cannot be altered
(easily). Data in ROM is ‘burned’ into the chips
Can sometimes be reprogrammed (PROMs) and sometimes
we have Erasable Programmable Read Only Memories
(EPROMs) (Need special equipment)
are often embedded into the
main circuit board
to provide the preliminary instructions when the computer is
initially turned on.
Other Memory Devices
Additional memory devices include CD
R) drives, CD Rewritable (CD
RW) discs, DVD devices, jump drives, ….
(Know the differences)
The speed of a CD drive is expressed in multiples of X,
which represents a data transfer speed of 153,600
bytes per second.
Due to improvements in technology, storage
capacity approximately doubles every 18 months.
Central Processing Unit
The ‘processor’ interprets and executes your
program’s instructions one at a time
Consists of the arithmetic and logic unit, the control
unit, and the registers (usually in the ALU and Control
Registers store bits (16
bit registers; 32
bit registers, …)
dissects the instruction and directs the
to perform the calculations / comparisons using
CPU has other registers too:
Instruction register; program counter, more
The notion of a stored
stored both program
instructions and data together in main memory.
Fetch instruction from primary memory (RAM)
Decode instruction (to see what it is to be done)
Execute the instruction using registers
CPU on a chip called a microprocessor
Circuit board also contains communications sockets,
etc. for connection with video displays, etc.
Main circuit board also contains the system clock
Instructions are in synch with these pulses
Some take a single pulse; others, more.
Often called clock speed.
All activities in a computer and controlled by the clock
with something we call ‘clock cycles.’
We may say that an instruction executes in two clock cycles.
is two or more computers connected
together to exchange information.
Each computer of a network has a
One technique to improve network speed is to divide
large messages into segments, called
Packets have fixed formats and other constraints…
Then send the individual packets across the network
with pieces of other messages sent by other users.
Local Area Networks and
Wide Area Networks
Area Network (LAN)
is designed to span
and connect a relatively small
number of computers.
Within a building or small area
You may connect to the LAN here in this classroom and see
these slides/ take notes on them, etc.
Area Network (WAN)
connects two or more
LANs, often across long distances.
LANs connected by a WAN are often owned by different
companies or organizations, and might be located in
Generally, one computer takes care of communications.
is a network
Grew out of U.S Government ARPA (and ARPAnet)
In 2000, number of computers connected to Internet = 10 million.
is a set of rules that governs how two things
The software that controls the movement of messages across the
Internet must conform to a set of protocols called
Transmission Control Protocol/Internet Protocol.
IP defines how information is formatted and transferred
TCP software handles the transmission and reconstituting of
messages, error control, etc. (contention, …)
Have layers of communications and different protocols…
connected to the Internet has an
identifies it among all other computers on the
IP Address vs Internet Address
An IP address is of the form 22.214.171.124.
Fortunately, Internet allows each computer to be
often referred to as its
of an Internet Address is the
of a specific
rest of the name
is local name
Can have ‘subdomains’ within domain for departments, etc.
of domain name is the ‘top level domain name’.
Some are: .edu .com, .org, .mil …
The Domain Name System
The Internet uses
another software program
Domain Name System
) to a
Each organization connected to the Internet
that maintains a list of all
its computers and their IP addresses.
Used for mapping.
The World Wide Web
World Wide Web
(also known as WWW or the
Web) makes the exchange of information easy.
Web software provides a
many different types of information can be accessed with a
Web: based on concepts of
to support jumping as needed.
manage large amounts of information. Basically used to originally
incorporates graphics, sound, animations, and video.
Hypertext and Browsers
Web Server: computer dedicated to
providing access to Web documents.
Web documents are written in a variety of
languages now. Originally, there was just
html. Now there are many with many
Browsers load / interpret documents provided
by a Web server.
Many documents are formatted using the
HyperText Markup Language
Links to Java programs can be embedded in html
documents and executed through Web browsers.
Uniform Resource Locators
Information on the Web is found by identifying a
browser to obtain and display.
An example URL is
We sometimes now just say, web address…
of URL is the
HyperText Transfer Protocol
in this example) which determines the way the browser
of the machine on which
the document is stored.
of information is the
of the file you
wish to view.
Default third piece: index.html
Another Sample URL
In this URL, the protocol is http (HyperText Transfer Protocol).
Machine referenced is
(web server found at
Information is stored in a ‘file’ in my home directory named
Fall2009.html (programmed in html)
by itself, refers to an index.html file stored in a
directory, broggio, within some UNF web server
World Wide Web
makes it possible to communicate via computers
around the world.
Internet IS a
makes that communication a straightforward and
enjoyable activity via software.
can be used on a LAN or even a single machine that is not connected to any
Information service based on a set of software applications
connecting millions of
Hundreds of countries are linked into exchanges of
news and opinions.
, which are centrally controlled, the
Each Internet computer, called a
, is independent. Its
operators can choose which Internet services to use and which
to make available to the global Internet community.
Remarkably, this anarchy by design works exceedingly well.
There are a variety of ways to
the Internet. Most
online services offer access to some
Internet Service Providers (ISP): Comcast, AOL, etc.
World Wide Web
World Wide Web
The documents are formatted in a markup language
HyperText Markup Language
) and a host
of other languages that support links to other documents,
as well as
, audio, and video
This means you can jump from one document to another
. Not all
are part of the World Wide Web.
There are several
make it easy to
the World Wide Web; Four of the
most popular being
, and others.
World Wide Web
The rest of this course explores the process
of designing and developing programs using
oriented language. Ours is Java.
All of the software we have discussed including
the Internet and Web protocols are simply (but not
simple) programs some programmer has written.
Next section discusses the purpose of
programming in general and introduces the
Java Programming Language