This presentation is a part of the COP2271C college level course taught at the Florida Polytechnic University located in Lakeland Florida. The purpose of this course is to introduce Freshmen students to both the process of software development and to the Python language. The course is one semester in length and meets for 2 hours twice a week. The Instructor is Dr. Jim Anderson. A video of Dr. Anderson using these slides is available on YouTube at: https://www.youtube.com/watch?feature=player_embedded&v=ar8cV0ynWAw

1. An Introduction To Software
Development Using Python
Spring Semester, 2015
Class #1:
Understanding
Computers

2. An Example Python Job Description
• Python developer (H3 Technologies, San Diego, CA, 5 months ago)
• Job Description: Job Title : Sr. Software Engineer -Python And C++
• Location : San Diego ,CA; Duration : 6 Months+(Contract / Contract to Hire)
• Job Description:
– Python Developer
– Desired skills:
– Python and Python Packages and Libraries: NumPy, SciPy, Pickle
– Relational and Non-Relational Database Technologies: SQL, MySQL, NoSQL,
MonoDB, Cassandra
– Practical working knowledge of Linux, C++
– Ability/Experience in optimization of Python 2.x and 3.x code for computational
and I/O efficiency
– Experience using web servers such as Apache or Tomcat in conjunction with Python
– Familiar with XML

3. What Is A Computer?
Image Credit: ota_photos, Alex Lomix, yum9me, Kevin Wu
CPU
(Microprocessor)
Memory
(RAM: Random
Access Memory)
Hard Drive
(Disk Drive)
Keyboard
(Input)
Display
(Output)
A computer is an electronic device that
stores and processes data.
A computer includes both hardware and software. In general,
hardware comprises the visible, physical elements of the
computer, and software provides the invisible instructions
that control the hardware and make it perform specific tasks.

4. What Is A Bus?
• A computer’s components are
interconnected by a subsystem called a
bus.
• You can think of a bus as a sort of system
of roads running among the computer’s
components; data and power travel
along the bus from one part of the
computer to another.
• In personal computers, the bus is built
into the computer’s motherboard, which
is a circuit case that connects all of the
parts of a computer together
Image Credit: LoveToKnow, Corp

5. What Is A Central Processing Unit?
• The central processing unit (CPU) is the
computer’s brain. It retrieves instructions
from memory and executes them. The CPU
usually has two components: a control unit
and an arithmetic/logic unit.
• The control unit controls and coordinates
the actions of the other components. The
arithmetic/logic unit performs numeric
operations (addition, subtraction,
multiplication, division) and logical
operations (comparisons).
• Today’s CPUs are built on small silicon
semiconductor chips that contain millions of
tiny electric switches, called transistors, for
processing information.
Intel 4004, 1971,
Clock rate 740kHz
Intel 8086, 1978,
Clock rate 10MHz
Intel Pentium, 1993,
Clock rate 66MHz
Intel Core i7, 2011,
Clock rate 4GHz
Image Credit: Devraj Goswami

6. What Goes Into A CPU?
• Every computer has an internal clock, which
emits electronic pulses at a constant rate.
• The unit of measurement of clock speed is the
hertz (Hz), with 1 hertz equaling 1 pulse per
second.
• In the 1990s computers measured clocked
speed in megahertz (MHz), but CPU speed has
been improving continuously and the clock
speed of a computer is now usually stated in
gigahertz (GHz).
• CPUs were originally developed with only one
core. The core is the part of the processor that
performs the reading and executing of
instructions.
• In order to increase CPU processing power, chip
manufacturers are now producing CPUs that
contain multiple cores.
Insides of the PS4 processor
Multi-Core CPU

7. How Is Information Stored
In A Computer?
• Both data and programs are stored in a computer.
• A computer is really nothing more than a series of
switches. Each switch exists in two states: on or off.
Storing information in a computer is simply a matter
of setting a sequence of switches on or off. If the
switch is on, its value is 1. If the switch is off, its value
is 0.
• These 0s and 1s are interpreted as digits in the binary
number system and are called bits (binary digits).
Image Credit: sdobie
1
0

8. The Binary Numbering System
• In mathematics and digital electronics, a binary
number is a number expressed in the binary
numeral system, or base-2 numeral system,
which represents numeric values using two
different symbols: typically 0 (zero) and 1 (one).
• Because of its straightforward implementation
in digital electronic circuitry using logic gates,
the binary system is used internally by almost
all modern computers and computer-based
devices such as mobile phones.
• Each digit is referred to as a bit.

9. Binary Math Time!
• 1
• 23
• 65
• 128
• 1,003
29 28 27 26 25 24 23 22 21 20
512 256 128 64 32 16 8 4 2 1
1
1 1 1 10
1111111111
1
10 0 0 0 0
0 0 0 0 0 0 0
1
1 1 1 1 1 0 1 0 1 1
512+256+128+64+32+16+8+4+2+1= 1023

10. Bits Make Bytes
• The minimum storage unit in a computer is a byte. A byte is composed of eight
bits. A small number such as 23 can be stored as a single byte. To store a number
that cannot fit into a single byte (1,003), the computer uses several bytes.
1 Byte = 00000000, 23 = 00010111, 1,003 = 00000011 11101011
• Data of various kinds, such as numbers and characters, are encoded as a series of
bytes. As a programmer, you don’t need to worry about the encoding and
decoding of data, which the computer system performs automatically, based on
the encoding scheme.
• An encoding scheme is a set of rules that govern how a computer translates
characters, numbers, and symbols into data the computer can actually work with.
• Most schemes translate each character into a predetermined string of numbers. In
the popular ASCII encoding scheme, for example, the character A is represented as
1000001 in one byte.

11. ASCII table
“A” = 65 = 1000001

12. How Big Is That Storage?
• A computer’s storage capacity is measured in bytes and multiples of the
byte, as follows:
■ A kilobyte (KB) is about 1,000 bytes.
■ A megabyte (MB) is about 1 million bytes.
■ A gigabyte (GB) is about 1 billion bytes.
■ A terabyte (TB) is about 1 trillion bytes.
• A typical one-page word document might take 20 KB. Therefore, 1 MB can
store 50 pages of documents and 1 GB can store 50,000 pages of
documents. A typical two-hour high-resolution movie might take 8 GB, so
it would require 160 GB to store 20 movies.
Image Credit: shehan peruma

13. Thanks For The Memories
• A computer’s memory consists of an
ordered sequence of bytes for storing
programs as well as data that the program is
working with.
• A program and its data must be moved into
the computer’s memory before they can be
executed by the CPU.
• Every byte in the memory has a unique
address. The address is used to locate the
byte for storing and retrieving the data.
• Since the bytes in the memory can
be accessed in any order, the memory is also
referred to as random-access memory
(RAM).
• The current content of a memory byte is lost
whenever new information is placed in it.

14. Don’t Forget: Storage Devices
• A computer’s memory (RAM) is a volatile form of data storage: any information
that has been stored in memory (that is, saved) is lost when the system’s power is
turned off.
Note: an exception to this rule is flash memory – non-volatile memory that can be
reprogramed. This is why some computers can remember where they were even
after they were turned off
• Programs and data are permanently stored on storage devices and are moved,
when the computer actually uses them, to memory, which operates at much faster
speeds than permanent storage devices can.
– Magnetic disk drives
– Optical disc drives (CD and DVD)
– USB flash drives
Image Credit: Gabriel Li

15. Let’s Talk: Input / Output Devices
Input Output
Image Credit: angelcalzado, Sir Adavis

16. Computers Use Networks To Talk With
Each Other
Image Credit: Emerson Posadas, All-free-download.com
There are many different types of networks:
LAN, WAN, WLAN, MAN, SAN, PAN, EPN & VPN

17. What Is Software?
Software means computer instructions or data.
Anything that can be stored electronically is software,
in contrast to storage devices and display devices
which are called hardware.
10 Input “What is your name?”
20 Input name$
30 Print “Hello”,name$
40 Print “The current time is”, sys_time
50 End
00001011 01010101
11100111 10011001
11110001 10101110
10000001 01111110
10101010
10 Input “What is your name?”
20 Input name$
30 Print “Hello”,name$
40 Print “The current time is”, sys_time
50 End

18. Programming Languages That Are
Used To Create Software
Computer programs, known as software,
are instructions that tell a computer what to do
Image Credit: ubergizmo

19. Where It All Starts:
Machine Language
Image Credit: SlideShare
Value Of AX
7
8
13
AX
13

20. One Level Higher:
Assembly Language

21. What We’ll Use:
High Level Languages

22. Everything Depends On The Operating
System
The operating system (OS) is the most important program that runs on a computer.
The OS manages and controls a computer’s activities.
The major tasks of an operating system are:
• Controlling and monitoring system activities
• Allocating and assigning system resources
• Scheduling operations

23. What We Covered Today
1. Learned what a computer is.
2. Discovered how CPUs have
evolved over time.
3. Reviewed the binary numbering
system.
4. Reviewed different types of
computer storage.
5. Studied the different levels of
computer programming:
machine, assembly, and higher-
level.
Image Credit: http://www.tswdj.com/blog/2011/05/17/the-grooms-checklist/

24. What We’ll Be Covering Next Time
1. Software
2. Programming
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