1 Final Exam Study Guide 4 Final Examination is scheduled on Wednesday May 9th at 4PM 4 There are 8 questions with or without sub- parts and the exam.

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Final Exam Study Guide

Final Examination is scheduled on Wednesday May 9th at 4PM

There are 8 questions with or without sub-parts and the exam carries 30 Marks

Let us look at the topics included in the exam

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Topics Included

Algorithms Operating Systems Processor Architecture Searching and Sorting a List Binary and Hex Numbers Bits , Bytes, Pixels

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Topics Included

Digital Logic and expressions Software Engineering Basic Concepts Waterfall model and spiral model Arrays, Contiguous and Linked Lists, Stacks,

Queues and Binary Search Trees Database Systems (Network and Relational) E-Commerce Concerns and Encryption Ethics in Computing

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Topics NOT in Exam

C++ Programming NOT in exam Micro Machine Language NOT in exam Networks NOT in exam 2GL,3GL, 4GL NOT in exam

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*Algorithms

An algorithm is a step by step method to solve a problem with a definite reachable termination state

Most algorithms can be developed by following the instructions below:– Read the problem statement and rewrite it in your own

words to make it simple

– Consider nouns used and identify the data items

– Consider the verbs used and identify the actions to be taken

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*Algorithms

– Write the initial algorithm in terms of WHAT is to be accomplished

– Refine each step of the initial algorithm to include the details of HOW the step would be accomplished

In the exam, expect a question that asks you to develop an algorithm for solving a given problem on computer

DO NOT WRITE A C++ PROGRAM IN YOUR ANSWER

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Architecture

The processor obtains instructions one by one from memory through a “bus” using PC

Instructions are loaded in IR(instruction register) in the control unit and operands are brought into the data path

ALU operates on the operands and result is sent to memory or held in registers

Can you identify all registers and their usage? Can you point out the steps in multiplying two numbers

that are stored in memory?

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Operating Systems

Operating systems are programs that run the computers

Distinguish between batch and interactive systems

Think about the “time-sharing” systems Think about Windows, UNIX and other

operating systems

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Searching and Sorting a List

We looked at the while statement that is needed in searching and sorting operations

while loop is recommended when it is not known how many times the loop will execute

We developed two algorithms for searching a list for the occurrence of a target value

In the first algorithm, the list was sorted so we had to stop the search if current value exceeded the target value

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Searching and Sorting a List

In the while loop continuation condition, we used logical AND

continue the search if target not found AND current entry is less than target AND the current entry is not the last entry

Incase of unsorted list, the condition “current entry is less than target” is deleted

Also look at steps involved in inserting a name into a list

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*Binary and Hex Numbers

Binary system has just two symbols 0 and 1 It represents all values in patterns of 0 and 1 Like decimal system, binary is also positional

number system It means that the position of a bit in a pattern carries

a weight Weights are powers of 2 increasing from rightmost

bit towards left, starting at 0 for integer values(Example: 1101)

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*Binary and Hex Numbers

Hex system has 16 symbols, all the way from 0 to F

It is also positional number system. For example, 1F, 1A, 2B Its digits carry weights expressed as powers

of 16 starting from 0 at the rightmost bit position in the integer values

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*Converting Binary/Decimal

Binary to decimal conversion assigns position numbers. These are written as powers of 2, then all products are added

Example: 1001 Conversion from decimal to binary involves

dividing the number repeatedly by 2 until a value less than 2 is left. Writing the remainders in each step from last value to first value will give us the binary equivalent

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Bits, Bytes and Pixels

A bit is a binary digit It can assume the value of 0 or 1 Collection of 8 bits is known as a byte A byte is the minimum unit in our computer

memory and hard disk jargon 1KB means 1024 bytes 1MB means 1024KB 1GB means 1024MB

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Bits, Byes and Pixels

Suppose that a file has 4776 characters Since each character has one bytes ASCII

code, the file occupies 4776 bytes In terms of KB, 4776/1024 means 4.66KB A CD contains 650MBand hard disk is 20GB.

How many CD’s can be copied into the hard disk?

(20*1024/650) equals 31.5

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Bits, Bytes and Pixels

An image has thousands of dots. Each dot is called a pixel. Each pixel takes up some memory space

A black and white image on 640x480 screen has 307,200 bits of information. You need 38,400 bytes to store this image ( 37.5KB)

If the image is colored, we will need 1 byte per pixel for 256-color image

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Digital Logic

Boolean logic consists of three operations AND,OR,NOT and two values 0 and 1

AND operation results in a 1 only if BOTH operands are 1

OR operation results in a 1 if ANY operand is equal to 1

NOT operation turns a 1 into 0 and a 0 into 1

Our focus is on converting real-life situations into logical expressions

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Software Engineering

We introduced the motivation for software engineering and why is it so important

We looked at waterfall model and spiral model of SE activities

Adapted from "Software Engineering A Practitioner's Approach" by Roger Pressman

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*WaterFall Model Diagram

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*The WaterFall Model

This model is a sequence of stages During analysis, the user requirements are

identified and systems specs. are prepared During design, the number of modules and their

interconnection is finalized. The data types and structure is specified

During coding, actual programming is done Testing is done to make sure there are no errors

(alpha-release and beta-release)

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Spiral Model

It was realized that the waterfall model is not optimal as it is a one-way model

If a problem is discovered in a later stage, there is no way to go back and correct the problem

Therefore, spiral model was proposed in which the SE activity occurs in a spiral thus giving a chance to correct the mistakes

Adapted from "Software Engineering A Practitioner's Approach" by Roger Pressman

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Spiral Model Diagram

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Data Structures

Arrays Contiguous lists Linked lists Stacks and Queues Binary Search Trees Expect one to two questions from these

topics, mostly specific

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Databases

We covered network database model and relational database model

In the network model, several information files are linked with physical disk addresses

In relational database model, a search is performed on a primary field in every file

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Encryption

Symmetric key encryption was covered with examples showing the use of XOR logical operation of the value with a key for both encryption and decryption

DES was introduced that uses a 56-bit key The problem of key distribution led to public-

private key algorithms where encryption and decryption is carried out with separate keys

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Ethics

Expect a short question related to ethics in computing. Maybe a specific case requesting your opinion

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How do you feel about computers?

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Pre_Exam Standing

CSIT120 Pre-Exam Standing

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40 45 50 55 60 65 70 More

Bins of Marks (50 means 45 to 49)Class Average approx 60

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