View
215
Download
1
Tags:
Embed Size (px)
Citation preview
1
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
2
Topics Included
Algorithms Operating Systems Processor Architecture Searching and Sorting a List Binary and Hex Numbers Bits , Bytes, Pixels
3
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
4
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
5
*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
6
*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
7
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?
8
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
9
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
10
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
11
*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)
12
*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
13
*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
14
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
15
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
16
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
17
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
18
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
19
*WaterFall Model Diagram
20
*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)
21
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
22
Spiral Model Diagram
23
Data Structures
Arrays Contiguous lists Linked lists Stacks and Queues Binary Search Trees Expect one to two questions from these
topics, mostly specific
24
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
25
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
26
Ethics
Expect a short question related to ethics in computing. Maybe a specific case requesting your opinion
27
How do you feel about computers?
THE
END
yep
no
28
Pre_Exam Standing
CSIT120 Pre-Exam Standing
0
2
4
6
8
10
40 45 50 55 60 65 70 More
Bins of Marks (50 means 45 to 49)Class Average approx 60
Nu
mb
er
of
Stu
de
nts