What is System Analysis and Design- An Introduction

System Analysis and Design (SAD)

Well, it is simply to understand the problem of any non-automated system; analyzing the core problem and after that making a very accurate and precise design of the problem and implementation of design in automated task which is further carried out by computer system is simply termed as SAD.

System Analysis and Design

What is a System Approach?

This is the simple Approach implemented in any system to automate it. Firstly problem is defined (Problem Definition).  It is followed by analysis and requirement of the tools to perform the task, and then we make a design of the problem.  Now comes the implementation pat and at successful completion we have to maintain it to longer time.

What are the characteristics of a System?

1.       Organization

2.      Interaction

3.      Interdependence

4.      Integration

5.      Central Objective

What are the elements of a System?

1.       Input/output

2.      Processor

3.      Control

4.      Feedback

5.      Environment

6.      Boundaries and Interface

   

                                               

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Operating System basics- Difference between multitasking and multiprogramming

How do we classify System?

A system can be classified broadly into 5 parts which are briefly categorized by their subparts given below:-

1.       Mainframe System

2.      Desktop System

3.      Multiprocessor System

4.      Real Time Systems/Time constraint

5.      Distributed

Operating System

We can categorie them further as:-

1.      Mainframe :-

1.       Multiprogramming System (Internal)

2.       Batch System (Ordered in a similar group)

3.      Time Sharing/Multitasking (Direct interaction with user)

2.     Desktop :-

                                 Well, everybody is well aware of these systems as they are        widely used in our surroundings/home.

3.     Multiprocessor/Multiple CPU :-

1.       Increase in throughput.

2.      Economy of Scale maintenance.

3.      Reliability is maintained.

4.     Real Time System/Time Constraint:-

1.    Hard (Satellite launching) – Time is constant.

2.    Soft (Multimedia)- Time varies accordingly.

5.     Distributed:-

1.     LAN (Local Area Network)

2.     WAN (Wide Area Network)

3.     MAN (Metropolitan Area Network)

NOTE: - Distributed System can also be further categorized as:-

                              1.     Client-Server System

                              2.     Peer-to-Peer System

What is the difference between Multitasking and Multiprogramming?

Let’s take an example to understand this very typical concept.  You run VLC Media player to play a song, at the same time you want to play the video song without closing the song.  This can be done by opening another VLC window. So, the operating system is executing the operation allowing the multitasking for you by giving different services to the user simultaneously. So, this is Multitasking. This is a direct process which has a visual effect to the user, i.e. user can watch it happening and thus termed as multitasking.  

Whereas the code written for the VLC (backend) with the help of which it is able to perform the concept of multitasking is termed as multiprogramming.  These both terms are confusing but carry a great significance in terms of operating system. This is an indirect concept that runs behind the screen but helps in making the things work in collaboration at the same time.

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Computer Architecture- A brief

What is Computer Architecture?

It is a theory behind the operational design of an operating system and the practical part of selecting and interconnecting hardware component to create a computer that need functional performance and cost goal.

Computer Architecture

Computer Architecture covers 4 main sub-categories. These categories are as follows:-

1.       Instruction Set

2.      Micro-Architecture

3.      System Design

4.      History

Now, we shall define each of the above stated categories.

1.       Instruction Set:-  It is a code that a central processor reads and acts upon, it is the machine language including the instruction set, word size, memory address mode, processor, processor register and data format.

2.      Micro Architecture: - It is also known as computer organization, describe the data path, data processing element and storage element and describe how they should implement ISA.

3.      System Design:- It includes all other hardware component within a computing system, includes data path such as computer buses and switches, memory controller, data processing other than CPU such as direct memory access.

Classification of Computers:-

          1. Desktop Computer

          2. Server Computer

          3.  Embedded Computer

Measuring and summarizing performance

1.       Performance (Speed with which a program can be executed)

2.      Response Time/Execution Time (Time b/w the start & completion of an event)

3.      Benchmark (Act of receiving a computer program, to get the cong. of any system)

4.      Throughput (Total amount of work done in a given time)

Relation b/w Response time and throughput

                         Performance=1/Execution

What are the types of Benchmarks?

1.       Kernel (Heart of a computer): They are small key pieces of real architecture containing key code. One can say that these correspond to all the program section of an operating system.

2.      Component Benchmark:  This is a program designed to measure the performance of computer’s basic components, automation of computer hardware, cache size and memory loading. It also has I/O benchmark followed by database benchmark.            

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What is PostMaster? - A Case Study

What is PostMaster? 

Here’s another problem on which to practice your object-oriented analysis: You have

been hired by Defective Software to start a new software project and to hire a team of

C++ programmers to implement your program. Sam Snett, vice-president of New

Product Development, is your new boss. He wants you to design and build PostMaster,

a utility to read electronic mail from various unrelated email providers. The potential

customer is a business person who uses more than one email product (for example,

Gmail, Hotmail, and Lotus Notes).

What is PostMaster  

The customer will be able to teach PostMaster how to connect to each of the email

providers. PostMaster will get the mail and then present it in a uniform manner,

enabling the customer to organize the mail, reply, forward letters among services,

and so forth.

PostMaster Professional, to be developed as version two of PostMaster, is already

anticipated. It will add an administrative assistant mode that will enable the user to

designate another person to read some or all of the mail, to handle routine corre-

spondence, and so forth. There is also speculation in the marketing department that

an artificial-intelligence component might add the capability for PostMaster to pre-

sort and prioritize the mail based on subject and content keywords and associations.

Other enhancements have been talked about, including the capability to handle not

only mail but discussion groups, such as Internet newsgroups and mail lists. It is

obvious that Acme has great hopes for PostMaster, and you are under severe time

constraints to bring it to market, although you seem to have a nearly unlimited

budget.

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