A Case Study of LINUX and UNIX

What is LINUX?

It is an operating system at the top.  It acts as an interface between the user and the machine to perform specific task.  The user performs some task in terms of input and this OS redirects the instruction to the machine in machine language.  After performing the specific task it sends the computed task back to the user as an output.  Well, all the operating system performs this task. Now, we shall study more about the LINUX operating system.  LINUX means “GNU/LINUX” because LINUX is almost always used with the GNU tools.

LINUX is very similar to other operating systems like windows and OS X.  There are certain measures that categories this operating system among others.  It is widely used operating system apart from Windows.  This operating system is run over various platforms from Pc’s to cellular phones.  Even supercomputers runs on LINUX. 

The important thing under consideration of the LINUX is that it is open source operating system.  Open source simply means that its source code is available to all the users and it can be modified.  No one individually owns LINUX.  The competition to impart much to this software adds much to this operating system.  About 1,000 developers across 100 different companies contribute to different kernels of this software.  Initially it was made for server as an operating system.  But this feature of open source has made LINUX to be used in any of the device in modern time.  It do not include executable (.exe) files hence it is all free from viruses and hacking free software.  This is the only reason that it is used in all of the major companies where security of database is highly important.

What is UNIX?

The UNIX dates back to 1969.  Since then, it has changed a lot and various versions are out till today.  It has built its versions for many platforms and different environments.  It is the previous version of LINUX.  The full form of UNIX is UNiplexed Information Computing System (UNICS), which was later termed as UNIX.  This name has been given because the UNIX was first developed in 1970s; it required the data and addresses buses to be uniplexed.  They were not multiplexed, hence it was named so. 

What are the differences between LINUX and UNIX?

1. The developers of UNIX have a specific target audience and platform for their operating system.  They have a clear idea what applications they have to optimize to give users the best results.  Commercial UNIX vendors can do anything since they can maintain consistency between different versions of UNIX.

Whereas the development of GNU/LINUX, is more diverse as compared to UNIX.  Here the developers come from different backgrounds and thus have different opinions and thinking.  There are no specific tools and restrictions with the LINUX.  The tools can be used on new editions without much testing.

2. Since the kernel is the most important part of any operating system.  The source code is not freely available for any of the commercial version of UNIX.  Whereas in the case of LINUX; it is freely available.  Both the terms have a different compiling and patching kernels and drivers.  With Linux and other open source operating systems, a patch can be released in source code form and end users can install it, or even verify and modify it if desired. These patches tend to be far less tested than patches from UNIX vendors. Since there is not a complete list of applications and environments that need to be tested on Linux, the Linux developers have to depend on the many eyes of end users and other developers to catch errors.

Henceforth we can say that both these operating systems works fine in their fields and due to the lack of (.exe) executable files it becomes virus less platform to work with.  The security issues are less in terms of hacking the database.   It’s open source code makes much difference for the development of the operating system in future and empowering it much times than before. 

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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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