Basic concepts of OPERATING SYSTEM

INTRODUCTION

          An operating system is a program that is an intermediary between a user and the computer hardware. Different levels in a computer system are shown below.

   An operating system provides an environment in which a user can execute programs. The purpose of an operating system is two fold:

·         To make the computer system convenient to use.

·         To use the computer hardware in an efficient manner.

OPERATING SYSTEM AS A RESOURCE MANAGER

   A computer system consists of hardware, the operating system, application programs and users .

          Hardware includes the central processing unit (CPU), memory and input / output (I/O) devices. These provide the basic computing resources. Application programs like compilers, database management systems, editors and many more allow users to use the hardware to solve their problems. The operating system controls and co-ordinates the use of the hardware among the various application programs of the various users. It provides an environment where software and data make use of the hardware in the computer system.

The operating system is a resource allocator. Many hardware and software resources are needed to solve a problem. These include CPU time, memory space, file storage, I/O devices and so on. The operating system as a manager of these resources, allocates resources to programs of users as required by the tasks. Since there is always a possibility of conflicts for resources because of more than one user requesting for resources, the operating system resolves the conflicts for efficient operation of the computer system.

The operating system as a control program controls the execution of user programs to avoid errors and improve use of the computer system.

A computer system has been developed to execute user programs there by making work easier for the user. But the bare hardware alone is not easy to use. Hence application programs are developed. These require certain common operations such as I/O device handling. The common functions of controlling and allocating resources are present in one piece of software – the operating system.

The primary goal of an operating system, that is convenience for the user is seen in small computers where as the secondary goal of efficient operation is important in large shared multi-user systems.

STORAGE STRUCTURE

Programs to be executed need to reside in the main memory. This is the memory that the CPU directly accesses. The main memory can be visualized as an array of bytes / words, each having its own address. Load / Store instructions allow movement of a word from the main memory to a CPU register and vice versa.

The Von-Neumann architecture brought in the concept of a stored program. The following is the sequence of steps in one instruction execute cycle:

 Instruction execute cycle

Program and data are to be in the main memory for execution. Ideally they should reside there permanently, which is not possible because main memory

·         is not all that big to hold all needed programs and data permanently.

·         is volatile (contents are lost when power is turned off).

·         cost is very high.

Secondary storage is an answer to the above listed problems. The main characteristics of secondary storage include

·         large storage space

·         Non-volatile or permanent storage

·         Low cost

Thus program and data need to be loaded from secondary storage to main memory during execution. Common secondary storage devices include disks and tapes.

STORAGE HIERARCHY

The various storage devices differ in speed, cost, size and volatility (permanence of storage). They can be organized in a hierarchy. Shown below are some different levels of hierarchy .

As one moves up the hierarchy, the devices are expensive but fast and as we move down the hierarchy, the cost per bit of storage decreases but access times increases (devices are slow). There usually exists a tradeoff in the amount of storage required at each level in the hierarchy. Of the various storage devices in the hierarchy, those above the disks are volatile and the rest are non-volatile.

          Thus the design of a computer system balances or makes a tradeoff of all the above factors namely speed, cost and volatility. It provides as much expensive volatile memory as necessary and as much inexpensive non-volatile memory as possible.

REGRESSION ANALYSIS CODE

#include<stdio.h>

#include<math.h>

void main()          

{

 char choice;

 void Regression();

 void Estimation();

 void Evaluation();

 void display();

 clrscr();

 do

 {

   printf("\nselect your choice\n");

   printf("0.display kloc and effort values\n");

   printf("1.Regression Analysisl\n");

   printf("2.Estimation Model\n");

   printf("3.Evaluation of Model\n");

   printf("4.Exit This Code\n");

   choice=getche();

   switch(choice)

   {

     case '0':display();

                 break;

     case '1':Regression();

                 break;

     case '2':Estimation();

                 break;

     case '3':Evaluation();

                 break;

     default:exit(1);

   }

   printf("\nsome other operation(Y/N)\n");

   choice=getche();

  }while((choice=='Y')||(choice=='y'));

}

void Regression()

{

 char choice;

 void linear();

 void hyperbola();

 void power();

 void display();

 clrscr();

 do

 {

   printf("select your choice\n");

   printf("0.display kloc and effort values\n");

   printf("1.Linear Regression\n");

   printf("2.Power Regression\n");

   printf("3.Inverse Regression\n");

   printf("4.Exit this Regression\n");

   choice=getche();

   switch(choice)

   {

     case '0':display();

                 break;

     case '1':linear();

                 break;

             case '2':power();

                 break;

     case '3':hyperbola();

                 break;   

     default:main();

   }

   printf("\nsome other operation(Y/N)\n");

   choice=getche();

  }while((choice=='Y')||(choice=='y'));

}

void linear()

{

  int i,n=13;

  float a,b,ab[13],bc=0,cd=0,de,ef=0,fg[13],gh=0,hi,kl;

  float kloc[13]={39,40.5,50,128.6,161.4,164.8,200,214.4,253.6,254.2,289,449.9,450};

  float effort[13]={72,82.5,84,230.7,157,246.9,130.3,86.9,287,258.7,116,336.3,1107.31};

  for(i=0;i<=12;i++)

  {

   ab[i]=kloc[i]*kloc[i];

   bc=bc+ab[i];

   cd=cd+effort[i];

   ef=ef+kloc[i];

   fg[i]=kloc[i]*effort[i];

   gh=gh+fg[i];

  }

  kl=ef*ef;

  de=bc*cd-ef*gh;

  hi=n*bc-kl;

  a=de/hi;

  b=(n*gh-ef*cd)/hi;

  printf("\na value is:%.3f",a);

  printf("\tb value is:%.3f",b);

}

void hyperbola()

{

  int i,n=13;

  float a,b,ab[13],bc=0,cd=0,de,ef=0,fg[13],gh=0,hi,kl;

  float kloc[13]={39,40.5,50,128.6,161.4,164.8,200,214.4,253.6,254.2,289,449.9,450};

  float effort[13]={72,82.5,84,230.7,157,246.9,130.3,86.9,287,258.7,116,336.3,1107.31};

  for(i=0;i<=12;i++)

  {

   ",a);

  printf("\tb value is:%.3f",b);

}

void power()

{

  int i,n=13;

  double a,b,aa,ab[13],kloc[13],effort[13],bc=0,cd=0,de,ef=0,fg[13],gh=0,hi,kl;

  double klocc[13]={39,40.5,50,128.6,161.4,164.8,200,214.4,253.6,254.2,289,449.9,450};

  double effortt[13]={72,82.5,84,230.7,157,246.9,130.3,86.9,287,258.7,116,336.3,1107.31};

  for(i=0;i<=12;i++)

  {

  kloc[i]=log(klocc[i]);

  effort[i]=log(effortt[i]);

  }

  for(i=0;i<=12;i++)

  {

   ab[i]=kloc[i]*kloc[i];

   bc=bc+ab[i];

  b=(n*gh-ef*cd)/hi;

  aa=pow(2.7182,a);

  printf("\na value is:%.3lf",aa);

  printf("\tb value is:%.3lf",b);

}

void display()

{

  int i;

  float kloc[13]={39,40.5,50,128.6,161.4,164.8,200,214.4,253.6,254.2,289,449.9,450};

  float effort[13]={72,82.5,84,230.7,157,246.9,130.3,86.9,287,258.7,116,336.3,1107.31};

  printf("\nSNO\tKLOC\tActual Effort\n");

  for(i=0;i<=12;i++)

  {

  printf("%d\t%.2f\t%.2f\n",i,kloc[i],effort[i]);

  }

}

float Basic()

{

  int i;

  float c,beffort[13],error[13],mm=0;

  float kloc[13]={39,40.5,50,128.6,161.4,164.8,200,214.4,253.6,254.2,289,449.9,450};

  float effort[13]={72,82.5,84,230.7,157,246.9,130.3,86.9,287,258.7,116,336.3,1107.31};

  printf("\nBASIC EFFORT \tERROR %\n\n");

  for(i=0;i<=12;i++)

  { +1,beffort[i],error[i]);

 }

 return mm;

}

float Halsted()

{

  int i;

  float a,b,c,beffort[13],error[13],mm=0;

  float kloc[13]={39,40.5,50,128.6,161.4,164.8,200,214.4,253.6,254.2,289,449.9,450};

  float effort[13]={72,82.5,84,230.7,157,246.9,130.3,86.9,287,258.7,116,336.3,1107.31};

  printf("\nBASIC EFFORT \tERROR %\n\n");

  for(i=0;i<=12;i++)

  {

   c=pow(kloc[i],1.50);

}

 return mm;

}

float Mittal()

{

  int i;

  float a,b,c,d,e,f,g,h,beffort[13],error[13],mm=0;

  float kloc[13]={39,40.5,50,128.6,161.4,164.8,200,214.4,253.6,254.2,289,449.9,450};

  float effort[13]={72,82.5,84,230.7,157,246.9,130.3,86.9,287,258.7,116,336.3,1107.31};

  printf("\nBASIC EFFORT \tERROR %\n\n");

  for(i=0;i<=12;i++)

  {

   c=pow(0.7*kloc[i],0.665);

   d=pow(kloc[i],0.665);

   e=pow(1.3*kloc[i],0.665);

   beffort[i]=(1*6*c+4*6*d+1*6*e)/6;

   error[i]=abs(((beffort[i]-effort[i])/effort[i])*100);

   mm=mm+error[i];

   printf("%d:%.3f\t%.3f\n",i+1,beffort[i],error[i]);

 }

 return mm;

}

syllabus for MTECH I sem

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Access your mobile phone remotely with this app.......!!!!!

Kerala startup company Livares Technologies has approach out with a new app PhoneAway that enable users to access their mobile phones remotely.

By using the 'PhoneAway' application, users can right to use contents in their phone from another mobile phone or PC. The app can be downloaded for free from Google Play store.

Jaseel Abdul Rafeek, chief modernism officer, Livares Technologies, thought PhoneAway is an utility app available now in Android platform. It offers a easy yet feature-wealthy experience for users to access their phones remotely.

The company is based primarily in Technopark here and establish Village, Kochi.

"PhoneAway keeps you in contact with your handset even if it's not in hands," supposed Rafeek.

After installing the application in the user's Smartphone, user has to register an another mobile phone number in the application - which could be used to get details from the original phone.

Besides, an appropriate communication channel - SMS, email, or both - should also be selected so as to facilitate communication.

Once installed, PhoneAway will run in the background on the original smartphone.

Users can start scheming the phone remotely, by giving a exact number of missed-calls or by transfer a specific SMS command to the phone, complete with a user-defined pass code for confirmation.

This will 'activate' the application - and internet connectivity will be switched on automatically, so as to make possible communication.

Users can perform a host of operations using the application. One of its key facial appearance is that users can fetch the phone's call log remotely to their email address or by text message to alternate mobile phone.

Additionally, users can also search and find contacts stored in the phone.

Users even have the facility to locate misplaced phones in silent mode by employing the 'remote-ringer' capability - whereby users can make the phone hoop, even if it is in quiet mode.

an extra major feature of the purpose is its ability to pin-point the phone's location using the phone's GPS, and send it to the user, to help users locate the mobile phone if it is lost.

New skill lets you think textures on touchscreen....

Smartphone users can now ‘feel’ images and objects seen on their touchscreen!

In a competition-changing innovation, engineers at Disney Research, Pittsburgh, have developed a new technique that allows you to feel the texture of objects seen on a flat touchscreen.

The novel algorithm enables a individual downhill a finger across a topographic map displayed on a touchscreen to feel the bumps and curves of hills and valleys, despite the screen’s smooth surface.

The skill is based on the actuality that when a person slides a finger over a real physical bump, he perceives the bump largely because lateral friction forces stretch and compress skin on the sliding finger.

By varying the resistance encountered as a person’s fingertip glides across a surface, the Disney algorithm can create a perception of a 3D bump on a touch surface.

The method can be used to reproduce the think of a wide variety of objects and textures.