What does an operating system do?

Elis [28]

A semiconductor material has an electrical conductivity value falling between that of a conductor, such as metallic copper, and an insulator, such as glass. Its resistivity falls as its temperature rises; metals behave in the opposite way. I hope this helps and have a great day! (Also brainliest would be appreciated but you don’t have to) :)

7 0

3 years ago

Read 2 more answers

[20 pts] Write the function rectangle(perimeter, area), which takes two positive integers, perimeter and area. It returns an int

MrRissso [65]

Hi, you haven't provided the programing language in which you need the code, I'll explain how to do it using Python, and you can follow the same logic to make a program in the programing language that you need.

Answer:

import math

def rectangle(perimeter, area):

l1_1 = (perimeter+math.sqrt((perimeter**2)-(16*area)))/4

l1_2 = (perimeter-math.sqrt((perimeter**2)-(16*area)))/4

l2_1 = area/l1_1

l2_2 = area/l1_2

print(l1_1,l2_1)

print(l1_2,l2_2)

if l1_1.is_integer() and l2_1.is_integer() and l1_1>0 and l2_1>0:

return(int(max(l1_1,l2_1)))

elif l1_2.is_integer() and l2_2.is_integer() and l1_2>0 and l2_2>0:

return(int(max(l1_2,l2_2)))

else:

return(None)

Explanation:

We import math to make basic operations
We define the rectangle function that receives perimeter and area
We calculate one of the sides (l1_1) of the rectangle using the quadratic equation to solve 2h^2 - ph + 2a = 0
We calculate the second root of the quadratic equation for the same side (l1_2)
We calculate the second side of the rectangle using the first root on w = a/h
We calculate the second side of the rectangle using the second root on w= a/h
We verify that each component of the first result (l1_1, l2_1) is an integer (using the build-in method .is_integer) and greater than 0, if True we return the maximum value between them (using the max function) as w
If the first pair of sides evaluate to False we check the second root of the equation and if they meet the specification we return the max value
if all the if statements evaluate to false we return None to indicate that not positive or integer sides were found

7 0

2 years ago

Create a program which will input data into a pipe one character at a time. Count the number of characters as they are written i

LenKa [72]

Answer:

a)

#include<stdio.h>

#include<stdlib.h>

#include<fcntl.h>

#include<unistd.h>

#define BUFSIZE 16

int main(){

//pipe descriptors

char msg[BUFSIZE];

char buf[BUFSIZE];

int pipefd[2];

if(pipe(pipefd) == -1){

//pipe creation error

perror("pipe");

exit(EXIT_FAILURE);

}

//pipe creation successfull

//write four messages

sprintf(msg , "apple");

write(pipefd[1], msg, BUFSIZE);

printf("Written %s\n", msg);

sprintf(msg , "boy");

write(pipefd[1], msg, BUFSIZE);

printf("Written %s\n", msg);

sprintf(msg , "cat");

write(pipefd[1], msg, BUFSIZE);

printf("Written %s\n", msg);

sprintf(msg , "dog");

write(pipefd[1], msg, BUFSIZE);

printf("Written %s\n", msg);

//read

read(pipefd[0], buf, BUFSIZE);

printf("Read: %s\n", buf);

read(pipefd[0], buf, BUFSIZE);

printf("Read: %s\n", buf);

read(pipefd[0], buf, BUFSIZE);

printf("Read: %s\n", buf);

read(pipefd[0], buf, BUFSIZE);

printf("Read: %s\n", buf);

close(pipefd[0]);

close(pipefd[1]);

return 0;

}

(b)

#include<stdio.h>

#include<stdlib.h>

#include<fcntl.h>

#include<unistd.h>

#include<wait.h>

#define BUFSIZE 16

int main(){

//pipe descriptors

char msg[BUFSIZE];

char buf[BUFSIZE];

int pipefd[2];

if(pipe(pipefd) == -1){

//pipe creation error

perror("pipe");

exit(EXIT_FAILURE);

}

//pipe creation successfull

//write four messages

if(fork() == 0){

//this is child

//close unused write end

close(pipefd[1]);

read(pipefd[0], buf, BUFSIZE);

printf("This is child process reading first message. Content is %s\n", buf);

read(pipefd[0], buf, BUFSIZE);

printf("This is child process reading second message. Content is %s\n", buf);

read(pipefd[0], buf, BUFSIZE);

printf("This is child process reading third message. Content is %s\n", buf);

read(pipefd[0], buf, BUFSIZE);

printf("This is child process reading fourth message. Content is %s\n", buf);

close(pipefd[0]);

//exit from child

exit(EXIT_SUCCESS);

}

//this is parent process

//close unused read end

close(pipefd[0]);

sprintf(msg , "apple");

printf("This is parent process. Writing first message into pipe\n");

write(pipefd[1], msg, BUFSIZE);

sprintf(msg , "boy");

printf("This is parent process. Writing second message into pipe\n");

write(pipefd[1], msg, BUFSIZE);

sprintf(msg , "cat");

printf("This is parent process. Writing third message into pipe\n");

write(pipefd[1], msg, BUFSIZE);

sprintf(msg , "dog");

printf("This is parent process. Writing fourth message into pipe\n");

write(pipefd[1], msg, BUFSIZE);

close(pipefd[1]);

//wait for child

wait(NULL);

return 0;

}

(c)

#include<stdio.h>

#include<stdlib.h>

#include<fcntl.h>

#include<unistd.h>

#include<sys/wait.h>

#include<sys/types.h>

#include<signal.h>

typedef struct sigaction Sigaction;

unsigned long long size = 0;

void alarmhandler(int sig){

//alarm fired writing blocked

printf("Write blocked after %llu characters\n", size);

exit(EXIT_SUCCESS);

}

int main(){

//pipe descriptors

int pipefd[2];

if(pipe(pipefd) == -1){

//pipe creation error

perror("pipe");

exit(EXIT_FAILURE);

}

//install handler

sigset_t mask , prev;

sigemptyset(&mask);

sigaddset(&mask , SIGALRM);

sigprocmask(SIG_BLOCK , &mask , &prev);

Sigaction new_action;

sigemptyset(&new_action.sa_mask);

new_action.sa_flags = SA_RESTART;

new_action.sa_handler = alarmhandler;

sigaction(SIGALRM , &new_action , NULL);

sigprocmask(SIG_SETMASK , &prev, NULL);

while(1){

//print size on multiple of 4

if(size != 0 && size % 1024 == 0){

printf("%llu characters in pipe\n", size);

}

//reset previous alarm

alarm(0);

//set new alarm for 5 seconds

alarm(5);

//write to pipe one character

write(pipefd[1], "A", sizeof(char));

size++;

}

return 0;

}

Explanation:

Output for a, b, c are pasted accordingly

4 0

3 years ago

Your computer is taking longer than usual to open files and you notice that your hard drive light stays on longer than usual. Wh

777dan777 [17]

There might be insufficient storage space so your computer usually takes a longer time to load.The bigger your file, the longer it takes to load. So the solution is to clear up your storage space

7 0

3 years ago

Write a class named Add that has the following data members, constructor, and methods:

taurus [48]

Answer:

A class is like a blueprint of object.

Explanation:

A class defines the kinds of data and the functionality their objects will have.

A class enables you to create your own custom types by grouping together variables of other types, methods and events.

In C#, we can create a class using the class keyword.

Here's a sample program:

using System;

namespace ConsoleApplication

{

public class Test

{

public static void Main()

{

Add a1 = new Add(70, 50);

a1.AddNumbers();

Console.ReadLine();

}

class Add

{

private int row;

private int column;

public Add(int r, int c)

{

row = r;

column = c;

}

public void AddNumbers()

{

Console.WriteLine(row+column);

}

output: 120

Explanation of the program:

I have created a class named Add. Within a class, row and column are two fields and AddNumbers() is a method. We also have constructor to initialize row and column.

In main method, If I need to invoke members of the class, I must create an instance of the class. We can create any number of instances using the single class.IN our program, a1 is the reference variable using which we can invoke members of the class. I invoked function in the class and passed arguments to the constructor while creating an instance.

Those values are assigned to method variables and it operated the addition. Thus the output is 120.

7 0

3 years ago