
Concept explainers
Explanation of Solution
Given C code:
//Include libraries
#include "csapp.h"
#include "sbuf.h"
#include<pthread.h>
#define NTHREADS 4
#define SBUFSIZE 16
//Declare variable
static int byte_cnt;
//Declare variable
static sem_t mutex;
//Define method init_echo_cnt
static void init_echo_cnt(void)
{
//Call method
Sem_init(&mutex, 0, 1);
//Assign value
byte_cnt = 0;
}
//Define method echo_cnt
void echo_cnt(int connfd)
{
//Declare variable
int n;
//Declare array
char buf[MAXLINE];
//Create instance
rio_t rio;
//Assign value
static pthread_once_t once = PTHREAD_ONCE_INIT;
//Call method
pthread_once(&once, init_echo_cnt);
//Call method
Rio_readinitb(&rio, connfd);
//Loop
while((n = Rio_readlineb(&rio, buf, MAXLINE)) != 0)
{
//Decrement
P(&mutex);
//Update value
byte_cnt += n;
//Display message
printf("server received %d (%d total) bytes on fd %d\n", n, byte_cnt, connfd...

Want to see the full answer?
Check out a sample textbook solution
Chapter 12 Solutions
Computer Systems: A Programmer's Perspective Plus Mastering Engineering With Pearson Etext -- Access Card Package (3rd Edition)
- using r languagearrow_forwardWrite a function to compute a Monte Carlo estimate of the Beta(3, 3) cdf, and use the function to estimate F(x) for x = 0.1,0.2,...,0.9. Compare the estimates with the values returned by the pbeta function in R.arrow_forwardWrite a function to compute a Monte Carlo estimate of the Gamma(r = 3, λ = 2) cdf, and use the function to estimate F(x) for x = 0.2, 0.4, . . . , 2.0. Compare the estimates with the values returned by the pgamma function in R.arrow_forward
- using r languagearrow_forwardusing r languagearrow_forwardYou are given a class that processes purchases for an online store. The class receives calls to: • Retrieve the prices for items from a database • Record the sold items • Update the database • Refresh the webpage a. What architectural pattern is suitable for this scenario? Illustrate your answer by drawing a model for the solution, showing the method calls/events. b. Comment on how applying this pattern will impact the modifiability of the system. c. Draw a sequence diagram for the update operation.arrow_forward
- The images I have uploaded are the part 1 to 4 and questions below are continue on the questions uploaded 5. C++ Class Template with Method Stubs #pragma once #include <iostream> #include <string> #include <stdexcept> #include <vector> template <typename T> class HashTable { private: struct Entry { std::string key; T value; bool isOccupied; bool isDeleted; Entry() : key(""), value(), isOccupied(false), isDeleted(false) {} }; Entry* table; size_t capacity; size_t size; double loadFactorThreshold; size_t customHash(const std::string& key) const { size_t hash = 5381; for (char c : key) { hash = ((hash << 5) + hash) + c; } return hash; } size_t probe(const std::string& key, bool forInsert = false) const; void resize(); public: // Constructor HashTable(size_t initialCapacity = 101); // Big…arrow_forwardthis project is NOT for graded(marks) purposes, please help me with the introduction. give me answers for the project. i will include an image explaining everything about the project.arrow_forwardJava Graphics (Bonus In this lab, we'll be practicing what we learned about GUIs, and Mouse events. You will need to implement the following: A GUI with a drawing panel. We can click in this panel, and you will capture those clicks as a Point (see java.awt.Point) in a PointCollection class (you need to build this). The points need to be represented by circles. Below the drawing panel, you will need 5 buttons: O о о ○ An input button to register your mouse to the drawing panel. A show button to paint the points in your collection on the drawing panel. A button to shift all the points to the left by 50 pixels. The x position of the points is not allowed to go below zero. Another button to shift all the points to the right 50 pixels. " The x position of the points cannot go further than the You can implement this GUI in any way you choose. I suggest using the BorderLayout for a panel containing the buttons, and a GridLayout to hold the drawing panel and button panels. Regardless of how…arrow_forward
- also provide the number of moves(actions) made at state A and moves(actions) made state B. INCLUDE Java program required(this question is not graded)arrow_forwardYou are given a class that processes purchases for an online store. The class receives calls to: • Retrieve the prices for items from a database • Record the sold items • Update the database • Refresh the webpage a. What architectural pattern is suitable for this scenario? Illustrate your answer by drawing a model for the solution, showing the method calls/events. b. Comment on how applying this pattern will impact the modifiability of the system. c. Draw a sequence diagram for the update operation.arrow_forward2. The memory management has contiguous memory allocation, dynamic partitions, and paging. Compare the internal fragmentation and external fragmentation for these three approaches. [2 marks] 3. Suppose we have Logical address space = 24 = 16 (m = 4), Page size=2² =4 (n = 2), Physical address space = 26 = 64 (r = 6). Answer the following questions: [4 marks] 1) Total # of pages ? 2) Total # of frames ? 3) Number of bits to represent logical address? 4) Number of bits to represent offset ? 5) Number of bits to represent physical address? 6) Number of bits to represent a page number? 7) Number of bits to represent a frame number / 4. What is translation look-aside buffers (TLBS)? Why we need them to implement the page table? [2 marks] 5. Why we need shared pages for multiple processes? Give one example to show the benefits. [2 marks] 6. How to implement the virtual memory by using page out and page in? Explain with an example. [2 marks] 7. We have a reference string of referenced page…arrow_forward
- Systems ArchitectureComputer ScienceISBN:9781305080195Author:Stephen D. BurdPublisher:Cengage LearningProgramming Logic & Design ComprehensiveComputer ScienceISBN:9781337669405Author:FARRELLPublisher:CengagePrinciples of Information Systems (MindTap Course...Computer ScienceISBN:9781305971776Author:Ralph Stair, George ReynoldsPublisher:Cengage Learning
- Microsoft Visual C#Computer ScienceISBN:9781337102100Author:Joyce, Farrell.Publisher:Cengage Learning,Operations Research : Applications and AlgorithmsComputer ScienceISBN:9780534380588Author:Wayne L. WinstonPublisher:Brooks ColeC++ Programming: From Problem Analysis to Program...Computer ScienceISBN:9781337102087Author:D. S. MalikPublisher:Cengage Learning




