The document discusses synchronization and semaphores. It begins by explaining how mutual exclusion can be achieved in uni-processors using interrupt disabling, but this does not work in multi-processors. It then introduces the test-and-set instruction, which can be used to implement mutual exclusion in multi-processors, but has performance issues due to busy waiting. Semaphores are then presented as a solution that avoids busy waiting by allowing processes to block when a semaphore value is 0. The rest of the document provides examples of using binary and general semaphores, and discusses POSIX semaphores.
This document discusses synchronization and semaphores. It begins by explaining how mutual exclusion can be achieved in uni-processors using interrupt disabling, but this does not work in multi-processors. Semaphores provide a solution using atomic test-and-set instructions. Semaphores allow processes to suspend execution and wait for signals. They avoid busy waiting by putting processes to sleep when the semaphore value is not positive. The document provides examples of using binary and general semaphores for problems like mutual exclusion and process synchronization.
This document discusses various constructs that can be used in Verilog testbenches, including loops, parallel blocks, named blocks, file I/O, and functions. It provides examples of while, repeat, forever loops as well as fork/join blocks for parallel execution. It also covers disabling blocks, opening and closing files, and reading and writing to files using commands like $fopen, $fdisplay, $fgets, and $fscanf. Functions are described as having inputs, a single output, and implementing combinational behavior using blocking assignments.
The document summarizes key concepts related to operating system kernels including process and thread management, synchronization mechanisms like semaphores and monitors, interrupt handling, and communication primitives. It describes data structures like process control blocks and priority queues used to implement these concepts. It also explains algorithms for operations on processes, synchronization, clock management, and interrupt servicing.
The document discusses process synchronization and concurrency control techniques used to ensure orderly execution of cooperating processes. It describes solutions to classical synchronization problems like the bounded buffer problem, readers-writers problem, and dining philosophers problem using semaphores and monitors. Atomic transactions are achieved through techniques like write-ahead logging and checkpoints to assure failures do not compromise data consistency.
OS Process Synchronization, semaphore and Monitorssgpraju
The document summarizes key concepts in process synchronization and concurrency control, including:
1) Process synchronization techniques like semaphores, monitors, and atomic transactions that ensure orderly access to shared resources. Semaphores use wait() and signal() operations while monitors provide mutual exclusion through condition variables.
2) Concurrency control algorithms like locking and two-phase locking that ensure serializability of concurrent transactions accessing a database. Locking associates locks with data items to control concurrent access.
3) Challenges in concurrency control like deadlocks, priority inversion, and starvation that synchronization mechanisms aim to prevent. Log-based recovery with write-ahead logging and checkpoints is used to ensure atomicity of transactions in
The document discusses various techniques for process synchronization and solving the critical section problem where multiple processes need exclusive access to shared resources. It describes the critical section problem and requirements that must be met (mutual exclusion, progress, and bounded waiting). It then summarizes several algorithms to solve the problem for two processes and multiple processes, including using semaphores which are basic synchronization tools using wait and signal operations.
This document discusses synchronization and semaphores. It begins by explaining how mutual exclusion can be achieved in uni-processors using interrupt disabling, but this does not work in multi-processors. Semaphores provide a solution using atomic test-and-set instructions. Semaphores allow processes to suspend execution and wait for signals. They avoid busy waiting by putting processes to sleep when the semaphore value is not positive. The document provides examples of using binary and general semaphores for problems like mutual exclusion and process synchronization.
This document discusses various constructs that can be used in Verilog testbenches, including loops, parallel blocks, named blocks, file I/O, and functions. It provides examples of while, repeat, forever loops as well as fork/join blocks for parallel execution. It also covers disabling blocks, opening and closing files, and reading and writing to files using commands like $fopen, $fdisplay, $fgets, and $fscanf. Functions are described as having inputs, a single output, and implementing combinational behavior using blocking assignments.
The document summarizes key concepts related to operating system kernels including process and thread management, synchronization mechanisms like semaphores and monitors, interrupt handling, and communication primitives. It describes data structures like process control blocks and priority queues used to implement these concepts. It also explains algorithms for operations on processes, synchronization, clock management, and interrupt servicing.
The document discusses process synchronization and concurrency control techniques used to ensure orderly execution of cooperating processes. It describes solutions to classical synchronization problems like the bounded buffer problem, readers-writers problem, and dining philosophers problem using semaphores and monitors. Atomic transactions are achieved through techniques like write-ahead logging and checkpoints to assure failures do not compromise data consistency.
OS Process Synchronization, semaphore and Monitorssgpraju
The document summarizes key concepts in process synchronization and concurrency control, including:
1) Process synchronization techniques like semaphores, monitors, and atomic transactions that ensure orderly access to shared resources. Semaphores use wait() and signal() operations while monitors provide mutual exclusion through condition variables.
2) Concurrency control algorithms like locking and two-phase locking that ensure serializability of concurrent transactions accessing a database. Locking associates locks with data items to control concurrent access.
3) Challenges in concurrency control like deadlocks, priority inversion, and starvation that synchronization mechanisms aim to prevent. Log-based recovery with write-ahead logging and checkpoints is used to ensure atomicity of transactions in
The document discusses various techniques for process synchronization and solving the critical section problem where multiple processes need exclusive access to shared resources. It describes the critical section problem and requirements that must be met (mutual exclusion, progress, and bounded waiting). It then summarizes several algorithms to solve the problem for two processes and multiple processes, including using semaphores which are basic synchronization tools using wait and signal operations.
DTrace is a comprehensive dynamic tracing framework created by Sun Microsystems for troubleshooting kernel and application problems on production systems in real time. It provides probes in the operating system and applications to monitor events, collects and aggregates data, and provides tools to analyze the data. DTrace can be used on Unix-like systems like Solaris, Linux, macOS, and in Node.js applications through a DTrace provider. It allows gathering insights about the system and application behavior without restarting or slowing the system.
This document contains questions and answers about I/O models and multiplexing in networking. It discusses blocking I/O, non-blocking I/O, I/O multiplexing using select and poll, signal-driven I/O, and asynchronous I/O. It also provides code examples of a concurrent TCP server using select to convert text to uppercase and a poll-based client-server application to handle both TCP and UDP requests for text conversion.
The document summarizes key concepts related to process synchronization. It introduces the critical section problem where processes need coordinated access to shared resources. Several classic solutions are described, including Peterson's algorithm and using semaphores. Mutex locks and their implementation using atomic hardware instructions like test-and-set are also covered. The concepts of deadlock and starvation that can occur without proper synchronization are briefly mentioned at the end.
Mca ii os u-2 process management & communicationRai University
This document discusses various techniques for process synchronization and concurrency control in distributed systems. It begins by introducing classical problems like the bounded buffer problem and solutions like semaphores. It then covers monitors and condition variables as higher-level synchronization constructs. Various examples of synchronization in real systems like Solaris, Linux, and Windows are provided. The document concludes with a discussion of techniques to ensure atomic transactions in the presence of failures, including log-based recovery, checkpoints, and concurrency control protocols like two-phase locking and timestamp ordering.
Operating system 24 mutex locks and semaphoresVaibhav Khanna
Mutual Exclusion - If process Pi is executing in its critical section, then no other processes can be executing in their critical sections
2. Progress - If no process is executing in its critical section and there exist some processes that wish to enter their critical section, then the selection of the processes that will enter the critical section next cannot be postponed indefinitely
3. Bounded Waiting - A bound must exist on the number of times that other processes are allowed to enter their critical sections after a process has made a request to enter its critical section and before that request is granted
Assume that each process executes at a nonzero speed
No assumption concerning relative speed of the n processes
This document discusses hardware and software solutions for critical section problems in multiprocessing systems. It introduces the TestAndSet instruction, which atomically sets a variable to true and returns its previous value. This can be used to implement mutual exclusion. Semaphores are also introduced as another synchronization primitive, with binary semaphores functioning similarly to mutex locks. Implementations of semaphores are discussed where processes block rather than busy wait, avoiding wasted CPU cycles. Deadlock and starvation scenarios are briefly described.
This document provides information about the 8th semester Network Security lab practical course for Computer Science and Engineering students at Shri Rawatpura Sarkar Institute of Technology-II in New Raipur, Chhattisgarh, India. It lists 10 experiments to be performed related to network security programming using TCP/IP, sockets, APIs, web security, cryptography, and more. It also provides sample code for some of the experiments and recommends books for reference.
Advanced patterns in asynchronous programmingMichael Arenzon
Using Futures as a basic building block for concurrent, async code has become pervasive in the past few years and for a good reason. However, when moving from the traditional synchronous code to the async one, a set of patterns that were obvious to implement before now seem to be more challenging. The aim of this talk is to show few examples of these patterns implemented with Scala futures in an async and non blocking manner. We will present the usage pattern and the implementation in order to show the principles of properly handling async code.
Gabriele Petronella - FP for front-end development: should you care? - Codemo...Codemotion
Functional programming is becoming pervasive in every branch of development, but why should you care? Can we reap the benefits of FP, if our job is to write web UIs? In this presentation, we'll see how FP fits into the front-end development picture and how we can leverage TypeScript to progressively migrate our codebases and start getting the most out of it.
forwarder.java.txt java forwarder class waits for an in.docxbudbarber38650
forwarder.java.txt
// java forwarder class
// waits for an inbound connection A on port INPORT
// when it is received, it launches a connection B to <OUTHOST,OUTPORT>
// and creates threads to read-B-write-A and read-A-write-B.
import java.net.*;
import java.io.*;
import java.util.*;
import java.text.*;
class forwarder {
public static String OUTHOST;
public static InetAddress OUTDEST;
public static short OUTPORT = 22;
public static short INPORT = 2345;
public static boolean DEBUG = true;
public static void main(String[] v) {
// get command-line parameters
if (v.length < 3) {
System.err.println("args: inport outhost outport");
return;
}
INPORT = (short)(new Integer(v[0])).intValue();
OUTHOST = v[1];
OUTPORT = (short)(new Integer(v[2])).intValue();
// DNS lookup, done just once!
System.err.print("Looking up address of " + OUTHOST + "...");
try {
OUTDEST = InetAddress.getByName(OUTHOST);
}
catch (UnknownHostException uhe) {
System.err.println("unknown host: " + OUTHOST);
return;
}
System.err.println(" got it!");
// initialize LISTENER socket
// wait for connection
ServerSocket ss = null;
ss = new ServerSocket(INPORT);// needs try-catch
Socket s1;
while(true) { // accept loop
s1 = ss.accept();// needs try-catch
// now set up the second connection from here to <OUTDEST,OUTPORT>,
// represented by a second socket s2
// Then create the two Copier instances, as described in the
// project description, and start() the two threads.
// At that point, this main loop simply continues
// by going back to the ss.accept() call.
} // accept loop
}// main
/**
* The Copier class handles unidirectional copying from one socket to another.
* You will need to create two of these in the main loop above,
* one for each direction. You create the Copier object, and then
* create and start a Thread object that runs that Copier.
* If c is your Copier instance (created with Copier c = new Copier(sock1, sock2)),
* then the thread is Thread t = new Thread(c), and you start the thread
* with t.start(). Or, in one step, (new Thread(c)).start()
*/
static class Copier implements Runnable {
private Socket _from;
private Socket _to;
public Copier (Socket from, Socket to) {
_from = from;
_to = to;
}
public void run() {
InputStream fis;
OutputStream tos;
try {
fis = _from.getInputStream();
tos = _to.getOutputStream();
} catch (IOException ioe) {
System.err.println("can't get IO streams from sockets");
return;
}
byte[] buf = new byte[2048];
int readsize;
while (true) {
try {
readsize = fis.read(buf);
} catch (IOException ioe) {
break;
}
if (readsize <= 0) break;
try {
tos.write(buf, 0, readsize);
} catch (IOException ioe) {
break;
}
}
// these should be safe close() calls!!
try {
fis.close();
tos.close();
_from.close();
_to.close();
} catch (IOException ioe) {
Syst.
This document discusses memory models, non-blocking primitives, and lock-free algorithms for concurrent programming. It provides code examples for implementing atomic operations like set, compareAndSet, and lazySet using the Unsafe class. It evaluates the performance of different producer-consumer algorithms like spin-wait, co-operative yielding, and buffering. The document suggests buffering generally performs best by avoiding busy-waiting and allowing other threads to run. It provides references for further information on lock-free programming.
Locks? We Don't Need No Stinkin' Locks - Michael BarkerJAX London
Embrace the dark side. As a developer you'll often be advised that writing concurrent code should be the purview of the genius coders alone. In this talk Michael Barker will discard that notion into the cesspits of logic and reason and attempt to present on the less understood area of non-blocking concurrency, i.e. concurrency without locks. We'll look the modern Intel CPU architecture, why we need a memory model, the performance costs of various non-blocking constructs and delve into the implementation details of the latest version of the Disruptor to see how non-blocking concurrency can be applied to build high performance data structures.
This document contains slides from a lecture on operating system concepts. It discusses topics like process synchronization, Peterson's solution to the critical section problem, synchronization hardware, semaphores, monitors, and atomic transactions. It provides examples of how these concepts can be used to solve problems like the bounded buffer problem and consumer-producer problem. The document contains 42 slides with code snippets and explanations of key synchronization concepts.
Verilog is a hardware description language commonly used for designing digital circuits. It allows both structural and behavioral modeling. Structurally, Verilog programs are built from modules containing instances of other modules or primitives. Behaviorally, modules contain initial and always blocks that use imperative code like assignments and conditionals. Verilog simulations execute events concurrently using a discrete event queue to model digital hardware behavior.
Verilog is a hardware description language commonly used for designing digital circuits. It allows both structural and behavioral modeling. Structurally, Verilog programs are built from modules containing instances of other modules or primitives. Behaviorally, modules contain initial and always blocks with imperative code. The always blocks model concurrent hardware processes that execute when signals change. Verilog supports both combinational logic with continuous assignments and sequential logic with blocking assignments in always blocks.
Verilog is a hardware description language commonly used for designing digital circuits. It supports both structural and behavioral modeling styles. Structural modeling involves describing a design using instances of modules and primitives, while behavioral modeling uses procedural code like always blocks. Verilog supports various data types including nets, regs, vectors, and user-defined types. It also has a four-value logic system. Testbenches provide stimulus and check results of simulated designs.
Lab Assignment 4 CSE330 Spring 2014 Skeleton Code for ex.docxMARRY7
/* Lab Assignment 4 CSE330 Spring 2014 */
/* Skeleton Code for ex0 of lab4 */
/* No code will be provided for ex1 of lab4 */
#include <stdio.h> /* for NULL */
#include <ctype.h> /* for atoi() */
#include <errno.h> /* for perror() */
#include <signal.h> /* for sigvec() etc. */
#include <sys/types.h> /* for <arpa/inet.h> */
#include <sys/socket.h> /* for PF_INET, etc. */
#include <netinet/in.h> /* for struct sockaddr_in */
#include <arpa/inet.h> /* for inet_addr() */
#include <sys/time.h>
#include "lab4.h"
/* this is in netinet/in.h; included here for reference only.
struct sockaddr_in {
short sin_family;
u_short sin_port;
struct in_addr sin_addr;
char sin_zero[8];
};
*/
/***************************************************************************/
#define LINESIZE 80
#define TYPE0TIMEOUT 3
#define TYPE1TIMEOUT 30
/* You should give a long timeout, like 30sec, otherwise */
/* duplicated responses from the server may cause some problem */
#define MAXRETRY 3
/***************************************************************************/
static char *RCSId="$Id: client2.c,v 4 2014/04/20 03:15:07 cse3300 Exp $";
/***************************************************************************/
/* some functions you may find useful if you implement them */
extern int stringToAddress(char *s, struct sockaddr_in *a);
extern int msgok(LABMSG *);
extern u_short msgchecksum(u_short *);
extern void alarmCatcher(void);
extern int tries; /* for retransmission routines */
int numtries;
/***** this will die ****/
FILE *logFile;
void die(char *s)
{
perror(s);
exit(2);
}
void startTimer(int secs)
{
alarm(secs);
}
void stopTimer(void)
{
alarm(0);
}
/* should change it by yourself if needed!!! */
void printResponse(LABMSG *mp, int ck)
{
int type;
mp->courseEtc = ntohs(mp->courseEtc);
type = ( (mp->courseEtc & MESSAGETYPE) !=0)?1:0;
printf("course=%d, Type=%d\n", mp->courseEtc&0x3fff,type);
if (ntohl(mp->cookie) != ck)
printf("Cookies don't match: sent %x received %x\n",mp->cookie,ck);
if (mp->courseEtc & REQRESP)
printf("response ");
else {
printf("request??\n");
return;
}
mp->result = ntohs(mp->result);
/*printf(" result = %x: ",mp->result);*/
if (mp->result&TRANSOUTCOME) { /* Check outcome */
printf("error: ");
switch (mp->result & 0x7fff) {
case ERROR_CHECKSUM:
printf("checksum failure\n");
break;
case ERROR_SYNTAX:
printf("syntax error\n");
break;
case ERROR_UNKSSN:
printf("unknown SSN %d\n", ntohl(mp->reqSSN) );
break;
case ERROR_SERVER:
printf("Unspecified Server Error\n");
default:
printf("Unknown Error.\n");
} /* case switch */
} else { /* successful transaction */
if(type)printf("Test succeeded.");
if (!type) /* Type 0 -- print SSN and Response */
printf(": %d -> %d\n", ntohl(mp->reqSSN), mp->result&0x7fff);
else
printf("\n"); /* XXX print number of responses */
}
}
/*-----------------------------------*/
/* added by ZXC:
this fun ...
Verilog is a hardware description language used for designing digital circuits. It allows circuits to be modeled both structurally using primitives and modules, and behaviorally using initial and always blocks. Structural modeling connects instances of modules and primitives, while behavioral modeling uses imperative code. Verilog supports both combinational logic using continuous assignments and sequential logic using blocking assignments in always blocks. It performs event-driven discrete event simulation and uses four-valued logic for nets and registers.
The document discusses data structures like stacks and queues. It provides examples of implementing queues using linked lists and arrays. Queues follow a First-In First-Out (FIFO) approach, with operations like enqueue to add an item at the rear and dequeue to remove an item from the front. Queues have various uses like simulations, with an example given of simulating customers at a bank with multiple tellers.
A presentation describing two different approaches that we took when making use of fuzzing to discover vulnerabilities in VoIP or Real-time communications software and libraries.
We describe our failures and also our successful findings when using AFL and also our custom fuzzer, gasoline against Asterisk, Kamailio, PJSIP, RTP proxy and other solutions.
Presentation can be found at https://www.youtube.com/watch?v=CuxKD5zljVI
The Liang-Barsky line clipping algorithm uses the parametric equations of a line to clip it against the boundaries of a clipping window. It initializes line intersection parameters t1 and t2, then calculates them for each edge to update t1 or t2 if needed. This is more efficient than Cohen-Sutherland as it requires only one division per edge. The clipped line is then drawn using the updated start and end points.
This document discusses lexical analysis in compilers. It defines lexical analysis as the first phase of a compiler that reads a stream of characters as input and produces a sequence of tokens. It describes how a lexical analyzer identifies tokens by using patterns and lookahead. Tokens are syntactic categories like identifiers, numbers, and keywords. The lexical analyzer removes whitespace and comments and returns each lexeme and line number to the parser. Separating lexical and syntactic analysis simplifies compiler design and improves efficiency and portability.
DTrace is a comprehensive dynamic tracing framework created by Sun Microsystems for troubleshooting kernel and application problems on production systems in real time. It provides probes in the operating system and applications to monitor events, collects and aggregates data, and provides tools to analyze the data. DTrace can be used on Unix-like systems like Solaris, Linux, macOS, and in Node.js applications through a DTrace provider. It allows gathering insights about the system and application behavior without restarting or slowing the system.
This document contains questions and answers about I/O models and multiplexing in networking. It discusses blocking I/O, non-blocking I/O, I/O multiplexing using select and poll, signal-driven I/O, and asynchronous I/O. It also provides code examples of a concurrent TCP server using select to convert text to uppercase and a poll-based client-server application to handle both TCP and UDP requests for text conversion.
The document summarizes key concepts related to process synchronization. It introduces the critical section problem where processes need coordinated access to shared resources. Several classic solutions are described, including Peterson's algorithm and using semaphores. Mutex locks and their implementation using atomic hardware instructions like test-and-set are also covered. The concepts of deadlock and starvation that can occur without proper synchronization are briefly mentioned at the end.
Mca ii os u-2 process management & communicationRai University
This document discusses various techniques for process synchronization and concurrency control in distributed systems. It begins by introducing classical problems like the bounded buffer problem and solutions like semaphores. It then covers monitors and condition variables as higher-level synchronization constructs. Various examples of synchronization in real systems like Solaris, Linux, and Windows are provided. The document concludes with a discussion of techniques to ensure atomic transactions in the presence of failures, including log-based recovery, checkpoints, and concurrency control protocols like two-phase locking and timestamp ordering.
Operating system 24 mutex locks and semaphoresVaibhav Khanna
Mutual Exclusion - If process Pi is executing in its critical section, then no other processes can be executing in their critical sections
2. Progress - If no process is executing in its critical section and there exist some processes that wish to enter their critical section, then the selection of the processes that will enter the critical section next cannot be postponed indefinitely
3. Bounded Waiting - A bound must exist on the number of times that other processes are allowed to enter their critical sections after a process has made a request to enter its critical section and before that request is granted
Assume that each process executes at a nonzero speed
No assumption concerning relative speed of the n processes
This document discusses hardware and software solutions for critical section problems in multiprocessing systems. It introduces the TestAndSet instruction, which atomically sets a variable to true and returns its previous value. This can be used to implement mutual exclusion. Semaphores are also introduced as another synchronization primitive, with binary semaphores functioning similarly to mutex locks. Implementations of semaphores are discussed where processes block rather than busy wait, avoiding wasted CPU cycles. Deadlock and starvation scenarios are briefly described.
This document provides information about the 8th semester Network Security lab practical course for Computer Science and Engineering students at Shri Rawatpura Sarkar Institute of Technology-II in New Raipur, Chhattisgarh, India. It lists 10 experiments to be performed related to network security programming using TCP/IP, sockets, APIs, web security, cryptography, and more. It also provides sample code for some of the experiments and recommends books for reference.
Advanced patterns in asynchronous programmingMichael Arenzon
Using Futures as a basic building block for concurrent, async code has become pervasive in the past few years and for a good reason. However, when moving from the traditional synchronous code to the async one, a set of patterns that were obvious to implement before now seem to be more challenging. The aim of this talk is to show few examples of these patterns implemented with Scala futures in an async and non blocking manner. We will present the usage pattern and the implementation in order to show the principles of properly handling async code.
Gabriele Petronella - FP for front-end development: should you care? - Codemo...Codemotion
Functional programming is becoming pervasive in every branch of development, but why should you care? Can we reap the benefits of FP, if our job is to write web UIs? In this presentation, we'll see how FP fits into the front-end development picture and how we can leverage TypeScript to progressively migrate our codebases and start getting the most out of it.
forwarder.java.txt java forwarder class waits for an in.docxbudbarber38650
forwarder.java.txt
// java forwarder class
// waits for an inbound connection A on port INPORT
// when it is received, it launches a connection B to <OUTHOST,OUTPORT>
// and creates threads to read-B-write-A and read-A-write-B.
import java.net.*;
import java.io.*;
import java.util.*;
import java.text.*;
class forwarder {
public static String OUTHOST;
public static InetAddress OUTDEST;
public static short OUTPORT = 22;
public static short INPORT = 2345;
public static boolean DEBUG = true;
public static void main(String[] v) {
// get command-line parameters
if (v.length < 3) {
System.err.println("args: inport outhost outport");
return;
}
INPORT = (short)(new Integer(v[0])).intValue();
OUTHOST = v[1];
OUTPORT = (short)(new Integer(v[2])).intValue();
// DNS lookup, done just once!
System.err.print("Looking up address of " + OUTHOST + "...");
try {
OUTDEST = InetAddress.getByName(OUTHOST);
}
catch (UnknownHostException uhe) {
System.err.println("unknown host: " + OUTHOST);
return;
}
System.err.println(" got it!");
// initialize LISTENER socket
// wait for connection
ServerSocket ss = null;
ss = new ServerSocket(INPORT);// needs try-catch
Socket s1;
while(true) { // accept loop
s1 = ss.accept();// needs try-catch
// now set up the second connection from here to <OUTDEST,OUTPORT>,
// represented by a second socket s2
// Then create the two Copier instances, as described in the
// project description, and start() the two threads.
// At that point, this main loop simply continues
// by going back to the ss.accept() call.
} // accept loop
}// main
/**
* The Copier class handles unidirectional copying from one socket to another.
* You will need to create two of these in the main loop above,
* one for each direction. You create the Copier object, and then
* create and start a Thread object that runs that Copier.
* If c is your Copier instance (created with Copier c = new Copier(sock1, sock2)),
* then the thread is Thread t = new Thread(c), and you start the thread
* with t.start(). Or, in one step, (new Thread(c)).start()
*/
static class Copier implements Runnable {
private Socket _from;
private Socket _to;
public Copier (Socket from, Socket to) {
_from = from;
_to = to;
}
public void run() {
InputStream fis;
OutputStream tos;
try {
fis = _from.getInputStream();
tos = _to.getOutputStream();
} catch (IOException ioe) {
System.err.println("can't get IO streams from sockets");
return;
}
byte[] buf = new byte[2048];
int readsize;
while (true) {
try {
readsize = fis.read(buf);
} catch (IOException ioe) {
break;
}
if (readsize <= 0) break;
try {
tos.write(buf, 0, readsize);
} catch (IOException ioe) {
break;
}
}
// these should be safe close() calls!!
try {
fis.close();
tos.close();
_from.close();
_to.close();
} catch (IOException ioe) {
Syst.
This document discusses memory models, non-blocking primitives, and lock-free algorithms for concurrent programming. It provides code examples for implementing atomic operations like set, compareAndSet, and lazySet using the Unsafe class. It evaluates the performance of different producer-consumer algorithms like spin-wait, co-operative yielding, and buffering. The document suggests buffering generally performs best by avoiding busy-waiting and allowing other threads to run. It provides references for further information on lock-free programming.
Locks? We Don't Need No Stinkin' Locks - Michael BarkerJAX London
Embrace the dark side. As a developer you'll often be advised that writing concurrent code should be the purview of the genius coders alone. In this talk Michael Barker will discard that notion into the cesspits of logic and reason and attempt to present on the less understood area of non-blocking concurrency, i.e. concurrency without locks. We'll look the modern Intel CPU architecture, why we need a memory model, the performance costs of various non-blocking constructs and delve into the implementation details of the latest version of the Disruptor to see how non-blocking concurrency can be applied to build high performance data structures.
This document contains slides from a lecture on operating system concepts. It discusses topics like process synchronization, Peterson's solution to the critical section problem, synchronization hardware, semaphores, monitors, and atomic transactions. It provides examples of how these concepts can be used to solve problems like the bounded buffer problem and consumer-producer problem. The document contains 42 slides with code snippets and explanations of key synchronization concepts.
Verilog is a hardware description language commonly used for designing digital circuits. It allows both structural and behavioral modeling. Structurally, Verilog programs are built from modules containing instances of other modules or primitives. Behaviorally, modules contain initial and always blocks that use imperative code like assignments and conditionals. Verilog simulations execute events concurrently using a discrete event queue to model digital hardware behavior.
Verilog is a hardware description language commonly used for designing digital circuits. It allows both structural and behavioral modeling. Structurally, Verilog programs are built from modules containing instances of other modules or primitives. Behaviorally, modules contain initial and always blocks with imperative code. The always blocks model concurrent hardware processes that execute when signals change. Verilog supports both combinational logic with continuous assignments and sequential logic with blocking assignments in always blocks.
Verilog is a hardware description language commonly used for designing digital circuits. It supports both structural and behavioral modeling styles. Structural modeling involves describing a design using instances of modules and primitives, while behavioral modeling uses procedural code like always blocks. Verilog supports various data types including nets, regs, vectors, and user-defined types. It also has a four-value logic system. Testbenches provide stimulus and check results of simulated designs.
Lab Assignment 4 CSE330 Spring 2014 Skeleton Code for ex.docxMARRY7
/* Lab Assignment 4 CSE330 Spring 2014 */
/* Skeleton Code for ex0 of lab4 */
/* No code will be provided for ex1 of lab4 */
#include <stdio.h> /* for NULL */
#include <ctype.h> /* for atoi() */
#include <errno.h> /* for perror() */
#include <signal.h> /* for sigvec() etc. */
#include <sys/types.h> /* for <arpa/inet.h> */
#include <sys/socket.h> /* for PF_INET, etc. */
#include <netinet/in.h> /* for struct sockaddr_in */
#include <arpa/inet.h> /* for inet_addr() */
#include <sys/time.h>
#include "lab4.h"
/* this is in netinet/in.h; included here for reference only.
struct sockaddr_in {
short sin_family;
u_short sin_port;
struct in_addr sin_addr;
char sin_zero[8];
};
*/
/***************************************************************************/
#define LINESIZE 80
#define TYPE0TIMEOUT 3
#define TYPE1TIMEOUT 30
/* You should give a long timeout, like 30sec, otherwise */
/* duplicated responses from the server may cause some problem */
#define MAXRETRY 3
/***************************************************************************/
static char *RCSId="$Id: client2.c,v 4 2014/04/20 03:15:07 cse3300 Exp $";
/***************************************************************************/
/* some functions you may find useful if you implement them */
extern int stringToAddress(char *s, struct sockaddr_in *a);
extern int msgok(LABMSG *);
extern u_short msgchecksum(u_short *);
extern void alarmCatcher(void);
extern int tries; /* for retransmission routines */
int numtries;
/***** this will die ****/
FILE *logFile;
void die(char *s)
{
perror(s);
exit(2);
}
void startTimer(int secs)
{
alarm(secs);
}
void stopTimer(void)
{
alarm(0);
}
/* should change it by yourself if needed!!! */
void printResponse(LABMSG *mp, int ck)
{
int type;
mp->courseEtc = ntohs(mp->courseEtc);
type = ( (mp->courseEtc & MESSAGETYPE) !=0)?1:0;
printf("course=%d, Type=%d\n", mp->courseEtc&0x3fff,type);
if (ntohl(mp->cookie) != ck)
printf("Cookies don't match: sent %x received %x\n",mp->cookie,ck);
if (mp->courseEtc & REQRESP)
printf("response ");
else {
printf("request??\n");
return;
}
mp->result = ntohs(mp->result);
/*printf(" result = %x: ",mp->result);*/
if (mp->result&TRANSOUTCOME) { /* Check outcome */
printf("error: ");
switch (mp->result & 0x7fff) {
case ERROR_CHECKSUM:
printf("checksum failure\n");
break;
case ERROR_SYNTAX:
printf("syntax error\n");
break;
case ERROR_UNKSSN:
printf("unknown SSN %d\n", ntohl(mp->reqSSN) );
break;
case ERROR_SERVER:
printf("Unspecified Server Error\n");
default:
printf("Unknown Error.\n");
} /* case switch */
} else { /* successful transaction */
if(type)printf("Test succeeded.");
if (!type) /* Type 0 -- print SSN and Response */
printf(": %d -> %d\n", ntohl(mp->reqSSN), mp->result&0x7fff);
else
printf("\n"); /* XXX print number of responses */
}
}
/*-----------------------------------*/
/* added by ZXC:
this fun ...
Verilog is a hardware description language used for designing digital circuits. It allows circuits to be modeled both structurally using primitives and modules, and behaviorally using initial and always blocks. Structural modeling connects instances of modules and primitives, while behavioral modeling uses imperative code. Verilog supports both combinational logic using continuous assignments and sequential logic using blocking assignments in always blocks. It performs event-driven discrete event simulation and uses four-valued logic for nets and registers.
The document discusses data structures like stacks and queues. It provides examples of implementing queues using linked lists and arrays. Queues follow a First-In First-Out (FIFO) approach, with operations like enqueue to add an item at the rear and dequeue to remove an item from the front. Queues have various uses like simulations, with an example given of simulating customers at a bank with multiple tellers.
A presentation describing two different approaches that we took when making use of fuzzing to discover vulnerabilities in VoIP or Real-time communications software and libraries.
We describe our failures and also our successful findings when using AFL and also our custom fuzzer, gasoline against Asterisk, Kamailio, PJSIP, RTP proxy and other solutions.
Presentation can be found at https://www.youtube.com/watch?v=CuxKD5zljVI
The Liang-Barsky line clipping algorithm uses the parametric equations of a line to clip it against the boundaries of a clipping window. It initializes line intersection parameters t1 and t2, then calculates them for each edge to update t1 or t2 if needed. This is more efficient than Cohen-Sutherland as it requires only one division per edge. The clipped line is then drawn using the updated start and end points.
This document discusses lexical analysis in compilers. It defines lexical analysis as the first phase of a compiler that reads a stream of characters as input and produces a sequence of tokens. It describes how a lexical analyzer identifies tokens by using patterns and lookahead. Tokens are syntactic categories like identifiers, numbers, and keywords. The lexical analyzer removes whitespace and comments and returns each lexeme and line number to the parser. Separating lexical and syntactic analysis simplifies compiler design and improves efficiency and portability.
graphs data structure and algorithm link listKamranAli649587
The document discusses graphs and graph terminology. It begins by introducing graphs as consisting of vertices and edges, and defines some basic graph terminology like directed/undirected graphs, paths, cycles, and connectivity. It then provides more detailed explanations and examples of graph terminology like degrees, weights, simple paths/cycles, and connectivity in directed graphs. The document serves to introduce the key concepts needed to understand and work with graphs.
lecture10 date structure types of graph and terminologyKamranAli649587
The document discusses tree traversal techniques and heaps. It begins by explaining tree traversal concepts and the three common traversal techniques: preorder, inorder, and postorder. It then discusses heaps, which are almost complete binary trees where the key of each node is less than or equal to its children's keys. Heaps support efficient insertion and deletion of minimum elements in logarithmic time and are used to implement priority queues. Code implementations of binary trees, tree traversals, heaps, and their operations like insertion and deletion are also provided.
Encoders convert input information like keyboard entries or switch states into binary codes for processing by digital systems. Decoders then convert the binary codes back into a format for output devices. Common examples include ASCII encoding text and BCD encoding decimals. Encoders have mutually exclusive inputs and output priority encoded binary codes. Decoders convert binary codes into at most one active output at a time.
This document discusses three types of radio propagation:
1) Line of sight propagation travels in a straight line up to the visible horizon.
2) Ground wave propagation follows the contour of the Earth and can be reflected by the magnetic field.
3) Sky wave propagation projects waves onto the ionosphere, where they are reflected back to Earth, allowing transmission over longer distances than line of sight. This is useful for broadcasting.
The document discusses control structures in programming, specifically different types of loops. It provides examples of for, do-while, and while loops. It explains the syntax and usage of each loop type, and how to avoid issues like infinite loops. Examples are given to iterate through a range of numbers and display output for each iteration. The document also discusses using loops and conditionals like if statements together in programs.
This document discusses basic data types, variables, literals, and constants in C++. It covers:
- The basic units of memory (bytes) and CPU operations (words)
- Types tell the compiler how much space an object occupies and what operations mean
- Literals are fixed values known at compile time that can initialize variables
- Variables are named, typed storage locations that can be assigned values
- Variables are defined to allocate storage and declared to specify their name and type
This document provides an overview of input and output in C++ using iostream.h instead of stdio.h. It discusses the standard iostream objects like cout and cin for output and input. It covers using the insertion and extraction operators << and >> for output and input. It also describes various format flags and manipulators that can be used to control formatting of output, like integer base, floating point precision, and justification.
1) Radio propagation models aim to predict signal strength and quality at a receiver based on transmission mechanisms like free space propagation, reflection, diffraction, scattering, and multipath effects between the transmitter and receiver.
2) Large scale path loss models describe average attenuation over distances much larger than the wavelength, while small scale fading models characterize rapid fluctuations over small distances due to multipath interference.
3) Common large scale models include free space, log-distance, two-ray ground reflection and diffraction models for outdoor environments and partition models for indoor. Small scale models characterize delay spread, coherence bandwidth, and use distributions like Rayleigh or Rician.
Cluster analysis is an unsupervised learning technique used to group unlabeled data points so that objects in the same cluster are more similar to each other than objects in different clusters. There are various clustering algorithms that differ in how they define clusters and find them efficiently. Popular cluster models include connectivity models based on distance, centroid models that represent each cluster by a single mean, and density models that define clusters as connected dense regions of data. Clustering is used in applications like market segmentation, social network analysis, and image segmentation.
The document discusses four major types of evaluation methods: case study, statistical analysis, field experiment, and survey research. It provides details on case study methods, including definitions, types of case studies, and steps to conducting a case study. Statistical analysis methods are also summarized, including descriptive statistics such as frequency counts and distributions, and measures of central tendency and variability. Mathematical modeling as a research method is briefly outlined.
A research paper involves surveying existing knowledge on a topic to present an original argument supported by others' ideas and evidence. It is focused on a specific issue, presents facts from multiple sources, and analyzes and interprets relevant literature to support the writer's own evaluation or conclusion. Key parts of a research paper include an introduction providing background, a literature review of related work, methods, results, and a conclusion summarizing findings and limitations.
CamScanner is a document scanning app that allows users to scan documents, receipts, whiteboards, and more using the camera on their mobile device. The app supports various file formats and allows users to annotate, share, and organize scanned files easily. CamScanner is available on both Android and iOS platforms.
This document is a detailed award sheet for the course "Information Security" for students in the 8th semester of the BS Computer Science program at Government College University, Faisalabad. It lists 19 students, their roll numbers, names, fathers' names, CNIC numbers, session, attempt number, internal marks, mid-term marks, final term marks, practical work marks, total marks, percentage, grade, and status (pass/fail). The highest-scoring student received 81.67% and an A grade, while the lowest-scoring student received 20% and failed the course. The award sheet requires signatures from the internal examination coordinator, department chairperson, and chairperson of the affiliation cell.
CamScanner is a document scanning app that allows users to scan documents, receipts, whiteboards, and more using the camera on their mobile device. The app supports various file formats and allows users to edit, annotate, share, and organize scanned files. CamScanner is available on both Android and iOS platforms and has over 500 million downloads worldwide.
The document discusses several software development lifecycle models including waterfall, V-shaped, spiral, evolutionary prototyping, iterative and incremental. It provides details on the waterfall, spiral and iterative incremental models. For each it describes their usage, advantages and disadvantages. The waterfall model is linear and sequential while spiral combines prototyping and waterfall features. The iterative model develops the system through repeated cycles and smaller portions to overcome weaknesses of waterfall.
This document discusses compilers and related topics. It begins by listing textbooks on compilers and then poses questions about compilers, languages, and the differences between low-level and high-level languages. It defines a compiler as a program that translates a program written in one language into another language. The document also discusses decompilers, cross-compilers, the analysis-synthesis model of compilation, and interpreters.
The document discusses database systems and database management system (DBMS) architectures. It describes the three-schema architecture with mappings between conceptual, internal, and external schemas. It also discusses DBMS languages like DDL, DML, and DCL. Finally, it summarizes common client-server architectures like two-tier, centralized, distributed, and three-tier architectures.
This document summarizes a chapter from an operating systems textbook that discusses deadlocks. It describes the deadlock problem, different methods for handling deadlocks including prevention, avoidance, and detection. Prevention methods aim to ensure a system will never enter a deadlock state, while avoidance allows the system to enter unsafe states but prevents deadlocks, and detection allows deadlocks to occur but includes an algorithm to detect them for recovery. The chapter covers characterization of deadlocks, resource allocation graphs to model deadlock states, and algorithms like the banker's algorithm for deadlock avoidance in systems with multiple resource instances.
Discover the cutting-edge telemetry solution implemented for Alan Wake 2 by Remedy Entertainment in collaboration with AWS. This comprehensive presentation dives into our objectives, detailing how we utilized advanced analytics to drive gameplay improvements and player engagement.
Key highlights include:
Primary Goals: Implementing gameplay and technical telemetry to capture detailed player behavior and game performance data, fostering data-driven decision-making.
Tech Stack: Leveraging AWS services such as EKS for hosting, WAF for security, Karpenter for instance optimization, S3 for data storage, and OpenTelemetry Collector for data collection. EventBridge and Lambda were used for data compression, while Glue ETL and Athena facilitated data transformation and preparation.
Data Utilization: Transforming raw data into actionable insights with technologies like Glue ETL (PySpark scripts), Glue Crawler, and Athena, culminating in detailed visualizations with Tableau.
Achievements: Successfully managing 700 million to 1 billion events per month at a cost-effective rate, with significant savings compared to commercial solutions. This approach has enabled simplified scaling and substantial improvements in game design, reducing player churn through targeted adjustments.
Community Engagement: Enhanced ability to engage with player communities by leveraging precise data insights, despite having a small community management team.
This presentation is an invaluable resource for professionals in game development, data analytics, and cloud computing, offering insights into how telemetry and analytics can revolutionize player experience and game performance optimization.
Do People Really Know Their Fertility Intentions? Correspondence between Sel...Xiao Xu
Fertility intention data from surveys often serve as a crucial component in modeling fertility behaviors. Yet, the persistent gap between stated intentions and actual fertility decisions, coupled with the prevalence of uncertain responses, has cast doubt on the overall utility of intentions and sparked controversies about their nature. In this study, we use survey data from a representative sample of Dutch women. With the help of open-ended questions (OEQs) on fertility and Natural Language Processing (NLP) methods, we are able to conduct an in-depth analysis of fertility narratives. Specifically, we annotate the (expert) perceived fertility intentions of respondents and compare them to their self-reported intentions from the survey. Through this analysis, we aim to reveal the disparities between self-reported intentions and the narratives. Furthermore, by applying neural topic modeling methods, we could uncover which topics and characteristics are more prevalent among respondents who exhibit a significant discrepancy between their stated intentions and their probable future behavior, as reflected in their narratives.
06-18-2024-Princeton Meetup-Introduction to MilvusTimothy Spann
06-18-2024-Princeton Meetup-Introduction to Milvus
tim.spann@zilliz.com
https://www.linkedin.com/in/timothyspann/
https://x.com/paasdev
https://github.com/tspannhw
https://github.com/milvus-io/milvus
Get Milvused!
https://milvus.io/
Read my Newsletter every week!
https://github.com/tspannhw/FLiPStackWeekly/blob/main/142-17June2024.md
For more cool Unstructured Data, AI and Vector Database videos check out the Milvus vector database videos here
https://www.youtube.com/@MilvusVectorDatabase/videos
Unstructured Data Meetups -
https://www.meetup.com/unstructured-data-meetup-new-york/
https://lu.ma/calendar/manage/cal-VNT79trvj0jS8S7
https://www.meetup.com/pro/unstructureddata/
https://zilliz.com/community/unstructured-data-meetup
https://zilliz.com/event
Twitter/X: https://x.com/milvusio https://x.com/paasdev
LinkedIn: https://www.linkedin.com/company/zilliz/ https://www.linkedin.com/in/timothyspann/
GitHub: https://github.com/milvus-io/milvus https://github.com/tspannhw
Invitation to join Discord: https://discord.com/invite/FjCMmaJng6
Blogs: https://milvusio.medium.com/ https://www.opensourcevectordb.cloud/ https://medium.com/@tspann
Expand LLMs' knowledge by incorporating external data sources into LLMs and your AI applications.
Interview Methods - Marital and Family Therapy and Counselling - Psychology S...PsychoTech Services
A proprietary approach developed by bringing together the best of learning theories from Psychology, design principles from the world of visualization, and pedagogical methods from over a decade of training experience, that enables you to: Learn better, faster!
PyData London 2024: Mistakes were made (Dr. Rebecca Bilbro)Rebecca Bilbro
To honor ten years of PyData London, join Dr. Rebecca Bilbro as she takes us back in time to reflect on a little over ten years working as a data scientist. One of the many renegade PhDs who joined the fledgling field of data science of the 2010's, Rebecca will share lessons learned the hard way, often from watching data science projects go sideways and learning to fix broken things. Through the lens of these canon events, she'll identify some of the anti-patterns and red flags she's learned to steer around.