ソフトウェアエンジニアの技術ブログ：Software engineer tech blog

CPU1 CPU2 CPU3

#include <pthread.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <assert.h>

void* f1(void* arg){
	int whos_better;
	whos_better = 1;
	while(1)
		printf("Thread 1: thread %d is better.\n", whos_better);

		return NULL;
}

void* f2(void* arg){
	int whos_better;
	whos_better = 2;
	while(1)
		printf("Thread 2: thread %d is better.\n", whos_better);

	return NULL;
}

int main(int argc, char **argv){
	pthread_t th1, th2;

	pthread_create(&th1, NULL, f1, NULL);	
	pthread_create(&th2, NULL, f2, NULL);

	pthread_join(th1, NULL);
	pthread_join(th2, NULL);

	pthread_exit(NULL);
}

Key Abstractions
1. file
2. file name
3. Directory Tree

#include 
#include 
#include 
#include 

int main(int argc, char **argv){
	int fd;
	ssize_t len;
	char *filename;
	int key, srch_key, new_value;

	if(argc < 4){
		fprintf(stderr, "usage: sabotage filename key value\n");
		exit(EXIT_FAILURE);
	}

	filename = argv[1];
	srch_key = strtol(argv[2], NULL, 10);
	new_value = strtol(argv[3], NULL, 10);
}

CPU
Memory: fast, random access, temporary
Disk: slow, sequential access, durable

CPU Register <- cache -> Main Memory
10 cycle latency, 256 bytes / cycle

Memory Hierarchy
CPU
Main Memory

Write Policy
Hit:
– write-through
– write-back

Miss:
– write-allocate
– no-write allocate

Virtual Address Abstraction
Kernel addresses, user stack, heap, uninitialized data, initialized data, code