[作業] 4/8 作業系統
(3.5)
Describe the actions taken by a kernel to context-switch between process.
(3.9)
Describe the differences among short-term, medium-term, and long-term
scheduling.
(3.10)
#include <stdio.h>
#include <unistd.h>
int main()
{
/*fork a child process */
fork();
/*fork another child process */
fork();
/*and fork another */
fork();
return 0;
}
How many process are created?
(3.11)
#include <sys/types.h>
#include <stdio.h>
#include <unistd.h>
int main()
{
pid_t pid, pid1;
/*fork a child process */
pid=fork();
if(pid<0) {/*error occurred */
fprintf(stderr, "Fork Failed");
return 1;
}
else if(pid==0){/*child process */
pid1=getpid();
printf("child: pid=%d ",pid); /*A*/
printf("child: pid1=%d ",pid1); /*B*/
}
else {/*parent process */
pid1=getpid();
printf("parent: pid=%d ",pid); /*C*/
printf("parent: pid1=%d ",pid1); /*D*/
wait(NULL);
}
return 0;
}
What are the pid values?
至於如何跑程式...舉例說明
首先連到工作站
然後打vim OS.c
按i就可以編輯文件
把複製的程式碼按右鍵，就會貼上去
按ESC，再輸入:wq 就會存檔離開
gcc OS.c -o OS_HW，這是在做編譯
OS_HW是編譯過的檔案
./OS_HW 來執行程式
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