operating system practiclas.docx - NAME - ankur tyagi(917)...

NAME - ankur tyagi(917) keshav
singh(975)
CLASS - B Sc(H) COMPUTER
SCIENCE III SEM
SECTION - A
SUBMITTED TO-MRS.RICHA GARG
1. WAP to display the following:

a. Kernel version
b. CPU type and model
c. Information on configured memory, amount
of free and used memory
#include<stdio.h>
#include<sys/vfs.h>
#include<sys/sysinfo.h>
#include<sys/utsname.h>
int main()
{
int r,a,q,p,b;
struct sysinfo s1;
struct utsname s2;
struct statfs s3;
r=sysinfo(&s1);
q=uname(&s2);
p=statfs("./",&s3);
a=(1024*1024);
b=(a*1024);
if(r==0&&q==0&&p==0)
{
printf("\nSystem name:%s",s2.sysname);
printf("\nVersion:%s",s2.version);
printf("\nRelease:%s",s2.release);
printf("\nMachine:%s",s2.machine);
printf("\nTotal RAM:%ldMB",(s1.totalram/a));
printf("\nFree RAM:%ld MB",(s1.freeram/a));
printf("\nUsed RAM:%ld MB",((s1.totalram-s1.freeram)/a));

printf("\nTotal Size of partition:%ldGB\n",(s3.f_bsize*s3.f_blocks)/b);
}
else
{
printf("ERROR\n");
}
return 0;
}
2. WAP to print file details including owner access
permissions, file access time, where file name is
given as a command line argument
#include<fcntl.h>
#include<sys\stat.h>
#include<stdio.h>
#include<stdlib.h>
int main(int argc,char *argv[])
{
struct stat statbuf;
int fd;
if(argc!=2){
printf(“wrong no. of arguments”);
exit 0;}
fd=open(argv[1],O-RDONLY|O_CREAT,0744);
fstat(fd,&statbuf);
close(fd);

printf(“Owner uid=%d\n”,statbuf.st_uid);
printf(“Group id=%d\n”,statbuf.st_gid);
printf(“Access Permission=%d\n”,statbuf.st_mode);
printf(“Size=%d\n”,statbuf.st_size);
printf(“No. of links=%d\n”,statbuf.st_nlink);
printf(“Last access time=%s\n”,ctime(&statbuf.st_atime));
printf(“Last modified time=%s\n”,ctime(&statbuf.st_mtime));
return 0;
}
3.WAP to copy a source file into the target file and
display the target file using system calls
#include<iostream>
#include<fcntl.h>
#include<stdlib.h>
#include<unistd.h>
using namespace std;
int main(int argc, char *argv[])
{
if(argc!=3)
{
cout<<"File name not found "<<endl;
exit(1);
}
int fd1=open(argv[1],0);
if(fd1<0)
{
cout<<"Error in opening file "<<argv[1]<<endl;
exit(1);}
int fd2=creat(argv[2], 0666);
if(fd2<0)
{

cout<<"Error in creating file "<<argv[2]<<endl;
exit(1);
}
char buf[500];
int count;
while(count=read(fd1,buf,sizeof(buf)))
{write(fd2,buf,count);}
close(fd1);
close(fd2);
return 0;
}
4.WAP (using fork() and/or exec() commands)
where parent and child execute :
a. same program, same code
#include<iostream>
#include<stdio.h>
#include<sys/types.h>
#include<unistd.h>
using namespace std;
int main()
{
pid_t pid;
pid=fork();
if(pid<0)
{
cout<<"this is a process";
}
else
{
cout<<"process continues";
}
return 0;
}
b. same program, different code
#include<iostream>
#include<stdio.h>
#include<unistd.h>

#include<sys/types.h>
using namespace std;
int main(){
pid_t pid;
pid=fork();
if(pid<0)
{
cout<<"new process not entered";
}
else if(pid==0){
cout<<"Child process";
}
else
cout<<"parent process";
return 0;
}
c. different programs
#include<iostream>
#include<stdio.h>
#include<unistd.h>
#include<sys/types.h>
using namespace std;
int main(){
pid_t pid;
pid=fork();
if(pid<0){
cout<<"No process entered";
}
else if(pid==0){
execlp("/bin/ls","ls",NULL);
cout<<"child process";
}
else {
cout<<"parent process";
}
return 0;
}
d. before terminating, the parent waits for
the child to finish its task