00409nam a2200133Ia 4500008004100000020001800041082001800059100002600077245002900103260003900132300000800171546000900179650008700188230312s9999||||xx |||||||||||||| ||und||  a81-7808-447-3  a005.43bTAN-M  aTanenbaum Andrew , S. 0aModern Operating Systems  bPearson EducationaNew Delhic2001  a951  aEng.  aComputervWhat is an Operating System ? Histroy of Operating system , System calls