00331nam a2200121 a 450000500170000002000150001708200200003210000210005224500580007326000360013130000210016770000210018820251203092008.0  a0201427753  a005.43,bD, bra  aBraun, Christoph  aUnix system security essentials, Christoph Braun, eng  aMenlo Prk, Addison-Wesleyc1995  aviii,155p.c22cm  aNixdorf, Siemens