From the developer: "The Boson IBM practice tests will prepare you for the actual IBM exam. This includes IBM AIX v4.3 System Support and IBM XML exams. More exams are being added. Each practice exam contains over 200 questions and explanations and has a money-back guarantee.
"Each test in this download allows unlimited use of a 12-question database. Registration gives you use of 200+ questions, answers, explanations, and use of flash-card mode."