CompTIA A+ 220-902 covers installing and configuring operating systems like Windows, iOS, Android, OS X and Linux. In addition to this the exam covers security, cloud computing and operational procedures. The official exam objectives are 1.0 Windows Operating Systems, 2.0 Other Operating Systems, 3.0 Security, 4.0 Software Troubleshooting, 5.0 Operational Procedures. Passing the 220-902 and 220-901 is required to receive the CompTIA Certification. Generally the 220-901 is completed first but it is not required.