This chapter examines the cloud technologies basics. The Cloud Security Alliance (CSA) is a non-profit organization, formed in 2008, that defines best practices for cloud security. Numerous corporations participate in this organization, including: Microsoft, Rackspace, VMware, HP Enterprise, Cisco, Citrix, RedHat, Symantec, among numerous others. It has numerous working groups that work in cloud standards, certification, and education, among several other areas. It provides a third-party assessment of a cloud service provider's security through the CSA Star Certification and assessment process. For individuals working in cloud computing, CSA provides cloud computing certifications, including the Certificate of Cloud Security Knowledge, and the Certified Cloud Security Professional. A disk image is a copy of the entire contents of a storage device. A virtual machine image is a single file which contains a virtual disk. A Virtual Machine is an emulator of a particular computer system.