 data exchanged is formatted SO that it is not blocked by firewalls at either end. A firewall is a software application that all incoming transmissions must pass through. Firewalls are programmed to accept only certain transmissions and to block known viruses. The software used to spin applications to the cloud makes the addressing formats compatible between the cloud's infrastructure and the customer's data center, and vice versa. Another complication of spinning applications to the cloud is that many users access applications from mobile devices. Companies have to figure out how to get applications to them when they're not sitting at their desk. Two issues are that the mobile user may be accessing an application from a location with poor mobile coverage and from a device with a small screen that makes it difficult to actually view the data easily. Moving applications from data centers to the cloud can involve rewriting them or changing internal processes. For example, operating systems and addressing schemes used by a particular cloud provider might be different from those utilized by its customer. Addressing schemes can include formats such as IP addresses assigned to databases and applications, and Media Access Control (MAC) addresses for individual computers. In addition, compatibility between the two www.TechnicalPDF.com infrastructures is important, because applications that reside on a provider's infrastructure interface might not be compatible with its customers' databases. Regulations and the Cloud Various state and national regulations mandate that organizations in fields such as banking, healthcare, pharmaceutical, and government retain files for specified lengths of time. In addition to archiving information with cloud providers, organizations often use these providers as a lower-cost emergency backup in the event that their data is destroyed in a natural disaster, fire, or computer hacking incident. Enterprises can store up to 1 petabyte (PB) of data in servers that are often as large as a refrigera