  Cloud Computing emerges from the global economic crisis as an option to use
computing resources from a more rational point of view. In other words, a
cheaper way to have IT resources. However, issues as security and privacy, SLA
(Service Layer Agreement), resource sharing, and billing has left open
questions about the real gains of that model. This study aims to investigate
state-of-the-art in Cloud Computing, identify gaps, challenges, synthesize
available evidences both its use and development, and provides relevant
information, clarifying open questions and common discussed issues about that
model through literature. The good practices of systematic map- ping study
methodology were adopted in order to reach those objectives. Al- though Cloud
Computing is based on a business model with over 50 years of existence,
evidences found in this study indicate that Cloud Computing still presents
limitations that prevent the full use of the proposal on-demand.

Distributed, Parallel, and Cluster Computing