IaaS service because building out a full infrastructure for  unpredictable requirements isn’t economical. In the case of PaaS  companies find that PaaS can offer value  during development and deployment  instead of having to  purchase many different tools. By providing the underlying  software infrastructure  PaaS can reduce organizational costs.  PaaS reduces many of the costs involved with the traditional  application development and deployment model including  server and storage overhead  operating systems  workload  and performance management software  network bandwidth   software maintenance  and support personnel. However   there are also some indirect value drivers for PaaS. These  include These materials are the copyright of John Wiley & Sons  Inc. and any  dissemination  distribution  or unauthorized use is strictly prohibited. ✓ Lowering skill requirements:  Perhaps only one or two  people in an organization have the skills necessary to  work with a certain kind of middleware. By providing the development tools and middleware  PaaS lowers the  skill level required to deploy applications and removes  the bottleneck that can form waiting for one specific person’s assistance. ✓ Reducing careless mistakes:  Mistakes  such as someone  forgetting to load a configuration file can take a week  before the problem is identified. Such mistakes add up  to time and money wasted and cause deployment delays.  With PaaS  such mistakes are reduced because the platform has been tested and is known to work. These  successful and well-understood patterns are an important  benefit of a PaaS. ✓ Some organizations are using IaaS for  cloudbursting  when  there are unexpected or planned high-load periods. The  flexibility of using IaaS means that the company doesn’t  have to overinvest in hardware. These companies must  be able to adapt to higher loads to protect themselves. ✓ Organizations may have a continuing need for additional  compute or storage resources over time and can use  a private IaaS to make those resources available on  demand for a variety of projects. For example  additional  public or private resources may be required as hardware  reaches end-of-service life. Cloud Services For Dummies  IBM Limited Edition  28