Cloud Computing allows companies to consumer computing services on demand.

Cloud providers divide this concept into three markets:

• IaaS (Infrastructure as a Service), less often ITaaS (IT as a Service): only hardware (servers) is dematerialized. Clients can start&stop virtual Linux/Windows servers on demand in datacenters, without having to care about underlying physical machines and costs (hardware maintenance, air conditioning, power supply etc.).
  • Pros: high flexibility, total control on systems (remote administration through SSH or Remote Desktop), can install all kinds of business software
  • Cons: need system admins as for classical on-premises server solutions


• PaaS (Platform as a Service): hardware, hosting and application framework are dematerialized. Clients push their existing application into the Cloud, or develop a new application with tools offered by providers.
  • Pros: deployment is automated, no software to buy or additional installation to perform.
  • Cons: limited to one or two technologies (eg.: Python or Java for Google AppEngine, .NET for Microsoft Azure, proprietary for force.com). No control upon underlying virtual machines. Only suitable for Web applications.


• SaaS (Software as a Service): hardware, hosting, application framework and software are dematerialized. Clients don't buy software anymore but consume it on demand, by paying for real usage. Software is hosted at the provider, in its own datacenter.
  • Pros: no installation, no upgrade (they're continuous at provider), no data migration etc. Payment per usage. Testing new software is easy.
  • Cons: limited by definition to the offered software. No control upon storage and data security associated with the software. Web applications responsivity not always good.
  • Did you know that by using Gmail, you're already consuming (free) SaaS?

For us, IaaS is by far our prefered market: it offers by far the largest opportunities, the best flexibility and the best control by allowing to migrate any existing business application into the Cloud, and to move any kind of server into the Cloud in order to reduce one's costs.