Computer Basics
Cloud Computing
Cloud computing
• makes available computer system resources on-demand.
• Available over the internet on pay-as-you-go basis.
• The user can just use the utilities without managing them.
• The services are infrastructure as a service (IaaS), platform as a service (PaaS) and software as a service (SaaS)
• Cloud can be public, private or hybrid
Public cloud
• Cloud service providers like AWS, Azure etc. provides resources over the internet on-demand
• Resources are shared
• Resources are delivered by third-party providers
• The customer gets latest infrastructure
• The services are cheap
• Services are by subscription or pay-as-you-go basis
Private cloud
• Cloud services are offered by a service provider or they reside on organization’s data center
• It is more secure because the resources are for specific users
• Resources are not shared
• As there are no multiple tenants, issues pertaining to these are not there
• The security helps in dealing with sensitive data
• Full control over hardware and software
Hybrid cloud combines public cloud and private cloud features
Infrastructure as a Service (IaaS)
• IaaS is a service model of cloud computing where cloud hosted servers, networks and storage can be accessed on demand
• The service is pay-as-you-go service
• Resources are scalable and elastic
• They can be hosted in public, private or hybrid clouds
• Latest technology available
• Available across many geographic locations
• Useful in test and development environments
• Example: Amazon Web Services, Microsoft Azure
Platform as a Service (PaaS)
• Cloud service provider provides complete development and deployment environment
• Cloud service provider provides computing platform including servers, networks, storage, development tools, database management systems, business intelligence services and middleware
• It helps in fast development of applications
• It helps in focusing on the application without worrying about environment
• Software maintenance will also be done if required
• It can be delivered through public, private or hybrid clouds
• Example: Windows Azure
Software as a Service (SaaS)
• Cloud service provider provides software on pay-as-you-go basis
• It is provided over the internet on demand
• Some of the examples of software delivered are office software, CAD software, payroll software, accounting software etc.
• Installation and maintenance is taken care of by provider
• Applications run on provider’s servers
• They can be accessed from anywhere through a thin client like web browser
• Example: GoToMeeting, Dropbox
Limitations
• Lack of customized services
• Security issues as the service not internal part of the Organization
• Has to abide by the policies of cloud service provider
• Legal aspects of having service outside the Organization has to be looked into
• Privacy of data is an issue
• Downtime of the cloud server may affect the Organization services