agile and waterfall - Software as a service (SaaS)

1.. What is   Agile software development ?

Agile_software_development

One of the differences between agile and waterfall, is that testing of the software is conducted at different points during the software development lifecycle. In the waterfall model, there is a separate testing phase after implementation. In Agile XP, testing is done concurrently with implemetation.
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2.Software as a service (SaaS) ?

software as a Service (SaaS) is a model of software deployment where an application is hosted as a service outside of the customer’s site and delivered to customers across the Internet.

saas - in nutshell

saas - deployment model
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Software_as_a_service

sometimes referred to as "on-demand software" , is a software delivery model in which software and associated data are centrally hosted on the cloud. SaaS is typically accessed by users using a thin client via a web browser.

SaaS has become a common delivery model for many business applications, including accounting, collaboration, customer relationship management (CRM), management information systems (MIS), enterprise resource planning (ERP), invoicing, human resource management (HRM), content management (CM) and service desk management.^[

The term "software as a service" (SaaS) is considered to be part of the nomenclature of cloud computing, along with infrastructure as a service (IaaS), platform as a service (PaaS),desktop as a service (DaaS), and backend as a service (BaaS).^[8]

Architecture

While an exception rather than the norm, some SaaS solutions do not use multi-tenancy, or use other mechanisms—such as virtualization—to cost-effectively manage a large number of customers in place of multi-tenancy.^[12] Whether multi-tenancy is a necessary component for software-as-a-service is a topic of controversy.^[13]

Open integration protocols

Since SaaS applications cannot access a company's internal systems (databases or internal services), they predominantly offer integration protocols and application programming interfaces (APIs) that operate over a wide area network. Typically, these are protocols based on HTTP, REST, SOAP and JSON.

References:

Developing a SaaS product? Scrum is NOT for you.

Scrum:
More methodical way of developing.

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