Vinay Singla

Data integrity is one of the most critical elements in any system. Data integrity is easily achieved in a standalone system with a single database. Data integrity in such a system is maintained via database constraints and transactions. Transactions should follow ACID (Atomicity, Consistency, Isolation, Durability) properties to ensure data integrity. Most databases support ACID transactions and can preserve data integrity. Next in the complexity chain are distributed systems. In a distributed system, there are multiple databases and multiple applications. In order to maintain data integrity in a distributed system, transactions across multiple data sources need to be handled correctly in a fail-safe manner. This is usually done via a central global transaction manager. Each application in the distributed system should be able to participate in the global transac... (more)

Architecting for Multi-Tenancy in the Cloud

Why is Software as a service (SaaS) gaining such momentum? What makes the SaaS proposition so compelling? “Faster time to capability” and “lower upfront cost” are two of the main reasons for this. For any organization looking into adding a system capability, once the buy or build decision is out of the way and the decision is to buy, there are two choices; either buy a software package and deploy it on premise OR subscribe to a SaaS provider. Deploying a software package on premise is no simple task. It can take months or even years to go-live with full functionality and realize ... (more)

The Overlapping Worlds of SaaS and SOA

Software as a Service (SaaS) is getting a lot of attention these days. The concept of SaaS is not new and has existed for a while. It has been referred to by other names such as Application Service Provider (ASP), Managed service provider (MSP), on-demand services, cloud computing, utility computing etc. SaaS involves exposing applications over the network on a subscription basis with the pay-as-you-go model. This model was earlier popular with only small businesses who didn't want to invest heavily in their own IT departments, but slowly, this model is making its way into medium... (more)