Saas vs. S+S
Saas is an architectural paradigm where a solution architecture can benefit from the economies of scale of the data and behavior of that architecture being built and hosted in the cloud by a third party in a multitenant fashion.

Software + Services is an architectural paradigm where a solution architecture can achieve some of the same economies of scale as Saas while simultaneously benefiting from the synergies and efficiencies of the data and behavior of that

architecture being partly built on premises and partly built by third parties in a multitenant fashion, as well as, partly hosted on premises and partly hosted in the cloud in a multitenant fashion.
The cloud meaning, from an application standpoint, a set of applications or services with standards based interoperable interfaces that can be easily reachable and easily composed from any platforms in any locations with an internet

connection. The cloud also meaning, from an infrastructure standpoint, a set of connected data centers providing elastic compute, elastic storage and other enterprise SLAs for those applications or services.
Multitenant meaning application routines, data and infrastructure meant to be built and hosted in a shared manner among multiple clients of the Saas organization.
In Software + Services the degree to which solution architecture is partly hosted on premesis or in the cloud, or, the degree to which the application is built from 3rd party services or software vs. homegrown software can be anywhere

along a spectrum of totally homegrown and hosted in house with small amount of 3rd party to almost totally a Saas model except for some code running on premises or close to the consumer of that data or behavior.
The "Software" in Software + Services alludes to data and routines executed or stored as close to the consumer as possible and/or on-premise inside corporate firewall. This could include everything from thick clients on desktops or

server software inside corporate firewalls to Silvelight web based applications to clients on roaming mobile phones.
The "Services" in Software + Services allude to data and routines running in the cloud. The cloud meaning, from an application standpoint, a set of applications or services with standards based interoperable interfaces that can be

easily reachable and easily composed from “the Software” which is hosted on any platforms in any locations with an internet connection. The cloud also meaning, from an infrastructure standpoint, a set of connected data centers

providing elastic compute, elastic storage capabilities and other enterprise SLAs for the “Services”.
The "+" in Software + Services is probably the most important part of the equation. The "+" alludes to the set of technologies and architectural patterns that provide the bridge out from the domain of the "software" to the domain of

the "services" and vice versa. There are certain challenges that must be met to achieve this connectivity which include identity projection, firewall traversal and possibly data synchronization.
Think of the "Software" and "Services" as the neutrons and electrons of the architecture. Then the "+" would be the strong nuclear force which combine to make the sum way more than its parts. The same way that neutrons and electrons

combine with the strong nuclear force to achieve the foundation of our reality, is the same way Software + Services will form the foundation of a global computing platform.
A smart man once said "The Network is the computer". I think this is what he meant.

Choices organizations make for their solution architectures from Saas to anywhere on the spectrum of Software + Services affect the costs, architectural flexibility and control of the infrastructure that hosts the solution and its data

and behavior.

You can also start left or right on this spectrum depending on your scenario. For example an organization with significant investments in on-premise software might be on the extreme left and start slowly by moving some small degree to

the right. A start up company might start out totally on the right with all thier software assets in the cloud but slowly move degrees to the left over time. A Saas ISV might have all the tiers of thier application hosted in the cloud

but bring some of it's power closer to the consumer by building a mesh enabled front end.


Costs of infrastructure
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Saas
Saas providers like salesforce.com manage large data centers that service all of their customers.
You gain cost savings on the capital expense of designing and provisioning a data center to support your application.
You gain cost savings on the operational expense of running and managing the lifecycle of that data center. The costs savings here are spread across all the tenants of that data center e.g. all the clients of salesforce.com. As

Salesforce learns more and more about how to improve their data center, from all their client experiences, those benefits are passed on to all their customers.
You gain many economies of scale.

Software + Services
Software + Services solutions leverage some of the Saas like economies of scale of cloud based infrastructure but also the computing power that is near the consumer of the application.
For example the ability to leverage the compute and storage of a mobile phone or laptop for the data and behavior of live mesh based applications.
This would provide some additional infrastructure cost savings vs. a solution entirely built and hosted in a Saas model.


Architectural flexibility of infrastructure
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Saas
Many Saas providers let you request additional compute and storage for your application on demand. If you are suddenly serving double your customers from last month you can pay for extra storage capacity.
If your application runs on servers alongside partner applications behind the same firewall you can imagine easier integration scenarios.

Software + Services
Software + Services solutions leverage some of the Saas like flexibility of infrastructure I just mentioned but also some additional architectural choices like disconnected client access or integrating with other on-premise or mobile

operating system software. This application can simultaneously leverage compose able Saas like services in the cloud for collaboration. For example the instant message client this same application would require some compute and

routines on centralized cloud servers to route and process messages.

Control of SLAs of the infrastructure
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Saas
With Saas Unfortunately you lose control. Not that losing control of the infrastructure of your data center is good or bad but a functional requirement of your solution architecture might be to have control over some SLA like the

geo-location of your servers that host your data.
Another affect of control of your SLA would be that salesforce.com might be able to guarantee .999 percent availability but you need .99999999.
Examples are flight control systems availability or a government or industry regulation that forces a health provider to keep machines that host patient data within the walls and behind the firewall of the provider organization.

Software + Services
Software + Services provide choice. If you need control of an SLA you can have it. You just run that part of your solution architecture on-premises and the rest you put in the cloud.
Example is NASA flight control system. You want that system to be inside the NASA space center in control of your specialized engineers but all the data it generates you can shoot up into the cloud for heavy analysis. You could

imagine an application that compares this archived analysis results with current real-time flight data to report deviations and anomalies.



Costs of the data
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Saas
Data must be backed up, recovered and protected.
Databases must be procured and installed.
With Saas provider you gain cost savings on the capital expense of purchasing and installing a database or designing and building a database schema and/or data warehouse.
You gain cost savings on the operational expense of managing the lifecycle of your database, backing up, recovering and protecting the data within it. The costs savings here are spread across all the tenants of the Saas data

architecture e.g. all the clients of salesforce.com. As Salesforce learns more and more about backup and recovery processes, or more efficient or effective data models across all their client experiences, those benefits are passed back

to all customers.

Software + Services
You may find that hosting your data in the cloud adds some overhead in terms of meeting compliance requirements.
This cost may be prohibitive or slow down your business. You may want to host a slice of your data in house, the slice that would be costly in terms of meeting compliance.


Architectural flexibility of the data
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Saas
Since your data model is similar if not the same as other clients of the Saas provider many data integration scenarios are easier to achieve with partners.
Data can be analyzed across Saas customers and aggregated results passed back to the benefit of all customers. Mergers and acquisitions would be easier and faster to execute. Even across different Saas providers if both Saas providers

have done integrations together before.

Software + Services
Having some of the data in the domain or location of the consumer of the data; be that on a mobile device offline or behind corporate firewalls may provide some required architectural choices.
Data stored on decentralized mobile devices can continue to work. In addition you can take advantage of peer to peer architectures for your data that may save you from using up too much of the clouds bandwidth and more of your

consumers bandwidth. You may have an application on a device that needs to share data across co-located devices. Or some of that data may need to reside in house to provide decision support for a set of machines on an assembly line.



Control of SLAs of the data
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Saas
With Saas unfortunately you lose control. Not that losing control of the SLAs around your data are good or bad but a functional requirement of your solution architecture might be to tag certain data for regulatory reasons in the

particular industry or sub industry you are in.

Software + Services
Cloud based data solutions offer high scalability but maybe not the performance you require.
Real time processing of flight data needs to happen quickly. You may not have 1000 users but just 5 engineers that need data analyzed real-time of the last 100 gigs of data. But the rest of the data can be archived in the cloud for

analysis by the entire staff of NASA as part of the same application.


Costs of building application features
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Saas
Features are already coded for you; you just ask to turn them on. You don’t have to buy programmers to create features.
Ongoing maintenance and debugging of application features are done by a team of many programmers highly in tune with the problem domain and the benefits of fixes are spread out to every one of the Saas providers clients.
Lessons learned are baked into the system across all of the experiences with the tenants of the application. Economies of scale on the ongoing improvement of the software are achieved.

Software + Services
Software + Services provide choice. While leveraging the economies of scale of Saas, S+S also allows you to defined specialized routines that apply to your specific scenario.
It may cost less for you to build these specialized routines in house as your team is highly performant in the unique aspects of your business needed these specialized routines.



Architectural flexibility of building application features.
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Saas
Saas lets you easily expose functionality to partners outside of your firewall from its central perch in the sky.

Software + Services
Software + Services lets you combine the architectural benefits of connectivity in the sky with the ability to connect to legacy on premises apps or software in client machines.


Control of SLAs of building application features
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Saas
With Saas unfortunately you lose control. You may want to log for auditing purpose every time an image from a radiology application is erased from a patient record.
You might have to live with the default feature set of a Saas provider that does not do this.

Software + Services
Software + Services give you back some control. You can connect to application features in the cloud and add your own features with specialized steps as you see fit.

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Comment by Gürcan SERBEST on February 19, 2009 at 5:40am
Hey Joan this knowledge is gr8. I must say that "Thank You"

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