Virtualization is all the rage these days. Chances are good that if you're not pursuing some sort of application or server virtualization strategy now, you probably will be in the near future; the potential cost savings are that compelling.
However, not all virtualization technologies are made the same. In fact the term virtualization has gradually expanded in scope during the past few years, now encompassing everything from classic virtual-machine monitors, such as VMware and Microsoft Virtual Server, to sophisticated virtualized application-deployment solutions.
Softricity's SoftGrid falls under the latter category. A Windows-based software virtualization platform, SoftGrid lets IT shops effectively eliminate one of the most challenging aspects to managing Windows applications: deployment and maintenance of the installed base. By dissecting and repackaging an application's installation image -- a process Softricity calls "sequencing" -- SoftGrid makes it possible to deliver the application to a Windows client without actually modifying the local file system or registry.
To accomplish this, SoftGrid intercepts application I/O calls and redirects them to a locally cached version in its virtual file system. In this regard, it is quite similar to Altiris SVS (Software Virtualization Solution), a product I reviewed earlier this year. However, whereas SVS is machine-specific, deploying a virtualized application to a specific client system, SoftGrid is focused on the user's log-in credentials. Applications follow the user from machine to machine, with all user settings and preferences preserved and reproduced independently of log-in location.
Another significant difference compared with SVS, SoftGrid uses streaming to deliver the virtualized code. When a user first launches the application, it delivers only certain portions of its code base -- those byte streams defined in the primary "feature block" when the application was sequenced. Subsequent use of the application runs entirely from the local cache until a previously uncached portion of the code base is requested, at which time the streaming process continues.
By contrast, SVS requires the entire virtualized application package to be delivered before it can be activated. SoftGrid can also run in this mode, a feature the company calls pre-caching, used primarily for mobile and/or occasionally connected users.
The advantage to streaming is that it allows for the aforementioned machine-independence. By tightly coupling its deployment model to AD (Active Directory), Softricity is capable of leveraging much of the roaming user profile functionality that debuted with Windows 2000. In fact, outside of the virtualization component, SoftGrid is essentially a natural evolution of the IntelliMirror technology, which forms the basis for Microsoft's current application management architecture.
Maintaining such close proximity to the Microsoft way can be a double-edged sword, however. For starters, it makes it difficult to use Softricity in a non-AD environment. You need at least a basic level of AD functionality -- a domain with DNS, for example, properly configured -- just to install the server components.