For example, to deploy an SVS package via AppStream you begin within the confines of the SVS administration utility. After you’ve captured an application install you need to export the layer to a VSA file. Next, you copy the VSA file to a system running the AppStream packager where you open the VSA and convert it into an AppStream ZIP package. Once that’s done you need to upload the package to the AppStream server and then provision it for distribution. All told, you’re forced to navigate across four different UIs (SVS admin, AppStream packager, AppStream upload/import utility, AppStream Web console) spanning three different runtime platforms (Windows, Java, Web). By contrast, with SoftGrid you remain within a single UI and platform (Windows), and importing an application requires just a single step (copying the package to the Content folder).

Click for larger view.

This spotty integration also extends to the delivery process. When testing SVS Pro against the aforementioned Office 2003 test bed, I clocked AppStream at no less than 1 minute and 45 seconds from initial user request to the appearance of the virtualized application. During this time AppStream was downloading nearly 50MB of data into the local SVS cache and generating just under 80Mbps of network traffic.

Compare this to the 9 to 13 seconds for SoftGrid or the 2 to 5 seconds for Thinstall, and you can see that, at least during the initial program load to cache, SVS Pro is far from a speed demon. However, on the positive side this large initial blob includes the most common code blocks required for all of the packaged executables. So while it might take longer to launch the requested application for the first time, subsequent launch requests -- either to the first application used or any of the other applications in the SVS package layer (in this case Word, Excel, PowerPoint, and Access) -- are serviced almost instantaneously.

An analysis of subsequent streaming requests (i.e. grabbing additional code to support functions not downloaded in the initial 50MB or more blob) showed a much more granular access pattern. All of which seems to point to an architectural tradeoff when dealing with streaming SVS packages: You need to download more of the package blocks to get the first application started, but these additional blocks help to eliminate the need for subsequent roundtrips to get additional applications loaded. To put this in perspective, you have to add up the initial startup times for Word, Excel, PowerPoint, and Access under SoftGrid (44 seconds) before you’ve achieved the same degree of functionality that the initial SVS Pro download provides.

One area in which the SVS Pro solution outshines both SoftGrid and Thinstall is in its support for Web-based access to packaged applications. The AppStream Web portal makes it easy for users to surf up and access the desired applications in a kiosk-like, on-demand fashion. In this regard, SVS Pro provides a solution that is closer to the subscription-based delivery model that has been the holy grail of commercial developers for nearly a decade.