This is the first part of a two-part article. Part two is published today.
Parsons, a $3 billion construction and engineering company, once had hundreds of fat clients on the desktops of its engineers. That spelled nothing but trouble for the IT staff. “We had cadres of IT folks who would go around with CDs, and they’d push the user aside and say, ‘Hey, go have a smoke while I download this application,’” says CIO Joe Visconti.
That was only the beginning. “If it was something like AutoCAD, it could take an hour to load, then the IT guy would have to configure it,” he recalls. “Then he’d get a call a few minutes later saying, ‘Hey, this is not running. Help me.’ Then, as soon as there was a patch or new release, someone would go through all the desktops again.”
Keeping track of which users had which versions of an application, who had various patches and so on was a nightmare, Visconti says. And if a user needed multiple versions of software for different engineering projects, the versions had to be installed and uninstalled as his needs changed.
That was the lay of the land in most IT shops as the century turned, and it’s the way things still are today at many companies. But new models of computing are taking hold as IT looks to reduce the cost and complexity of managing PCs. Among these are the virtualisation and streaming of desktop applications, with the goal of moving the management of desktops to the data centre, where it can be done more easily, more securely and often more cheaply.
The virtualisation and streaming of applications evolved from a long heritage. In the 1970s, dumb terminals connected to mainframes. The big desktop boxes were aptly named; all they did was collect keystrokes and deliver boring green text. Then in the 1980s came minicomputers and PCs, connected in a paradigm-busting arrangement called client/server computing. These desktop machines were far from dumb; they were called “fat clients” because they were fully loaded with processors, memory, disk drives, I/O devices, operating systems and application software.
In the 1990s, things got a bit more complicated. IT managers discovered that still more tiers could bring even better performance, flexibility and scalability. Applications could be broken into presentation, business logic, data access and data storage layers, each residing where it worked best.
At the same time, there was a backlash against the cost and complexity of fat clients, and some IT managers turned to “thin clients” and “network computers,” basically dumb terminals with a grade-school education.
But these days, operating system upgrades, new applications, bug fixes and security patches have escalated in frequency. Users are more likely to install their own applications and even demand that IT install special software for them. Substantial portions of IT staffs travel from desktop to desktop, keeping PCs running properly.
Enter virtualisation -- which isolates the application from the operating system and other applications -- and streaming, which delivers the application to the user.
By moving the management of desktops to the data centre, this combination can reduce hundreds of desktop environments to one that’s under lock and key, while giving the user the illusion that he still has a fat client. Or a server can hold multiple desktop images, each tailored to a specific user’s work based on profiles stored in a directory.
Then, when the user needs them, those applications -- and sometimes complete operating environments -- can be “streamed” over the network to the desktop, where they execute locally, without the server and communications overhead that comes from traditional client/server or thin-client computing. Some products allow the streaming of just those pieces of software actually needed for that session -- perhaps just 20 per cent of an application’s code -- minimising the demand for bandwidth, memory and disk.
Virtualisation allows the streamed applications to reside in their own self-contained operating environments. They can be encapsulated, with their own Dynamic Link Libraries (DLL) and registry settings, so that multiple versions of an application can coexist without conflicting. When something goes wrong -- say, a PC gets a virus infection -- a new desktop image can be streamed to the user without a visit from IT.
But there are some caveats. A robust network is required to avoid delays while streaming occurs -- although applications can sometimes be started before they are fully downloaded, and parts or all of commonly used applications may be cached locally. If a connection can’t be maintained, as with a laptop in motion, whatever software is needed until a connection is restored must be cached to a local disk. And there are enough differences from traditional computing methods to require some attitude adjustments on the part of both users and IT support staffers.
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