Windows 7 migrations are occurring throughout the business world, but not without expense and hassle. One of the most difficult questions is how to let applications designed for Windows XP and earlier versions of Windows make the trip into the next generation of Microsoft-based computing.
Windows powers 96% of corporate PCs, according to a Forrester report released last year. But despite years of experience selling to businesses, Microsoft hasn't eliminated the application compatibility problem.
"Microsoft has clearly done a better job preparing the hardware and software ecosystem for Windows 7 than it did for Windows Vista, but significant work still remains for IT managers responsible for application inventorying, testing, remediation and packaging," Forrester said.
Estimates vary widely, but at least a sizable minority of Windows XP applications will have to be replaced or rewritten to make the upgrade to Windows 7. If your firm is already on Windows Vista, the compatibility problem won't be nearly as bad. But with that in mind, let's go over some best practices for tackling application compatibility during Windows 7 deployments.
1. Make a list
This one's pretty obvious, but crucial, particularly for large businesses. Glenn Jones, an IT project leader who is heading up a Windows 7 migration for 11,000 users at Molex, a global component supplier, explains that simply using Windows XP Mode to shoehorn old applications into Windows 7 would have created more complications than it was worth. So, Jones and team used the Microsoft Application Compatibility Toolkit to analse more than 16,000 lines of data, representing 650 applications.
"We went through every single application that was on that list to identify if they were valid and still being used," Jones says. "The tool also helped identify some of them that were Windows 7-compatible."
After a lengthy analysis period, Molex decided to eliminate many applications, while adding others, eventually settling on 341 applications that would be used with Windows 7. "We found a lot of opportunities to consolidate onto fewer applications," Jones says. "We had a few that still required Internet Explorer 7, but we were able to either give access to them through terminal servers temporarily, or upgrade them to become compatible."
Jones gathered key people at Molex together for a four week session on migration issues, including what the Windows 7 image would contain. But it turned out application compatibility was the most complicated portion. Looking back, Jones says Molex could have stretched out the whole migration analysis process to at least three months, and spent four weeks alone just on application issues.
2. Choose the right tools
While Jones at Molex used Microsoft's Application Compatibility Toolkit (ACT), that's not the only option. Unfortunately, no tool is perfect, and manual work will be required. "The market for application compatibility assessment tools is still young," Gartner analysts Michael Silver and Stephen Kleynhans wrote in a report titled "Application Compatibility Assessment Tools for Windows 7 Migrations," published in December.
ACT, which is free, is relatively straightforward to install and run, and includes a component to test Internet Explorer applications, Gartner says. But it still requires more manual application testing work than most paid tools, and it's unlikely to evolve into a best of breed application. The process of moving applications after testing is completed is difficult with ACT.
"Once testing is completed and results are recorded, ACT includes another tool, Compatibility Administrator, to enable technicians to select shims to apply to the application to improve its compatibility with Windows 7," Gartner says. "This process is manual and time consuming, and requires technical expertise to understand why the application is failing and select the proper shims to fix it. The application is then tested and shimmed iteratively until it is fixed."
"We see more similarities between the products than differences," Gartner says. "The products don't actually test applications or examine runtime behaviour, but examine installation packages to understand application compatibility and make changes to the installation packages, the way the applications are installed or the way Windows runs them. These products are best suited to organisations with a reasonable amount of control of their application portfolios as they are more likely to be able to compile a repository of application installation files."
The products can examine compatibility with Windows 7, Microsoft's App-V virtualisation software, Citrix XenApp and Windows Server 2008 R2.
Both products have tools for testing Internet Explorer applications, which comes into play a lot for businesses that built apps for IE6. However, "because many browser applications are not hosted on customers' servers, there is a limit to what end user organisations can do to fix browser applications," Gartner writes.
There are a couple of differences between App-DNA and ChangeBASE. For one, the method of fixing applications is different.
"AppTitude has a more conservative approach that presents the tester with alternatives, while AOK attempts more automated application fixes by MSI Windows Installer (MSI) configuration updates and [changes]," Gartner says. "ChangeBASE claims its tool can fix more applications. However, its methodology may be riskier and requires more application retesting after the fix."
There will also be variations between App-DNA and ChangeBASE when it comes to availability of testing tools for third party products, including application virtualisation tools. Make sure the one you choose actually supports all the technologies you need.
3. Estimate your costs
This can all get expensive pretty quickly. Application compatibility assessment tools usually sell for £60 to £120 per application, according to Gartner.
"Most large organisations have hundreds or thousands of applications (the rule of thumb is one application for every 10 users)," Gartner says. "However, the cost of a technician doing application testing and remediation is around £30 per hour (loaded with benefits and overhead), and because many applications require one to four days to manually test, these tools can provide ROI easily."
Some organisations may want to use a combination of Microsoft's ACT and a paid tool to minimise cost. But the upgrade process will be costly both in terms of dollars and your IT employees' time.
"Packaged application replacements will require two people for three weeks for each application that needs to be replaced (240 hours)," Gartner says in another report released last December, titled "Toolkit: The cost to Migrate to Windows 7." The majority of custom applications that need to be repaired will take up about 10 person hours, but will vary widely.
Gartner estimates software costs per PC at £60 for each application that needs to be repaired and £120 for each application that needs to be replaced, although these numbers can be expected to change depending on the application.
Of course, there are also operational costs related to technician salaries that should be figured into a cost assessment. But a well planned migration should save money and time. "Customers claim that application compatibility assessment tools, when combined with application virtualisation tools, reduced packaging cost and turnaround time by 33% to 50%," Gartner says.
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