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Overcoming the many challenges of a Unix-to-Windows migration

Switching from Unix to Windows means new programming languages, Web services, security and more. Ease the transition with planning and emulators.

With Unix losing steam in the enterprise, enterprises are on the lookout for new destinations for their workloads,...

and Microsoft Windows is one possible landing spot.

But the path from an old system to a new one is strewn with bumps and ruts that force companies to plan carefully. You can avoid a lot of bumps in the road as you tackle a Unix-to-Windows migration.

Global revenue for RISC and Itanium Unix servers decreased by 54.8% in the first quarter of 2013 compared to the same period in 2012, said Adrian O'Connell, research director at Gartner Inc., noting it's more of the same for Unix servers.

Corporations are migrating to alternative platforms that offer lower costs and more flexibility, such as Microsoft Windows, Gartner reports. While Unix revenue plummeted in the first quarter, revenue for x86 servers predominately running Windows rose by 1.8%.

Yet enterprises need to exercise caution in the move from high-cost Unix systems to lower-priced Windows servers. "Most hardware migrations fail," said Michael Howard, CEO at Unicon Conversion Technologies Inc., a reseller firm that specializes in platform migration.

These failures occur for many reasons.

Roadblocks in the Unix to Windows migration

The first step is identifying the systems' similarities and differences. Unix systems tend to rely on Apache for Web services, while Windows relies on Internet Information Services (IIS). Though they provide the same basic functions, Apache and IIS use different terminology and accomplish tasks via different methods. IT staff need training even if the new system seems similar.

Corporations should verify that the Windows servers in the migration are fully patched and feature the latest security functions.

Administrators have to learn new programming languages. Perl, Python, PHP and Java are quite common under Unix. On the Windows side of the equation, Visual Basic, .NET and Visual C++ are more popular.

Application programming code can cause other problems. "In many cases, corporations tinker with applications and customize them for their own use," Howard said. "When they go to move the application to the new system, the conversion often is not clean." In some cases, the changes were made years ago, not well documented -- in some instances, not documented at all -- and therefore difficult to decipher.

Hardware migrations involve dozens and in some cases hundreds of applications. "Businesses need to start small and establish reasonable time frames for how long the migration process will take," said Howard. Firms often underestimate the work required and try to rush the process.

Enterprise applications and platforms are reflections of business processes, so those processes will likely be affected by the Unix-to-Windows migration. Business processes are dynamic: They are constantly maturing, being recreated, evolving and becoming obsolete. The complex, time-consuming nature of migrations means that a system could look different by the time the migration wraps up. Enterprises need to make sure that their migration plan is flexible enough to accommodate changes in business processes.

Security is a key concern on any enterprise system, and generally it has been tighter on Unix systems than on Windows servers. Unix was designed from the ground up as an enterprise operating system. Windows was geared more toward personal computing and gradually evolved to take on more business functions. Hackers have focused on breaking Windows. Consequently, Windows sports a wide and ever-changing array of security holes that Unix simply doesn't have. Corporations should verify that the Windows servers in the migration are fully patched and feature the latest security functions.

Businesses want to deploy security at granular levels. Although one-size-fits-all centralized security is simple to deploy, it does not meet every company's needs. Some firms require folder- and document-level security for sensitive information, such as accounting data and customer billing numbers. Many Windows applications rely on Microsoft's Active Directory for security functions, so Unix IT departments will need to learn to use AD.

Data also must be properly stored and protected. Even if a firm uses two different computers for its Unix-to-Windows migration, it is still possible to delete vital information on either host. Having a sound backup and recovery plan before the process starts helps ensure that the business can resolve these problems by restoring the data, if necessary.

Migration tools and emulators

Although scarce, a few tools exist from Microsoft and partners to ease the Unix-to-Windows transition. Scripting program Windows PowerShell is built on the common language runtime featured in the Microsoft .NET Framework architecture. Microsoft also offers Unix emulation on Windows via the Subsystem for Unix-based Applications. For database management system issues, the Microsoft Assessment and Planning tool identifies potential database migration candidates and the SQL Server Migration Assistant helps perform the migration.

Unix emulation on Windows is also provided by UWin, an open source tool. Microsoft channel partners MKS Inc. and Orbital Technologies Inc. offer custom services and various programming tools for businesses moving from Unix to Windows.

About the author:

Paul Korzeniowski is a freelance writer who specializes in cloud computing and data-center-related topics. He is based in Sudbury, Mass., and can be reached at

This was last published in October 2013



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Are you switching from Unix to Windows?
UWIN is nice but not as good as Cgywin. I personally use FireCMD - to run both UWIN and Cygwin in Windows.
The way is to Linux not Windows
Is this an April 1st article?
running unix for 25 years 24/24, 7/7 without any problem
When I was faced with this problem some years ago I ported the applications to Linux. This was a relatively painless transitions that was able to use cheap commodity hardware. This was a lot more cost effective than a complete rewrite for a windows platform.
It is unfortunate and somewhat sinister that Paul Korzeniowski chose not to even mention option of Linux or world famous FreeBSD UNIX-like Operating Environments for migrating from 'legacy" UNIX base, even if the article was intended to focus on Windows.

His designation as a freelance 'writer' is appropriate since any qualified and experienced technology professional or company with considerable know-how in the UNIX/Linux and Microsoft environments knows full well that (a) the migration from high end UNIX to Windows is most probably three to four times to cost of migrating to Windows. In many instances, it is virtually impossible – within reason - to port Python, Ruby, Cobol and Perl applications to significantly less flexible and productive VBScript and dotNet base in less than several years work and with substantial lost productivity and reliability.
(b) Windows has never proven - even with new Server 2012 releases to attain anywhere near even 75% of the performance, reliability and flexibility of quality Linux and FreeBSD, much less the proprietary UNIX infrastructure. (c) In evaluations done by US and European Financial Stock Exchanges with Windows and RedHat Enterprise Linux, Windows failed, sometimes miserably in 'real world' testing comparisons and one notable implementation, resulting in every USA and International Stock Exchange, most all banking systems relying almost solely on these non-Windows systems.

Likewise Netflix found similar testing results and therefore recently chose FreeBSD over Windows for server appliances to reliably stream 'millions' of movies every week to their subscribers, while also saving millions of $dollars in technology by not requiring three times the Windows infrastructure to be eve somewhat competitive. Verisign, one of the largest and prominent Domain Registration Firms also had similar experience, ending with Linux and FreeBSD as their OS footing.
Even if the overall and long term costs, as well as total time taken for a migration from UNIX to Windows were same, the critical issues of rock solid "reliability" and very strong "security" should ultimately make any such migration consideration a non-starter, and instead be replaced by plan for migration to Suse Enterprise Linux or RedHat Enterprise Linux, at much lower overall and long term costs, including minimal or no retraining.
Most of the apps providers doesn't support Unix or Linux and when they have products for these plattforms, don't support all the important features as in Windows.
Entities running high end proprietary UNIX run "high" en databases like Oracle, IBM DB2, Sybase or even Free/Open Source software (FOSS) PostgreSQL,, against which Microsoft SQL Server cannot compete in performance, reliability and especially scalability.

Therefore those written specific to Microsoft Windows would automatically be unable to support the workloads, security and robustness that UNIX users would require in any migration.

Unfortunately most Microsoft technologists have little or no real world, comprehensive experience and expertise in UNIX/Linux, and most always view he technology user space from the narrow and limited Redmond angle, which is sad but revealing in it's ignorance.