Ensuring compatibility with Windows XP

Windows XP is not just far superior to its predecessors; it also supports most programmes designed to run on older versions of Windows. Windows Middle East takes you through the application compatibility technologies that have been built into this new operating system.

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By  Vijaya George Published  January 9, 2002

I|~||~||~|Windows XP has, without doubt, created a new respect for Microsoft. Not only is the new OS 34 per cent faster than Windows 2000 and 27 per cent faster than Windows 98 SE, it also supports a broad base of applications designed for earlier versions.

This has been done through the development of a whole host of application-compatibility technologies and special tools that will enable XP users to extend the use of these programmes to work with Windows XP as well. For one, Microsoft has ensured that the most popular applications and devices are compatible with Windows XP.

This includes support for over 12,000 devices. Approximately 90% of 1500 popular applications were tested and work as-is on Windows XP or work fine if you run them in a Windows Compatibility mode. The new OS comes with user-friendly compatibility tools such as Windows Update, a Programme Compatibility Wizard and Hardware trouble-shooters that provide people with real-time information on compatible hardware and software solutions.

But first, why are application-compatibility technologies necessary?
To answer this, you need to understand why compatibility problems arise in the first place. Several reasons could lead to incompatibility.

1. Usually applications are optimised to run on a specific version of an operating system. Therefore, an application that was running well, for instance, on Windows 2000 may not run as well on Windows XP. This leads to an application-compatibility problem, when the user tries to run the programme on XP. This may be especially true when migrating many older applications to Windows XP, because it is built upon the foundation of Windows NT and 2000, and not the consumer-oriented line of operating systems such as Windows 95, Windows 98, and Windows Millennium Edition.

2. An Application that ran well on an earlier version of Windows may fail to function properly on Windows XP because it may expect older formats of Windows data, or it may expect user information, such as that in personal and temporary folders, to be in specific locations or formats.

3. An application may refuse to run when Windows reports new, later version numbers.

4. Those who upgrade their computers specifically from Windows 95, 98, or Me may encounter compatibility problems, because applications written exclusively for that platform may use programmatic methods of hardware access that are not permitted on Windows XP. Moreover, direct hardware access can reduce the stability of an operating system.

||**||II|~||~||~|How do you get past issues such as an application that use programmatic methods of hardware access?

To resolve such problems and enable a richer user experience with legacy applications, Microsoft has integrated application compatibility technologies into Windows XP. So, whenever an application is installed on the new OS, whether in the course of a system upgrade or during regular operations, there are in-built application compatibility tools to counter these blocks.

How do XP’s compatibility technologies operate?

Basically, the Windows XP application compatibility technologies depend on database files to identify and fix applications that may not otherwise run on Windows XP. There are database files used to upgrade from Windows 95 and 98, and Windows Millennium and others for Windows NT and 2000 as well. So, application compatibility technologies of Windows XP fall into two distinct groups: the migration compatibility technologies, which help migrate applications when upgrading from previous versions of Windows; and the compatibility fixes, compatibility modes, and Application Help, which together support the installation and operation of applications on the Windows XP operating system.

What happens when migration compatibility technologies operate?

While setting up Windows XP, sometimes a user is warned of any major compatibility problems that are likely. This is the work of the two database files, MigDB.inf and NTCompat.inf. Their job is to identify known application compatibility problems that arise when you migrate to the new OS. They do this by running a compatibility check during Windows XP Setup. Then an upgrade report is generated by Setup showing you a list of incompatible applications along with hardware compatibility information.

If there is a compatibility issue, what do I do?

Apply a compatibility fix or a collection of fixes. Windows XP gives you that option. Fixes provide simple solutions to the most common compatibility problems. What a compatibility fix can, for instance, do is provide the credentials of a previous operating system and deceive an older application into functioning properly. They can also be targeted at specific problems known to crop up with certain applications. Such fixes permit the operating system to ignore certain warnings or delay heap and memory release calls. Microsoft has included roughly 200 such compatibility fixes in the SysMain database file of XP.

||**||III|~||~||~|A little different from the former are the Compatibility Modes, which are essentially bunches of compatibility fixes. What a compatibility mode does is that it mimics the environment of a previous operating system to ensure the correct functioning of an application. They provide an environment for running programmes that more closely reflects the behaviour of either Microsoft Windows 95 or Microsoft Windows NT 4.0. These modes resolve several of the most common issues that prohibit older programmes from working correctly with newer versions. Programmes that experience problems after migrating to XP can, for instance, be started in one of these compatibility environments. Let’s take an example. Say, you have loaded Windows XP.

And you have an application that works well on Windows 95 but doesn’t necessarily run well on XP. All you have to do is choose for that specific application to run on the Windows 95 mode by choosing that option in XP. Windows 95 Compatibility Mode, for instance, has approximately 50 of the most common fixes applied to older Windows 95 applications so they can function properly on Windows XP. Now, there are three different kinds of modes depending on who is using it. The End-user mode enables users to access five basic modes through the interface: Windows 95, Windows 98/Windows Me, Windows NT 4.0, Windows 2000, 256 colours, and 640 x 480 screen resolution. This is the one the average home user would employ. The System modes, are usually used by independent software vendors (ISVs), system administrators, and other IT professionals. This includes, apart from the end-user modes, the Limited User Account security mode and the Profiles mode.
The former is used when an application must operate under a limited security context for a particular user. The latter can be used to assist an application in determining how to interact with Windows XP user profiles. They can be accessed and set using tools like QFixApp or Compat-Admin. These two tools are available in the Application Tool kit. System administrators or other IT professionals can also use the Custom mode. Custom modes, once created, can apply only to the specific application that a user is installing, and can use any specific fix in that package.

Even if Windows XP has already applied individual compatibility fixes from SysMain, users can still choose to apply one of the compatibility modes. When a compatibility mode is applied, all the contained fixes are concatenated and applied to the application whenever it is run. This can be a helpful option in treating compatibility problems for which fixes are unavailable in the SysMain database, from Microsoft online or from the software vendor.

||**||IV|~||~||~|What happens if there is no fix for a compatibility problem?

If there is no fix, the Application Help generates a localised message telling the user that a problematic process is about to initiate. A dialogue box appears containing a brief message about the problem, with the severity indicated by an icon. If the icon is a yellow triangle with an exclamation mark, then the application is not blocked, which means that the user will still be able to run the programme. If the icon is a red stop sign, then the application is blocked, which means that the user cannot run the programme. Click on the Details button to get more information. Application Help is most commonly used to block low-level applications such as antivirus and disk-access utilities that were not written for or intended for use on Windows XP. Microsoft has deliberately blocked the installation of such applications to avert serious problems that would compromise system integrity. This will also ensure greater system stability.

While approximately 1,000 of the most popular applications are covered in XP’s application database files to counter incompatibility, there are many that are not necessarily included, such as custom-built or niche applications. For cases like these, Microsoft provides additional services and tools that can help.

Automated update services, courtesy Microsoft

Two absolutely useful features have been included with XP.

Dynamic Update: If your computer is connected to the Internet when Setup begins, XP checks for new drivers more current than those included on the Windows XP installation CD, software patches, and other critical updates, and downloads them for automatic installation in the course of the setup routine. This ensures that you always have the most current drivers and compatibility files available on your machine. Dynamic Update packages are regularly posted to the Windows Update Web site.

Windows Update: http://windowsupdate.microsoft.com/default.htm) This is the place to go for product enhancements, such as service packs, device drivers, and system security updates. So, if your computer is connected to the Web when you install a new application, Windows XP will not only refer to the local database files (SysMain and AppHelp), but will also search online at Windows Update for applicable compatibility fixes and other crucial data pertaining to the application.

||**||V|~||~||~|What else does Windows XP have to counter incompatibility?
In the user interface, users have access to some of the application compatibility tools. If you have loaded Windows XP, go to Start/All Programmes/ Accessories and check out the Programme Compatibility Wizard. This is designed to assist users in applying compatibility fixes to their own applications. More experienced users can modify the properties of an executable file using the Compatibility tab in the application’s Properties dialogue box to apply compatibility fixes, while network administrators and IT support staff can use tools such as QFixApp and CompatAdmin to apply custom compatibility fixes to applications, and then distribute those bundles of compatibility fixes to the users on the network.

Two application compatibility tools are available within the Windows XP user interface: the Programme Compatibility Wizard and the compatibility shell extension. Users can easily access and use these tools to adjust their application compatibility settings. These are designed to assist users with applications that are released after Windows XP, providing recourse in cases where the SysMain database has no information, and Windows Update cannot offer service.

Programme Compatibility Wizard

In a large corporate environment, users can often rely on an internal technical support group for help in resolving application compatibility problems. At home or in smaller enterprise environments, you may have to perform your own application support.

This is where the user-friendly Programme Compatibility Wizard comes into play. The Programme Compatibility Wizard is part of the Windows XP Help and Support Centre. It provides a convenient and simple tool for adjusting application compatibility settings. This wizard uses the compatibility fixes and Compatibi-lity Modes provided by the SysMain database file.

||**|||~||~||~|How do I use the Programme Compatibility Wizard?

Start/All Programmes/Accessories/Programme Compatibility wizard will take you there. After the welcome screen, the next asks you to choose the programme that you want to run with compatibility settings. You could either choose an application from a list of programmes, use the programme from a CD or locate it manually. This will, in turn, take you to the application itself. You will be asked to select a compatibility mode/OS in this case for the programme. i.e. which one do you think will the application run best with.

There are four main options:

Microsoft Windows 95

Microsoft Windows NT 4.0 (Service Pack 5)

Microsoft Windows 98/Me

Microsoft Windows 2000

You also have the option of bypassing the compatibility modes for the application. Once you have selected the option you want, the Programme Compatibility Wizard allows you to configure display settings to use with the application. Colour depth and screen resolution are often the source of blocking problems for older applications. The fixes enabled in the wizard force the application to a screen resolution of 640 x 480 pixels, or force the colour depth to 256 colours. In addition, you can also turn off the Windows XP visual themes for applications such as educational titles or games that may encounter problems with them.

Lastly, test the compatibility settings you have selected.

Does it run correctly? If it does, you can make those settings permanent so that they will be invoked automatically every time you run the application. Otherwise, go back and choose another set of options. More advanced users can choose the Compatibility Shell Extension method, which is a more direct means to adjust the basic application compatibility settings. The same functionality provided by the Programme Compatibility Wizard is available on the Compatibility tab of an executable file’s Properties dialogue. The compatibility shell extension creates a Compatibility tab for each executable file. The exposed compatibility settings are separated into two group boxes: Compatibility mode and Display settings. The former enables you to select the operating system on which the executable file will run correctly. This applies the appropriate compatibility mode whenever the executable file is run. The Display settings group box lets you apply changes to the colour depth, screen resolution, and Windows XP visual themes. Tools for Creating a Custom

Application Compatibility Database:

In addition to the user interface tools for application compatibility, there are two tools that are designed for the use of experienced system administrators and IT support staff: QFixApp and Compat-Admin. These are helpful in supporting applications not catalogued in the local or online application compatibility databases. Both can be found in the Application Compatibility Toolkit, available with your XP CD or alternatively on Microsoft’s web site. The tool QFixApp is a small application that provides an interface to the database of compatibility fixes included with XP. The tool is relatively simple to use. Browse for the executable file to be fixed and select the compatibility modes or fixes you want to apply.

This is a manual process unlike Programme Compatibility Wizard, which is semi-automated. This, however, gives you precise control over the compatibility fixes applied to your application. Another benefit to QFixApp is that it doesn’t require the application to be included in the list of applications with known compatibility problems. QFixApp can be very useful to those who want to determine the correct fixes to apply to their custom applications. QFixApp.exe enables you to select any executable file and apply to it one or more of the 200 fixes available in the SysMain database. You can use QFixApp to identify which combinations of fixes enable your application to work on Windows XP.

CompatAdmin : In a larger network environment there may be more applications that require the help of Windows XP application compatibility technologies. Because of the distributed nature of large networks, getting the correct bundle of compatibility fixes to users may be difficult.

Microsoft has provided the Compatibility Administration Tool (CompatAdmin) to help administrators easily assemble and distribute packages of compatibility fixes. This tool provides an interface for browsing and editing the Windows XP compatibility fix database. It allows you to select any executable file and apply one or more of the numerous fixes available in the operating system. When you’ve determined all of the fixes needed to run the application, you can use CompatAdmin to create a package to deploy these fixes to other Windows XP-based computers. CompatAdmin includes a search capability that locates “fixed” applications on your system or network drives, and analyses them for the group of fixes being used. This helps simplify the process of creating a package of compatibility fixes to deploy. CompatAdmin contains a list of the applications that Microsoft has identified as needing one or more compatibility fixes to operate correctly on Windows XP. It provides support for creating and maintaining custom compatibility databases. This is one of the most useful aspects of the tool. Using Windows XP promises to be an experience like never before. Its compatibility technologies ensure that. All you need is a good processor speed, hard disk space and RAM to handle this new comer.

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