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Hyper-V hyped

Posted on 5 Mar 2008 at 16:50

Jon Honeyball calls for the Hyper-V hypervisor to have a less stupid name, and David Moss looks at file synchronisation under Windows XP and Vista.

There's another big difference in Vista: the user is spared the logon and logoff synchronisation dialogs. This isn't quite as rosy as it sounds, however, because the only reason they're spared the logoff dialog is that Vista doesn't actually do a sync at logoff. Instead, Vista does "hidden from the user" synchronisations on a regular basis while the user is logged on, which is actually a very efficient process, but does mean your users will have to perform a manual sync when they log off if they want to be sure they have the latest versions of all server files cached on their local machine. A full logon synchronisation takes place shortly after the user establishes a connection with the server and is authenticated, so the only potential problem exists at logoff, and it can be solved by the user either logging off and then on again quickly (thus forcing the logon synch to take place) or by using the Windows Vista Sync Center - which is accessed via Control Panel and provides an easy way to set up synchronisation partnerships, review existing ones, see if there have been any synchronisation conflicts, and so on.

A number of new features come with Windows Vista's offline files, not the least of which is the removal of the 2GB limit for offline files that XP had, but one of the nicest in terms of network traffic is something called Binary Differential Transfer. What this means is that whenever you make a change to a file on your local workstation, only the change gets sent to the server rather than the whole file.

The same isn't true in the opposite direction - this is a client-side implementation only - butit's a huge step in the right direction toward lowering the network load that constant synchronisation can impose. Hopefully, the technology can be extended in futureto do the same thing from the server side.

Where Windows Vista has its Sync Center, Windows XP has the Synchronisation Manager. This applet is used to set up offline file synchronisation, or indeed offline web page synchronisation. Unlike XP, Vista doesn't have the habit of popping up a dialog box to tell you when you're offline:you'll either like this feature or you won't.

The way to tell whether you're offline under Vista isto look at a folder window and see what it says about the folder's status with regard to whether it's working onlineor offline.

Also, if you've selected only some files in a folder tobe available offline, under Vista when you're offlinethe other files in that folder will appear greyed out with a red "X" next to them, to indicate they're notcurrently available.

The combination of Windows XP and Windows Vista systems on the same network makes it far from easy to troubleshoot problems, because each operating system brings its own set of rules and behaviours, and they'renot always compatible.

I'm still trying to track down the reason why some users can't delete any files at all, which might seem great froma safety point of view, but is actually a real problem - I'llreport back here in a future issue.

David Moss