Daylight Saving problem

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jstrong
Posts: 44
Joined: Sun Feb 16, 2003 6:59 pm

Daylight Saving problem

Post by jstrong »

As you may recall, I have AISBackup running on an XP machine that backs up data from an Apple Mac on a Local Network.

Afer we moved to British Summer Time last night, both machines automatically updated their time, but AISBackup is performing a full backup of all files in the backup set. As the total backup is 30 GigaBytes, I prefer that this would not happen until I plan for it.

I noted that there was a fix earlier for NTFS drives, but perhaps this doesn't work with the Mac?

Thanks a lot

Jim
Barry
Site Admin
Posts: 1529
Joined: Tue Aug 20, 2002 3:16 pm

Daylight saving transition: Non-Windows Shares

Post by Barry »

The problem is that Mac and Linux network drives look like NTFS drives to Windows. The NTFS file system bases all dates on a system called Universal Coordinated Time (UTC), so the time shown in Windows Explorer changes by one hour when daylight saving kicks in.

Unfortunately UTC causes Mac and Linux files look like they have been modified after the daylight saving transition.

This link describes the ‘feature’:

http://www.codeproject.com/datetime/dstbugs.asp

We will have to make a change to AISBackup to get this working properly.

Barry
jstrong
Posts: 44
Joined: Sun Feb 16, 2003 6:59 pm

Post by jstrong »

Thanks for the information, Barry! I suspected it was something like that, but - having had the Mac since July 2003 - it has taken up until now to be certain that it had happened to me, believe it or not! :-)

Ah we,l. no harm in doing a fresh backup every 6 months or so - and nice now to remember that it is going to happen - and set up my backup space accordingly!

Jim
Barry
Site Admin
Posts: 1529
Joined: Tue Aug 20, 2002 3:16 pm

AISBackup daylight saving transition problems (Mac & Lin

Post by Barry »

Linux behaved similarly to the Mac , except the time may be set to “Use UTC”, which allows AISBackup to work across daylight saving transitions.

I do not know if there is a similar setting on the Mac, or indeed, if you would want to set it.

Barry
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