[TxMt] Atomic Saving / Saving Question

[Ryan Schmidt]

On 01.02.2005, at 11:57, Sune Foldager wrote:

> On 1. feb 2005, at 5:26, Paul Kline wrote:
>
>> What is atomic saving?
>
> Atomic saving makes sure that the old version of the file on disk is  
> replaced with the new one in on, atomic, operation. This is sometimes  
> needed when the files you are writing might at the same time be read  
> by other running programs. Technically it's writing the file with  
> another name, then renaming the new file into the old file (destroying  
> the old file in the process).
>
> The disadvantage of atomic saves (for some), is that the file gets a  
> new inode-number each time which will break hard-links and might upset  
> aliases if they are not pointing correctly.

Apple has been promoting this practice for ten years or more, and  
aliases have always worked with it in the past. As I understand it,  
part of the reason for Apple providing a function to do this is  
specifically so that aliases continue to function. The documentation  
[1] says that the "file ID" is preserved, though I don't know if that's  
the same thing as an "inode number."


[1]  
http://developer.apple.com/documentation/Carbon/Reference/File_Manager/ 
file_manager/function_group_21.html