Backup...How Are File Differences Determined ???

[mark4man]

hello...

so...I'm really tired of backing up my PCs (2) & the time it takes, by simply moving important folders to an external hard drive again & again...(or using a backup system, e.g. Paragon, etc.) I like the idea of using Microsoft's backup system (running XP Pro | 2002 | SP3)...in order that...the 1st time I backup it will of course take a long time...but each subsequent time it will only backup new or changed files.

Questions:

1) What is this method called & how is it accomplished...??? (as explained above, whereby subsequent backups are specific to new or changed files)

2) If I revise a file...ANY file...& do not change the file name (for example...I open 'image1.JPG' in Photoshop...make a few changes to sharpen the image...& save it as the same name; 'image1.JPG')...will MS Backup detect the changes in that file & replace the old image1.JPG w/ the new one...???

i.e., how does MS Backup determine how a file is changed, so it knows to back it up...???

thanks,


mark4man
XP Pro | 2002 | SP3

[tfspry]

Q1 - I think you will want an Incremental Backup. An incremental backup backs up only those files created or changed since the last normal or incremental backup. It marks files as having been backed up (in other words, the archive attribute is cleared). If you use a combination of normal and incremental backups, you will need to have the last normal backup set as well as all incremental backup sets in order to restore your data.

Q2 - The Archive Attribute gets reset each time you save the file.

You can check the Archive status of a file using Windows Explorer. Right click a file, then Properties>Advanced. If "File is ready to be archived" is checked, then the file will be part of incremental backup.

If you don't want to have multiple incremental backups, you can use a "differential backup". A differential backup copies files created or changed since the last normal or incremental backup. It does not mark files as having been backed up (in other words, the archive attribute is not cleared). If you are performing a combination of normal and differential backups, restoring files and folders requires that you have the last normal as well as the last differential backup.

Note: Your query may get more feedback if you ask a Moderator to transfer this to the "Security & Backups" forum. You'll also get some advice on non-Microsoft backup programs.

These links may be useful to explain the two methods...
Incremental Vs. Differential Backups

Wikipedia explanation

[mark4man]

If you are performing a combination of normal and differential backups, restoring files and folders requires that you have the last normal as well as the last differential backup.

Tim...I think actually the 'differential' is the backup I want,

what I want to do...to save time...is 1st perform a full, normal backup. then, perhaps weekly, perform a backup where only files that are new...or files that have changed, are backed up.

so...going back & reading your quote it seems that you are saying that the full normal backup goes into it's own archive...& the differential backup goes into it's own archive...& the files from the full backup that are changed are moved to the differential...??? therefore...for a succesful restore...the full archive gets restored & the most recent differential archive gets restored...???

thanks,


mark4man