Do incrementals/differentials look at archive bit or to full backup file?

I'm curious if TI (I'm on TI 10), when creating an incremental or differential, looks at the archive bits in the data, or if it looks at the full image of its own backup set?

The reason for this question is I'm wonder if I had two backup sets running during the same time frame, if they would be truly independent of each other, or if they would confuse each other.

I'm not actually going to do this exact scenario, but lets say I set up backup location A and backup location B, on the same external hard drive. I set up two tasks, one for each backup location. Each task is run daily (at different times of the day, not concurrently), and each one is set (in backup locations) to create a new full after X number of incrementals. Would the incrementals look to the full backup file in their own backup location, each independently, or would the incrementals going on in the other backup location cause the wrong files to written, or file to not be written, in them? Will both backup sets keep full integrity?

 

Real backup programs ignore the Archive bit.
That bit is a remaining artifact of the original MSFT file systems.
Indeed, if you find a program that relies on, or alters, the Archive bit, then ferget about the program.

 

Not a very clear answer, but I'm assuming you mean TI does not use the bit.

And from that I'll try to extrapolate the answer to the other part of my post,

 

Even back in DOS days, the archive bit was turned on and off for so many reasons that no program could rely on the bit's meaning unless it had exclusive rights to the file between the time the bit was set and when it read the bit for status and few programs had such exclusive rights.

I can't imagine any program using the archive bit except perhaps for very temporary purposes, but even then, it'd be a sign of poor programming.

Some folks say the A bit is the Asinine bit, and tells you nothing.

 

I still want to make sure of the answer to this question, archive bit or not:

"I'm wonder if I had two backup sets running during the same time frame, if they would be truly independent of each other, or if they would confuse each other.

I'm not actually going to do this exact scenario, but lets say I set up backup location A and backup location B, on the same external hard drive. I set up two tasks, one for each backup location. Each task is run daily (at different times of the day, not concurrently), and each one is set (in backup locations) to create a new full after X number of incrementals. Would the incrementals look to the full backup file in their own backup location, each independently, or would the incrementals going on in the other backup location cause the wrong files to written, or file to not be written, in them? Will both backup sets keep full integrity?"

 

This question was answered some time ago but regarding V9 which does not have Backup Locations. I doubt Backup Locations would change the answer and more likely would reinforce the answer.

An incremental looks at the full/incremental chain associated with the archive name and will not be confused with a different full/incremental chain because they will either have different names or be in a different folder/location.

You can make archiveA on day1 and archiveB on day2. On day3 if you make an incremental based on A it will archive the changes of the disk from day1 and will include any changes that were recorded in archiveB made on day 2. If on day3 you made it based on archiveB it would only include the changes made since day2.

Anytime you are considering methods for backup you should test the result to ensure it is what you intended.

 

Thank you, that's exactly the answer I was looking for.