Gaticus any clear result from your BSA tests so far?

Any easy way to check if my Armamentarium BSA has been loaded properly?

Thanks everyone, I keep learning a lot due your replies:)

Yes. A BSA cannot override another BSA, as others have said. A BSA can override loose files though.

I have also mostly figured out the BSA load order, I think. It's somewhat complicated. I still need to test more.
Master archives are always loaded first, followed by any other BSA in SArchiveList in the order listed.
Other BSA's are loader in the order of the ESP's timestamp. If one ESP has more than one BSA, those BSA's are loaded in alphabetic order.
The BSA timestamp is used when invalidating loose files.

The interesting bit here is that a BSA can override another BSA only if there is a loose file that invalidates the first BSA. The second BSA can then invalidate the loose file.
Dunno how that could be useful though, really. The only thing I could think of is that BSA-alteration could be used to force precedence, but that presents problems of it's own.

So the game is actually paying attention to this?



Rather than just this?

How does the BSA invalidate loose files? I assume you checked with loose files that were different than the BSA files but with the same name?

Is it that if an esp uses the BSA files also has a later timestamp than an esp that uses the loose ones?

Yes. This proves it:

SArchiveList=ArchiveInvalidationInvalidated!.bsa, Test-B.bsa, Oblivion - Meshes.bsa, Oblivion - Textures - Compressed.bsa, Oblivion - Sounds.bsa, Oblivion - Voices1.bsa, Oblivion - Voices2.bsa, Oblivion - Misc.bsa

The texture from Test-B.bsa is used. (when there is also a loose file to first invalidate the vanilla texture)
The file creation date of Test-B.bsa was set back to 2005 to ensure that the timestamp wasn't the cause.

Actually, is it paying attention to the MasterArchive settings? I'm not sure, but it does recognize which BSA's are the vanilla ones and loads those first.
Because your BSA's are not named after the MasterArchives, I'm guessing that Oblivion would treat yours without precedence, so my proof would be incorrect for your case.

edit*
I just tested and it doesn't appear that the MasterArchives settings are relevant..

SMasterMiscArchiveFileName=Oblivion - Misc.bsaSMasterVoicesArchiveFileName2=Oblivion - Voices2.bsaSMasterVoicesArchiveFileName1=Oblivion - Voices1.bsaSMasterSoundsArchiveFileName=Oblivion - Sounds.bsaSMasterTexturesArchiveFileName1=Oblivion - Textures - Compressed.bsaSMasterMeshesArchiveFileName=Oblivion - Meshes.bsaSArchiveList=ArchiveInvalidationInvalidated!.bsa, Test-A.bsa, oMeshes.bsa, oTextures - Compressed.bsa, oSounds.bsa, oVoices1.bsa, oVoices2.bsa, oMisc.bsa, Test-B.bsa

I renamed my bsa's, so the MasterArchive settings are referring to invalid files.
Test-A.bsa is being used in this case. If I remove Test-A from the list, then Test-B is used.
So it seems there is some setting within the bsa itself telling oblivion that it's an official archive.
I'll have to rebuild entirely new vanilla BSA's and see if it makes a difference.


The precedence is determined by the timestamp of the BSA vs the loose file.
EG. a loose file that replaces some vanilla texture and a BSA with a more recent timestamp that also replaces the vanilla texture.
The loose file invalidates the vanilla texture and the newer BSA overrides the loose file.
If there is no loose file, then the vanilla one would be used because it was never invalidated.

The ESP's timestamp is used to determine the load order of the BSA's themselves, regardless of the BSA's timestamp.
IE, whichever BSA is loaded first will supercede any later loading BSA regardless of the BSA timestamp, unless the first is invalidated by a loose file.

So what if an esp loads high with an early time stamp but the BSA has a much later time stamp and the files in it compete with a BSA that has an earlier time stamp but the esp associated with it loads later?

Then I've seen some give the advice to make sure and set the timestamp on the BSA via OBMM - I'm not sure if that only effects the vanilla BSA archives or all - if all then that could be problematic - yes or no?

thanks for looking at this.

Then the BSA that is associated with the first loaded ESP is priority. Doesn't matter when the BSA was created, it is loaded first so no other BSA can override the files in it unless the first is invalidated by a newer loose file.
Only then could another BSA override the loose file, if the BSA is newer.

Timestamps do not affect the precedence of the BSA's themselves.
The timestamps do affect invalidation though, when a loose file is present. The advice is correct.
Eg. if you have a modded v1.1 game with loose textures and you upgrade to SI, then the vanilla BSA timestamps will have changed and it will cause the BSA to override the loose files.

Oblivion loads BSA's in this order:
1. MasterArchives
2. Anything else in the SArchiveList, in the order listed
3. BSA's associated with an ESP, in plugin load order. If there are multiple BSA's for one ESP, they are loaded alphabetically.

Seems counter-intuitive that an earlier loading esp'd BSA would override a later loading esp'd BSA. Especially when a later timestamp on loose files wins against the same early loading BSA.

Wonder why that is the case.

[edit] clarified

I seem to have answered the question to my satisfaction:


The game didn't care one bit about removing those names. Everything loaded according to the SArchiveList setting.

Are you 100% sure? The MMM installation instructions tell people using MMM in FCOM to rename the MMM bsa to
"FCOM_Convergence_Mart's Monster Mod.bsa" to be loaded with the active "FCOM_Convergence.esp", and if this didn't work, it would have been known by now.

I've always been led to believe you can't use underscores in BSA names, but they obviously do work or AFK_Weye.bsa would not be loading its assets into the game.

Ok, that was weird. I just tested again.
No, MyMod_More.bsa will indeed work.

What is weird is that I have Test.esp, Test-A.bsa and Test_B.bsa. To avoid conflict, I renamed Test-A.bsa to Test1-A.bsa thinking that would prevent it from being loaded, but no!
When I tested before, Test1-A was overriding Test_B, so it seemed that Test_B was not loaded but it was just superceded.

It seems that the prefix need only be the name of the ESP. No special rules.
So MyModMore.bsa should work. Or any other name that begins with 'MyMod'. I just tested this too, to be sure and TestA.bsa works.
Maybe in previous versions of Oblivion it is different though.

I recall someone else posting about this ... Axil I think and he (if that was who it was) stated that he found it random which got priority between BSA. probably the forum has purged that info.

I'm hoping you nailed down the logic that may lead to better solutions.

Test1-A.bsa still starts with the exact name of an active esp, so there's no reason for it to not being loaded. But good, it means that the rule is as general as I thought: As long as the bsa's name starts with the exact, full name of an active bsa, it will be loaded.

Gaticus sorry I havent followed this but you might find the following links helpful with research done if you have not seen them before and are furthering the research on the common files in bsa problem.

They are a bit old so anyone new to the subject be careful what you try from these links, some methods are complicated and can be destructive... Redirection as used with Wrye Bash and OBMM is still the best/safest method out of the two methods that work.

Anyway first one you probably know all about the subjects covered here http://devnull.sweetdanger.net/archiveinvalidation.html

Further down on there http://devnull.sweetdanger.net/archiveinvalidation.html#AIExplained

From that point scroll down to Technical Details sub heading, where you will find the conclusions drawn reference common file names in bsa's.

Unfortunately what was linked further on reference all the testing carried out is now lost, but among that lot you may find associations with what you have experienced in testing.

I could understand why it would seem to be random. There are alot of variables and they make it very difficult to do consistent testing.
I have had to redo my tests a dozen times because of little variations that throw a monkey wrench into things leaving all previous tests to question.

If I didn't stumble on the invalidation trick, I might not have sorted it out either. By using invalidation, I was able to create consistency.


Yes, I've read that article and I'm aware of how the invalidation works. Thanks though.
The invalidation problem is caused by hash collisions.

The BSA overlap issue is kind of the reverse problem to be simple.
With invalidation, a loose file causes the hash key for that file in the BSA to be deleted or otherwise ignored.
With BSA overlaps, the hash key for the file in the first BSA prevents the 2nd BSA from loading it's file, because the key already exists.

This is why we can override a BSA with another only if there is a loose file that invalidates the first BSA.

Ok, so if you are doing a patch for a mod that has a BSA, you have to release any modified meshes or textures as loose files then, correct?

That seems like the correct conclusion. BSA files should contain unique content only (but can be replaced by loose files in a patch).

Theoretically, you might be able to create a BSA patch by having the patched BSA load BEFORE the original BSA.

Hi! :wavey:

BAIN + loose files ftw, absolutely. There are no advantages whatsoever to the alternative(s).

Keeps everything simple, clear, and hassle-free. :thumbsup:

You guys might find this interesting, I just ran into it after unpacking and PyFFI'ing my oblivion - meshes bsa. If the bsa is dated later than loose files the bsa will override them, I'm not sure about the specifics but all of my body mods were overridden by the BSA until I dated it back to 2006.

Yup, thats another one of those reasons even us Wrye Bash fanatics keep OBMM around, occasionally it comes in handy with one of its abilities - Reset BSA timestamps.

Small question, is there a limit on how many BSAs can be loaded from a single ESP?

In light of the recent missing meshes and stuff related to BSA loading, I'm thinking of renaming all my BSAs to use DLCShiveringIsles.esp like "DLCShiveringIsles - Armamentarium.bsa" etc to ensure loading.

I thought I was pretty good with OBMM, but this is one of the features I have been unable to locate so far. I'm using a separate freeware for that, SetFileDate. It was recommended by Psymon and works very well. Need to dig into OBMM once more...

Utilities -> Archive Invalidation -> Reset BSA Timestamps