The DirSet system has been used since 1.28c

The traditional way of modding EAW was to put files in the root folder. Filemanager programs were written to do this.
OAW would place copies in the root folder and delete the copies when needed.
So files were being continually added and removed from the root folder. This causes disk fragmentation.

Disk fragmentation raised its ugly head when multiskins came in. In my "B17G_01" skin folder there are 302 files of which 119 are TPCs. It is the 8-bit version and the 24 bit would need another 119 512x512 BMP files, making around 420 for just one skin. Multiply this by several skins, and you can see why disk fragmentation accelerated when skin copies were loaded for one scenario, then deleted when the user switched theatres.
The "DirSet" system uses files which the exe reads to find the paths to the files it needs. The files themselves stay put, so apart from the "Dir.set" file no files are copied to the root folder or erased from it.

The original EAW had many faults, the worst of which was having 30 individual skinfile sets, 30 individual *.flt files, but single "pnames.dat", "planes.dat", "loadout.dat" and "FSMPLANE.WSP" files containing the data for all 30 planes.
In the 1.28 development we fixed that, made "planes" folders, so that we could use planesets containing "PDir.set" and "FMDir.set" files. However, we were still locked into the slot system.

That "B17G_01" folder is for Slot 6. If we wanted something else in slot 6 and to have that skin in slot 7 then Mike would have to produce a second version of the identical graphics using the "PB24A" names instead of the "PBB17" names.

The slot free system wad introduced as a massive breakthrough in 1.30, and has continued in 1.40.
It does not use the "PP38H"...."PV1V1" names at all. They all became "Plane".
Only one version of the skin folder is needed, because it can be used in any slot. This saves the modder time and effort, and there are fewer files needed by the player.

Plane builders do not need to worry because they can still make their files using the old names, and put them in the root folder of a 1.28 set-up for testing. When they are complete they can be sent to Sandbaggers and downloaded for use of players running EAW 1.2....1.29. They can also be downloaded for conversion to 1.40 format using the conversion software, giving us the best of both worlds.

At this point I must declare that I am no longer interested in developing exes other than EAW140. It has other features that previous versions do not have, and I am not prepared to add them to previous versions such as 1.28c/e/f and 1.29.

With a bit of change in perspective I find that the slotless system is also good for 3dz modding. As I built the four planesets for the MED upgrade I came across a lot of 3dz model errors.

For instance, I'm not sure why but the prop transparency was screwed up on the new hi-res P-40, displaying the dreaded blocky prop syndrome. Rather than going back to 3dz Studio and laboriously tracking down the mapping error that causes this I simply went to the older P-40 model folder which I knew had a good prop and copied over the appropriate files to the new P-40 folder.

Another feature that is flying under the radar right now is the ability to "port" different planes into different scenarios by editing a planeset file.

I envision a warehouse full of planes so that a player could set up their own unique suite of aircraft for any scenario. It would be very easy, for instance, to drop a P-39 or a Zero into the ETO to see how they would do.

The only thing we haven't addressed in all of this is how the planesets affect campaigns. I know that's not important in the online world and single mission mode but you would be surprised how may offline players only play in campaigns.

After I built the four planesets for the MED upgrade it occurred to me that I should have been more careful with the order I included the planes since much of the campaign system of files is based on specific slots. These files determine what squadron emblems you see, what enemy planes you will encounter and a whole host of other important info.

As we go forward with the MED upgrade I will go back and edit the plansets to re-order the list so that the same planes are used but there will be some logic in the campaigns.

I'm bringing it up because we will need to address this going forward.

Agreed Ray.
When making planesets for older scenarios I try to make at least one with the same planes in the same order as the original.
Unfortunately the original DAW had a completely crazy order with some planes actually switching from Allied to Axis and vice-versa. Malta was better

Understand that Jel. Before my "time off", I did start modding for 129 with extensive dir.set/plane folder use, but I haven't made the leap to 1.40 and all its subsequent development. At the moment I am comfortable back with 128C, and I am aware that other players also still use that version, as at least part of their EAW experience. There seems to be no reason why players can't have 128C, 129 and 140, and dip in at will. Your 128C-2016 setup easily achieves that end.

I'm currently working out how best to use the basic planeset/dir.set setup first implemented with 128C. The idea is to bring to convenient use some of those older scenarios that haven't/can't make the leap to 140, but still provide a lot of fun. DOM's "Attack in the West" is the first example I'm working on.

Absolutely

Maybe I missed something but why wouldn't these older scenarios be able to be brought up to 1.4?

Maybe not things like RAW or the Flying Tiger scenarios which, let's fact it, never ran right in the OLD execs but some of the well put together early scenarios, like New Guinea.

Ray - there's probably only an absolute bar to updating with the scenarios managed by their own manager, which work by swapping planes in and out of the basic folder. AITW is a good example. Dunkirk in its original form is another. Possibly Finland.

As I found out by working with Dunkirk in 129, there may well be other ways of bringing those into the newer regime using planesets and planes folders, but it requires a lot of time consuming work, and is essentially a complete rewrite. It would also require me to invest a fair amount of time taking on board all the updating, and all the extra modding knobs and levers available in 140. At the moment there is a certain inertia preventing that.

I have still have limited time to give to EAW, though I might have more when I partially retire in September. Until then I can get quicker working results, and a great of fun bring these older setups into 128C. And players can download Jelly's 128C-2016 setup and enjoy them as well as 140.

Ah, I never tried the scenarios that included their own manger. Just seemed like more work than I was able to commit to.

Plus as I said, there was a certain "wonkiness" to many of those early attempts at expanding the EAW world. That's not meant to be insulting, just factual.

FWIW, going forward we are finally seeing a unification of the EAW worlds. Better late than never.