Research PHYSFS and look at the DOSBox sourceforge site for source code.

PhysFS patch

and we don't care about people with big libraries of so called "abandonware".

First of all you should distinguish from good intents and bad intents.

As many hobby development projects everything starts from a need or from an idea. My idea was to create a custom file system contained in a single file that could be used by DosBox just for the fun of writing one.

So actually you don't care about abandonware ("so called" can be kept for your self, since abandoware exists and it is actually legal if you take care to be sure of what you are trying to use) but I don't care either. It was the reason that pushed me to think about that but nothing more. To write a custom file system just for fun (and marginally with its own purpose) while trying to make it work together with DosBox.

I didn't ask for something to keep a library of games altogether in a zipfile, otherwise I wouldn't have chosen a development forum, right? I was asking to clues about the DosBox source code and how it actually manages IO with filesystem (either HDD, either CDFS, either whatever) and how complex would it be to add a completely custom solution. So next time try to be less rude and more mannerly. Thanks.

Presuming the worst is good to warn people but it's not undoubtedly a winning strategy.

Actually from what I see from source most of what is needed for a different filesystem seems to reside in

dos/drives.h which defines the DriveManager (the one used to mount/unmount things?) and the various signatures for localDrive, fatDrive, cdromDrive, etcetera.

These classes are then implemented in respective files drive_local, drive_fat and so on..

so basically to be able to add a custom mount (eg mount c myfile.what -t whatever) I should add a new class signature in drives.h, add its implementation and then add the custom type somewhere). Am I right?

Should I care something more? Thanks in advance, don't know if the question is too technical, I'm still new to the forum (as DosFreak implicitly noted with his picky reply 😀 )

Jackoz wrote:

abandoware exists and it is actually legal

No it doesn't and no it isn't

What are you asking for really? .img/.ima works fine. No need to reinvent the wheel

Don't be pedantic, I'm not using the abandonware word to mean "a software that no one cares about so I think it's free and I reserve myself the right to do whatever I want with that". I'm talking about obsolete software that has been actually made free by their copyright holder so that they became AL ALL EFFECTS actually freeware (battle chess? daggerfall? one must fall? I can cite dozens, but this actually goes out of the scope of my topic).

I was just asking some infos about how the DosBox source code is structured, I thought that that forum was the right one and I already found two rude answers. Nice to see that, I'll just study it by myself 😀

What does "do not reinvent the wheel" mean? I suppose you are not a developer.

Am I allowed to try to develop whatever I want? I think yes.
Did I ask you if it is worth doing not? No.
Did you try at least to answer my question? No.
Does my will to extend an open source project hurt you? I don't think so.

I don't actually see the point of your reply, I just see you being biased..

Jackoz wrote:

software that has been actually made free by their copyright holder

The word you want is freeware.

The separate matter of abandoware is a questionable subject.

I was just asking some infos about how the DosBox source code is structured, I thought that that forum was the right one and I already found two rude answers. Nice to see that, I'll just study it by myself

to add my two cents of rudeness, have fun studying it.
I don't see much rudeness in Dosfreaks answer, except for the kneejerk reaction to abandonware, which is the way we do things here. If you talk about freeware, say freeware. The term abandonware will ALWAYS get you this reaction here.
Other than that he gave you a valid answer pointing at physfs.
Leileilol wasn't really rude either, pointing out the obvious abandonware thing (as I wrote it will get you this reaction) and asking for what you really want.
Also pointing at img/ima support in 'Dosbox is valid too, since you can easily use img as a filesystem to store games and you can mount them already quite easily.
The structure of Dosbox is simple and quite self explanatory as you more or less seemed to have found out.

Your intro in to this forum went the possible worst way it could go. Maybe you should act less rudely and more mannerly on the next try.

Dominus, I didn't want to be rude or whatever about anything..

When I usually introduce myself somewhere I like to assume that people won't think I'm a 18 years old kid asking "OMFG, WHERE CAN I DOWNLOAD THE GAMES FOR DOSBOX?!?!!111". If my answers seemed from a wounded man that's because everything moved on the word "abandonware" while it wasn't of any kind of importance.

That's why I felt like being pushed in an angle without actually doing anything. I can get the semantic difference between word freeware and abandonware and, without even thinking about it, I just thought that it was ok to use the word to distinguish freeware software from 2010 from old freeware games (for which I like to use abandonware word, I'm not even english 😁 ). In any case I don't think we want to start a disquisition about the etymology of the term itself.

Like you said it's just started in the worst possible way without a precise reason, I was just curious about the feasibility of what I was wondering about, nothing more nor less. You seem all veterans here, just try to identify oneself with me and you'll understand why I acted that way: I was wondering about DosBox file system management, never cared about abandonware or everything else and I just received complains about that work or suggestions about do not even try doing anything 🙁

Hugs and kisses to everyone!

It may have felt to you that you were being attacked, but please don't take it too hard, as there are technical and legal issues involved. Every few days there is someone that posts here asking for help with some abandonware game that they downloaded. Sometimes this is not mentioned and those that are trying to help cannot replicate the issue because they are working from a legitimate copy and the issue is because their game is (as are many abandonware games) ripped, cracked, hacked or in someway modified from the original, often in unconventional ways. This creates a support nightmare.

Then there are the legal issues involved. The ScummVM project had a legal challenge from LucasArts that almost killed the project, even though they hosted no copyrighted material, nor were they promoting piracy. The DOSBox team needs no similar incident. It is not merely semantics. Abandonware has no legal status. Most software that gets called abandonware is still owned and copyrighted by someone and corporations are loath to let go of IP, regardless of how little profit that may be gained by it in the future. Then you have entities such as the ESA that can look for such things to give busy work to their lawyers to justify the fees that they charge the software manufacturers.

Abandonware sites already try to associate DOSBox with the games they have. No need to draw farther attention. Freeware and shareware do have legal status and pose no legal threat. This is why it is so important to make a distinction between them.

First rule of VOGONS: You do not mention "abandonware"
Second rule of VOGONS: You DO NOT mention "abandonware"

word to distinguish freeware software from 2010 from old freeware games (for which I like to use abandonware word, I'm not even english

If you mean old freeware games then name it like that, because the term abandonware
is usually brought up if somebody assumes all games that are old enough are
"freeware" in the sense of being able to download/get them at wish. This is illegal
as it's copyrighted material.

About the topic: i didn't get yet what you're trying to achieve, but for customized
drive interfacing check how the cdrom stuff works (cdromDrive class which subclasses
localDrive) and the Virtual_Drive class (z-drive).

mr_bigmouth_502 wrote:

First rule of VOGONS: You do not mention "abandonware"
Second rule of VOGONS: You DO NOT mention "abandonware"

Yes, now I got it 😀
In any case I was meaning the abandonware as the commercial one that became freeware.. and I ask sorry for this big misunderstanding, I allow all of you to lash me..

I would hope this listing is still maintained:
List_of_commercial_video_games_released_as_freeware