Elizabeth Figura is a Wine developer at Code Weavers.

We discuss how Wine and Proton make it possible to run Windows applications on other operating systems.

Transcript

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Intro

[00:00:00] Jeremy: Today I am talking to Elizabeth Figuera. She's a wine developer at Code Weavers. And today we're gonna talk about what that is and, uh, all the work that goes into it.

[00:00:09] Elizabeth: Thank you Jeremy. I'm glad to be here.

What's Wine

[00:00:13] Jeremy: I think the first thing we should talk about is maybe saying what Wine is because I think a lot of people aren't familiar with the project.

[00:00:20] Elizabeth: So wine is a translation layer. in fact, I would say wine is a Windows emulator. That is what the name originally stood for. it re implements the entire windows. Or you say win 32 API. so that programs that make calls into the API, will then transfer that code to wine and and we allow that Windows programs to run on, things that are not windows. So Linux, Mac, os, other operating systems such as Solaris and BSD. it works not by emulating the CPU, but by re-implementing every API, basically from scratch and translating them to their equivalent or writing new code in case there is no, you know, equivalent.

System Calls

[00:01:06] Jeremy: I believe what you're doing is you're emulating system calls. Could you explain what those are and, and how that relates to the project?

[00:01:15] Elizabeth: Yeah. so system call in general can be used, referred to a call into the operating system, to execute some functionality that's built into the operating system. often it's used in the context of talking to the kernel windows applications actually tend to talk at a much higher level, because there's so much, so much high level functionality built into Windows. When you think about, as opposed to other operating systems that we basically, we end up end implementing much higher level behavior than you would on Linux.

[00:01:49] Jeremy: And can you give some examples of what some of those system calls would be and, I suppose how they may be higher level than some of the Linux ones.

[00:01:57] Elizabeth: Sure. So of course you have like low level calls like interacting with a file system, you know, created file and read and write and such. you also have, uh, high level APIs who interact with a sound driver.

[00:02:12] Elizabeth: There's, uh, one I was working on earlier today, called XAudio where you, actually, you know, build this bank of of sounds. It's meant to be, played in a game and then you can position them in various 3D space. And the, and the operating system in a sense will, take care of all of the math that goes into making that work.

[00:02:36] Elizabeth: That's all running on your computer and. And then it'll send that audio data to the sound card once it's transformed it. So it sounds like it's coming from a certain space. a lot of other things like, you know, parsing XML is another big one. That there's a lot of things. The, there, the, the, the space is honestly huge

[00:02:59] Jeremy: And yeah, I can sort of see how those might be things you might not expect to be done by the operating system. Like you gave the example of 3D audio and XML parsing and I think XML parsing in, in particular, you would've thought that that would be something that would be handled by the, the standard library of whatever language the person was writing their application as.

[00:03:22] Jeremy: So that's interesting that it's built into the os.

[00:03:25] Elizabeth: Yeah. Well, and languages like, see it's not, it isn't even part of the standard library. It's higher level than that. It's, you have specific libraries that are widespread but not. Codified in a standard, but in Windows you, in Windows, they are part of the operating system. And in fact, there's several different, XML parsers in the operating system. Microsoft likes to deprecate old APIs and make new ones that do the same thing very often.

[00:03:53] Jeremy: And something I've heard about Windows is that they're typically very reluctant to break backwards compatibility. So you say they're deprecated, but do they typically keep all of them still in there?

[00:04:04] Elizabeth: It all still It all still works.

[00:04:07] Jeremy: And that's all things that wine has to implement as well to make sure that the software works as well.

[00:04:14] Jeremy: Yeah.

[00:04:14] Elizabeth: Yeah. And, and we also, you know, need to make it work. we also need to implement those things to make old, programs work because there is, uh, a lot of demand, at least from, at least from people using wine for making, for getting some really old programs, working from the. Early nineties even.

What people run with Wine (Productivity, build systems, servers)

[00:04:36] Jeremy: And that's probably a good, thing to talk about in terms of what, what are the types of software that, that people are trying to run with wine, and what operating system are they typically using?

[00:04:46] Elizabeth: Oh, in terms of software, literally all kinds, any software you can imagine that runs on Windows, people will try to run it on wine. So we're talking games, office software productivity, software accounting. people will run, build systems on wine, build their, just run, uh, build their programs using, on visual studio, running on wine. people will run wine on servers, for example, like software as a service kind of things where you don't even know that it's running on wine. really super domain specific stuff. Like I've run astronomy, software, and wine. Design, computer assisted design, even hardware drivers can sometimes work unwind. There's a bit of a gray area.

How games are different

[00:05:29] Jeremy: Yeah, it's um, I think from. Maybe the general public, or at least from what I've seen, I think a lot of people's exposure to it is for playing games. is there something different about games versus all those other types of, productivity software and office software that, that makes supporting those different.

[00:05:53] Elizabeth: Um, there's some things about it that are different. Games of course have gotten a lot of publicity lately because there's been a huge push, largely from valve, but also some other companies to get. A lot of huge, wide range of games working well under wine. And that's really panned out in the, in a way, I think, I think we've largely succeeded.

[00:06:13] Elizabeth: We've made huge strides in the past several years. 5, 5, 10 years, I think. so when you talk about what makes games different, I think, one thing games tend to do is they have a very limited set of things they're working with and they often want to make things run fast, and so they're working very close to the me They're not, they're not gonna use an XML parser, for example.

[00:06:44] Elizabeth: They're just gonna talk directly as, directly to the graphics driver as they can. Right. And, and probably going to do all their own sound design. You know, I did talk about that XAudio library, but a lot of games will just talk directly as, directly to the sound driver as Windows Let some, so this is a often a blessing, honestly, because it means there's less we have to implement to make them work. when you look at a lot of productivity applications, and especially, the other thing that makes some productivity applications harder is, Microsoft makes 'em, and They like to, make a library, for use in this one program like Microsoft Office and then say, well, you know, other programs might use this as well. Let's. Put it in the operating system and expose it and write an API for it and everything. And maybe some other programs use it. mostly it's just office, but it means that office relies on a lot of things from the operating system that we all have to reimplement.

[00:07:44] Jeremy: Yeah, that's somewhat counterintuitive because when you think of games, you think of these really high performance things that that seem really complicated. But it sounds like from what you're saying, because they use the lower level primitives, they're actually easier in some ways to support.

[00:08:01] Elizabeth: Yeah, certainly in some ways, they, yeah, they'll do things like re-implement the heap allocator because the built-in heap allocator isn't fast enough for them. That's another good example.

What makes some applications hard to support (Some are hard, can't debug other people's apps)

[00:08:16] Jeremy: You mentio...