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The Windows repo is massive, at least 100GB. Consider that the component equivalent to Linux, the NT kernel, is but a small part of the whole thing. And it is i

The Windows repo is massive, at least 100GB. Consider that the component equivalent to Linux, the NT kernel, is but a small part of the whole thing. And it is indeed a single large project, where every commit has to leave the entirety of Windows in a good state. So if you change some widely used function, you need to fix every single caller in all of Windows. Also, the build system evolves along with the product, so it is checked into the repository as well. The right version of the build system is whatever is in the timestamp you are building. So there’s your seemingly elusive good reason for keeping large binaries in the repo. And while I worked there, the object files from the nightly build were also checked in, so you could rebuild mostly-unchanged components quickly. The alternative to doing it this way is to introduce version management between components, which is totally unnecessary complexity. Windows is one product and all of the components (or subsets thereof) ship together. As far as internal-only interfaces are concerned, version N does not need to work with N-1 or N+1, only N. That is a massively simplifying assumption that makes a lot of things much easier. There is a reason why all the big tech companies operate this way. Microsoft, Google, and Facebook, all have one giant repository with their entire product.

dingo_bat 9y ago
> There is a reason why all the big tech companies operate this way. Microsoft, Google, and Facebook, all have one giant repository with their entire product. Cool, but that doesn't explain why Office and Windows need to share the same repo. Ditto for gmail and chrome os. Ditto for fb messenger and whatever face recognition algorithm they use.
- DaiPlusPlus 9y ago
  Office and Windows don't share the same repo...
- marcoperaza 9y ago
  I see how my post could have led to that interpretation. That’s not what I meant. There are certainly many many repos in use across Microsoft, for all sorts of different projects. Office doesn’t share the same repo as Windows. And neither does the toolchain (compiler/linker/etc.); only the binaries are checked into the Windows repo. Those are truly separate products, which need to work across different versions of Windows.
InclinedPlane 9y ago
I worked at a game company for a while and one of the interesting things there was that there really wasn't a good way around checking in binaries to the repo. First off, a lot of your "source" assets are properly in binary form (images, for example), because that was the most compact form for them to exist, by orders of magnitude, and also because trying to generate them from some other non-binary representation would add tremendous overhead to development work. On top of that, building the entire product from "source" might involve tens to hundreds of thousands of hours of CPU/GPU time. So you just didn't do that. Instead you built everything in parallel and checked the results in somewhere, that would then get bundled together into the final product. There are ways around doing things this way, for sure, but given that you can just go pay a fairly insignificant amount of dollars to some company and get a VCS that won't choke.

dingo_bat 9y ago

> There is a reason why all the big tech companies operate this way. Microsoft, Google, and Facebook, all have one giant repository with their entire product. Cool, but that doesn't explain why Office and Windows need to share the same repo. Ditto for gmail and chrome os. Ditto for fb messenger and whatever face recognition algorithm they use.

DaiPlusPlus 9y ago
Office and Windows don't share the same repo...
marcoperaza 9y ago
I see how my post could have led to that interpretation. That’s not what I meant. There are certainly many many repos in use across Microsoft, for all sorts of different projects. Office doesn’t share the same repo as Windows. And neither does the toolchain (compiler/linker/etc.); only the binaries are checked into the Windows repo. Those are truly separate products, which need to work across different versions of Windows.

InclinedPlane 9y ago

I worked at a game company for a while and one of the interesting things there was that there really wasn't a good way around checking in binaries to the repo. First off, a lot of your "source" assets are properly in binary form (images, for example), because that was the most compact form for them to exist, by orders of magnitude, and also because trying to generate them from some other non-binary representation would add tremendous overhead to development work. On top of that, building the entire product from "source" might involve tens to hundreds of thousands of hours of CPU/GPU time. So you just didn't do that. Instead you built everything in parallel and checked the results in somewhere, that would then get bundled together into the final product. There are ways around doing things this way, for sure, but given that you can just go pay a fairly insignificant amount of dollars to some company and get a VCS that won't choke.