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Fix small typos in linux-build-methodology.md #109947

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6 changes: 3 additions & 3 deletions docs/project/linux-build-methodology.md
Original file line number Diff line number Diff line change
Expand Up @@ -18,7 +18,7 @@ The most important aspect of compatibility across Linux distributions is the ver

1. Build on an old distribution

The Python ecosystem's [manylinux](https://github.com/pypa/manylinux) project uses this approach. They provide docker images that use Linux distributions based on specific versions glibc or musl libc, and come with a standardized set of build tools from that distribution preinstalled.
The Python ecosystem's [manylinux](https://github.com/pypa/manylinux) project uses this approach. They provide docker images that use Linux distributions based on specific versions of glibc or musl libc, and come with a standardized set of build tools from that distribution preinstalled.

The [Red Hat Developer Toolset](https://docs.redhat.com/en/documentation/red_hat_developer_toolset/12/html/user_guide/chap-Red_Hat_Developer_Toolset#sect-Red_Hat_Developer_Toolset-About) also takes this approach. It provides backports of more recent compiler toolchains to older Linux distributions, allowing these distributions to target the distribution-provided C library using newer compilers.

Expand Down Expand Up @@ -144,8 +144,8 @@ deps & builder --> base

## Evolution of libc targeting

In .NET 7 when this project started, we learned that Amazon Linux 2 had an older glibc than we initially targed in our arm64 builds. We had been targeting glibc 2.27 from Ubuntu 18.04. We [enabled](https://github.com/dotnet/runtime/pull/80866) compatibility with Azure Linux 2 by moving the arm64 builds to target Ubuntu 16.04 with glibc 2.23. At that time we still used an Ubuntu host image to build the arm64 product, but now we were targeting a different version than the host, which was an Ubuntu 18.04 image.
In .NET 7 when this project started, we learned that Amazon Linux 2 had an older glibc than we initially targed in our arm64 builds. We had been targeting glibc 2.27 from Ubuntu 18.04. We [enabled](https://github.com/dotnet/runtime/pull/80866) compatibility with Amazon Linux 2 by moving the arm64 builds to target Ubuntu 16.04 with glibc 2.23. At that time we still used an Ubuntu host image to build the arm64 product, but now we were targeting a different version than the host, which was an Ubuntu 18.04 image.
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Oops, nice catch!


.NET 8 was the first release that [unified](https://github.com/dotnet/runtime/issues/83428) all of our Linux builds to use cross-compilation, and to build on a Microsoft-supported Linux distribution (CBL-Mariner 2.0 at the time of release). Before this our x64 glibc and musl builds were not using a sysroot. With this setup we unified all of the Linux builds to target a common version of glibc (2.23 from Ubuntu 16.04) or musl libc (1.2.2 from Alpine 3.13).

In .NET 9 we [moved](https://github.com/dotnet/dotnet-buildtools-prereqs-docker/pull/1015) our builds to Azure Linux 3.0, which was easy to do thanks to the separation between the host and target versions. We also discovered that our supported Linux distributions were moving to 64-bit `time_t` on arm32 to solve the [Y2038](https://github.com/dotnet/runtime/blob/main/docs/design/features/y2038.md) problem. The flexibility of the sysroot approach made it easy to update our arm32 builds to target a more recent distribution with support for 64-bit `time_t`, without requiring any other changes to the build images.
In .NET 9 we [moved](https://github.com/dotnet/dotnet-buildtools-prereqs-docker/pull/1015) our builds to Azure Linux 3.0, which was easy to do thanks to the separation between the host and target versions. We also discovered that our supported Linux distributions were moving to 64-bit `time_t` on arm32 to solve the [Y2038](https://github.com/dotnet/runtime/blob/main/docs/design/features/y2038.md) problem. The flexibility of the sysroot approach made it easy to update our arm32 builds to target a more recent distribution with support for 64-bit `time_t`, without requiring any other changes to the build images.