QEMU no more
We are elminating support for QEMU, and here is why. You can still use QEMU if you want, but you will need to manually configure and run it.
QEMU was our first environment for building Cosmos. It offered us several advantages:
- It can emulate ARM processors which are important in the future to Cosmos.
- Its small and can be embedded in the Cosmos install so users can be ready to go with one less prerequisite.
- Its free!
Problems
However bugs and issues with QEMU directly delayed the release of Milestone 5 but more than 2 months.
- QEMU is developed exclusively by Linux developers and no Windows builds are provided. This also means that Windows specific issue are typicaly ignored.
- To build on Windows requires several out of date and hard to obtain specific cygwin versions.
- There is a IP4 bug that has existed for several years on Windows that affects GDB and serial connections. A solution has since been found, but not after spending nearly 2 months fixing and rebuilding QEMU on Windows.
- Step over in GDB does not function on assembly code.
- Serial functionality when using polling (as required my our debugstub so as not to interfere with the OS) has serious problems and often provides random garbage.
Replacement
Becuase of this we have dropped support for QEMU in the debugger. Its simply too time consuming to support. When virtualization will not do and emulation is required, we will use Bochs instead.
For users VMWare Player has advanced and more feature are available. VMWare Player is free and the new preferred FREE virtualization for Cosmos.
