- Porting an operating system is a complex task requiring infrastructure such as compilers, debuggers, and libraries.
- Digital's Alpha Migration Tools Group ported Linux to the DEC Alpha with goals: free, resource-efficient, high performance, source compatibility, and fast schedule.
- Initial port used Linux 1.0 code base, 32-bit implementation, existing Digital Unix PALcode and SRM firmware.
- Designed a 32-bit address space with partitions to avoid user-kernel collisions: user, unused, kernel VM, mini-KSEG, kernel code/data/stack.
- Used Cygnus-modified GCC for 32-bit Alpha code, cross-compilation on Digital Unix and Intel Linux.
- Debugging was done on an Alpha instruction simulator (ISP) before using real hardware.
- Developed a bootloader in stages: first simple, then with ext2 filesystem support, then compressed kernel loading.