xv6 work continued from the MIT PDOS team

xv6 is a re-implementation of Dennis Ritchie's and Ken Thompson's Unix Version 6 (v6). xv6 loosely follows the structure and style of v6, but is implemented for a modern x86-based multiprocessor using ANSI C.

Enchancements from the original XV6:

• fixed broken SMP due to a QEMU regression
• added users, groups, and permissions
• organized files into /etc, /bin, and /dev
• ACPI support; falls back to MPS if it fails.
• reboot(1), which can either halt (-h) or poweroff (-p)
• organized file structure support; kernel and userland has a clear separation.
• syscall fuzzing (in the works)
• D language support (look in d/)
• fixed general system ABIs and behaviors to make them align with POSIX.
• doubly indirect block pointer inodes (max filesize 1MiB -> 512MiB)
• ls(1) now has -h, -l, -i, and -p

dependencies

• gcc/clang
• ld/lld
• objdump, objcopy, ar, ranlib
• dmd/ldc2/gdc
• qemu
• gmake

BUILDING AND RUNNING XV6

run "make qemu" with a compiler capable of producing ELF files.

On linux-based systems and FreeBSD systems, this means the native compiler.