ZAE — ZAE All-purpose Environment

The userland for the sic kernel: the programs that live in /bin and the static files of the root filesystem. They are ordinary hosted C programs built against libc (musl ported to sic). Nothing here is linked into the kernel; make produces build/initrd.tar, which zaeboot loads next to the kernel and sic unpacks into its tmpfs root at boot.

bin/      one C file per program -> /bin/<name>
rootfs/   copied verbatim into the image (/etc/motd, /usr/src/hello.c, ...)
ports/    third-party software, one directory per package with its own Makefile,
          patches/ and fetch rule; each installs into ports/<name>/build/root,
          overlaid onto the image. Currently: tcc (the Tiny C Compiler),
          doom (doomgeneric with Freedoom Phase 1 as the game data - id's
          shareware WAD isn't redistributable; `make DOOM_WAD=none` leaves
          the data out and `doom -iwad /disk/doom.wad` uses your own;
          video is `/dev/fb0`, input is `/dev/console` in raw scancode mode),
          python2 (Python 2.7.13, static, `python2 -m sictest`) and zlib
          (a library for the others: installs into the sysroot, not the image).

Programs: init (prints /etc/motd, sets PATH, mounts the first zaefs volume it finds on /disk — the root partition on an installed system, or a freshly formatted NVMe scratch disk in QEMU — and respawns the shell), sh (builtins cd pwd exit export help; pipelines with |, redirections < > >>, & for background jobs, ^C interrupts the foreground job), grep, wc, sleep, kill, yes, threads (pthreads smoke test), ls, cat, echo (echo words > file), hello, uname, env, crash (deliberately faults), mkfs.zaefs/mkfs.fat/mount/umount (persistent storage; mount -t fat), sicinstall (installs the running system onto a disk: GPT with an ESP for UEFI, a raw boot partition for BIOS and a zaefs root — one disk boots on both firmwares), insmod/rmmod/lsmod (kernel modules, shipped in /lib/modules from the kernel build), beep (a sine wave through /dev/dsp), test (libc/fork/exec/wait/pipes/signals/threads/filesystem/zaefs/FAT/mmap/modules/tcc/sockets self test, run by the kernel at boot if present).

Networking: net (show interfaces; net eth0 ADDR MASK [GATEWAY], net dns SERVER), dhcp (one-shot DHCP client; init runs it on eth0 at boot and it writes /etc/resolv.conf), ping, nc (nc HOST PORT, nc -l PORT, -u for UDP), fetch (HTTP GET: fetch -o file http://host/path), httpd (httpd -p 80 /some/dir &, a static file server). Name resolution is musl's own resolver over UDP, so any program using getaddrinfo works. In QEMU use -netdev user,id=n0,hostfwd=tcp::8080-:80 -device e1000,netdev=n0: the guest gets 10.0.2.15 from DHCP, the host is 10.0.2.2, and curl localhost:8080 reaches an httpd inside.

tcc runs on sic and compiles against the same musl the ZAE tools use: the port ships musl's headers and static libs in /usr/include and /usr/lib, so tcc /usr/src/hello.c -o /tmp/hello && /tmp/hello works at the shell. Output binaries get the sic image base and OS/ABI byte; -run is not supported yet.

Adding a program: drop bin/foo.c with a normal main and run make; it shows up as /bin/foo. Programs are linked statically at 0x8000000000 (--image-base), because sic's user address space starts above the kernel's 4 GiB identity map.

make ARCH=powerpc builds the same programs for the 32-bit big-endian PowerPC port (image base 0x10000000, build/powerpc/); the tcc, doom, python2 and zlib ports are x86-only and are skipped there (modules come from the kernel build as on x86). sicinstall writes x86 boot code and is not useful on a Mac. make ARCH=aarch64 likewise (image base 0x8000000000, build/aarch64/, linked with the libc's libcompiler_rt.a).

Optional packages (the zwm window server and the zde desktop live in their own repos) install a tree into $SYSROOT/rootfs/, which make overlays onto the image as-is.

Installing on a machine

Boot the live system from a USB stick (write zaeboot-bios.img or a sicinstalled stick to it; UEFI and BIOS both work), then:

/ $ ls /dev            # find the target: sda/sdb (SATA), nvme0n1 (NVMe), hda (IDE)
/ $ sicinstall /dev/sda

It erases the disk, writes a GPT (ESP + sicboot + zaefs root), installs zaeboot for both firmwares and copies the running system. Reboot from that disk. The installed system still boots from the kernel + initrd; the zaefs root partition is mounted on /disk for persistent storage.

Building

Same toolchain as the kernel (clang + ld.lld, plus tar with USTAR support).

All four sic projects meet in a sysroot rather than knowing each other's paths: $SIC_SYSROOT, default ~/.sic/sysroot (or make SYSROOT=...). ZAE reads the libc, the kernel's ABI headers and modules from there, so run make install in sic and libc first, then:

make            # build/initrd.tar
make install    # -> $SYSROOT/boot/initrd.tar, where zaeboot picks it up

Contributing

Patches need a Signed-off-by: line (DCO 1.1). Read CODE_OF_CONFLICT and CONTRIBUTING.

License

Copyright (C) 2026 Rigby Foundation. Licensed under the GNU General Public License, version 2 only (SPDX-License-Identifier: GPL-2.0-only); see LICENSE. Every source file carries an SPDX tag. Third-party software under ports/ keeps its own licence (tcc: LGPL-2.1-or-later, see ports/tcc/NOTICE; Python: PSF licence; zlib: zlib licence); only the port glue is ours.