for a blast from the past, type:
make test
you now are running the recovered 1.4 shell and can do a lot including: (this builds the kernel)
cd /usr/src/sys
make
or, for a quite strange experience,
src/usersim/sim bin/man sh | less
(run the simulated z80 micronix man program on sh, and pipe it to linux less)
three version numbers turn up in here and they do not mean the same thing. this tree is released as micronix 2.0, which is the number the kernel prints in its banner and the number the distribution disks in dist/ are named for. 1.4 is the distribution userland - the shell and the commands in disks/dist, recovered from the original disks. 1.61 is where the kernel source was recovered from: it is the provenance of that source and not what the tree now is.
micronix 2.0 is a substantially enhanced kernel, not the 1.61 kernel with a new number on it. the boards are discovered at boot and each driver is a module placed only if its card answers, so one kernel boots the SS1, the Wunderbus and the MultIO; the buffer cache hashes its headers and keeps the data in segments behind a window, with room for over a hundred buffers against 1.61's fifteen; the task maps are per-process and a switch no longer copies one, and each process has its own u page and stack; exec builds its arguments straight into the new image, and execve adds an environment; and the system call table has grown dup2, ftruncate, ioctl, reboot and execve. src/micronix/sys/FEATURES-2.md is the full account, with the counts taken from the two kernels.
micronix 2.0 - release notes, 21 oct 2026
this is the first release of micronix in 42 years. it is a complete source release, with significantly enhanced functionality and much higher performance on the same hardware:
an entirely new C compiler and tool chain. it exploits the Z80
chip for significant speed and space improvements over the
Whitesmith's compiler. in addition, it accepts most of ANSI C.
up to 128K of ram is used as a buffer cache, greatly reducing
disk i/o.
it exploits the mpz80 hardware contexts to make context switches
much cheaper.
exec now allows a large number of arguments, limited by memory
size.
unix 7th edition changes: ioctl, lseek, dup2, O_APPEND,
ftruncate, environment variables, bourne shell, make, less and
many others.
a network interface has been added supporting an ESP32 connection.
the ESP32 runs tcp/ip and wifi; rcp copies files over rsh, and nd is
a network disk on the same card - a block device that can serve a
volume with no local controller.
the console is chosen at boot: the morrow multio ACE or the compupro
SS1's 2651. wunderbus ACEs and the serial lines give additional
terminals, so the machine is multi-user over serial.
halt and reboot commands are added.
format utilities running natively for all supported disk
controllers.
modular device drivers: all block device drivers share a single
4k segment, so many different drivers can be loaded on the same
kernel.
automatic interrupt probing: all disk controllers can be strapped
to any unused S100 VI line, and it will be automatically
detected.
automatic detection of interrupt controllers: the morrow multio,
wunderbus I/O and compupro system support are all supported.
the tool chain is self-hosting: the source tree rebuilds itself
natively, and the second generation is byte-identical to the first
(make verify).
drivers for the following controllers have been added, along with
boot rom support if running the included mon5.0:
morrow hdc/dma, dj/dma, hdca
compupro disk1, disk2, disk3
s100computers.com dual ide, scsi
disk partitioning. micronix only used up to 32MB of a disk. a
new disk labeling facility made disks self-describing, so the
kernel no longer needs to know disk geometry.
the source tree, the build instructions and the 1.4 userland / 1.61 kernel provenance are in this file. make test runs the recovered 1.4 shell; the d1 simulator and usersim run the system without the hardware, and the 2.0 distribution media are under dist/ and attached to the 2.0 release. the tree is Apache 2.0 (LICENSE); the Z80 instruction tables in src/include/z80.h carry the zlib/libpng notice in LICENSE.z80.
Morrow Designs Micronix and tools updated 21 Oct 2026
directories:
filesystem: built by the top level makefile from the distribution disks this is used by the usersim to run against it holds the source and rebuilds itself natively (cd /usr/src; make)
disks: floppy images recovered from the net, version 1.4 and 1.3
wslib: the whitesmith's libraries, burst apart and disassembled - gone from the top level; what remains is under attic/wslib and attic/wssrc, with the rest of the retired material
src/micronix: the source tree for things that are to be built natively, including libraries, commands and the kernel. this is gradually being fleshed out with replacements for the micronix utilities that I don't have source for, namely all of them. notable additions: a v7 make the PWB yacc, lex, expr and fd2, and 2.11's awk tar, msh (the shell), less, diff and mv an in-memory, ansi-only, vi subset derived from stevie 2.11's ls and cp a working pwd, rm, mknod the ccc compiler, described below
src/micronix/lib: additions and replacements for the whitesmith's library.
src/micronix/sys: kernel source, recovered from a micronix 1.61 build (see the version note above), with include files. the formatting of the original source was really quirky and archaic, so I re-indented it to a more K&R like style. it is NOT ansi, and compiles with ccc (see below).
src/micronix/stand: ghidra-driven rewrite of the cold boot loaders for the kernel
src/micronix/include: include files rejiggered to make porting from v6 and v7 easier
src/tools: file system checkers, dumper and extractor object file tools, including an overachieving nm and a rootin' tootin' fire-breathing disassembler that knows about hitech objects, whitesmith's objects, and com files, does code tracing, and allows a symbol file to be fed in.
src/lib: libraries for file system, disassembly, and random utility
src/usersim: micronix user mode simulator, including upm, the cp/m emulator. it is quite solid.
special files are symlinks that name the device - bdev(maj,min) or
cdev(maj,min) - and the block devices are real: mount() and umount()
go through the host fslib, with -D <devdir> pointing at a directory of
bdev(maj,min) links to images. mkfs, fsck, icheck and the rest open
the raw device the same way.
build it on any random unix box (centos is baseline),
and run: sim
src/hwsim: a hardware level mpz80 simulator that boots the micronix kernel. it includes the ability to load+run the monitor roms, load symbol tables, has an ICE-like debugger with breakpoints, single step, disassembler, and so on. furthermore, it has a modular architecture that allows plugging in different chip simulators.
it runs cp/m and boots micronix to a shell, with interrupt controller,
trapping, memory mapping, and disk reading and writing for the disk
controllers (djdma, hddma, hdca, ide, ncr5380, and CompuPro's
disk1/disk2/disk3), the ND network card, the SS1 and the MultIO.
the card list is the DRIVERS line in src/hwsim/d1/GNUmakefile.
there's a means for importing and exporting data to cp/m via the
inp: and out: devices in pip, so hex files can be shipped to get
programs in and out.
the djdma simulator reads IMD files directly, and writes produce
a delta file that is loaded at the next startup, so there's no
modification of the original IMD. the imd utility can generate
a merged IMD file that contains any changes.
src/include: library include files for the emulation
ccc: this tree's own c compiler, written from scratch - cpp, c0, c1, peep, asz and ld, the passes in src/micronix/libexec and the driver and friends in src/micronix/cmd. it cross builds on the host (mxccc) and natively inside micronix (ccc), and targets both micronix and cp/m - -m micronix links libu, -m cpm links libcpm, and both link the one pure libc. everything in this tree builds with it.
extra/v6, extra/v7, extra/2.11 oh, yeah. this is the real mc-coy. this is useful for reference and tool source grabbing. the porting to micronix is simple, if tedious. the include files are subtly different.
publicdocs: almost everything I could find on the micronix hardware - flattened from extra/docs - and miscellaneous morrow stuff that may be useful.
extra/decomp: a decompiler that knows about code flow, system calls, and with the goal of generating recompilable C. very much a WIP. probably throw away now that ghidra exists.
extra/sim: a bunch of 8 bit simulators for cribbing ideas/code from. these all are licensed by thier original authors, so...
two simulators, two experiences.
usersim (src/usersim) is the easy one: it hosts micronix's system calls on linux and runs against filesystem/, no simulated hardware, no disk images. build once, then
make
src/usersim/sim
hwsim (src/hwsim/d1) is the real machine - the Morrow MPZ80, the monitor rom, the real kernel, every controller in its card list - and it boots micronix to a '#' shell on a simulated disk. it is the one that needs setup.
the short boot, from a standing start:
make
cd src/micronix && make bootstrap
make -C src/micronix/stand/boot bootimgs
disks/hdinstall/create_vol myvol # a bootable volume
disks/hdinstall/boot_vol myvol # boot it, console in an xterm
boot_vol passes -c 0x70c: boot the hdcdma straight, skip the monitor, and put the console in an xterm of its own. the boot block mkfs left on cylinder 0 loads /micronix.
the performance build is the same simulator with the debug machinery compiled out - d1p, or d1 -F - and it runs at roughly a 30 mhz z80, which makes it pleasant to use rather than watch. everything works at that speed: multi-user logins, a compile on one terminal while ps runs on another.
the full install, from the distribution - build the diskettes, provision a two-disk machine, and install it automatically:
dist/create_dist 8 # 9 diskettes into dist/mx2.0-8-*.IMD
disks/hdinstall/build_dist # two 34 MB volumes + the install script
disks/hdinstall/dist_boot # boot and install all 9, watch the xterm
build_dist and dist_boot drive the install through /dev/mediachg, the out-of-band media changer: the guest program chg swaps the floppy images in the simulator without an eject syscall, and the install script loads and copies each diskette in turn. the grammar is src/micronix/sys/MEDIACHG.md.
the whole flow, the disk-label model and the boot loaders are in docs/INSTALLATION.md, disks/hdinstall/README and sys/DISKLABEL.md.
a command-line tool, src/tools/hwsim (built by make at the top of the tree), that drives the simulator the way the per-card scripts do by hand. the simulated platforms are defined in sim.json at the top of the tree: each entry under "sims" names the emulator and kernel, the monitor and level-1 boot roms, the boot device, the console and clock configuration, the wiring profile, the root and swap device tokens, and the volumes - controller, unit, geometry and image for each. the "mediasets" in the same file name the floppy IMD sets, and -f names a different platform file.
a sim is a collection of volumes, and a volume is a disk on a controller
-
its geometry and its card, not a role. the verbs:
hwsim format mnix initialize (geometry label) hwsim partition mnix label (default slice table) hwsim mkfs mnix mkfs (filesystem + boot) hwsim boot launch d1/d1p from config + volumes hwsim add
hwsim del : hwsim list the sims defined in the file hwsim show one sim's definition
root and swap are the kernel's setdev arguments, named as device tokens (hdcdma:0a), not volume attributes; -c packs boot, nomon, the xterm mask and the clock from named fields. the common case - build and boot the sample two-disk sim (q540-dual):
src/tools/hwsim format q540-dual # initialize both m40 volumes
src/tools/hwsim partition q540-dual # the default slice table
src/tools/hwsim mkfs q540-dual # filesystem + boot on slice a
src/tools/hwsim boot q540-dual # d1p, packed -c, both disks wired
the full design - the json schema and the bit tables - is src/tools/PROVISION.md. build_dist and dist_boot are the same thing done by hand, and the media changer (sys/MEDIACHG.md) is how a boot's floppies get loaded.
this github is prettily referenced in my cybernecromancy site:
https://retro.zen-room.org/morrow-micronix/user-mode-simulator