Overview

MK90/Unix 0.7

User and system reference for the Elektronika MK90.

Overview

MK90/Unix is a compact operating system for a 16 KiB MK90, booted from a 32 KiB 27C256 cartridge. It provides a Unix-style command shell, MKS2 files and directories, a text editor, cooperative multiprogramming, a two-process pipe and the on-device MBC-16 BASIC compiler.

This is the reference for the distributed 0.7 binary. Command names and BASIC keywords are shown exactly as entered. Firmware messages, command guides and this reference are in English.

Reference packages

Package	Contents
Getting started	Install the ROM, mount a data cartridge, compile the included demonstration.
mk90.commands	All 33 registered commands, parameters, examples, effects and diagnostics.
mk90.system	Process slots, cooperative scheduling, stack ownership, IPC and memory.
mk90.basic	MBC-16 syntax, statements, functions, compiler and runtime.
mk90.api	Native task, file, block-device and pipe calling contracts.
Alphabetical index	Command, language and system entries, with offline search.

Quick start

With a writable, already formatted MKS2 data cartridge in SMP1:

mount /dev/smp1 /mnt/smp1
cp /mnt/smp0/demo.bas /mnt/smp1/demo.bas
cd /mnt/smp1
mbc demo.bas
./demo.mbx

For installation and first-time formatting, see Getting started.

Release scope

Area	Implemented in 0.7
Shell	33 names; space-separated arguments; a single two-stage pipeline.
Multiprogramming	Four fixed context slots: shell, foreground child and two background slots; cooperative scheduling.
Storage	SMP driver, fixed mountpoints and MKS2; one partition per supported-size volume.
BASIC	MBC-16 signed 16-bit integer subset, compiled to MBX1 bytecode.
Expansion	UART, floppy and CF drivers are not present.

The Unix-style interface does not imply Linux, POSIX, ELF or a general PDP-11 operating-system ABI. See Limits and compatibility.

Release and distribution

Official binaries are freeware; operating-system source code remains private. Copyright and distribution policy. The HTML manual works offline after extraction: open index.html. It uses local assets and does not need a server.

See the included validation report for this release’s CPU-model regression results. That model executes the generated PDP-11 instructions with 16 KiB RAM; it is not cycle-accurate and does not replace a test on the physical MK90.