Overview

MK90/Unix 0.6

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 0.6 binary. Command names and BASIC keywords are shown exactly as entered. The firmware’s existing messages are often Italian; their meaning is explained here 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 0.6
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.

The release passed 69 tests in the native CPU model used during development. 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.