---

SCAL/UX™ - the operating system for those who take scalability seriously

Welcome to the SCAL/UX repository.

The First Hobbyist's Operating System with Virtual Memory Compression

SCAL/UX is a Unix-like operating system targeting amd64 PCs. It is internally structured into three components: the core kernel, DeviceKit, and the POSIX services.

The core kernel implements basic primitives: scheduling, virtual memory management, synchronisation, and simple message-passing. These services are used to implement a POSIX personality by the POSIX services. DeviceKit implements an object-oriented driver framework in Objective-C, with adapters to expose relevant devices to the POSIX personality. All three are implemented in kernel-space and are logically distinct but currently quite closely coupled.

This is a rewrite of much of the system. It is not very functional at all yet. The previous iteration had a number of working ports (including the BASH shell and GNU Coreutils) but many components suffered from being written to accommodate inadequate scheduling, synchronisation, and intercommunication primitives. This iteration aims to address these flaws. The previous iteration is in the old-22-08-07 branch.

Building

The SCAL/UX operating system has a BSD Make based meta-build system loosely inspired by pkgsrc. You need an existing SCAL/UX toolchain for now and mlibc headers installed into a sysroot. Other tools required to build are Meson, xorriso...

To-do

• vm_kernel doesn't do TLB shotodowns for unmaps of kernel wired memory; problem?

Third-party components

Several third-party components are used. These are some of them:

• mlibc: Provides libc.
• liballoc: Provides one of the in-kernel allocators.
• nanoprintf: used for kprintf.
• NetBSD:
  • (kernel-3/dev/fbterm/nbsdbold.psfu): Bold8x16 font used for FBTerminal.
  • (kernel-3/dev/nvmereg.h): NVMe register definitions.
• Solaris (kernel-3/dev/fbterm/sun12x22.psfu): Sun Demi Gallant font available for FBTerminal
• ObjFW: provides an Objective-C runtime.
• limine/limine-terminal-port (some files inkernel-3/dev/fbterm/): used by FBTerminal to provide a terminal.
• LUX ACPI Implementation (kernel-3/dev/acpi/lai): ACPI implementation from Managarm used by Acpi* drivers.
• LZ4 (kernel-3/libkern/lz4.{c,h}): Used by VM Compressor to compress pages.
• libuuid (kernel-3/libkern/uuid*)
• Linux (kernel-3/ext2fs/ext2_fs.h): Ext2 filesystem definitions

Licence

Code original to SCAL/UX is licenced under the Mozilla Public Licence v2.0. Other components are under their own licences