SUB-OS: Modular Monolithic Linux-Compatible Operating System

   _____ _    _ ____          ____   _____ 
  / ____| |  | |  _ \        / __ \ / ____|
 | (___ | |  | | |_) |______| |  | | (___  
  \___ \| |  | |  _ <|______| |  | |\___ \ 
  ____) | |__| | |_) |      | |__| |____) |
 |_____/ \____/|____/        \____/|_____/ 

SUB-OS is a multi-architecture, production-grade modular monolithic operating system kernel engineered in C, C++17, Assembly, freestanding bare-metal Rust (no_std), and the custom SUB Language (.sb). Built for high performance, memory safety, modularity, and Unix/Linux compatibility, SUB-OS supports 64-bit x86 (x86_64), 64-bit ARM (aarch64), and 32-bit ARM (armv8i / AArch32) targets.

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🌟 Key Architecture & Capabilities

• 🧵 Kernel Concurrency Core (kernel/wait.c, kernel/futex.c, kernel/rcu.c):
  • Wait Queues & Completions: Sleeper parking with timed waits, one-shot completion barriers, and a static entry pool so a blocking path never re-enters the allocator (waitinfo).
  • Futex Hash Table: 32 buckets with value re-check on the slow path, requeue support, and an fmutex_t sleeping mutex built on the uncontended-fastpath protocol (futexinfo).
  • Tiny RCU: Lock-free readers with nesting depth tracking, deferred call_rcu/kfree_rcu callbacks, grace-period accounting, and rcu_assign_pointer/rcu_dereference publish barriers (rcuinfo).
• 🧱 Core Data Structures (lib/rbtree.c, lib/kfifo.c, lib/hashtable.c):
  • Red-Black Tree: Linux-compatible parent-pointer rbtree with full insert/erase rebalancing, forward and reverse in-order iteration, and a black-height invariant validator.
  • kfifo Ring Buffer: Power-of-two byte ring with free-running indices, so the wrap path costs one mask instead of a branch per byte.
  • Hash Table: Separately-chained FNV-1a table with string or u64 keys and rehash-on-growth at a 3/4 load factor.
• 💾 Block Page Cache (mm/page_cache.c):
  • Write-back cache of 4 KB pages keyed by (device, page index), indexed through the kernel hash table.
  • CLOCK second-chance eviction with dirty write-back, pinning, per-device flush and invalidate, and live hit-rate telemetry (pagecache).
• 🧪 In-Kernel Test Harness (kernel/ktest.c):
  • KUnit-style suites with assertion macros, per-case pass/fail reporting and timing.
  • 6 built-in suites, 21 cases, 735 assertions covering rbtree, kfifo, hashtable, RCU, futex, wait queues, page cache and libcore — runnable from the shell (ktest) or the desktop KTest Runner.
• ⚡ Freestanding C++17 OOP Kernel Engine (kernel/cpp/):
  • Bare-Metal C++ Runtime: operator new/delete, sized deallocation, placement new, pure virtual handlers (__cxa_pure_virtual), and .init_array global constructor dispatcher.
  • Modern Generic Containers: Pure freestanding Vector<T>, UniquePtr<T> (with polymorphic converting constructors and custom deleters), dynamic String, and move semantics (kernel::move, kernel::forward).
  • Object-Oriented Device Driver Model: Abstract Device base class with BlockDevice, CharDevice, VirtualRamDiskDevice (512B sector emulator), and VirtualNull/VirtualZero concrete classes managed by the DeviceManager singleton.
  • C++ Microbenchmark Engine: Validates zero-overhead abstractions, virtual method dynamic dispatch latency across 500,000 iterations, and dynamic container throughput.
  • Interactive C++ Commands: cppinfo (Kernel telemetry), cppdevs (OOP device tree), cppbench (Microbenchmarks), and cpptest (Polymorphic dispatch verifier).
• 🐍 Interactive In-Kernel Snake Game (userland/lazybox/snake.c):
  • Full-featured ANSI terminal game featuring real-time keyboard control (WASD and Arrow keys), dynamic food generation, score counter, body growth, wall/self collision detection, and autonomous simulation mode (snake --demo).
• 🔮 SUB Programming Language Kernel Signature & In-Kernel VM (sub/ & kernel/sub/):
  • Native .sb Kernel Modules: Key subsystems written directly in the custom SUB language:
    • sub/signature.sb: Kernel identity, OS signature, and author credits.
    • sub/power_governor.sb: Dynamic CPU P-state thermal scaling and frequency/voltage calculations.
    • sub/benchmark.sb: Recursive Fibonacci and integer matrix benchmark algorithms.
    • sub/easter_egg.sb: Interactive kernel quotes and easter eggs.
  • In-Kernel SUB Virtual Machine & AST Interpreter (subi): Run .sb scripts or inline expressions live from the shell (subi file.sb or subi -e "var x=10; print(x*2)").
• 🦀 "Rust for SUB-OS" Memory-Safe Kernel Layer (rust/src/):
  • Freestanding Bare-Metal Rust: Compiled with rustc 1.75+ in pure no_std mode with static FFI bindings.
  • Memory-Safe Cryptography: RFC-8439 ChaCha20-Poly1305 AEAD authenticated cipher, CSPRNG entropy source, FIPS-202 SHA3-256 (Keccak-f[1600]), FIPS-197 AES-128, and RFC-4648 Base64 codec.
  • Zero-Copy ELF Binary Parser: Header and segment inspector validating ELF-64/32 binaries and architectures (readelf).
  • Memory Fragmentation & Buddy Telemetry: Order 0-10 buddy allocator tracking and external fragmentation indexes (buddyinfo).
  • Storage & Disk Parsing: Memory-safe MBR and GUID Partition Table (GPT) header and partition decoder (fdisk).
  • Fast VFS Directory Cache (dcache): 64-entry LRU path hash table for single-cycle file and directory lookups.
  • Kernel Health Watchdog & Heartbeat Monitor: Subsystem sanity checker and anomaly detector.
  • Zero-Copy JSON Tokenizer: High-speed JSON key-value query engine for kernel configuration and REST API parsing.
  • NetFilter Packet Evaluator: Stateful firewall rule matcher and packet counter.
• 🎯 Multi-Architecture HAL:
  • x86_64 (AMD64 / Intel 64): Custom 2-stage MBR bootloader, E820 BIOS memory mapping, 4-level PML4 48-bit paging, GDT, 256-entry IDT, 8259 PIC, 8254 PIT timer, Hardware FPU/SSE (CR4.OSFXSR).
  • aarch64 (ARMv8-A 64-Bit): Exception levels (EL1), 16-entry vector table, ARM Generic Interrupt Controller (GICv2), ARM Generic Arch Timer (100 Hz), Stage-1 39-bit VA MMU, PL011 UART.
  • armv8i (ARM32 / AArch32): Banked exception mode stacks (IRQ, ABT, UND, SVC), VMSAv7 1MB Section MMU, GICv2 distributor, CP15 Generic Timer, VFP/NEON FPU, PL011 UART.
• 🎛️ Linux-Style Kconfig TUI Configurator (make configure):
  • Full interactive lxdialog GUI interface (Royal Blue backdrop, floating modal windows, drop shadows, and menu hierarchy).
  • Dynamic Kbuild-style selective compilation based on .config and include/config/autoconf.h.
• 📁 Storage & Filesystem Layer:
  • FAT32 (VFAT) storage driver with directory traversal and /mnt/fat32 auto-mounting.
  • Second Extended (EXT2) Linux filesystem driver.
  • Virtual File System (VFS): POSIX open, read, write, close, seek, mount interface.
  • Synthetic DevFS (/dev), ProcFS (/proc), and Sysfs KObject Hierarchy (/sys).
  • Dynamic in-memory RAM disk (/dev/ram0).
• 🖧 Hardware Device Drivers:
  • Storage Controllers: NVMe PCIe SSD, AHCI SATA 6Gb/s, IDE/ATA Hard Disks, VirtIO-Block.
  • Network Adapters: Intel 82540EM Gigabit Ethernet, Realtek RTL8139 Fast Ethernet, VirtIO-Net 10GbE.
  • Multimedia & Display: Bochs/VBE dynamic resolution video adapter, 2D TrueColor Canvas Rasterizer, Intel High Definition Audio (Azalia HDA), AC'97 sound codec, Formant TTS synthesizer, 8-Bit Melody player.
  • Bus & Sensors: PCI bus enumerator, USB 3.0 Extensible Host Controller (xHCI), HWMON CPU temperature and fan tachometer sensors, VirtIO-RNG hardware entropy generator, Unix98 PTY subsystem.
• 🌐 Networking, Firewalls & Daemons:
  • Full L2–L4 IPv4 protocol stack with dynamic ARP, ICMP Echo (ping), UDP, and full 3-way handshake TCP state machine.
  • NetFilter stateful packet inspection firewall (iptables).
  • Built-in OpenSSH 2.0 Daemon (sshd) on port 2222.
  • Built-in Micro HTTP REST API Server (httpd) on port 8080.
• 🔒 Kernel Security & Async Engine:
  • Linux Security Module (LSM) enforcing POSIX capabilities and DAC.
  • X.509 Cryptographic Keyring with signature verification.
  • In-Kernel eBPF Register Virtual Machine and verifier.
  • io_uring lockless asynchronous Submission/Completion ring buffers.
  • Preemptive multi-tasking scheduler with Round-Robin quantum and spinlock synchronization.
  • Systemd-style unit manager (systemctl), cron background scheduler (crond), and RFC 5424 Syslog engine.
• 🧰 LazyBox Userland Suite (85+ Linux, Rust, C++ & SUB-Lang Applets):
  • Interactive shell with history, quote-aware tokenization, tab autocompletion, ANSI cursor editing, and script runner (sh).
  • GNU-compatible Nano visual text editor.
  • Text Processing Suite (userland/lazybox/coreutils.c): sort, uniq, cut, tr, rev, tac, nl, seq, diff, xxd, du, factor, sum and truncate, all reading through the VFS and handling the zero-length synthetic nodes procfs and sysfs expose.
  • Kernel Diagnostics: ktest, rcuinfo, futexinfo, waitinfo and pagecache.
  • Full utilities: ls, cat, touch, mkdir, rm, cp, pwd, cd, tree, find, wc, head, tail, stat, df, mkfs.vfat, hexdump, neofetch, uname, free, uptime, top, ps, pstree, kill, dmesg, netstat, ifconfig, ping, traceroute, curl, ssh, tts, alsamixer, sensors, rustinfo, chacha20, sha3sum, base64, cryptobench, fdisk, rfilter, dcache, watchdog, jsonquery, subinfo, subi, subpower, subbench, subquote, cppinfo, cpptest, snake, and more.

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🏛️ Comprehensive Architecture

+------------------------------------------------------------------------------------+
|                             USERLAND & SYSTEM SUITE                                |
|  Interactive Shell | GNU Nano | Snake Game | Script Runner (sh) | LazyBox (85+ Apps)|
|  Micro HTTP Server | SSH 2.0 Daemon | Service Manager (systemctl) | Syslog Engine  |
+------------------------------------------------------------------------------------+
|                       SUB LANGUAGE IN-KERNEL VM & MODULES                          |
|  subi Interpreter | OS Signature | CPU Power Governor | Recursive Math Benchmark   |
+------------------------------------------------------------------------------------+
|                      FREESTANDING C++17 OOP KERNEL ENGINE                          |
|  Virtual Method Dispatch | RAII | Polymorphism | Telemetry Classes | Templates     |
+------------------------------------------------------------------------------------+
|                       RUST-FOR-SUB-OS MEMORY-SAFE SUBSYSTEM                        |
|  ChaCha20 CSPRNG | SHA3-256 Keccak | AES-128 | Base64 | GPT/MBR | NetFilter Matcher|
|  VFS DCache Table | Kernel Health Watchdog | Zero-Copy JSON | Hardware Sensors     |
+------------------------------------------------------------------------------------+
|                         VIRTUAL FILE SYSTEM LAYER (VFS)                            |
|  vfs_namei | RAMFS (/) | /dev (devfs) | /proc (procfs) | /sys (sysfs) | FAT32 | ext2|
+------------------------------------------------------------------------------------+
|         NAMESPACES, INTER-PROCESS COMMUNICATION & ASYNC I/O ENGINE                 |
|  PID/UTS Isolation | Pipes | Message Queues | Shared Memory | Semaphores | io_uring|
+------------------------------------------------------------------------------------+
|                   CORE KERNEL SERVICES, SECURITY & TRACING                         |
|  Preemptive Scheduler | Fast Syscalls | Dynamic Modules | eBPF Virtual Machine     |
|  LSM POSIX Capabilities | X.509 Keyring | Workqueues | Telemetry & Kernel Tracer   |
+------------------------------------------------------------------------------------+
|               NETWORKING, NETFILTER FIREWALL & SOUND ARCHITECTURE                  |
|  Ethernet | ARP | IPv4 | ICMP | UDP | TCP | DHCP | DNS | Sockets | NetFilter FW   |
|  Embedded HTTP Server (8080) | SSH Server (2222) | Intel HDA | AC'97 | Formant TTS |
+------------------------------------------------------------------------------------+
|                             DEVICE DRIVER TREE                                     |
|  NVMe PCIe SSD | AHCI SATA | ATA IDE | VirtIO-Blk | Ramdisk (/dev/ram0)            |
|  Intel E1000 NIC | RTL8139 NIC | VirtIO-Net | USB 3.0 xHCI | HWMON Sensors         |
|  Bochs VBE Display | 2D Canvas | VGA / TTY1-4 | 16550 Serial | PL011 UART          |
+------------------------------------------------------------------------------------+
|                        HARDWARE ABSTRACTION LAYER (HAL)                            |
|  x86_64 (AMD64/PML4) | aarch64 (ARMv8-A/GICv2/MMU) | armv8i (AArch32/Section MMU)  |
+------------------------------------------------------------------------------------+

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🚀 Quick Start Guide

1. Prerequisites

Install the standard build essentials, cross-compilers, and Rust toolchain:

# Ubuntu / Debian
sudo apt update
sudo apt install build-essential g++ nasm qemu-system-x86 qemu-system-arm \
                 gcc-aarch64-linux-gnu binutils-aarch64-linux-gnu \
                 gcc-arm-linux-gnueabihf binutils-arm-linux-gnueabihf \
                 rustc cargo dialog python3

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2. Linux-Style TUI Configuration

Launch the interactive Kconfig configurator:

make configure

(Also available via make menuconfig)

Fast Architecture Presets:

make x86_64_defconfig    # Configure for x86_64 (Intel / AMD 64-Bit)
make aarch64_defconfig   # Configure for 64-bit ARM (Cortex-A57)
make armv8i_defconfig    # Configure for 32-bit ARM (Cortex-A15)

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3. Compilation & Live Emulation

Target: x86_64 (Default)

make x86_64_defconfig
make
make run

Port forwardings automatically configured in QEMU:

• SSH Server: ssh root@localhost -p 2222 (Password: root)
• HTTP REST API: http://localhost:8080/api/status

Target: aarch64 (ARMv8-A 64-Bit)

make aarch64_defconfig
make ARCH=aarch64
make run ARCH=aarch64

Target: armv8i (ARM32 / AArch32)

make armv8i_defconfig
make ARCH=armv8i
make run ARCH=armv8i

Graphical Window Emulation (Optional SDL/GTK GUI)

make run-gui

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🧰 LazyBox Command Matrix (85+ Utilities)

Category	Commands Included
Core & Shell	lazybox, sh, echo, env, export, whoami, id, date, cal, jsonquery, subi
Filesystem & Search	nano, ls, cat, touch, mkdir, rm, cp, pwd, cd, tree, find, wc, head, tail, stat, df, mkfs.vfat, grep, hexdump, dcache
Networking & Routing	ifconfig, ping, traceroute, arp, dhclient, nslookup, dnscache, netstat, iptables, rfilter, httpd, sshd, curl, wget, ssh, e1000e
Hardware & Storage	lspci, lsdev, lsblk, fdisk, hdparm, sensors, speaker, beep, mouse, alsamixer, tts, virtinfo, gpuinfo, cpufreq
Security & Cryptography	su, passwd, useradd, certcheck, capsh, ipcs, chacha20, sha3sum, base64, aead, cryptobench
SUB Language & System	subinfo, subpower, subbench, subquote, pstree, kill, shm, readelf, buddyinfo, tscinfo, systemctl, service, crontab, logger, logread, watchdog, rustinfo, cppinfo, cpptest, cppdevs, cppbench
Entertainment & Games	snake, matrix, calc, vtart
Kernel & Tracing	lsmod, insmod, rmmod, slabinfo, trace, unshare, io_uring_test
Diagnostics & Metrics	neofetch, uname, free, uptime, top, htop, ps, dmesg, vmstat, iostat
System Control	clear, help, sleep, reboot, shutdown, poweroff, tty

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📦 Official Release

Download precompiled kernel binaries and bootable disk images from GitHub: 👉 SUB-OS v0.0.1-beta Release

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📄 License

SUB-OS is distributed under the open-source MIT License. See LICENSE for details.