ThunderOS v0.10.0 - System Control

Summary

ThunderOS v0.10.0 publishes the System Control milestone from main. This release adds graceful shutdown and reboot support from user space and includes the release-hardening work needed for the public ThunderOS repository.

Changes

• Added sys_poweroff() and sys_reboot() together with the poweroff and reboot userland utilities
• Added SBI SRST, legacy SBI, and QEMU test-device fallback paths for reliable shutdown and reboot on the supported QEMU environment
• Hardened VirtIO, ext2, signals, errno handling, process isolation, and build/test workflows since v0.9.0
• Added SECURITY.md, CodeQL, dependency review, and pinned documentation dependencies for the public release path
• Aligned release metadata, documentation, and runtime banners to v0.10.0

Verification

• make clean && make -j2 && make test
• make -C docs clean html SPHINXOPTS='-W --keep-going'

ThunderOS v0.9.0 - Synchronization

ThunderOS v0.9.0 - Synchronization

This release adds blocking I/O and synchronization primitives to ThunderOS.

Features

Wait Queues

• Core sleep/wakeup mechanism for blocking I/O
• Integrated into pipe read/write for proper blocking behavior
• Processes sleep when pipe is empty (read) or full (write)

Mutexes & Semaphores

• mutex_t with lock/unlock/trylock operations
• semaphore_t with wait/signal/trywait operations
• Owner tracking for mutexes

Condition Variables

• cond_t for thread coordination
• Wait atomically releases mutex and sleeps
• Signal wakes one waiter, broadcast wakes all

Reader-Writer Locks

• rwlock_t allowing multiple concurrent readers or one exclusive writer
• Writer priority to prevent starvation

New Syscalls (16 total)

Category	Syscalls
Mutex	SYS_MUTEX_CREATE, SYS_MUTEX_LOCK, SYS_MUTEX_TRYLOCK, SYS_MUTEX_UNLOCK, SYS_MUTEX_DESTROY
Condition Variable	SYS_COND_CREATE, SYS_COND_WAIT, SYS_COND_SIGNAL, SYS_COND_BROADCAST, SYS_COND_DESTROY
RWLock	SYS_RWLOCK_CREATE, SYS_RWLOCK_READ_LOCK, SYS_RWLOCK_READ_UNLOCK, SYS_RWLOCK_WRITE_LOCK, SYS_RWLOCK_WRITE_UNLOCK, SYS_RWLOCK_DESTROY

Test Programs

Test	Result
mutex_test	8/8 PASS
condvar_test	All PASS
rwlock_test	7/7 PASS

Release Criteria Met

• ✅ Blocking I/O works properly with wakeup mechanisms
• ✅ Pipes block readers when empty, writers when full
• ✅ Mutex/semaphore primitives functional
• ✅ No busy-waiting in kernel

ThunderOS v0.8.0 - Compatibility

Version 0.8.0 - Compatibility

Major release with POSIX compatibility features.

Job Control & Signals

• Process groups and sessions
• Background processes with &, fg, bg, jobs
• Ctrl+C sends SIGINT, Ctrl+Z sends SIGTSTP

I/O & Shell

• I/O redirection (>, <, >>)
• Pipes (cmd1 | cmd2)
• Command history (up/down arrows)
• Tab completion
• Shell scripting support

Filesystem & POSIX

• ext2 file/directory removal
• Relative path resolution
• Environment variables
• File permissions and ownership (chmod, chown)

Graphics Console

• Framebuffer console with VirtIO GPU
• Bitmap font rendering (8x16)
• GPU-backed virtual terminal

Bug Fixes

• Fixed nested trap sscratch corruption causing instruction page fault

ThunderOS v0.7.0 - Virtual Terminals and VirtIO GPU 2D Driver

What's New

This release adds a virtual terminal system with 6 independent shells (VT1-VT6), switchable via ESC+1-6.

Key Features

• Virtual Terminals: 6 VTs with ESC+1-6 switching
• VirtIO GPU 2D driver: 800×600 framebuffer support
• 4 new syscalls: gettty, settty, getprocs, uname
• 6 new utilities: ps, uname, uptime, whoami, tty, kill
• Per-terminal input buffers and process isolation
• Refactored shell (ush.c)

Stats

• System calls: 32 → 35
• Shell commands: 18 → 23

See CHANGELOG.md for full details.

ThunderOS v0.6.0 - User Shell

ThunderOS v0.6.0 - User Shell

This release introduces significant improvements to the test infrastructure, code quality, and developer experience.

🎨 Highlights

• Clean Code Refactoring: Major refactoring of kernel main with helper functions and named constants
• Improved Build Output: Colorful, categorized build output for userland programs
• CI Pipeline Fixes: Resolved TERM environment variable issues for non-interactive environments
• Test Infrastructure: Added CI mode detection for reliable automated testing

✨ New Features

• User shell with interactive command support
• ELF binary loading and execution
• Comprehensive userland programs (cat, ls, pwd, mkdir, rm, etc.)

🔧 Improvements

• Refactored kernel/main.c with 8 static helper functions
• Replaced magic numbers with named constants
• Added TERM environment variable handling to test scripts
• Improved CI workflow with duplicate output removal
• Enhanced build script with visual progress indicators

📚 Documentation

• Updated CHANGELOG with detailed v0.6.0 notes
• Updated ROADMAP with release status
• Added code quality and testing documentation

🛠️ Technical Changes

• Test runner now detects CI mode automatically
• Build output categorized by program type (shell, utilities, test programs)
• Removed backup files and dead code

Full Changelog: v0.5.0...v0.6.0

ThunderOS v0.5.0 - Communication

🎉 ThunderOS v0.5.0 - Communication

This release introduces process communication capabilities to ThunderOS, enabling multi-process applications through fork(), pipes, and signals.

✨ Highlights

Fork System Call

• Complete process forking with full memory isolation
• Parent receives child PID, child receives 0
• Independent address spaces with copy-on-write semantics
• Proper trap frame and page table duplication

Pipe-Based IPC

• Non-blocking anonymous pipes for inter-process communication
• 4KB circular buffer per pipe
• sys_pipe() syscall for pipe creation
• read()/write() operations on pipe file descriptors

Signal Handling

• SIGCHLD signal sent when child process exits
• waitpid() blocks parent until child terminates
• Process reaping to prevent zombie processes

🐛 Bug Fixes

• Fixed trap frame preservation across context switches
• Fixed child process return values (child now correctly returns 0)
• Fixed page table switching order in scheduler (moved after context_switch_asm)

📚 Documentation

• Added comprehensive sys_fork() documentation to syscalls.rst
• Added complete pipe IPC documentation (pipes.rst)
• Updated CHANGELOG.md with all v0.5.0 changes
• Marked ROADMAP.md v0.5.0 criteria complete

✅ Testing

• DMA Tests: 10/10 passing
• Memory Isolation Tests: 15/15 passing
• Boot: Clean with no debug output
• Userland: fork_test and pipe_test validate functionality

⚠️ Known Limitations

• Pipes are non-blocking (return EAGAIN when empty)
• No pipe capacity limits enforced yet
• Signal handling limited to SIGCHLD only
• Blocking I/O deferred to v0.10.0

📦 Syscalls Added

• sys_fork() - Fork current process
• sys_pipe() - Create anonymous pipe pair

See CHANGELOG.md for complete details.

ThunderOS v0.4.0 - Persistence

ThunderOS v0.4.0 - "Persistence"

Fourth release of ThunderOS featuring persistent storage capabilities with VirtIO block device driver, ext2 filesystem, and ELF program loader.

� Highlights

• VirtIO Block Driver: Modern MMIO interface with 64-bit addressing, DMA integration
• ext2 Filesystem: Full read/write support with 4KB blocks, files up to ~4MB
• Virtual Filesystem (VFS): Abstraction layer for multiple filesystem types
• ELF64 Loader: Execute RISC-V programs from disk with memory isolation
• Interactive Shell: Commands for ls, cat, and program execution
• Comprehensive Documentation: Complete internals docs for all new components

📦 New Components

Storage Stack

• kernel/drivers/virtio_blk.c - VirtIO block device driver (525 lines)
• kernel/fs/ext2_*.c - ext2 filesystem implementation (2,250+ lines)
• kernel/fs/vfs.c - Virtual Filesystem layer (499 lines)
• kernel/core/elf_loader.c - ELF64 program loader (216 lines)
• kernel/core/shell.c - Interactive shell (358 lines)

User Programs

• userland/hello.c - Hello world program
• userland/cat.c - File display utility
• userland/ls.c - Directory listing utility

🔧 Technical Specifications

• VirtIO: Modern MMIO at 0x10008000, 256-entry descriptor rings, DMA-capable
• ext2: 4KB blocks, 128/256-byte inodes, direct + single indirect blocks
• ELF: ELF64 RISC-V executables, isolated page tables, NX protection
• VFS: 64 file descriptors, mount point management, POSIX-like API

📖 Documentation

New comprehensive documentation:

• VirtIO Block Driver Internals (docs/source/internals/virtio_block.rst)
• ext2 Filesystem Implementation (docs/source/internals/ext2_filesystem.rst)
• VFS Architecture (docs/source/internals/vfs.rst)
• ELF Loader (docs/source/internals/elf_loader.rst)

🚀 Usage

# Build ThunderOS
make clean && make

# Create disk image with ext2 filesystem
./build_disk.sh

# Run with VirtIO block device
make qemu-disk

In ThunderOS shell:

ThunderOS> ls /
ThunderOS> cat /test.txt
ThunderOS> /bin/hello

✅ Testing

All tests passing:

• VirtIO I/O operations (100-600 polling iterations)
• ext2 read/write operations
• ELF program loading and execution
• Shell commands (ls, cat, program execution)
• GitHub Actions CI with disk image creation

📊 Statistics

• Total Lines Added: ~10,500
• New Files: 54
• Components: 4 major subsystems (VirtIO, ext2, VFS, ELF)
• Documentation: 4 comprehensive RST files (3,200+ lines)

🔗 Links

• CHANGELOG - Detailed release notes
• ROADMAP - Future development plans
• Documentation - Technical documentation

🎓 What's Next (v0.5.0 - "Communication")

• Inter-process communication (pipes)
• Shared memory support
• Signals (SIGKILL, SIGTERM, etc.)
• VirtIO network driver
• Basic TCP/IP stack

---

Full Changelog: v0.3.0...v0.4.0

ThunderOS v0.3.0 - Memory Foundation

ThunderOS v0.3.0 - Memory Foundation

Release Date: November 10, 2025

Overview

Advanced memory management infrastructure for device drivers, including DMA allocation, address translation, and memory barriers. This release builds the foundation for VirtIO device drivers in v0.4.0.

✨ New Features

DMA Memory Allocator

• Physically contiguous memory allocation for device DMA
• Address tracking (physical and virtual)
• Memory zeroing support
• Region statistics and validation

Memory Barriers

• Complete RISC-V fence instruction suite
• Full, read, write, and I/O barriers
• Data synchronization barriers
• Instruction synchronization (fence.i)

Enhanced Address Translation

• Virtual-to-physical translation with page table walking
• Physical-to-virtual helpers
• Kernel virtual address utilities
• Error handling for invalid addresses

Testing & Documentation

• 10 comprehensive tests for DMA, barriers, and translation
• Exhaustive Sphinx documentation
• API reference and usage examples

📊 Release Criteria (All Met)

• ✅ DMA allocator works reliably
• ✅ Virtual-to-physical translation accurate
• ✅ Memory barriers implemented for device I/O
• ✅ Foundation ready for VirtIO device drivers

🔧 Technical Details

• DMA Region Tracking: Linked list with magic number validation
• Memory Barriers: RISC-V fence instructions (rw, r, w, io)
• Address Translation: 3-level Sv39 page table walking
• Platform: QEMU virt machine (tested with 128MB-512MB RAM)

📦 Toolchain Updates

• Switched to riscv64-unknown-elf-gcc (bare-metal toolchain)
• Updated Dockerfile for CI/CD compatibility
• Fixed GitHub Actions build issues

See CHANGELOG.md for complete details.

ThunderOS v0.2.0 - User Space

🎉 ThunderOS v0.2.0 "User Space" - RELEASED!

Release Date: November 9, 2025

🚀 Major Milestone

Complete user-mode support with memory protection, system calls, and exception handling.

✨ Key Features

• User-mode processes with privilege separation (U-mode)
• 13 system calls fully implemented and tested
• Memory isolation between processes using Sv39 paging
• Exception handling - graceful user process termination
• Automated testing with 6/6 tests passing

📋 System Calls

write, exit, getpid, sleep, getppid, getuid, getgid, setuid, setgid, getcwd, chdir, time, sbrk

🧪 Testing Results

• ✅ User programs run safely in unprivileged mode
• ✅ Memory protection enforced (page faults handled gracefully)
• ✅ System calls work reliably
• ✅ User exceptions don't crash the system

📁 Files

• • Kernel binary
• • Raw binary

*Ready for v0.3.0 "Persistence"push origin release/v0.2.0 🎯

ThunderOS v0.1.0 - First Boot

See CHANGELOG.md for details.