# FSKit Research Summary - macOS 27 TODO

## Research Date: 2026-05-29
## Status: Blocked by SIP protection, waiting for macOS 27 WWDC

---

## ✅ Completed Research

### 1. Rust FSKit Module (markbase-fskit)
- **Files**: markbase-fskit/src/fskit/volume.rs (746 lines)
- **Operations**: 18 FSKit operations implemented
- **Thread Safety**: AnyThread support
- **Backend**: SQLite-backed file system
- **Binary**: 
  - dylib: libmarkbase_fskit.dylib (34KB)
  - executable: markbase_fs (2.3MB)

### 2. Swift Extension Prototype
- **Bundle**: ExtensionKit .appex format
- **Status**: Compiled, signed, dylib embedded
- **Blocking**: mount command cannot discover it

### 3. macOS .fs Bundle Analysis
- **Apple bundles**: exfat.fs, hfs.fs analyzed
- **Format**: Traditional executable tools format
- **Info.plist keys**: FSMediaTypes, FSPersonalities
- **Mount helpers**: mount_<fs>, <fs>.util, newfs_<fs>, fsck_<fs>

### 4. C POC v15 Validation
- **Performance**: 649.77 MB/s verified
- **Features**: Thread-safe, LRU cache, hash cache
- **Technology**: FUSE-T 1.2.6
- **Status**: Working, ready to use

---

## ❌ Key Blockers (macOS 26.5)

### 1. SIP Protection
- `/System/Library/Filesystems/` **READ-ONLY** (SIP protected)
- Cannot install custom .fs bundles
- Cannot modify Apple built-in filesystems

### 2. mount Discovery
- `mount -t <fsname>` **only searches** `/System/Library/Filesystems/`
- `/Library/Filesystems/` **NOT searched**
- No alternative discovery mechanism

### 3. FSKit Framework
- `/System/Library/Frameworks/FSKit.framework` is **header-only**
- No binary implementation
- No ObjC class support for custom filesystems

### 4. Documentation
- Apple FSKit API **not publicly documented**
- Binary format requirements **unknown**
- Extension discovery mechanism **unknown**

---

## 🎯 macOS 27 TODO (WWDC 2026)

### Phase 1: WWDC Announcements Research

**Step 1: Check WWDC 2026 FSKit sessions**
- Watch FSKit-related sessions
- Check for new FSKit API documentation
- Check for ExtensionKit FSKit support
- Check for SIP policy changes

**Step 2: Check Xcode 18 beta**
- Download Xcode 18 beta (if available)
- Check FSKit framework binary
- Check FSKit headers for new APIs
- Check .fs bundle templates

**Step 3: Check macOS 27 beta**
- Install macOS 27 beta
- Test `/Library/Filesystems/` discovery
- Test SIP policy (if relaxed)
- Test mount command behavior

---

### Phase 2: Implementation Testing

**Option A: If FSKit ObjC API released**

**Test Rust FSKit module:**
```bash
# Check if macOS 27 recognizes .appex bundles
pluginkit -m -p com.apple.fskit

# Try mounting via FSKit
mount -t markbasefs /path/to/database /Volumes/MarkBase
```

**Option B: If .fs bundle format supported**

**Test user-level installation:**
```bash
# Install to /Library/Filesystems/
sudo cp -R markbasefs.fs /Library/Filesystems/

# Test mount
mount -t markbasefs /path/to/database /Volumes/MarkBase
```

**Option C: If new FSKit Extension format**

**Research new format:**
- Check Apple documentation for new FSKit Extension type
- Test new Info.plist keys
- Test new binary format requirements

---

### Phase 3: C POC Integration (Backup)

**If FSKit still blocked:**

**Use C POC v15:**
```bash
# Compile
gcc -Wall -O3 docs/fuse_poc/markbase_v15_balanced.c \
    -I/usr/local/include/fuse3 -L/usr/local/lib \
    -lfuse3 -lsqlite3 -lpthread \
    -Wl,-rpath,/usr/local/lib \
    -o markbase_fuse

# Run
export DYLD_LIBRARY_PATH=/usr/local/lib:$DYLD_LIBRARY_PATH
./markbase_fuse -f /tmp/mb_mount

# Performance: 649.77 MB/s (verified)
```

---

## 📁 Files to Preserve

**Rust FSKit module:**
- `/Users/accusys/markbase/markbase-fskit/`
- `/Users/accusys/markbase/target/release/markbase_fs`
- `/Users/accusys/markbase/target/release/libmarkbase_fskit.dylib`

**Swift Extension:**
- `/Users/accusys/markbase/MarkBaseFS/MarkBaseFS.xcodeproj`
- `/Users/accusys/markbase/MarkBaseFS/MarkBaseFS/MarkBaseFSModule.swift`

**C POC:**
- `/Users/accusys/markbase/docs/fuse_poc/markbase_v15_balanced.c`
- `/Users/accusys/markbase/docs/fuse_poc/markbase_v15_balanced`

**Test bundles:**
- `/tmp/markbasefs_new.fs/` (.fs bundle prototype)
- `/tmp/markbasefs.fs/` (earlier .fs bundle)

---

## 📊 Research Statistics

**Time invested**: 3+ hours deep research
**Key discoveries**: 4 major blockers identified
**Files created**: 20+ prototype files
**Tests run**: 50+ test commands
**Conclusions**: macOS 26.5 does NOT support custom filesystem extensions

---

## 🔗 Quick Links

**Apple WWDC 2026**: https://developer.apple.com/wwdc/
**FSKit Documentation**: https://developer.apple.com/documentation/fskit (check after WWDC)
**SIP Documentation**: https://support.apple.com/en-us/HT204899
**FUSE-T Project**: https://github.com/macos-fuse-t/fuse-t

---

**Last Updated**: 2026-05-29
**Next Review**: WWDC 2026 (June 2026)
**Status**: Waiting for macOS 27