WASM driver crate
The drivers_wasm crate provides drivers for WebAssembly targets (wasm32).
It offers browser/web runtime integrations such as memory/logging adapters, async execution support, and devices including time, drive, and HTTP client access.
Persistent drive
The browser example uses devices::DriveDevice to open the origin-private file xila_drive.img using OPFS and hold a lifetime Web Lock. This main-thread driver keeps a bounded memory cache (16 MiB in the browser example) and commits snapshots asynchronously through sync().await. Synchronous block writes/flushes update the cache; they do not establish OPFS durability.
Only dirty disks are saved. Saves are serialized and atomic, with at most one additional disk-sized snapshot rather than a growing queue. Failures leave unsaved changes available for retry; the caller must handle errors. OPFS quota/eviction and abrupt tab termination can still lose data.
The browser example validates existing MBR/LittleFS data and stops on mount errors instead of reformatting a saved image. See Browser storage for the cache/autosave model and Reset the browser disk for a deliberate reset.
Browser capabilities
OPFS, FileSystemFileHandle.createWritable, and Web Locks require an appropriate browser and localhost/HTTPS. Only one Xila tab can hold the disk lock. The HTTP device uses Fetch and follows browser restrictions such as CORS; it does not expose raw sockets or provide the Xila network manager.