173 lines
5.1 KiB
Markdown
173 lines
5.1 KiB
Markdown
Here’s a clean **v0.1 draft for ASL-HOST**, scoped to what we discussed — minimal, environment-focused, without touching semantics or storage encoding. This is the runtime/host interface layer that bridges ASL-STORE(-INDEX) to a real system.
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---
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# ASL-HOST v0.1 – Host/Runtime Interface for ASL Stores
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## 1. Purpose
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**ASL-HOST** specifies the **runtime contract** between an ASL store and the host environment.
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It defines **what the host must provide** for an ASL store to operate correctly, without imposing:
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* Storage semantics
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* Encoding
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* Policy
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* Security beyond minimal integrity guarantees
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It supports **POSIX filesystems, ZFS, object stores**, or other backing layers.
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---
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## 2. Core Concepts
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| Concept | Definition |
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| ----------------- | ------------------------------------------------------------------------- |
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| **StoreHandle** | Opaque reference to a host-provided store instance |
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| **StoreLocation** | Host-defined location where a store exists (path, URI, mount point, etc.) |
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| **AppendUnit** | Minimum atomic write unit for the append-only log |
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| **SnapshotID** | Opaque identifier of a host-provided snapshot |
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| **HostClock** | Monotonic counter or timestamp source |
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| **HostIdentity** | Unique machine or user identity for signing or domain minting |
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---
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## 3. Store Instantiation
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### 3.1 Store Creation
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* `CreateStore(location: StoreLocation) → StoreHandle`
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* Must guarantee crash-consistent initialization.
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* Location may be:
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* POSIX path
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* ZFS dataset
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* Object store bucket
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* StoreHandle is **opaque**, only valid while the store exists on host.
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### 3.2 Store Open
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* `OpenStore(location: StoreLocation) → StoreHandle`
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* Host must provide durable, consistent view.
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* Opening an existing store must not corrupt previous data.
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### 3.3 Store Close
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* `CloseStore(store: StoreHandle)`
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* Ensures all writes are persisted to durable media.
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* Optional: triggers host-specific flush or checkpoint.
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---
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## 4. Atomic Append / Log Operations
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* Host must provide **atomic append** semantics.
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* Minimum guarantees:
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* Sequential ordering (logseq monotonicity)
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* Crash consistency (partial writes are not visible)
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* AppendUnit:
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* Defined by host; could be page-size or object-size
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* ASL-STORE must tolerate host’s granularity
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---
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## 5. Snapshot Management
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* Optional but recommended.
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* Host provides:
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* `CreateSnapshot(store: StoreHandle) → SnapshotID`
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* `MountSnapshot(store: StoreHandle, id: SnapshotID) → StoreHandle`
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* Guarantees:
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* Snapshot captures a consistent view of sealed blocks
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* Mounting snapshot produces read-only store handle
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* Host may use:
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* ZFS snapshot
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* POSIX filesystem copy-on-write overlay
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* Object store versioning
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---
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## 6. Durability & Crash Semantics
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* Host must ensure:
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* Writes are durable after append or flush
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* Crash recovery restores store to last durable state
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* Open, unsealed blocks may be lost without breaking invariants
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* StoreHandle and append-only log are **atomic units** visible to ASL-STORE
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---
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## 7. Minimal Identity & Logging
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* Host must provide:
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* `HostClock()` → monotonic timestamp / counter
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* `HostIdentity()` → machine or user ID for signing / domain minting
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* Optional log for debugging or auditing
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---
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## 8. Error Semantics
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* Operations may return:
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* `STORE_OK`
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* `STORE_EXISTS`
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* `STORE_NOT_FOUND`
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* `STORE_IO_ERROR`
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* `STORE_CONCURRENT_MODIFICATION`
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* ASL-STORE must handle errors deterministically
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---
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## 9. Security Considerations
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* ASL-HOST does **not enforce cryptography**.
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* Host may provide optional:
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* Encryption at rest
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* Access control
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* Secure snapshot mechanisms
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* Certificates and trust are handled in **ASL-AUTH**, separate layer
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---
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## 10. Example Implementations
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| Backend | How ASL-HOST maps |
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| ---------------- | ---------------------------------------------------------------------------------- |
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| POSIX filesystem | StoreLocation = path; append = write+fsync; snapshot = overlayfs copy |
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| ZFS dataset | StoreLocation = dataset; append = zfs sync; snapshot = zfs snapshot |
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| Object store | StoreLocation = bucket/namespace; append = object PUT; snapshot = versioned bucket |
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---
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## 11. Versioning
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* Spec version: **0.1**
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* Backward incompatible changes must bump major version.
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* Minimal compliance: implement store creation/open/close and append guarantees.
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---
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## 12. Summary
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**ASL-HOST v0.1**:
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* Defines **runtime contract** between ASL store and host
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* Provides **store handles, atomic append, snapshots, identity**
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* Layered cleanly above ASL-STORE(-INDEX), below system or OS
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* Keeps **semantics, encoding, and trust separate**
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---
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If you like, I can **draft ASL-AUTH v0.1** next, and then show how **SystemRescue could instantiate ASL-HOST with POSIX/ZFS to seed a personal domain**. That would give a complete view for your rescue scenario.
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Do you want me to do that next?
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