Karyos 0.1.0-alpha.1

The first Karyos alpha, for evaluation only. It contains the embedded driver on Linux and macOS and the cross-process control path on Linux.

Released: 2026-10-15

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0.1.0-alpha.1 is an early alpha for evaluation. It is not for production use, and nothing in it is published to crates.io. APIs, wire formats and shared-memory layouts will change.

What works

• Embedded driver, on Linux and macOS. Publication and subscription in one process over log buffers:
  • exclusive publication (offer, try_claim) and concurrent publication from several handles;
  • claims with a commit deadline: a stuck claim is aborted and its readers skip it;
  • required subscribers, which bound the publisher and are never lapped, and optional subscribers, which are lapped and rejoin at the head with the lost range reported;
  • copy delivery: a handler always reads a private copy, so a slow handler never pins shared memory;
  • stream removal, publication seal, and mapping generations with a cutover that client handles follow;
  • driver counters, read in process.
• Cross-process control path, on Linux.
  • The driver admits a client process over its Unix socket, with credential and process exit checks.
  • A protocol version exchange refuses an incompatible pair before any mapping.
  • The client's command ring, the broadcast buffer and the counters are passed as sealed shared-memory regions.
  • A client and its resources are released by its process exit proof (pidfd). A killed client is released; a stopped one keeps its slot and resumes; a restarted driver starts a new instance while the old mappings stay valid for the clients that hold them.
  • Entry points: EmbeddedDriver::with_ipc and do_work on the driver side, karyos_client::ipc::attach on the client side. There is no example binary yet.
• Libraries for later releases, usable directly: the keyed conflation table, the bounded record journal, trace records, sampling, clock calibration and latency histograms, the deterministic simulator and the benchmark harness.

What does not work yet

• Cross-process data streams: a publication or subscription in a process other than the driver's. Planned for 0.1.0-alpha.2.
• Also planned for 0.1.0-alpha.2, in embedded mode: the observer reader role, the snapshot and close rejoin policies, handling the loss of a required participant (heartbeats and the hold, continue and abort policies), conflated subscriptions, tracing on the data path, per-stream observability, the error log and the operational tools (karyosd, karyos-stat, karyos-errors).
• Later phases: UDP transport, network I/O backends, lanes, guards, timed transmission and wire security; Archive and replay; Cluster.

Known limitations

• Cross-process IPC is Linux only. On macOS, IPC is embedded, in one process.
• A process with write access to the driver's directory or mappings is outside the isolation boundary. Deployment permissions must prevent that access.
• Liveness heartbeats are not implemented: a paused client keeps its resources until it exits or detaches.
• Every admitted process can write to the shared-memory regions; read-only tool access does not exist yet.
• Hosted CI is not running; the gates are run locally.
• A restarted driver's listen may be refused for a moment while a process forked at that instant still holds the old socket; the tests retry for up to 2 s.
• A thread pidfd must not count as an exit proof. Linux 6.8 rejected PIDFD_THREAD itself; Karyos's own rejection of a real thread pidfd was not tested, because exercising that path requires Linux 6.9 or later.

Evidence

Functional evidence only: Docker and virtual machines say nothing about latency on physical hosts.

Upgrading

There is no earlier release. Expect breaking changes in 0.1.0-alpha.2.