Why five layers: how Runix drew its AI infrastructure stack

Runix Lab describes what it builds as five layers: agents, gateway, models, data and infrastructure, drawn on top of the compute the customer already owns. Each line between two AI infrastructure stack layers is drawn where an interface can be written down and the thing beneath it replaced without the thing above noticing, the test Unix applied to files, pipes, the kernel and system calls. This post explains where each line comes from, why each layer must stand alone, and what the diagram cannot show.

Where the lines come from

Unix lasted because its layers were honest with each other. A program opened a path without knowing whether a disk or a terminal was behind it. A tool read standard input and wrote standard output, so any two could be joined. The kernel did the work for every program, and POSIX later wrote the call interface down so one program could run on machines from different vendors. Userland sat on top and changed freely. The original paper, The UNIX Time-Sharing System (Ritchie and Thompson, Communications of the ACM, 1974), still states the idea most clearly.

The test behind each boundary is the same: can the interface be written down, and can the implementation below it change without the code above it changing? Applied to an AI system in production, it finds five such interfaces: a path, a stage boundary, a served model, one API, and the program on top. That is why five layers, not four or seven. Rebuild AI Unix gives the mission; this post gives the geometry.

Below all five sits Layer 00: the customer's own GPUs, cloud capacity, object storage and Kubernetes. Runix sells none of it; the stack runs on it and replaces none of it.

Five AI infrastructure stack layers, one Unix idea each

Each layer rebuilds one idea, and each is a product with a literal status.

Why each layer must be usable alone

A Unix tool is useful by itself; the pipe is a bonus. The same rule holds here as a design constraint: a layer that only works when the layers around it are also bought is a bundle, and a bundle hides which part is actually good.

It shows up in three places. Each product has its own interface, written down: a mount or an SDK, a stage with inspectable output, an API, a diff in a repository. Each has its own price, per deployment, engagement, project, token or plan, not a share of a platform fee. And each has its own status, which is why the statuses differ: four of the seven products in early access, three in development, none described as more than it is.

The handoffs are optional by construction. A model tuned by Runix Models can sit behind Router next to hosted providers, or be called directly. Runix Code can route its model calls through Router, or not. Most teams start at one layer, where their problem is.

The two paths through the stack

Layers are a static picture; what moves through them are two paths, and the stack overview draws both. The request path runs top down: an application or agent calls Router, which sends the request to a hosted provider or a model tuned by Runix Models. The data path runs bottom up: raw material is read from the bucket through Runix FS, cleaned in Pipeline's stages, given a domain's rules by Runix Data, and lands as training and evaluation sets for Models.

The paths meet at Models, where the kernel analogy earns its place: a model is both what a request runs on and what the data path produces. Keeping the paths separate is the pipe idea applied across layers: cleaning data differently does not change how a request is routed, and a provider's bad hour does not reach a training job.

What the AI infrastructure stack layers leave out

A layered diagram is a claim about interfaces, and it is silent about things that decide whether the system works.

Runix Lab is the brand of Runix AI Inc, and the five layers are its answer to what an operating system for enterprise AI should consist of. The company page lists each product with its literal status and the terms a team would contract under; the layers are a map of the work, drawn to be adopted one at a time.

Questions this raises

Do I have to adopt all five layers?

No. Each layer is a separate product with its own interface, price and status, and most teams start at the one where their problem is: the gateway, the data layer or the file system.

What sits under Layer 01?

Layer 00: the customer's own GPUs, cloud capacity, object storage and Kubernetes. Runix sells none of it; the stack runs on it and replaces none of it.

Which layers are available today?

Runix Router, Runix Models, Runix Data and Runix FS are in early access; Runix Pipeline, Runix Code and Runix Comic are in development. The statuses are literal.

Related to this post: What Runix is, and how we work. Tell us what you are building and we reply within one business day.