---
layout: article
title: DC Downloads
description: Data Controller release assets and how to verify them
---

# Downloads

Data Controller releases are published on the [releases page](https://git.datacontroller.io/dc/dc/releases) of the source repository. Every release carries the same set of assets:

| Asset | Use |
|---|---|
| `frontend.zip` | The pre-built web frontend, for deployments that serve the frontend from a web server (SAS 9 full deploy, Viya separated deploy) |
| `sas9.sas` | SAS 9 full deployment program (stored processes + frontend registration) |
| `demostream_sas9.sas` | SAS 9 streaming deployment program (demos and evaluations) |
| `viya.sas` | Viya streaming deployment program (backend + frontend) |
| `viya_noweb.sas` | Viya separated deployment program (backend only) |
| `viya_noweb.json` | The Viya backend services as a SASjs Drive JSON deployment bundle |
| `sasjs_server.json.zip` | SASjs Server deployment bundle (all services, for [SASjs Server](https://server.sasjs.io) deployments) |
| `SHA256SUMS` | SHA-256 checksums for every asset above |

Which asset you need depends on the deployment route - see [SAS 9 Deployment](/dci-deploysas9) or [SAS Viya Deployment](/deploy-viya).

## Verifying a download

Every asset is covered by the `SHA256SUMS` file, which the release pipeline generates over the exact files it uploads. To verify a download:

1. Download the asset (for example `frontend.zip`) from the [releases page](https://git.datacontroller.io/dc/dc/releases).
2. Download `SHA256SUMS` from the same release into the same folder.
3. Run the check:

```bash
sha256sum --check SHA256SUMS --ignore-missing
```

Each asset that matches reports `OK`. The `--ignore-missing` flag means you only need the files you actually downloaded - the check skips assets you did not fetch.

On Windows, `certutil` can compute the hash of a single file for comparison against the value listed in `SHA256SUMS`:

```
certutil -hashfile frontend.zip SHA256
```

### What the checksum proves

A matching checksum confirms the asset is byte-for-byte the file the release pipeline uploaded. It catches corrupted and tampered downloads - interrupted transfers, proxies or mirrors that altered the file in transit.

It is not a cryptographic signature. The hashes travel in the same release as the files they cover, so they protect the download path, not the release itself: a compromise of the forge would allow both the asset and its checksum to be altered together. For download integrity - the typical concern when fetching deployment artifacts over the internet - it is the standard check.

## Integrity inside SAS

The SAS deployment programs embed the frontend and services as generated SAS code. Once `%inc`'d, their integrity is established by the check above at download time; SAS also writes nothing to disk outside the `appLoc` you point it at, and the programs can be [reviewed in full](https://code.datacontroller.io) (or in the [source repository](https://git.datacontroller.io/dc/dc)) before you run them.