The download is a disk image containing one application. Drag it toApplications and open it; there is no installer, no helper tool, and nothing running when the app is not.
On first launch it copies its system image into~/Library/Application Support/ipnx/v8, creates an account on the emulated machine named after your macOS short user name, and logs you in. That takes about half a minute. Afterwards it resumes from a snapshot and is ready almost immediately.
What you are downloading
Around twenty megabytes, most of it a complete Eighth Edition system — the kernel, the commands, the source, the manual and the games. It expands to a 516 MB disk on first launch, because that is the size of the emulated drive; the compressed form is small because a 1985 Unix genuinely was. Nothing is fetched at runtime.
Signed, and how to check
The app is signed with a Developer ID certificate and notarised by Apple, so it opens without a Gatekeeper warning and without your having to right-click it. You do not have to take that on trust — macOS will tell you itself:
codesign -dv --verbose=2 /Applications/ipnx.app
Authority=Developer ID Application: Hello Tham Pty. Ltd. (RPL5R637DS)
Authority=Developer ID Certification Authority
Authority=Apple Root CA
TeamIdentifier=RPL5R637DS
spctl --assess --type execute --verbose /Applications/ipnx.app
/Applications/ipnx.app: accepted
source=Notarized Developer ID
The certificate names a company, and the project does not. That is deliberate and worth explaining rather than hiding. ipnx is a personal, non-commercial project, published from a personal account, because the 2017 statement that makes Research Unix distributable at all reaches non-commercial use only. A Developer ID certificate, however, has to belong to an enrolled Apple developer team, and the one available here is Hello Tham Pty. Ltd.. So the signature names the team that holds the key; the work, the licence position and the responsibility are personal.
Requirements
- macOS 26 or later
- Apple silicon — the VAX and WE32100 cores are built for arm64 only
- About 700 MB of disk once the machine has been provisioned
Not on the App Store yet
It will be, but not for this edition. The App Store submission waits for Tenth Edition — the part of this project that has not been done before — so that what arrives there is the restoration rather than the rehearsal. Until then this page is the distribution.
Source
Everything is on GitHub: the app, both emulator cores and their patches, the V8 source tree, and the build that turns the second into the disk the first ships. The releases page keeps every version.