[TUHS] UNIX on Tandem

[George Michaelson via TUHS]

I worked briefly with a non-stop set-up long after this. What sold them to
corporates was (in my opinion) both fault tolerant design and an SLA.

An australian engineer in telecommunications of that era told me they ran
their metropolitan area network as a fault tolerant dual ring, and like
tandem had to tell Sales droids to STOP pulling line cards (CPU cards for
tandem) in front of prospective buyers, because it triggered an automatic
fault report and spares shipment cross country.

It's probably urban myth with an element of maybe true.

Yes, the design was about redundancy but the sell was gold era IBM managed
services: you bought a package.

G

On Sat, 10 Jan 2026, 4:42 am Charles H Sauer (he/him) via TUHS, <
tuhs at tuhs.org> wrote:

> On 1/9/2026 12:59 AM, Tom Lyon via TUHS wrote:
> > Ran across this citation today.  Anyone ever seen this paper?  Known of
> the
> > system?   I'm pretty sure they're talking about Tandem(TM), not just
> > generic tandem.
> >
> > A Distributed UNIX System-The Tandem Experiment. A. M. Usas, Proc Natl
> > Electron Conf, 34 (October 1980), pp 16-8.
>
> Doug Jewett and other people instrumental in the early days of AIX went
> on to Tandem in Austin to create the Tandem S2 (MIPS-based) hardware and
> a fault-tolerant reworked version of SVR3 for that hardware.
>
> Doug suggests that Peter Norwood's paper at
> https://archive.org/details/tandemsr7-1/page/n11/mode/2up is likely the
> best introduction.
>
> Doug also suggests "This paper touches on some of the hardware and the
> software aspects of S2: D. Jewett, "Integrity S2: A Fault-Tolerant Unix
> Platform," Proc. 21st International Symposium Fault-Tolerant Computing,
> July 1991." However, I don't know of an accessible version of that
> reference.
>
> Charlie
>
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