off-topic, but I can't resist the flamebait: best minicomputer?

John Benson jsbenson at
Thu Jan 15 23:43:14 CET 2004

Like I said, I can't resist the temptation...

Tandem practically invented the commercially useful, networked minicomputer.
Up to 16 loosely-coupled processors with distributed microkernel OS
architecture per system connected via a SAN (System Area Network), RAID 1
(mirrored disk volumes), SSI (Single System Image, with single logon, of
course), multiple-system database commits, shared-nothing fault-tolerance:
you had all this back in the late 70's. You could also add another network
level to harness up to 255 16-processor systems together. This gave Tandems
the linear expandability that allowed their "minicomputer" systems to scale
up to and overtake the IBM big iron. As a matter of fact, it was the Tandem
expandability (since you could have multiple channels per processor, 16
processors per system, 255 systems per Expand network) that provided the I/O
bandwidth to enable the ATM explosion.

Stock exchanges used to melt down automatically when their legacy systems
choked on excessive trading volume. For years, NASDAQ has used Tandems, and
needs to proactively decide when to suspend trading because the Tandems
handle pretty much whatever is thrown at them.

They're fault-tolerant, too. That's why a some of your 911 systems use them,
because some people feel that 911 has to work all the time, like stock
exchanges and ATM networks.

The problem is, Tandems are the unsung heroes of data processing because
they're embedded so deeply in the infrastructure. You place your trade with
a discount broker, not a Tandem. You see a Diebold or perhaps an NCR ATM,
not a Tandem.

Go back to the top and look at the lineup of late 70's Tandem features.
Chances are, you didn't read about them in Byte or wherever until the
eighties or nineties. Fact is, pretty much everybody has been following
Tandem's lead for decades, however much they posture as "industry leaders."

When I started working on Tandems in the late 70's and they were expected to
run weeks, months and years without stopping, I remember reading an article
in which a Unix guy bragged that his system had actually run two or three
weeks without crashing. Even now, in the 2000's, people still periodically
reboot their Unix and NT servers to scare away the memory leak bogeymen,
even if everything appears to be working fine. Anyone advocating that for a
Tandem system even 20 years ago would have been dispatched to the nearest

Unix boxes: carried the Multics banner forward, and pioneered lots of
software technology. Macs and PCs: added GUIs to the mix. Tandem: you never
heard about it, because it never broke.

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