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An eight-processor Origin 300 hung because a register window the model forwarded to the interrupt registers turned IRIX's heartbeat LED into another processor's interrupt mask.

IRIX on the emulated Origin 300 reported a stream of secondary-cache errors because the processor model dropped the performance counter's event select, so the counter meant for corrected ECC errors counted clock cycles.

Getting a two-processor Origin 300 to boot its stock diagnostics reliably meant describing the machine's processors, network identity and reset state the way the firmware checks them, and then surviving the emulator's own SMP timing.

The emulated gigabit adapter swapped every frame's payload twice for a net effect of nothing; removing the redundant swap won two to three times on receive, and the single-CPU ceiling underneath was the interpreter, not the adapter.

A node lost both its processors on a fraction of eight-processor boots, because the second processor's hardware alive hold gave way to the emulator's own translation bookkeeping before its partner's signal arrived.

Init died about one boot in five on a second-node Origin 200 processor because the R10000's random-replacement TLB register stepped by exactly one each consultation and phase-locked with the kernel's TLB sweep; stepping it by the virtual clock scatters the placement.

A doubleword served through a 32-bit device slot came back with its halves transposed, panicking IRIX at kernel init, and the window's register test had baked its golden from the transposed order so it passed against the bug.

Forty-seven seconds named three unrelated timer bugs, because it is the counter's own wrap period, with a guest that never armed the timer, a guest that raced it, and a comparator model that sampled the clock twice.

A firmware step that read as a hang was executing its own code out of an I/O region.

The last wall before IRIX booted was a processor register the model stored and never applied.

The emulator's own network stack rejected the vendor firmware's legitimate netboot packets, settled against a real Octane2's capture and a reference server, not against the emulator itself.

The stock PROM reaches sash on two processors, and the hard part was the emulator's scheduler.

Five separate defects each kept the emulated ethernet dead, and any one was enough.

The route from an empty Origin 200 model to an authenticated OpenBSD root shell.

SGI's own 1998 PROM prints its banner and answers at its diagnostic monitor.

A SCSI hang traced to two writers sharing one mailbox register.

Three apparent defects that yielded to narrower evidence.

Why an Origin 200 needs an emulator and why this fork is permanent.

IRIX draws its own graphical login and desktop on an emulated SGI Origin, with an absolute tablet pointer and working sound.

IRIX 6.5.30 installs from a blank disk and boots to a login on an emulated SGI Origin 300, the first of the Bedrock generation, and reaches eight processors across two chassis.

IRIX 6.5.30m boots to a multiuser root login on eight R10000 processors across four nodes of the emulated SGI Origin 2000, reaches that login on fifteen consecutive cold starts, and passes SGI's field diagnostics.

IRIX 6.5.30 installs over the network onto a blank disk and boots to a multiuser root login across two Origin 200 chassis, four processors on two cache-coherent modules.

IRIX 6.5.30's installation kernel boots and runs on the emulated Origin 200, read by the vendor kernel as current hardware, the first netboot to a live console.

An unmodified mainline Linux kernel boots to a networked multiuser login across four processors and two nodes of the emulated Origin 200.

The emulated Origin 200 passes SGI's own factory power-on diagnostics and runs SGI's field diagnostic kernel with no miscompare.

OpenBSD 6.9 installs to a disk and boots to a root login on the emulated Origin 200, the first OS to run on any emulated SGI Origin.

A tour of the Origin 200 architecture and its missing crossbar.

Verbatim machine transcript.

Verbatim machine transcript.

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Verbatim machine transcript.

Verbatim machine transcript.