The secret sauce and core of the Petabit router was the "Matrix", a first-of-its-kind programmable ASIC, extremely complex and powerful, providing multi-terabit wire-speed backplane switching .

Then there were the route processors and the line cards, large PCB blades with tens of layers, sprinkled with FPGAs and RISC SOC processors (at the time the Power PC SOC were the most capable of their kind)

And software - lots of it, from the CLI, to routing stacks, OAM functionality, inter-process communications among the stacks on the different cards,  and drivers controlling all aspects of the hardware components.

And for sure there were issues and bugs, sometimes obscure and hard to trace to either software, FPGA microcode of simply intermittent circuitry issues on the extremely complex PCBs.

Testing the software on the real hardware was the culmination of a process involving lots of unit testing and simulation. A lot of ingenuity went into streamlining the software development and testing.

Developing and testing the FPGA code was no easy task either. Luckily we were able to develop FPGA simulation workbenches allowing to exercise the test microcode as it were running for real.

Best practices were in place, from source code review and automated analysis, to modularization, to hardware simulation environments built on virtualized infrastructure and to rigorous version control and integration

Each new proposed solution and enhancement was subjected to scrutiny during the engineering review meetings - these were workshops involving presentations, whiteboarding, questioning, debate and clarification on the solutions.

These were multi-disciplinary events were the participants were domain SMEs from all the technical teams and the goal was to examine from all angles the proposed designs.

The Petabit Router labs were the place were integration and system testing were conducted on the real equipment for the periodic releases. Also the place were hard-to-pinpoint issues surfaced and were investigated.

There is much more to say about the Hyperchip technology but let's keep it short ... it's all history.