IRIX and Software

On what hardware did pre 5.0 Flint run?

Just curious. I know Flint 5.0 used an Indigo2 IMPACT with the Indigo2 IMPACT Video Option, I know the hardware for most of the newer versions, but I couldn't find information about older Flint versions. Anyone knows it?
:PI: :Indigo: :Indigo: :Indigo: :Indy: :Indy: :Indigo2: :Indigo2IMP: :Octane: :Fuel: :540: Image