Same person as torpcoms on the Level1Techs forums, RCS Wiki, Github, Reddit, Diaspora (diasp.org server), GNU Social (gnusocial.no server), probably some other places as well.

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Timelines for POWER

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The Power ISA evolved from the PowerPC ISA which in turn was an evolution of the POWER ISA used by POWER1 and POWER2 chips.

POWER ISA → PowerPC ISA → Power ISA

When the Power ISA 3.0B specification lists all available instructions, it specifically mentions what version of which architecture introduced the instruction; this gives a fairly quick history of the ISA itself:

Key to Version column in Power ISA 3.0B instruction list
Code Explanation
P1 Instruction introduced in the POWER Architecture.
P2 Instruction introduced in the POWER2 Architecture.
PPC Instruction introduced in the PowerPC Architecture prior to v2.00.
v2.00 Instruction introduced in the PowerPC Architecture Version 2.00.
v2.01 Instruction introduced in the PowerPC Architecture Version 2.01.
v2.02 Instruction introduced in the PowerPC Architecture Version 2.02.
v2.03 Instruction introduced in the Power ISA Architecture Version 2.03.
v2.04 Instruction introduced in the Power ISA Architecture Version 2.04.
v2.05 Instruction introduced in the Power ISA Architecture Version 2.05.
v2.06 Instruction introduced in the Power ISA Architecture Version 2.06.
v2.07 Instruction introduced in the Power ISA Architecture Version 2.07.
v3.0 Instruction introduced in the Power ISA Architecture Version 3.0.
v3.0B Instruction introduced in the Power ISA Architecture Version 3.0B.