
Ah Paula, Agnus and Denise - a tear of nostalga rolls down my cheek...
Indeed, they did get upgraded in the latter models, such as the Amiga 1200 and 4000, which had the AGA graphics architecture. This allowed the new 8bit 256 colour modes, and the incredible hack called Hold And Modify, which calculated the colour of each pixel as a mathematical difference from the preceding pixel, allowing the entire 16bit pallette to be used on-screen.
If memory serves me correctly, the motherboards were all named after B52 hits (the 1000 being Love Shack, and the 500 being Rock Lobster), while the custom chips were all named after the founders girlfriends (Amiga itself being spanish for 'girlfriend').
A little disturbing then, that the latter chips became Fat Agnus, and Gary. But I digress.
There will always be a swing between seperats and onboard, just as we repeatedly switch between parralell and serial buses in our constant strive for speed improvements. I believe it was when AMD intergrated the memory controller into the first Athlon, that they finally eeked out a performance advantage over Intels rival silicon.
It goes to show that the underlying design principle doesn't really matter, it's down to the practical implementation at the end of the day. I strongly suspect that after the industry has exhausted the capabilities of the SATA standard, it's replacement could very possibly be a parralell solution again.
When the next big IC revolution hits (which is starting to look like nano component design) there will be a huge re-integration of all these disparate components.
back to my digression...
When the Amiga crashed, it used to reboot to a black screen, with a red flashing box at the top, exclaiming "Guru Meditation" followed by a reference number.
Why?
The Amiga founders used to make controls for huge arcade games, one of which being a full-sized surfboard. When they tried to get it working with thier precious new Amiga, it crashed, flickering colours across the screen when the board moved.
Being new-age kinda guys, they then preceeded to meditate on said board, the less flicker, the more centrered thier kalma. Shortly after, the term made it's way into the firmware.