conservative coalescing. This improvement adds a criterion to decide when two live ranges can be merged. Mainly, in addition to the non-interfering requirements, two variables can only be coalesced if their merging will not cause further spilling. Briggs et al. introduces a second improvement to Chaitin's works which is biased coloring. Biased coloring tries to assign the same color in the graph-coloring to live range that are copy related.

Linear Scan 

Linear scan is another global register allocation approach. It was first proposed by Poletto et al. in 1999. In this approach, the code is not turned into a graph. Instead, all the variables are linearly scanned to determine their live range, represented as an interval. Once the live ranges of all variables have been figured out, the intervalstrash
can to store files to be deleted; it would
even bulge when full - again with the metaphors.
Apple’s first product with a graphical user
interface, and mouse, was the Apple Lisa,
released in 1983.
It was a super advanced machine, with a super
advanced price – almost 25 thousand dollars
today.
That was significantly cheaper than the Xerox
Star, but it turned out to be an equal flop
in the market.
Luckily, Apple had another project up its
sleeve: The Macintosh, released a year later,
in 1984.
It had a price of around 6,000 dollars today
– a quarter of the Lisa’s cost.
And it hit the mark, selling 70,000 units
in the first 100 days.
But after the initial craze, sales started
to falter, and Apple was selling more of its
Apple II computers than Macs.
A big problem was that no one was making software
for this