Compressing program binaries with reduced compression ratios. One or
several pre-processing acts are performed before performing compression
using a local sequential correlation oriented compression technology such
as PPM, or one of its variants or improvements. One pre-processing act
splits the binaries into several substreams that have high local
sequential correlation. Such splitting takes into consideration the
correlation between common fields in different instructions as well as
the correlation between different fields in the same instruction. Another
pre-processing reschedules binary instructions to improve the degree of
local sequential correlation without affecting dependencies between
instructions. Yet another pre-processing act replaces common operation
codes in the instruction with a symbols from a second alphabet, thereby
distinguishing between operation codes that have a particular value, and
other portions of the instruction that just happen to have the same
value. Local sequential correlation compression such as PPM is then
performed.