
The Evolution of Mac OS X 9 3 7
Among user space tasks, Mach has always been planned to be
able to support UNIX, MS-DOS, and other operating systems
running as user tasks. This ability to be able to run a number
of operating systems on top of the kernel was one of Mach's
original goals.
The Evolution of Mac OS X
The first computers had no operating systems. They were
rooms full of electronic components that were programmed
with circuit boards and switches, many of which had to be set
by hand. Management of the computer and its resources was
done by someone armed with a sign-up sheet; bills for the use
of the machine were sent