
Inside the machine
established, and larger machines use a variety of systems, with UNIX one of
the few that is found almost universally.
In the early days of desktop machines, each manufacturer tended to use a
different operating system, though a standardized system called CP/M was
available. The use of incompatible operating systems meant that a disk
created using one type of machine could not be read on any other, and even
when CP/M was used on different machines only the
8
in type of disk could
be guaranteed to be usable on any CP/M machine. The manufacturers of
computers intended for serious business applications therefore used CP/M
an