Parallel port the ports in this manner in many cases, though this is often fairly hidden. In SCO UNIX and Linux, the first parallel port is available via the filesystem as /dev/lp0. Linux IDE devices can use a "paride" (parallel port IDE) driver. For consumers, USB and computer networks have replaced the parallel printer port, for connections both to printers and to other devices. Many manufacturers of personal computers and laptops consider parallel to be a legacy port and no longer include the parallel interface. Smaller machines have less room for large parallel port connectors. USB-to-parallel adapters are available that can make
Parallel algorithm wall, and thus multicore systems have become more widespread, making parallel algorithms of more general use. The cost or complexity of serial algorithms is estimated in terms of the space (memory) and time (processor cycles) that they take. Parallel algorithms need to optimize one more resource, the communication between different processors. There are two ways parallel processors communicate, shared memory or message passing. Shared memory processing needs additional locking for the data, imposes the overhead of additional processor and bus cycles, and also serializes some portion of the algorithm. Message passing processing uses channels and message boxes but this communication