slowdown is a program that contends with I/O-hungry processes. The "nice" program does a good job of handling CPU priorities, but doesn't help much when you have a process that is moving tons of data; other processes can continue to starve for I/O, making a system painful to use, as during a backup, while tripwire is running, etc. slowdown manages another process by sleeping for a user-specified number of seconds or fractions of seconds, each time some data is moved using, for example, read(), write(), send(), recv(), etc.