When a user is editing files with a real-time editor (lets call RTE), every keystroke generates an interrupt signal. The operating system must then schedule the editor process to take the appropriate action for this keystroke. Suppose we had a system with a 1 GHz clock cycle, and we had 100 users running RTE typing at a rate of 100 words per minute. Assume an average of 6 characters per word. Assume also that the OS routine handling keystrokes requires, on average, 50,000 clock cycles per keystroke. What fraction of the processor load is consumed by all of the keystroke processing? Note that this is a very pessimistic analysis of the load induced by keyboard usage. It's hard to imagine a real-life scenario with so many users typing this fast.