With regard to printer output, how was the word spool derived? 4. Describe how multiprogramming systems differ from timesharing systems. 5. What is the most critical factor in the operation of hard real-time systems? 6. Multiprocessor systems can be classified by the way in which they communicate. How are they classified in this chapter? 7. How is a distributed operating system different from a networked operating system? 8. What is meant by transparency?