COS 425
                                  Homework # 5
                             100 pts, 25 pts each.

                        Due: Thursday, May 2nd, 1996.


Your answers should be brief, one to several paragraphs each (as necessary).

1) (a) What is a serial schedule? 
   (b) What is a serializable schedule? 
   (c) What is a serial schedule correct? 
   (d) Why is a serializable schedule correct?


2) (a) Discuss how serializability is used to enforce concurrency control.
   (b) Why is serializability sometimes considered too restrictive a
       measure for correct schedules?

3) (a) Describe briefly the wait-die and wound-wait protocols used for 
       preventing deadlocks. 
   (b) Is one method preferred over the other?


4) (a) Describe briefly what the write-ahead logging protocol is. 
   (b) Why is writing-ahead important?