next up previous
Next: About this document ... Up: sheet23 Previous: sheet23

CS1001/CS1011 Problem sheet

This is only for students not doing CS1031, but other students may take a copy.

CM students will do this sheet in their normal tutorials (probably on Tuesday 18/Nov/2003). Other students not doing CS1031, including CSwBM, will do this in a special examples class 3pm Monday 17/Nov/2003 in room 1.10.

1. Here is a question from 1998: discuss why is it now common for a PC to have at least 500Megabyte hard disc, 8MByte of RAM, a CD-ROM drive, and a windowed user interface, when a few years ago it would have had none of these.
Write an equivalent question for 2003, and answer it! You could start by finding out how much memory, disk space, etc. is available on the PCs you use in this department.

2. List the differences between hard disks and CD-ROMs. Why is it that, although every year new hard disks can store more information, CD-ROMs have essentially the same capacity as when they were introduced?
List the differences between CD-ROMs and DVDs. Why is it that DVDs, although similar in many ways to CD-ROMs, are treated as a new device rather than just a higher capacity CD-ROM? For example, why are the cases for the disks of different sizes, although the disks themselves are the same size?

3. Estimate very roughly, making whatever assumptions necessary, the amount of data to be transferred over a network to:
(a) Send 100 email messages
(b) Spend 30 minutes editing a 10 page document whose permanent copy is held on a networked file server
(c) Undertake a 30 minute World Wide Web tour of an Art Gallery
(d) Participate in a 30 minute video conference.
Discuss the implications for demand for networking capacity.

4. Why is process management a privileged operation in operating systems like Linux? How does a single cpu appear to support simultaneous activity by several independent processes?
Suppose a system employing paged virtual memory system is supporting three processes using 1MByte, 2MBytes and 4Mbytes of memory respectively. What would be the disadvantage of having only 1Mbyte of memory available for all these processes? Would 4Mbytes be adequate? Would there be any advantage in having 8Mbytes?

5. A system has 100MBytes of user file space. Suppose user A has files occupying 80Mbytes, user B 5Mbytes and user C 5Mbytes.
Suppose user A creates a new 10MByte file then user B a 1Mbyte file. What happens?
Now suppose user A has a filestore quota of 80Mbytes, B and C have 10Mbytes each. What happens when the same files are created?
What is the primary purpose of filestore quotas now that discs are so cheap?


next up previous
Next: About this document ... Up: sheet23 Previous: sheet23
Pete Jinks
2003-11-11