1. CS 241 Section (11/18/2010)

2. In Section Today…
MP7
Networking
File System Intro

3. MP7 MP7 is due tonight is 11:59:59pm.
Contest results based on due-date
Usual late submission policy applies for grading purposes (30% off for up to 1 day late)
Contest results announced in-lecture on Friday (at beginning of lecture)
Must be in attendance to claim prize
Some nice prizes by Intel

4. MP7

5. Networking Review Major TCP Benefits TCP:
Connect via a 3-way handshake
Reliable, ordered delivery
Single endpoint per connection
TCP:
Extremely useful protocol features
High Overhead

6. Networking Review Major UDP Benefits Stateless protocol Low overhead
No connection, no pre-defined endpoint
Low overhead
No reliable delivery
No ordered delivery
Generally faster round trip time than TCP

7. Networking Review TCP and UDP BOTH Provide:
IP Routing
Port-based delivery
The address “ :80” could refer to TCP or UDP.
Q: How do we know that address is likely TCP?

8. Networking Review Would TCP or UDP be best to be used for…
Streaming Audio/Video?

9. Networking Review Would TCP or UDP be best to be used for…
Streaming Audio/Video? UDP
Instant Messaging?

10. Networking Review Would TCP or UDP be best to be used for…
Streaming Audio/Video? UDP
Instant Messaging? TCP
Simple File Transfer?

11. Networking Review Would TCP or UDP be best to be used for…
Streaming Audio/Video? UDP
Instant Messaging? TCP
Simple File Transfer? TCP
Short, infrequent status updates of non-essential information?
BitTorrent Peer Updates
DNS, DHCP, etc

12. Networking Review Would TCP or UDP be best to be used for…
Streaming Audio/Video? UDP
Instant Messaging? TCP
Simple File Transfer? TCP
Short, infrequent status updates of non-essential information? UDP
BitTorrent Peer Updates
DNS, DHCP, etc

13. MP8 MP8 is scheduled to be released on Monday over break (Nov. 22nd)
The MP is designed as a one-week MP.
However, you have 2.5 weeks to work on it.
One week during break
One full week after break, and until Wednesday of the next week.

14. MP8 Broad Topic: Programming Concepts Used:
Make a web server!
Programming Concepts Used:
Socket Programming
Multi-threaded Programming
More on it in section in two weeks…

15. UNIX File Systems Introduction
Nearly every modern file system is based on a directory structure: /
/usr/
/usr/kingst/
/usr/kingst/svn/
/usr/kingst/svn/mp7/
/usr/kingst/svn/mp7/alloc.c

16. UNIX File Systems Introduction
Each and every directory contains at least two links to files:
/ A reference to itself.
/ A reference to its parent.
Every other reference will be some form of a file or link.

17. UNIX File Systems Introduction
Information about the contents of a directory is stored in a directory file.
A directory file is simply a table containing two pieces of information:
The i-node ID of the file
The name of the file

18. UNIX File Systems Introduction
Information about the contents of a directory is stored in a directory file.
A directory file is simply a table containing two pieces of information:
The i-node ID of the file
The name of the file

19. UNIX File Systems Introduction
Much like many MP7 implementations, an i-node simply contains data about a file.
File size
Location (on disk) of the file’s contents
Modification date, creation date, etc.
File’s owner
File’s permissions …
NOT THE NAME OF THE FILE (directory file)

20. UNIX File Systems Introduction

21. UNIX File Systems Introduction
Main lecture will discuss more on i-nodes and file systems over the next week...
We’ll discuss i-node details next week