http:^^www.cs.washington.edu^education^courses^461^sp96^cse461-bboard.shtml

This data set contains WWW-pages collected from computer science departments of various universities

Richard
<hr size=4><a name="831141718001">To: cse461@cs
cc: lazowska@cs, borning@cs
Subject: <b>Warning</b>
Date: Fri, 03 May 1996 09:41:52 PDT
From: <b>Richard Ladner &lt;[e-mail]&gt;</b>
</a>


There were quite a few students not in class today. 
I just want to warn those of you that did not come
to class today that I covered the binary tree
protocols in depth.  This topic is not covered
deeply in the book.

There will be an assignment on this topic next week
and the topic has appeared on some of my final exams
in the past.

I know that attendence is not manditory, but I am
concerned that those of you missing class
regularly are not receiving the quality education 
that you are paying for.

<hr size=4><a name="831148662001">To: cse461@cs
Subject: <b>Bad Calculation</b>
Date: Fri, 03 May 1996 11:37:29 PDT
From: <b>Richard Ladner &lt;[e-mail]&gt;</b>
</a>


The calculation I did in class calculating the number
of bits on a 1km wire running at 10 Mbps was wrong.

What I wrote was
5 x 10^-6 sec x 10^7 b/sec = 500.

The correct calculation is 
5 x 10^-6 sec x 10^7 b/sec = 5 x 10^1 = 50.

Thus, two frames cannot &quot;pass in the night&quot;.  Needless
to say jamming is done probably because it is safer
and scales up to longer wires and higher bandwidths.

That'll teach me to try doing a calculation in real
time.  

Please, please stop me during class
when you see me make such errors.  

Richard
<hr size=4><a name="831335453001">Date: Sun, 5 May 1996 15:30:49 -0700
From: <b>wchan@calvin (William Chan)</b>
To: cse461@cs
Subject: <b>project stuff</b>
</a>

Except for protocol 6, when there is a timeout, the simulator 
always says the timeout was for frame 0. I've changed worker.c
so that it tells which sequence number it timed out on. You
can get the new worker.c from the simulator directory. Let me
know if you find other bugs.

Also, if you haven't noticed, I've put a solution to project 1
in /cse/courses/cse461/simulator/solution1.

I don't think I'll be able to finish grading project 1 by
Wednesday. But if you're a C novice and want me to give you
some feedback before you hand in part 1 of project 2, let me know.

-- william
<hr size=4><a name="831482675001">Date: Tue, 7 May 1996 08:24:26 -0700 (PDT)
From: <b>Barak Water &lt;[e-mail]&gt;</b>
To: [e-mail]
Subject: <b>Sim and Linux</b>
</a>

For what it's worth, in case anyone is interested or even mildly curious, 
in a moment of frustration with Grizzly being really *S L O W* I ftp'ed 
the simulator to my Linux box, compiled it, and discovered to my pleasure 
that it not only compiles but behaves the same as on Grizzly.
This may be old news to some; but it seemed worth mentioning...

Take care all,

Barak Water

<hr size=4><a name="831510895001">To: cse461@cs
Subject: <b>What to read in Chapters 4 and 5</b>
Date: Tue, 07 May 1996 16:14:45 PDT
From: <b>Richard Ladner &lt;[e-mail]&gt;</b>
</a>


You will definitely need to read the following
sections in Chapters 4 and 5.

4.1
4.2.1
4.2.2
4.2.3
4.3.1
4.3.2
4.3.3
4.3.4
4.5.1
4.5.2

5.1
5.2.1
5.2.2
5.2.3
5.2.5
5.2.6
5.2.7
5.3.1
5.3.2
5.3.3
5.4 intro

More reading from Chapter 5 will be given later.
<hr size=4><a name="831630498001">Date: Thu, 9 May 1996 01:28:09 -0700
From: <b>wchan@calvin (William Chan)</b>
To: cse461@cs
Subject: <b>part 1 solution</b>
</a>

I've put a solution to part 1 of project 2 in the simulator
directory in the file p7.c. Good luck on part 2!

-- william
<hr size=4><a name="831686249001">Date: Thu, 9 May 1996 16:57:25 -0700
From: <b>wchan (William Chan)</b>
To: cse461@cs
Subject: <b>ack timer in protocol 8</b>
</a>

In p8.c, I had:

typedef enum {frame_arrival, cksum_err, timeout, network_layer_ready} event_type;

But in order to use the ack timer, it should be changed to:

typedef enum {frame_arrival, cksum_err, timeout, network_layer_ready, ack_timeout} event_type;

I've just fixed this in p8.c in the simulator directory.

You can start the ack timer by calling start_ack_timer() and 
stop it by calling stop_ack_timer(). When the ack timer goes off,
an event ack_timeout occurs.

-- william
<hr size=4><a name="832006302001">To: cse461@cs
Subject: <b>Queuing Theory</b>
Date: Mon, 13 May 1996 09:51:34 PDT
From: <b>Richard Ladner &lt;[e-mail]&gt;</b>
</a>


I probably didn't explain myself very well.  Let me 
give an example.

We have two incoming lines and one outgoing line to
a switch each with the same bandwidth b.
               _____
              |     |
     A -------|     |
              |     |-------- C
     B -------|     |
              |     |
               -----

We know that cell arrivals on A are at a statistical
rate of b/2 and similarly for B.  Thus, the overall
arrival rate at the switch is b.  This will
cause the average queue length at the switch to be
infinity.  If the arrivals are Poisson, which
basically means that the arrivals are completely
independent, then it can be proven that this is true.

It appears on the surface that the switch can handle
the arrival rate of b.  Indeed it can, assuming it
has unbounded storage space.  If storage space is
bounded, then it will eventually overflow.

Richard 
<hr size=4><a name="832025025001">Date: Mon, 13 May 1996 15:03:39 -0700
From: <b>wchan@lupine</b>
To: cse461@cs
Subject: <b>project 1</b>
</a>

Sorry about the delay. Project 1 has been graded, and you should 
have received your score. If you haven't, but you did turn in the 
project, let me know.

-- william
<hr size=4><a name="832231750001">Date: Thu, 16 May 1996 00:29:05 -0700
From: <b>wchan@lupine</b>
To: cse461@cs
Subject: <b>project 3 ready</b>
</a>

I've put project 3 on the web and put xerox copies outside the
professor's office. If you want a hardcopy before Friday, go
to the professor's office at Sieg 311 and pick up a copy. Otherwise,
we will distribute them on Friday in class.

The handout is lengthy, because there is quite a bit of background
information. But in terms of the code you need to write, it's not too
long. This is the first time we gave an assignment involving &quot;real&quot;
network programming. If you think it's too hard or too easy, let us
know. Again, for those of you who are less familiar with C, don't
hesitate to ask me C questions. I hope you'll have some fun doing this
assignment. ;-)

-- william
<hr size=4><a name="832282209001">Date: Thu, 16 May 1996 14:29:47 -0700
From: <b>wchan (William Chan)</b>
To: cse461@cs
Subject: <b>IRC</b>
</a>

One of you asked about project 3:

&gt; &lt;In this assignment, we will focus on UDP, on which we will
&gt; &lt;build a simple chat application allowing multiple users to talk with one 
&gt; &lt;another on the Internet
&gt; &lt;(similar to IRC). 
&gt; 
&gt;   what is IRC ?

IRC stands for Internet Relay Chat. Glad that you didn't know it.
It's a super time sink...  You can take a look at the FAQ at:
	ftp://cs-ftp.bu.edu/irc/support/alt-irc-faq

-- william
<hr size=4><a name="832630531001">To: cse461@cs
subject: Question on assignment 8.
Date: Mon, 20 May 1996 15:15:17 PDT
From: <b>Richard Ladner &lt;[e-mail]&gt;</b>
</a>


Question:

Regarding Assignment #8, we were wondering how the switch works.  Is 
there one queue for all incoming traffic or are there separate queues for 
each sender/receiver?  Are these channels independent of each other?

Answer:

The important thing is that there is a single buffer
pool for all arrivals.  When a packet arrives and
there is a buffer free it gets the packet.  The
full buffer is then put on the outgoing queue.
Once the packet is sent the buffer becomes free
again.  

<hr size=4><a name="832821583001">Date: Wed, 22 May 1996 20:20:35 -0700
From: <b>Demian Godon &lt;[e-mail]&gt;</b>
Organization: University of Washington
To: [e-mail]
Subject: <b>reading</b>
X-Url: http://www.cs.washington.edu/education/courses/461/cse461-bboard.shtml#831510895001
</a>

What sections beyond 5.4intro would you recommend reading?  That is, are there any 
in particular?
<hr size=4><a name="833240877001">Date: Mon, 27 May 1996 16:47:53 -0700
From: <b>wchan (William Chan)</b>
To: cse461@cs
Subject: <b>project 2 graded</b>
</a>

If you have turned in project 2, you should have received 
your grade. If not, let me know.

(I sent the grade to your CSE account, not your EE or .u account.)

-- william
<hr size=4><a name="833382017001">To: cse461@cs
Subject: <b>Office Hours</b>
Date: Wed, 29 May 1996 08:00:04 PDT
From: <b>Richard Ladner &lt;[e-mail]&gt;</b>
</a>


I cannot make my office hour today at 11 am.

Because the exam is on Tuesday, I will have special
office hours on Friday and Monday.

Office hours until the exam.

Thursday:  11 - 12  (regular office hour)
Friday: 11 - 12
Monday:  11 - 12

You are welcome to make an appointment for another time
if you cannot make these times.

Richard
<hr size=4><a name="833416024001">To: cse461@cs
Subject: <b>What to read for the Final</b>
Date: Wed, 29 May 1996 17:26:57 PDT
From: <b>Richard Ladner &lt;[e-mail]&gt;</b>
</a>


Chapter 1
Sections
1.1
1.2
1.3
1.4

Chapter 2
Sections
2.1.3
2.3.1
2.4.4
2.4.5
2.6.1
2.8.3
2.9

Chapter 3
Sections
3.1
3.2
3.3
3.4
3.5 intro
3.5.1
3.6

Chapter 4
Sections
4.1
4.2 intro
4.2.1
4.2.2
4.2.3
4.3 intro
4.3.1
4.3.2
4.3.3
4.3.4
4.5 intro
4.5.1
4.5.2

Chapter 5
Sections
5.1
5.2 intro
5.2.1
5.2.2
5.2.3
5.2.5
5.2.6
5.2.7
5.3 intro
5.3.1
5.3.2
5.3.3
5.4 intro
5.4.1
5.4.2
5.4.3
5.4.4
5.4.5
5.4.6
5.4.7
5.5 intro
5.5.1
5.5.2
5.5.4
5.5.10

Chapter 6
Sections
6.1 intro
6.1.1
6.1.2
6.1.3
6.2 intro
6.2.1
6.2.2
6.2.3
6.2.3
6.2.4
6.4.3
6.4.7

Chapter 7
Sections
7.1 intro
7.1.1
7.1.2
7.1.3
7.1.4
7.1.6
7.7.3

<hr size=4><a name="833560786001">To: cse461@cs
Subject: <b>Final Exam</b>
Date: Fri, 31 May 1996 09:39:35 PDT
From: <b>Richard Ladner &lt;[e-mail]&gt;</b>
</a>


This is a reminder to bring an 8 1/2 X 11 inch blue book
to the final exam.  You may use as many pages as you like
for your handwritten notes.  Be sure and leave some pages
for the final itself.

The final is 8:30 - 10:20 on Tuesday, June 4th.

I have special office hours today and Monday from 11 to
12.  If you need to make an appointment because you
cannot make those time, please send me e-mail.

I'm rooting for all of you to do well on the final.

Good luck,

Richard
<hr size=4><a name="833715502001">Date: Sun, 2 Jun 1996 04:38:17 -0700
From: <b>wchan@calvin (William Chan)</b>
To: cse461@cs
Subject: <b>461</b>
</a>

I just sent out two messages to each of you:

1  your project 3 grade and comments (sent to your CSE account)
2  all your homework, project and midterm grades (sent to your 
   email address in the class mailing list). Please verify that
   the grades are correct.

Let me know if you didn't receive either message.

good luck on the exam!
-- william

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