Microcomputer Systems 810:023 Spring 2006
READ BEFORE THE FINAL: Ghostbusters and problem
solving should be
read before the final exam period, which is 1-3 p.m. on Wednesday of
finals week. Please also look at the
Waggle Dancing Bees.
More details about the final exam coming here over the weekend on
Saturday or Sunday.
Here is the LAST ASSIGNMENT/Take Home
Quiz, which was handed out and started in the hands-on class on
Tuesday, April 25th. It corresponds to the first section of the last
chapter in the textbook, which should be read carefully while you do
these capture files with your textbook on the
ethereal CD-ROM. They are referred to in the
LAST ASSIGNMENT/Take Home Quiz
Here is an animation of some Ghostbuster's
What is PUBLIC KEY
What is DIGITAL
Page 73-74 Questions 1-5 (ftp) Due on 4/20/Thursday
Page 99 Questions 1, 3 and 7 (TCP) Due on 4/20/Thursday
length Vignere ciphers:
The ghost.txt file with Vignere cipher length = 2, 3, 6, 12 and 24.
Notice how the statistical pattern of some letters being the most
frequent and some being the least frequent are obscured more
as the Vignere cipher goes from two characters up to 24 characters!
Showing only the 4 or 5
most frequent letters and the 3 or 4 least frequent for 2, 3, 6, 12 and 24.
MEMORY and TIC: Memory
from DRAM to SRAM to cache and the gap between DRAM speed and CPU
speed, which keeps getting worse (Moore's Law).
CSMA/CD and repeaters and
segments. QUIZ THREE on 02/23/Thursday.
Hamming Codeword concepts and practice, for
error correction and error detection issues. The CRC method of
detecting errors will NOT be on the Thursday, February 23rd quiz.
There are 5 issues to consider when connecting two nodes or computers
with some media like cable. They are EFERA.
Errors, Reliability and Access are E, F, E, R, A.
- Encoding the digital data on the signals that
the analog media can transmit, and decoding it back
to the digital binary pattern when received.
- Sentinel approach and byte count approach to know
the end of a frame. Detecting the exact start of
a frame is the other issue. "Not me" and "Mine"
- Error detection
- Even and odd parity. Hamming codewords.
CRC (Cyclic Redundancy Check)
- Reliable delivery
- Sliding windows. Timers and ACKs.
Automatic resend after timer goes off if no ACK from destination host.
- Access control
we have already studied. The CSMA/CA and token passing we
have yet to study, but will look at them later on.
The Spring 1999 web page,
the Spring 2000 page,
Spring 2001 810:023 page,
Spring 2002 810:023 page,
Spring 2003 810:023 web page,
Spring 2004 810:023 web page,
Spring 2005 810:023 web page
all are useful to see what kinds of topics are covered in this class.
Keep in mind, the rate of change for networks,
PCs and operating systems means the class will change quite a bit in response.
- Review of one question from CLASS
Tuesday, January 24th.
Another useful clarification for your IP protocol and subnet masking
knowledge: SUBNET MASKS --
Understanding of TCP/IP protocol
at the Network Layer IP addressing level, and applying that to
subnetworking your network. (Email note from February 6th, 2002 for
- Solution to the Hobbits (Frodo.middleearth.com, etc.) subnets
grouping problem #4, and the other, shorter problems.
subnetsPractice and IP
numbers group exercise SOLVED IN DETAIL, and perhaps very helpful.
You may need to take notes on it. If you do not understand it, WRITE IT
OUT. Consume some ink, to more effectively think. If the ink don't
flow, the understanding don't grow (as fast or as tall or as deep).
Just the solution to #4 GROUPING the
middleearth.com devices and hosts on which subnet problem.
Here is email note #1, for
your convenience and in case you did not receive it. What to read or
preview, if you get the chance.
Networking terms and concepts - This LAN is your LAN. This LAN in
my LAN folksong lyrics
by Woody Guthrie.
Spring 2006 course reviews/previews
- Here is Binary (base two) along with
some information on Hexadecimal (base 16), Octal (base 8) and
our good friend, decimal (base ten).
- Class #1 (Monday, January 9th) handouts are one
on binary subnet mask values and another
on binary basics and IP numbers and
subnetting, with class A, class B, and class C information.
We'll cover this in classes 2 and 3.
PowerPoint Slides: IP addressing,
subnet masks and IP numbers.
Slides: Chapter 11 IP, subnet
masks for OLDER BROWSERS and CEEE lab.
- How does the CRC
(Cyclic Redundancy Check) work?