[mac] airport self-assigned IP address AGAIN!!

First time in Champaign library with the MBP. Same self-assigned IP address problem with open network. After deleting preference files in /Library/Preferences/SystemConfiguration/, still no good.

So I logged in as different users but still it's to no avail. I rebooted a few times, delete some per-user preference files. And switched user again, this time it works miraculously.

I tried to look up documents of the 802.11 IO devices on apple's developer center but found nothing. Apple seemed to be very closed in this regard.

One theory is that the virtual network interfaces installed by Parallel 3.0 might be the culprit. I uninstalled Parallel but it's hard to verify this theory. Hope this is the last time I have to deal with this issue.

Weird Airport Problem: Self-Assigned IP Address

Very frustrating...

http://discussions.apple.com/thread.jspa?threadID=2322497&tstart=90

The final solution that works:

Deleting

• /Users/YourUserName/Library/Preferences/com.apple.internetconnect.plist
• /Users/YourUserName/Library/Preferences/ByHost/com.apple.networkConnect.<12>.plist
  

saves the day!

/Library/Preferences/SystemConfiguration/com.apple.airport.preferences.plist


To read:

Tutorial: Preferences Files: The Complete Story

Preferences Files: The Complete Story (Part V); How .plist files become corrupt and troubleshooting the results

from CNET macfixit

PowerPoint Tricks - Adding Custom Anchor Points

The AutoShapes in PowerPoint can be conveniently connected using "connectors". However, most AutoShapes only have a few pre-defined "anchor points" which the connectors can connect to. The following is a way to add custom anchor points to an AutoShape:

1. Convert the AutoShape to Freeform
   
2. Right click the shape to select "Edit Points"
3. Choose "Add point" at where you want the new anchor point to be

About PCI-e

A tutorial of PCIe.

http://zone.ni.com/devzone/cda/tut/p/id/3767

• Similar to network protocols, the architecture of PCIe consists of layers: physical layer, data-link layer, transaction layer, software layer.
  
• Lane - a basic physical layer channel, a device can request more than one lanes and combine those lanes for higher bandwidth
• Data-link layer: enable reliable data transmission between pairs. Use sequence number, CRC, and retransmissions to ensure reliable communication.
  
• Transaction Layer: creates request packets and serve corresponding response packets from the data-link layer. Provide address spaces.

Northbridge
Southbridge


IO Virtualization
Part 1: http://www.embedded.com/design/networking/217701325

• What is IO virtualization? why is it needed?

System Questions

1) x86 & ARM platform

2) qualcomm snapdragon vs samsung ARM
both ARM-based?
ASIC: application specific IC
SoC: system-on-chip
integrated processors for embedded systems
bus, I/O chipsets, memory controllers (RAM,ROM,...), graphics accelerator

3) NAND vs NOR
NAND can be denser (most usb flash memory)
NOR is more reliable? (used for BIOS ROM)

4) HDMI mirror?

5) embedded controller (EC)

6) bluez

7) at command set (for serial terminal?)

8) SSD, DRAM, SRAM, flash memory
SRAM: static RAM, faster, expensive, less power in idle state
DRAM: dynamic RAM
SDRAM: synchronous DRAM
EEPROM: early flash, byte-wide erasable, flash is usually page-wide erasable

Interview Questions

1. Simulate a seven-sided die using only five-sided

2. Giving Two Strings, Find out whether they are Anagrams or not?

3. find the longest palindrome in a string?

4. find longest common substring in 2 strings using suffix tree

Some terms:

• suffix tree of a string S: a tree whose edges are labeled with strings, such that each suffix of S corresponds to exactly one path from the tree's root to a leaf.
• trie: each edge is labelled with a single character
• radix tree, Patricia tree/trie: edges are labelled with a string instead of single character
  

suffix tree: a special type of radix tree

• How to construct suffix tree?
• How to find longest common substring using suffix tree?

DP algorithm runs in O(mn).

Reference:
Fast String Searching With Suffix Trees

Algorithm Reviews

Foundation of Algorithms Using C++ Pseudocode, 3rd Edition.
By Richard Neapolitan and Kumarss Naimipour

Chapter 5 Backtracking
Backtracking is the technique to prune non-promising nodes in the state space tree.

CLRS
Ch 11 Hash Tables

11.3 Hash Functions

11.4 Open Addressing
Uniform hashing: idealized hashing function selects a permutation with equal prob.
Linear Probing: h(k,i) = ( h'(k) + i ) mod m
Quadratic Probing:
Double Hashing