Traffic Safety Resources, MacBook Pro purchase decision

Added three resources to

http://www.techtransfer.berkeley.edu/tse/ts_resources.php


Research MacBook Pro purchase decision:

I can get the "new" (but not very) 15" MBP 2.4GHz/2 G/200 G for $ 1,799 with educational discount

I can get a refurbished old 15" MBP 2.2GHz/2 G/120 G for $ 1,449 ($ -350)


I can wait for a Q3 update, expected to be based on Intel's Montevina chipset, and likely to include some real changes on Apple's part.

Checking my web server for errors

My Apache error logs don't tell me enough about 404s. They don't tell me:

User-agent:
If the user-agent is a web crawler, I don't care about bad links on our site; they're probably already fixed and the crawler still has the bad link in their index.

Referrer:
If the 404 is from a bad link on our site, I want to know the originating page.

Query:
Most 404s come from cross-site scripting (XSS) attacks. Without the query part of the URL, it's impossible to distinguish these.

Today I am using tail and grep to check the last few days' worth of 404s:

$ tail -20000 access_log_www | grep -F '" 404'

As it happens, we get about 10,000 requests/day, so to see n days' log entries I just look at the last n0,000 lines in the access logs (tail -20000).

Only 0.2% of requests are 404s, so grep has to winnow through a lot of chaff to find them. To speed it up, I use grep -F, which turns off the regular expression engine.

The string 404 can appear in other places (the file size field, the user-agent field) so I grab the double quote in the last position of the URL field. Naturally that means I have to single-quote the search pattern.

Statistical aside:
How much time does grep -F save?

Here are the results of 10 greps on 20,000 lines, 5 with and 5 without the -F arg:

grep      real  0.486    user  0.460    sys  0.070
grep      real  0.493    user  0.460    sys  0.020
grep      real  0.507    user  0.430    sys  0.080
grep      real  0.510    user  0.490    sys  0.010
grep      real  0.541    user  0.500    sys  0.130
grep -F   real  0.455    user  0.480    sys  0.040
grep -F   real  0.458    user  0.420    sys  0.050
grep -F   real  0.458    user  0.430    sys  0.050
grep -F   real  0.458    user  0.470    sys  0.040
grep -F   real  0.523    user  0.600    sys  0.050

grep (no -F) costs:
7.87% in real time
-2.50% in user time (saves time?)
34.78% in system time (big percentage of a small number)
more than grep -F

put another way, grep -F saves:
7.29% in real time
-2.56% in user time (costs time?)
25.81% in system time (big percentage of a small number)
versus grep

Edits Friday Feb 22, 2008

I looked through the About pages of our site today and made some changes:

Contact Us:

• Changed info about parking. (The page still said we have free parking: if visitors went by that, they could get a $40 parking ticket!)
• Cleaned up mailtos and phone number display.

Wednesday, Feb 13

a.m.:
Read traceroute and netstat documentation
Read micronet thread on Sharepoint/CalShare and Sakai/bSpace
Read Network World web site
p.m.:
read eWeek

Tuesday 12 February

a.m.:

• Read about IP filtering with netfilter and iptables
• Read Blocking international network traffic to your server
• Read Traffic Safety Center headlines
• Edited 4 or 5 records in clearinghouse that had unqualified URLs

p.m.:

• Read about DNS and DNS appliances
• Read about specifying laptops
• 'tail' errors.log on www and fix broken links etc.

Is Your Homepage Immature?

Indi Young, in this essay, suggests that your home page reflect how your brand directives change over the year. We certainly have seasonal things like publication of the annual catalog, various conferences, ???, yet our home page is relatively static through the years.

Also suggests varying themes of the sort that might begin "we support ..." Ours might be "...train..." "..."

The wording is important; a while ago I read a synopsis of a web marketing book that coined the phrase "care words" for words that prompt a visceral response in your audience.

In retooling our home page, we ought to replace the random decorative images, and use more space for actual mission-related "brand directives."