Month: December 2010

by

Panoramic Image of Woods and 3 Driveways

Using the Motorola Droid X, I took about 10 photographs at 5MP, freehand.  Then I used Hugin, the open source image stitching software.

I had never stitched images together, but I must say this tool is impressive.  The images were all various shades, angles, and since taken freehand, not straight.

However, see the result below…

by

Simondale Excavating from Warriors Mark, PA

Simondale Excavating is doing an excellent job of leveling some ground on a hillside.  If you need any excavation work in the Altoona/Tyrone/Huntingdon/State College area (or nearby), do not hesitate to call Jim or Matt at (814) 632-8590.

Upon meeting Jim Simondale and Matt Simondale, I was very impressed by their knowledge, demeanor, and interest in my project.  I met with them 3 times on site prior to starting this project, and every detail has been covered as discussed.

This may seem like a small thing, but I appreciated that all of their equipment (trucks, excavators, bull dozers, etc…) were newer models, very well maintained, clean (as is reasonable), and had their logo painted neatly across.  All signs of being professional.

[As I understand it, they are also do quite a number of septic systems and sand mounds.]

Update: June 2011: Matt and Jim and their crew came out again and did another whole round of grading, moving, and excavating.  They built and/or surfaced over 1/4 mile of slate covered roads, dug a pond, corrected some frost damage to earthen banks, and made everything really nice.  I thought the price estimate was very fair, and they came in dead on, despite doing a number of extras.  Here is an updated photo:

—
Outstanding view from the top of the hill.

See how nice the grading of the bank is?  All done with the large excavator pictured above.

And Mr. Ezra, standing on top of the hill…

by

Essentials of DNS: understand the basics well

DNS stands for “Domain Name Service”.  It is the mechanism in which the internet is able to map a name (eg http://www.sgasoftware.com) to an IP address (eg 12.34.56.78).

This writeup is not designed to be 100% technically accurate.  Rather, it is designed to give a layman understanding of relevant parts of the DNS system.
Much more comprehensive information can be found here: http://en.wikipedia.org/wiki/Domain_Name_System

A bit on IP Addresses and Routing

Packets of data to move to and fro across the internet based entirely on IP Address.  At every “network meeting point” on the internet, there is a router which examines all traffic to find out where it is headed, and then sends it to the next step.  This process is repeated at each “network meeting point” until the traffic arrives at the destination.
There is a popular utility called “Trace Route”, which will demonstrate all of the routers that a packet of data must go through to get from where you are to where it is headed.  In the following example, I ran a traceroute to http://www.google.com.
Notice the first step was a DNS lookup, converting www.google.com to 72.14.204.99. 
c:\>tracert www.google.com
Tracing route to www.l.google.com [72.14.204.99]
over a maximum of 30 hops:
  1    <1 ms    <1 ms    <1 ms  192.168.0.1   (our office router/gateway))
  2     1 ms    <1 ms    <1 ms  10.1.10.1     (our cable modem (another router/gateway)
  3    15 ms    13 ms    12 ms  96.179.208.1
  4     9 ms     9 ms    10 ms  ge-2-20-ur01.blairsville.pa.pitt.comcast.net [68.86.146.165]
  5    14 ms    10 ms     9 ms  te-9-1-ur01.indiana.pa.pitt.comcast.net [68.86.100.178]
  6    10 ms    55 ms    30 ms  te-9-3-ur01.punxy.pa.pitt.comcast.net [68.87.173.81]
  7    12 ms    18 ms    19 ms  te-9-1-ur01.ruralvalley.pa.pitt.comcast.net [68.86.100.122]
  8    21 ms    63 ms    53 ms  te-6-3-ar01.pittsburgh.pa.pitt.comcast.net [68.87.173.73]
  9    28 ms    29 ms    27 ms  te-3-1-0-0-cr01.chicago.il.ibone.comcast.net [68.86.90.181]
 10    25 ms    28 ms    25 ms  pos-1-6-0-0-pe01.350ecermak.il.ibone.comcast.net [68.86.87.130]
 11    43 ms    44 ms    44 ms  as15169-1.350ecermak.il.ibone.comcast.net [75.149.230.198]
 12    48 ms    52 ms    58 ms  209.85.254.130
 13    37 ms    39 ms    39 ms  209.85.248.222
 14    36 ms    43 ms    41 ms  66.249.94.46
 15    42 ms    39 ms    39 ms  iad04s01-in-f99.1e100.net [72.14.204.99]
Trace complete.
In true geek fashion, after 15 hops, our packet reached 1e100.net.  Google was derived from the word Googol, which is a number with 1 and 100 zeros.  Henceforth, 1e100.net stands for something to that effect.

Why does this matter?

It is important to understand that computers are binary, and therefore require input to be ultimately converted to binary.  An IPv4 address is simply 32 bits, but rather than presenting it as 11000000.10101000.00000000.00000001, humans find it more convenient to look at it like 192.168.0.1.  However, that is still a far cry from a human readable name like mail.domain.com.
This is where DNS comes into play.  DNS is a system which allows people to use names, while still providing for computers to use the numbers.  Of the many benefits of DNS, it allows you to move a domain to another IP address while keeping the domain name the same. 

Common Types of DNS Records

DNS records come in several types:
A record
Points to a specific IP address.  “A” stands for “Address”.

This means that appcove.com should resolve to 74.205.111.168
appcove.com.            70755   IN      A       74.205.111.168
CNAME record
Points to another record.  “CNAME” stands for “Canonical Name Record”
This means that http://www.appcove.com should resolve to appcove.com and in turn resolve to 74.205.111.168
www.appcove.com.        86400   IN      CNAME   appcove.com.
MX record
Specifies a domain which will handle incoming email for the domain.
This means that mail sent to @appcove.com will be handled by APPCOVE.COM.S9A1.PSMTP.com, and if that does not work, send it to APPCOVE.COM.S9A2.PSMTP.com and so on.  The weight indicates which server should be tried first — the lower the weight, the better.
appcove.com.            86400   IN      MX      40 APPCOVE.COM.S9B2.PSMTP.com.
appcove.com.            86400   IN      MX      10 APPCOVE.COM.S9A1.PSMTP.com.
appcove.com.            86400   IN      MX      20 APPCOVE.COM.S9A2.PSMTP.com.
appcove.com.            86400   IN      MX      30 APPCOVE.COM.S9B1.PSMTP.com.
NS record
Delegates a DNS zone to use the given authoritative name servers.  “NS” stands for “Name Server”.
This means that DNS for appcove.com is to be handled by either ns.rackspace.com or ns2.rackspace.com.
appcove.com.            57957   IN      NS      ns.rackspace.com.
appcove.com.            57957   IN      NS      ns2.rackspace.com.
TXT record
Specifies arbitrary text associated with a name.  “TXT” stands for “Text”
The provides a mechanism for the DNS system to be extended with different bits of text about a domain name.  The following TXT record stores SPF information, used to specify what servers are allowed to send mail on behalf of appcove.com.
appcove.com.            86400   IN      TXT     "v=spf1 include:fogcreek.com include:aspmx.googlemail.com ip4:207.126.144.0/20 ip4:64.18.0.0/20 ip4:74.125.148.0/22  ~all"

DNS Propagation

DNS is a distributed system.  This means that there are thousands of DNS servers scattered around the globe.  Most internet providers will have their own DNS servers.  Most hosting providers will have their own DNS servers.  Etc…
How do they all stay in sync?  They do and they don’t!
Every DNS entry has a corresponding TTL value associated with it.  TTL means “time to live”.  This value, expressed in seconds, states how long a given DNS entry is valid before it must be refreshed from the “authoritative” DNS server for the given domain.  Typically, the TTL is set to 86,400 seconds, or 1 day.
With a TTL of 1 day, any changes to authoritative DNS records may take up to a full day (or more) to propagate around the internet.  This is worth keeping in mind before you engage in any important DNS changes.
The proper way to change DNS is to first, at least 48 hours prior to the transition period, change the TTL to a very low value (like 5 minutes).  It will still take at least a day for this to fully propagate to all relevant DNS servers.   However, once they are all aware that the TTL is 5 minutes, they will frequently check your authoritative server for updates every 5 minutes or each time a new request comes in for one of your DNS records, whichever is longer.
In other words, DNS servers only look up what they are asked to look up.  Then they retain it for the TTL period, and finally discard it (only to repeat if needed).
Authoritative DNS
Every domain must be registered with a registrar.  Part of this registration information for every domain, is the DNS servers to use as “authoritative dns information” for that domain.   These NS records are transmitted to the root nameserver system. 
Every top level domain (com, net, edu, org, us, gb, br, uk, au, etc…) all have their own authoritative DNS servers.  This information is kept in the world’s root name servers, which are currently:
a.root-servers.net.     117655  IN      A       198.41.0.4
a.root-servers.net.     196594  IN      AAAA    2001:503:ba3e::2:30
b.root-servers.net.     113829  IN      A       192.228.79.201
c.root-servers.net.     120655  IN      A       192.33.4.12
d.root-servers.net.     113757  IN      A       128.8.10.90
e.root-servers.net.     115554  IN      A       192.203.230.10
f.root-servers.net.     121256  IN      A       192.5.5.241
f.root-servers.net.     280321  IN      AAAA    2001:500:2f::f
g.root-servers.net.     113755  IN      A       192.112.36.4
h.root-servers.net.     116456  IN      A       128.63.2.53
h.root-servers.net.     206320  IN      AAAA    2001:500:1::803f:235
i.root-servers.net.     115856  IN      A       192.36.148.17
i.root-servers.net.     337685  IN      AAAA    2001:7fe::53
j.root-servers.net.     119155  IN      A       192.58.128.30
If you lookup the NS record for com at one of the above root servers, you will be told this:
d.gtld-servers.net.     16131   IN      A       192.31.80.30
g.gtld-servers.net.     74653   IN      A       192.42.93.30
f.gtld-servers.net.     111162  IN      A       192.35.51.30
c.gtld-servers.net.     33590   IN      A       192.26.92.30
j.gtld-servers.net.     171076  IN      A       192.48.79.30
a.gtld-servers.net.     2665    IN      A       192.5.6.30
a.gtld-servers.net.     8352    IN      AAAA    2001:503:a83e::2:30
i.gtld-servers.net.     78083   IN      A       192.43.172.30
k.gtld-servers.net.     14957   IN      A       192.52.178.30
b.gtld-servers.net.     127812  IN      A       192.33.14.30
b.gtld-servers.net.     168301  IN      AAAA    2001:503:231d::2:30
e.gtld-servers.net.     29652   IN      A       192.12.94.30
h.gtld-servers.net.     47519   IN      A       192.54.112.30
l.gtld-servers.net.     41990   IN      A       192.41.162.30
m.gtld-servers.net.     42456   IN      A       192.55.83.30
If you lookup the NS record for appcove.com at one of the above “com” servers, you will be told this:
appcove.com.            172800  IN      NS      ns2.rackspace.com.
appcove.com.            172800  IN      NS      ns.rackspace.com.
Finally, we have the authoritative DNS servers for appcove.com.  Now, if you lookup the record for http://www.appcove.com at ns.rackspace.com, you will be told this:
www.appcove.com.        86400   IN      CNAME   appcove.com.
Finally, if you lookup appcove.com at it’s authoritative server ns.rackspace.com, you will be told this:
appcove.com.            86400   IN      A       74.205.111.168
by

Test Post with ecto

I’m making a test post with ecto. Ecto is desktop publishing solution for the Mac platform, which works with wordpress among others.

For starters, here is a picture:

201012022310.jpg

And here is some source code:




  def Select(Account_MNID):




    return App.DB.Row(”’




  SELECT




  “Account_MNID”,




  “Name”,




  “CreateDate”,




  “ChangeDate”,




  “Address1”,




  “Address2”,




  “Address3”,




  “City”,




  “State”,




  “Zip”,




  “Country_MSID”,




  “Phone”,




  “Fax”,




  “Email”,




  “Note”,




  “Perm_Active”




  FROM




  “ACRM”.”Account”




  WHERE true




  AND “Account_MNID” = $Account_MNID




  ”’,




      Account_MNID = Account_MNID




      )








It is important to me that code shows up correctly once posted. For clarity, I will take a screenshot of the code…



201012022313.jpg


Lastly, I need to see what happens when I post a high quality photo from my desktop…


I did this one by dragging the photo from Finder onto this Ecto window.



2010-11-24_11-13-11_968.jpg


As an edit, I clicked the insert image button, and used a preset to specify 700px wide, but as a thumbnail…. Let’s see.



2010-11-24_11-13-11_968.jpg


Ok, good side… Pictures and text seem to flow pretty well. Bad side… Code formatting was lost. I should try wrapping it in the [ sourcecode ] wrapper… I’ll do that next…





  # vim:encoding=utf-8:ts=2:sw=2:expandtab




  import Extruct




  import re




  import uuid




  import hashlib




  





  from .. import App, ACRM




  from . import Validate




  





  from AppStruct.Util import *




  from datetime import date




  





  Insert_Validate = App.GetHook(‘CCRM.Account.Insert_Validate’)




  Insert_Execute = App.GetHook(‘CCRM.Account.Insert_Execute’)




  





  #============================================================================




  





  def Select(Account_MNID):




    return App.DB.Row(”’




  SELECT




  “Account_MNID”,




  “Name”,




  “CreateDate”,




  “ChangeDate”,




  “Address1”,




  “Address2”,




  “Address3”,




  “City”,




  “State”,




  “Zip”,




  “Country_MSID”,




  “Phone”,




  “Fax”,




  “Email”,




  “Note”,




  “Perm_Active”




  FROM




  “ACRM”.”Account”




  WHERE true




  AND “Account_MNID” = $Account_MNID




  ”’,




      Account_MNID = Account_MNID




      )




  




For sourcecode, I guess I’m still stuck editing the HTML.


Look at the markup that was generated with a simple copy/paste from Github…



201012022333.jpg


What is the best way to post source code examples?

			

	
	



			
				



	
	


		
					

				 by 			

				
A four wheeled wooden vehicle

	


		

		
Too many days in a row, I had not had enough “hands on” work to do.  So I decided to build a little toy that Zechariah would like.  Four wooden wheels, some bolts and washers, and a block of wood for the body, and we made a cool little car (or skateboard).


In the middle of it, this little girl showed up all by herself in the workshop wanting to help.  So she put all the washers on.


Anna placing washers on the wheel.


 


Eli, of course, was there as well turning the wrench.  We used 5/16″ bolts with a smooth shaft for the first 1″ or so as an axle.  We just turned them right into the wood, drilling the hole in the wheels a bit bigger, and the hole in the body a bit smaller for a snug fit.


Eli turning the wrench.


 


Here are the scraps left over after bandsawing.  I did a quick job of cutting them, so they were not exactly round.


After cutting the wheels


 


I used a drill press and a rasp to round out and smooth the wheels down.


Rounding the wheels


Finally, here is Zechariah quite fond of his new toy.  Another confirmation that we don’t need super-slick toys — kids love stuff that is simple.


Finished product with a happy owner.