### Internet

Inter-Network. The Internet was created at a University to attempt to connect computers between each others from "far away places" (i.e. two buildings in the same University). The main concept was to create a set of protocols to make the systems work. Namely, the SMTP, FTP and TELNET. Now we have many others such as the well known HTTP, which is based on the TELNET concept.

## Bad move for PHP unpack()! So unpack() stopped working?

Today I noticed many errors on one of my websites. Looking closer into it, I noticed that the code for the mo_references Drupal module stopped working.

It took me some time, especially because the code seemed to work just fine as all the files could easily be displayed.

Actually, that was not the case. The unpack() character 'a', which I used, was transformed from a simple string that gets trimmed, to all the characters, including the NULL characters. Ouch! Now we have to use the 'Z' character instead.

I use it to unpack() a tar file by loading 512 bytes of data in a ...

## HP Printer options not offering "Color: Off" option anymore

As I upgraded to Ubuntu 13.10, I noticed that I lost the option to turn off the color when printing.

Looking around all the available options, no one to make it black and white (although the old option was saying something like: Color: Off; it was somewhat weird.)

Now that option is completely gone. There is no way for me to turn off my HP Printer color when I am in Acrobate or LibreOffice. I searched on the Internet to see whether that was just HP trying to get you to use colors on your printer or whether the option was available... somewhere else.

Indeed, I had to go to the System ...

Somehow my NVG 510 broadband light started blinking red a couple of time in the last few days. I've been wondering why and I think I have the answer now.

In most cases it may just be that the broadband signal disappears for too long and the modem disconnects.

However, in my case, I think it was because they made an upgrade (a push!) on the modem because a few things do not work as expected anymore. (i.e. I cannot access the nsh shell anymore...)

Whenever software is upgraded, the likelyhood that you have to reset the whole thing is very high. I had to restart twice and even after that, ...

## Useful online network tools

I'm starting this page and hope to think about it again at a later time when I find additional tools... but as I have network problems I often need these types of services to make sure I can get the information I need.

For more Network stuff, click on the Network tag!

http://alexis.m2osw.com/nvg510/my-ip.php [Super clean version!]

### What is my DNS?

This one is for people who setup a DNS to make sure that it can accessed from all over the world. It ...

## Creating a drive mirror with LVM, including exact partition cloning

LVM today can create a mirror of your data without having the need for mdraid (or hardware raid).

Problem is, I did not find any documentation that makes sense and there doesn't seem to be a graphical interface that can help you with that (at least not under Ubuntu Gnome.)

So... I decided to spend the time because that's probably less time anyway than trying to create and maintain and md device.

The fact is, it is rather simple, but requires quite a bit of knowledge.

### Copying the Partitions Exactly

First, I wanted the partitions to be exactly the same and using fdisk did not ...

## Getting Ubuntu to playback DVDs

In order to playback a DVD you need to make use of commercial encryptions (also called codecs.) Actually Ubuntu calls them "non-free". The reality is these are patented and protected so people cannot just ripoff a DVD. Which is not true at all since pretty much any computer can play DVDs and thus can copy all the data. Anyway, because Ubuntu is by default for free software, it doesn't include all the necessary DVD stuff. This being said, they provide 100% of all the necessary code, pre-compiled and all you have to do is install it all with apt-get as follow.

(You must be root to ...

## Strange VC error: No files were found to look in. Find was stopped in progress.

Strangest thing happened to me today! I'm working on a project with VC 2005 (yeah! pretty old version for 2012, I know!)

I use the Search in files which usually works great but today I got this strange error:

No files were found to look in. Find was stopped in progress.

And no real reason why it would say that!?

Searched on the Internet and found a page mentioning the problem.

When searching it is possible to stop the process with Ctrl-C or Break or, it seems, Ctrl-Scroll Lock.

In my case my bag was a bit on the keyboard pressing on one or more of those keys! Moving my bag was ...

## Drupal paths that won't work!

As I created a new site to list all of my accounts on the Internet, I thought the folder where those accounts appear should be called profiles. But somehow autopath did not generate the URL Alias as expected.

http://www.alexiswilke.me/profiles/

I tried several times and each time it returned an empty alias. Then I tried adding the alias by hand and that was accepted by Drupal, but when I then tried to go to that page it failed with an Apache error which at first I found odd. Then I recalled that there was a folder named profiles in the top directory of Drupal. The Drupal code (from the

## Norton Anti-Programmers

Today I discovered why I was having a few hurdles last week.

The IT department pushed the installation of Norton Anti-virus with some Internet controls, whatever the exact name is...

The utility installs itself intrinsically in the operating system. This means it actually transforms a certain number of low level functions to manipulate your data files and check them as soon as they are created.

The potential results are that as your compile files:

1. The file may be found to be locked (Norton locks it to verify it even if the compiler isn't finished.)
2. The file may be removed ...

## Skip Postgrey test with a Postfix restriction map

By default, when postfix is installed with postgrey, all the emails that are not blocked by some other means are all passed to postgrey.

What if you have a customer who doesn't want to wait forever to get his/her emails?

Well... you need to bypass postgrey (and good luck to him/her in regard to heavy spamming...)

The setup requires two additional entries as defined here:

# in main.cf
smtpd_restriction_classes = permissive
permissive = permit

Here we define a new class called "permissive" (which is case sensitive!) and that we will use in the restriction access file.

## Diverse Realty

Want a New Home?

Call Alex at
+1 (916)
220 6482

Alexis Wilke, Realtor
Salesperson
Lic. # 02024063

Cory Marcus, Broker
Lic. # 01079165

## Terms of Site Index

Find the page/content you are looking for with our index.

• favorite
• fix
• multiple
• number

All software make use of numbers. Everything is a number. The most basic number in a computer is 0 or 1. This is called a bit. These are represented with electricity. Although in most cases we see it as 0 - Ground and 1 - Voltage (i.e. 1 volt), the bit representation in software and in hardware may be interpreted either way (i.e. a 0 could mean that the voltage is 1V and not 0V.)

Combining these zeroes and ones we offer end users to handle much larger numbers. With 8 bits, you can have numbers from 0 to 255 (unsigned) or -128 to +127 (signed.) Now a day, computers can handle a much larger number of bits in one cycle. Most processors use 64 bits but they can calculate numbers on 128, 256, and for some 1024 bits at once. Also with parallelism, the size can be viewed as even larger (i.e. handling a 64 bit number in 1,536 threads like on my old nVidra Quadro 600 is equivalent to one large number of 98,304 bits! That would be 2 power 98,304 possibilitie or about 2.8359e+29592 in decimal.)

Integers are easy to handle. Although when working on math problems you generally see the set of avaialble numbers as equivalent to N although mathematicians know that computers can really only handle a limited set of numbers. For example, on a 64 bit computer, the usual range is -9223372036854775808 to 9223372036854775807, This is generally enough although at times some equations have to be reworked to avoid really large or small intermediate numbers that work fine in math equations, but not so well on computers.

Now, math also includes other sets of numbers such as D, R, and C. Computers do not offer any way to represent numbers in R or C but they can offer D to some extend. These numbers are called floating point numbers because we do math using an exponent. The exponent makes the decimal point "float" in any location as the number used for the exponent offers. Using a 64 bit floating point, you can have positive and negative numbers with precision varing betwee 10-308 and 10+308. This includes a positive zero (+0) and a negative zero (-0), which is import in a few cases (although +0 = -0 is true, you can get the sign of a number and distinguish both zeroes). Note that at first decimal numbers were going to also have a positive and negative zero, but it was instead decided to have one more negative number (remember, with 8 bits we have signed numbers from -128 to +127, this is because in the positive numbers we have a 0 which we don't have in the negative numbers.)

• programmer