Each digit in octal is 3 digits in binary, so 0₈ is 000₂, 1₈ is 001₂, … 7₈ is 111₂. Because it is simple to convert octal to binary, I would suggest that you convert octal to binary and then to decimal or hex.

Unix style operating systems use octal to define file permissions. Each file has a 3 octal digit code. The first digit defines the user’s permissions. The second defines the group’s permissions. The final digit defines everyone else’s permissions.

These permissions are based in binary. The first digit is to allow reading of the file. The second digit is to allow writing to the file. The third digit is to allow execution of the file.

A file with permissions of 777 allows everyone to do everything, while 664 allows the owner and group to read and write, but everyone else only gets to read the file.

Check back Wednesday for a discussion of binary truth tables.

Home work:

Convert the following from octal to decimal:
777₈
377₈
664₈
1234567₈
7654321₈
111₈

How do we have 16 digits? Simple, hexadecimal uses the digits 0-9 and the letter A-F. 0-9 is the same in hexadecimal as decimal. The digits A-F in hexadecimal are 10-15 in decimal. Here is a conversion chart of single digit hexadecimal:

Hexadecimal, sometimes simply called hex, is very easy to translate to and from binary. This is because each digit in hex is 4 digits in binary. All you have to do is replace the hexadecimal digit with the binary equivalent. For instance, the number FF₁₆ is 11111111₂.

Converting a binary number to hex works just slightly different. When you convert a number from hex to binary, you can work from left to right or right to left. When you convert a number from binary to hex, you must work from right to left. This is because a binary number might not be the correct length to work from left to right.

That’s all for today, check back Friday for Octal, or base 8. Here’s some homework:

Convert the following hexadecimal numbers to binary and decimal:
A2₁₆
FFFFFF₁₆
100₁₆
CCCCCC₁₆
A2B₁₆
FA6F₁₆
123₁₆
321₁₆
1000₁₆
10000₁₆

Here’s how to do it. Write 2₁₀ binary numbers down, say 1111₂ and 111₂. Make sure to align them on the right, same as you would to add decimal numbers. This should be on your paper/notepad:

 1111
+ 111

Starting from the right, add the first two digits. 1₂ + 1₂ is 10₂, so write 0 as the right most digit and carry the 1.

Moving on to the next digit, 1₂ + 1₂ + 1₂(carried) = 11₂, or 3₁₀, so write 1 as the next digit and carry the 1.

Third digit is the exact same. 1₂ + 1₂ + 1₂(carried) = 11₂, or 3₁₀, so write 1 as the next digit and carry the 1.

For the Forth digit, 1₂ + 1₂(carried) is 10₂, so write 0 as the right most digit and carry the 1. Drop down the carry, because 1 + 0 is 1 no matter what base you are working with. There’s the answer.

 1111
+ 111
-----
10110

Checking the solution is as simple as opening Windows calculator. If you’re not in scientific view, switch to it from the view menu. Select “Bin” for binary mode. Then put in the math problem, same as any other. Now that you know about calculator, try not using it.

Vocab: A digit in binary can be refered to as a bit, so 64-bit, means 64 binary digits.

Homework:

Create 8 or 9 random binary addition problems. If you want to make it hard, write out 64 digits, or bits, for each binary number.

Before I cover conversion, let’s talk for a second about bases. That’s what this series boils down to. I’m not talking about military bases, but number bases. Binary is base 2, meaning that there are 2 digits. Because decimal uses 10 digits, it is base 10.

When a number is of a certain base, you denote that by putting a subscripted 2, or 10, immediately after the number. So 100₂ means 100 in binary, while 100₁₀ means 100 in decimal. If you don’t fully grasp this, I’m sure you will once you finish the exercises for today.

So, we all know that 1₂ is 1₁₀, but what does 10₂ equal in base 10? It’s 2₁₀. Check out this chart:

For every extra zero on the binary side, the decimal side doubles. This is because binary is base 2. You can say that, counting from the right in binary, each digit placement is worth double the previous.

You can use this chart to convert a binary number to a decimal number. For every 1, add the decimal equivilent. For instance, the number 111₂ is 1₁₀ + 2₁₀ + 4₁₀ which is 7₁₀. Another example is 1001₂, which is 8₁₀ + 1₁₀, or 9.

OK, converting binary to decimal is the easier part for today. On to converting decimal to binary. You do pretty much the same thing as converting binary to decimal, but in reverse. The first step is to grab a scrap piece of paper, or open notepad.

To walk through the process, I’ll convert 105₁₀ to binary. The first step is to find the decimal number in the chart that is closest to 105₁₀ without going over, which is 64₁₀. 64₁₀ is 1000000₂, so write that binary number on the first line. The second step is to subtract 64₁₀ from 105₁₀, which is 41₁₀.

Then we repeat. So, 32₁₀, or 100000₂, is the next number. Write 100000₂ on the second line, making sure to line up the numbers on the right side, same as you would for decimal. Then subtract 32₁₀ from 41₁₀, which is 9₁₀.

Then we repeat. So, 8₁₀, or 1000₂, is the next number. Write 1000₂ on the second line, making sure to line up the numbers on the right side, same as you would for decimal. Then subtract 8₁₀ from 9₁₀, which is 1₁₀.

Then we repeat. So, 1₁₀, or 1₂, is the next number. Write 1₂ on the second line, making sure to line up the numbers on the right side, same as you would for decimal. Then subtract 1₁₀ from 1₁₀, which is 0₁₀.
Because, we have reached zero, we can move on the last step. On your paper/notepad should be:

1000000
100000
1000
1

All you have to do is combine these. Starting on the left, any column that has a 1 in it, write a 1, or if the column only has zeros, write a 0. This yeilds: 1101001₂. Converting this back to decimal will let you know you did it right.

Homework:

Convert the following binary numbers to decimal:
1001
1101
10
10000011
10101010
10110010
100011

Convert the following decimal numbers to binary:
37
123
251
6
192
168
68

Remember to convert it back to check your work. Check back Monday when I’ll discuss adding binary numbers.

Binary is simply a number system that only has two digits, 0 and 1. The number system that we are taught all throughout school is decimal, which has ten digits, 0 thru 9. There are other number systems that are used when working with computers as well; hexadecimal uses 16 digits, 0-9 and the letters a-f, while octal uses eight digits, 0-7. Any whole number can be easily represented in any of these numbering systems.

Here’s the binary equivalent of the decimal numbers 0-10:

You may notice that in binary, 1 + 1 = 10. That’s because you have to carry the 1, just like 1 + 9 = 10 in decimal. Once you can wrap your mind around this, you’ll be on your way to understanding binary. Like everything else in life, it just takes time and practice.

Below are some binary numbers to increase by 1:
1001
1000001001001
11111
111000
10101110
101001

Try to add 1 to each of those numbers, if you find it difficult, then re-read the post and try again. If you find it easy, try to count from 1 to 100000000 in binary. BTW, 100000000 is only 256 in decimal.

Check back in a few days for the next part in the series: conversion from decimal to binary and back to decimal.

My first problem was getting the oil drain plug to budge. Luckily, my Dad had taught me a trick to loosen a lugnut. It’s a lot easier if you slip a pipe over the wrench and pull/push on the end of the pipe. This worked like a charm! The computer equivalent: There’s usually a plastic tab, which may take searching to find, that will release the component.

Problem #2: I bought the wrong oil filter wrench. This was easily fixed by going back to the parts house to get a different wrench. 99.9% of the time, computers use philips head screws, but every once in a while you’ll need a flat head or allan wrench.

Once everything was done, I cranked up the car. To my dismay the oil light kept blinking. A quick check of the oil dipstick showed there was too much oil! I drained some out twice and everything was fine. Having too much oil is like having too much RAM. All computers put a max on the amount of RAM. The difference is that if you don’t check, you’ll never know.

In the end, I learned a lot. I learned that changing oil isn’t as easy as people make it look. I also learned why a lot of people don’t work on their car or their computer. If you do repair something correctly, which isn’t hard to do, you beel a grand sense of accomplishment.

Don’t let this article diswade you from attempting to repair your computer or your car yourself. Sure, I had trouble doing the most basic of maintenence, but have you ever met anyone who got everything right the first time? If you know of someone like this, please let me know.

I would like to thank my sister-in-law, Robin, for her help on the phone. You truely are a life saver!

If you have cable internet, the signals come into your house over the cable lines. The cable modem converts these signals into an ethernet (looks like a wide phone jack) connection.

If you have DSL internet, the signals come into your house over the phone lines. The DSL modem converts these signals into an ethernet (looks like a wide phone jack) connection.

From the ethernet connection, the internet travels to your router. The router does several important things. It acts as a firewall, blocking people on the internet from accessing your home network. It provides any computer directly connect with a unique IP address which helps the router know what computer is sending/receiving data from the interent.

An IP address is a set of 4 numbers, each 0-255, which identifies a computer on a network. The router uses something called a subnet which is just a group of IP addresses. Most routers use the subnet 192.168.0, which includes all the addresses from 192.168.0.1 to 192.168.0.254. The router is the 192.168.0.1. These addresses might not be the same as your router is using because every router is different.

Because the router has a firewall, you don’t need a firewall on any computer connected to the router, wired or wireless. That means that Windows won’t have to work as hard to protect your computer because you can turn Windows’ firewall off.

A home network isn’t limited to only having computers. A printer can be connected to the network instead of to a computer. After installing the printer software to a computer connected to the network, you can print from another room! A VOIP (Voice Over IP) phone, such as ViaTalk or Vonage, can be connected to the router as well. The list doesn’t stop there either.

Most corporations do not use Linux because they think the change over will cost them a lot of money. While this may be true for almost any large bank of computers, the cost in the long-run is much better with Linux than Windows. Cost is only 1 benefit of changing over to Linux.

Another benefit is security. Almost every program designed to run on Linux is created by the community, so bugs and security holes are found and fixed quicker than Microsoft can do it. The updates can be pushed using a free program found on the internet and installed on every machine, or individual ones.
The change over does require some user training, but it’s pretty simple to learn. At my work, we use a lot of free software that is available for Window and Linux; however, we run Windows on all our machines, except the web servers which run Linux.

Most people will use an app for business, another for email, and a basic web browser. If the business app was written for Windows, the change over cost can be astronomical, but if the app is web based, the change over cost is minimized. Email is email and the web is the web, no matter what program you use to access it.
Watch out though! Sarbanes-Oxley entangles Linux with a lot of red tape. This is mainly due to the fact that the CEO is personally responsible for all reporting of intellectual property information as well as all financial information.

If a corp is simply using it as an OS, the red tape is only a couple of levels thick. If anything is modified, the layers of red tape can amass pretty quickly. This is due to the wording of the GPL, the most common open source software license for Linux programs.

I asked the tech guy at my work if we could do a change over and he said it would be a bunch of red tape, mainly due to the rewriting of policy and building desktop OSs from scratch. I agree with the building the OS from scratch, which I have done before and is pretty simple once you’ve done it a few times. Policies need to be rewritten anytime an OS change over takes place, so go ahead and make the policies!

Anyways, for any corporation just starting out, go with Linux. It’s a lot cheaper than Windows, $0 vs. $300. It can be a pain to set up if you are not familiar with it, but you’ll save $300 per machine. That’s enough to pay someone for 30 hours of work at $9.29, $0.71 is taken off the top for business paid FICA taxes. Plus if you buy all the same machine, once it’s setup on one, you can simple copy hard drives to get it on all the other machines.

The legality of emulators has always been a big debate. For the most part, if you own the physical game, then it is perfectly legal to have a backup copy on your computer. The legality of the actual emulator is a bit more complicated. Most emulators were written from the released specs of the system and the trial and error method of getting games to work.

Emulators are illegal if they reverse engineer the system software, called the BIOS, that runs on the gaming console. There are other aspects of emulators that may or may not be legal. I am not an authority in these aspects, so I won’t go into it here. My best advice is to contact a lawyer if you feel that something isn’t completely legal.

The games that you own can be easily downloaded using a P2P file sharing program. Again, it is perfectly legal to have a backup copy of anything that you own, so downloading this stuff won’t get you into trouble.

If you’re ready to start enjoying the games of yester-year, hop over to Google.com and search of SNES emulators, or whatever console you want. Just remember that neither I, nor this site, take any responsibility for your actions what so ever.

I knew how to enter a program and load and run a program almost instantly. Programming, on the other hand came very slowly. I was constructing my own programs by the age of 8. I started to work on a Monopoly program, but it never came into fruition. I got to the point where the board would be displayed and the dice would roll random numbers, but never got any further.

I wrote other little programs, most of which I cannot recall any more. I do recall fixing my brother’s program once. He was enrolled in a computer course at a local college. He was writing a small program that rolled a die, but the die always rolled in the same sequence. He forgot one line of code that gave the random number generator a seed. A random number generator needs a seed, normally set to the time, to generate different results each time the program is run.

In late 1992, my parents purchased an AST 486DX computer. It cost over $2000, a big change from today’s computer prices. I quickly found the program to run custom programs and off I went to create more programs, most of which I do not recall, but still have backups of somewhere. Hey, 16 years is a long time and things get shuffled around too much to keep up.

That is, in a nutshell, how I got started programming. When I started, I knew that was my calling. I am thrilled to have a programming job now. It took me a while, but here I am.

One of the things I love about computer programming is that it is an always changing field. There is always something new to learn, every day. I would just like to thank my uncle for showing me the door. Without that, I would probably be in a completely different field of work.