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HP Color LaserJet Pro Multifunction M479fdn Laser Printer

My new M479nfd printer, scanner, fax

Click to get this printer on Amazon.com where I'm an affiliate.

Not too long ago, I ordered a new color drump for my old printer and replaced it. Not very long after that the print simply decided to not print at all anymore. Literally, it would pass the page through just fine but it had nothing on the page. I know it was working since it was printinA picture of my old dinosaur printer, also from HP (an L2550 color laser printer)g just fine the day before and there was still plenty of black ink (it would have had the light on if the black was not enough.)

I'm thinking that may have been a ploy by the manufacturer to push me to buy a new printer...

In any event, ...

Don't Repeat Yourself When Writing Software

Nature tends to repeat itself, or reproduce with similar structure, but code should not.

For a very long time now, we have been using languages that support having functions that one can call. That was not always the case, although even really old versions of BASIC had a GOSUB instruction, which it had no concept of local variables so it was rather difficult to use safely.

Functions allow you to avoid repetition. You write a small snippet of code (or maybe not that small) within a function and then you call that function to reuse that snippet over and over again. Good programmers tend to do that even with one liners. However, many others often think: well, it's just one line, why don't I return copy & paste that wherever I need it, it's going to be faster.

Linux to the rescue!

Xtra-PC, a complete ready to go OS on a thumb drive

Doug and I have always thought that Linux would become the primary OS of today.

We've seen it go up and down, but now it's really becoming powerful, between OpenOffice, Chrome, The Gimp, Krita, Audacity, and many other tools, you can do so much that it more and more renders the expense of running MS-Windows less and less viable for most.

Now there is this new company offering a thumb drive with an optimized version of Linux called Xtra-PC which boots really fast and offers all the basics that one needs to run a computer. There is nothing to install, the OS will automatically detect ...

How small are computers getting?

Mini-computer versus Mouse

Click on picture to see on Amazon.com (which I'm an affiliate of).

Computer Stick

Looking at Mini Computers, I found this Fanless Mini PC based on the Intel Atom Z8350 processor by SmallRT. The picture includes a mouse to give you an idea of the size of that thing. It's tiny! Maybe not what you want, but you can already do a lot with that little one.

The connector on the left side is an HDMI plug which spits out 4K of video graphics. It's just totally amazing to me. Of course, we had the Pi3 and now we have the Pi4... but those are computers for hackers. Here we're ...

Safely Processing a Queue of Jobs

What is a Queue

In software a queue is a container which is used to add items on one side and remove them on the other in a very efficient manner.

Sorted Queues

When used by a Journal, a queue is often going to support some kind of sorted order. Some jobs are more important than others and these should be built sooner. In other words, we give those jobs a higher priority and we sort the queue by priority first then using the time at which the job gets inserted.

Note that the C++ std::queue and std::unque containers do not offer anyway to support a priority. Instead you have to use ...

Docker, an advanced chroot utility

Chasm—just like a Docker creates a chasm between two sets of software

SECURITY WARNING

Before installing Docker and containers with services on your Linux system, make sure to read and understand the risks as mentioned on this Docker and iptables page. Especially, Docker will make all your containers visible to the entire world through your Internet connection. This is great if you want to indeed share that service with the rest of the world, it's very dangerous if you are working on that container service since it could have security issues that need patching and such. Docker documents a way to prevent that behavior by adding the following rule to your firewall:

iptables -I DOCKER-USER -i eth0 ! -s 192.168.1.0/24 -j DROP

This means that unless the IP address matches 192.168.1.0/24, the access is refused. The `eth0` interface name should be replaced with the interface name you use as the external ethernet connection. During development, you should always have such a rule.

That has not worked at all for me because my local network includes many other computers on my LAN and this rule blocks them all. So really not a useful idea.

Instead, I created my own entries based on some other characteristics. That includes the following lines in my firewall file:

*filter
:DOCKER-USER - [0:0]

-A DOCKER-USER -j early_forward
-A DOCKER-USER -i eno1 -p tcp -m conntrack --ctorigdstport 80 --ctdir ORIGINAL -j DROP
-A DOCKER-USER -i eno1 -p tcp -m conntrack --ctorigdstport 8080 --ctdir ORIGINAL -j DROP
-A DOCKER-USER -i eno1 -p tcp -m conntrack --ctorigdstport 8081 --ctdir ORIGINAL -j DROP

My early_forward allows my LAN to continue to work. These are my firewall rules that allow my LAN computers to have their traffic forwarded as expected.

Then I have three rules that block port 80, 8080, and 8081 from Docker.

Docker will add new rules that will appear after (albeit not within the DOCKER-USER list) and will open ports for whatever necessary service you install in your Dockers.

Note that the only ports you have to block are ports that Docker will share and that you have otherwise open on your main server. If Docker opens port 5000 and your firewall does not allow connections to port 5000 from the outside, then you're already safe. On my end I have Apache running so as a result I block quite usual HTTP ports from Docker.

Docker

As we are helping various customers, we encounter new technologies.

In the old days, we used chroot to create a separate environment where you could have your own installation and prevent the software from within that environment access to everything on your computer. This is particularly useful for publicly facing services liek Apache, Bind, etc.

Icecream Locks?!

I like technology, but I think that at times, it just goes too far.

Today I found out that a company is actually selling an Ice Cream Lock. Yes! A lock so people can't easily open your ice cream, at least not without either picking the lock or breaking the ice cream box.

It's a simple lock with a combination and if you don't know that combination, you just won't be able to open the ice cream box. Here are some pictures:

Locked Ice Cream

Click the image to see more on Amazon.com
(Note that I'm an affiliate)

Now, I really think technology is going too far! indecision

Enjoy!
Alexis

Best C++ Books

Once in a while someone will ask me which book is best to start learning programming. The fact is that I do not know because I'm already an advanced programmer and it's rather difficult for me to get back to the basics (it feels like a waste of my time, sorry...)

That being said, at Made to Order Software, we've mainly been a C++ shop. We also do a lot of C, PHP, JavaScript and touch many other languages as required by the tasks we perform (bash, cmake, perl, C#, Java, etc.)

That being said, I wanted to underline some of the best C++ books available today. Especially, in the last ...

Brief Overview of CRISC Certification Exam

The CRISC, also known as Certified in Risk and Information Systems Control, is a vendor-neutral certification that validates a professional’s knowledge and experience in the fields of information system control & risk management. The certificate is developed and administered by ISACA and designed for the individuals who work with organizations in mitigating business risks and implement information system controls.

Organizations in today’s world must consistently enhance their infrastructure so that they can survive and thrive in today’s competitive environment. It is a ...

No more excuses! Protect your passwords on your computer with strong encryption.

More and more, we hear talks about hackers entering personal accounts on systems such as Facebook, Twitter, Instagram and many others. There are many reasons why someone's account will be hacked. One of them is the lack of imagination for their password. Plus, some people use the same password for all of their accounts.

So, if you do it right, you will end up with many passwords. On my end, I have one password per account and that means about 400 passwords... That's totally unmanageable in a fairly standard human brain. For this reason, you end up writing down all your passwords on ...