Linux Kernel

Linux Hardware and Software Layers

There are four main layers with Linux which are monolithic and are tied into the one system. The base layer is the hardware which can talk through the kernel, using it to interact through drivers for the software to function. The next layer is the kernel which acts as a bridge between the hardware and the software.

The next layer of this Linux hardware and software stack is the Shell which is normally Bash. This is where the Command Line Interface (CLI) commands are used and talk through to the kernel to manage the hardware. The top layer is the user interface where the user uses the Graphical User Interface (GUI) for things like web browsers and text editors.

Linux is Monolithic

The way that Linux is monolithic is tied to its architecture. This architecture is designed to have all core services run together as a group in a Kernel Space. This Kernel Space is something that is a privileged and highly secure area of memory. This design is making Linux fast and efficient based on lower delays between core services.

The other type of kernel is called the Microkernel which uses a user space on certain operating systems like Minix 3 or the Apple IOS which uses XNU that is more of a hybrid kernel. X not Unix (XNU) is a specialized hybrid monolithic and microkernel that is used by Apple to provide the benefits of both types of kernels.

Four Main Jobs of the Kernel

These are managing device drivers, system calls, process management, and memory management. Device drivers are the actual assembly code for each of the items of hardware that talk between the hardware and the kernel. System calls are the actual requests from software to specific hardware for things like writing data to the disk.

Process management is where the kernel decides what process gets run and how long it can be in the CPU. The memory management function of a kernel is where the kernel decides how much RAM and for how long it stays in memory. The kernel has more functions like preventing and mitigating conflicts in processes and acting like a superuser to manage security and resources needed to perform tasks.

Conclusion

The kernel is a concept that doesn’t get talked about enough. This concept of a kernel is the essence of Linux which in reality is more a kernel than an operating system. You can get more in depth into this topic by including them in your studies. Studying has saved me more time on certification exams and will be something that will allow me to remain consistent. Study well guys and be a lifelong learner.

Information Technology Roadmap

Information Technology Roadmap

There are some aspects of information technology that are more relevant for building a career roadmap. Depending on how you want to go about it you can tailor your roadmap to the IT career that you want to be in. This roadmap will help guide you in your career. When setting up a roadmap there are things that you will want to do like getting a broad IT skill set that will help you in your career.

Roadmap

The way that I went about it was to do the CompTIA ITF+ and then the A+ was next. The things that I was doing would correlate with the Tech+ and the current version of the CompTIA A+ exam. I would also recommend putting in at least one cloud certification like the AWS Certified Cloud Practitioner or the AZ-900.

I did this to understand more about the underlying technology in hardware and software components of PCs. This has helped develop more skills as I now hold ten certifications in IT. The path that I am taking was thought out more along the fundamental pathways for Azure, AWS, Linux, and Cisco certifications.

My Own Roadmap

I want to be able to help guide your journey and allow you to see how I am going about my own roadmap. You don’t necessarily need to have ten certifications, but you would need both skills and certifications. The reason that I am going about doing these certifications is so that I can tailor my roadmap more towards a CIO, CTO or CISO job role which is something that would need deep technical knowledge.

One of the things that I am doing is focusing more on the Cisco and Microsoft technologies before other certification paths. This will be something that can help with Cloud Networking and Network Security which are two of the subjects that I am pursuing. Later on I might do Network Forensics but want to save that for future studies.

Building Your Roadmap

For your own roadmap, I would recommend that you start with the fundamentals and get a wider view of Information Technology. This should be before you decide what skills and certifications you would need to have on your own roadmap. Going broadly in IT has helped my own business as I can do more roles as needed and understand the technical side of my content writing business.

Conclusion

Giving something back is what the next part of my journey is about. This advice to tailor your own career by tailoring your roadmap will help in your career journey and future in IT. By taking the time to understand and plan what you want to do with your career you can gather the skills and certifications needed for your career.

History of Linux and FOSS

 History of Linux

For the history of Linux, it is best to understand more about Unix. Unix was made in 1969 by Bell Labs by Ken Thompson and Dennis Ritchie. It was intended to be a multi-user system and was rewritten with C in 1973 for portability. Unix was released to the public by Bell Labs with Version 6 in 1975 for general use. 

In 1983, Robert Stallman created the GNU Project to create a free Unix- like system which is something that Linux eventually evolved from. Linus Torvalds started Linux as a personal hobby project back in 1991. This was a similar model to the GNU Project and was licensed under the GNU General Public License.

In 1992, the GNU Project and the Linux Kernel were merged under the GNU GPL which allowed for an open-source version of Linux. There are different distributions that came out like Debian and Slackware in 1993 allowing for more distributions and flavors later on. There are three main distributions today that most Linux systems are derived from. They include Debian, Red Hat and Arch Linux mainly, which are where the different flavors originate from.

History of FOSS

FOSS is something that grew out of the general cooperation of building software in the 1960’s and 1970’s. It was built on the concept of free software which Robert Stallman’s GNU Project and Free Software Foundation helped with the development of Free and Open-Source Software later on using Linux and other distributions. The Free Software Foundation was made in 1985 by Robert Stallman.

In 1998, the term open-source was coined by the Open-Source Initiative which helped the development of different companies and organizations contributing to other open-source projects in the corporate world. This is something that is happening still today. Linux is used heavily in web servers, cloud computing and in mobile devices like Android.

Knowledge Byte

The history of Linux is something that I have studied for in college and also when studying for the LPI Linux Essentials certification that I have. There are some ways to study for the Linux Essentials which include a study plan, having three or more resources and also keeping a schedule of each section that you have selected for your study sessions. It is also good practice to eat healthier and get enough sleep, so you are not having issues with energy or your mental health.

Conclusion

These are some of the events that contributed to Linux and FOSS. There are companies that continue to contribute to open-source projects like Git and Apache Server. The development of more distributions and flavors is getting Linux to be a more portable operating system than Windows. Linux is now used to power corporate systems and supercomputers along with embedded systems.

OSI Model vs. TCP/IP Model

 The OSI Model (Open Systems Interconnection) is essentially a reference model that helps IT technicians understand the different layers. For the TCP/IP Model, this is the Transmission Control Protocol/ Internet Protocol that is a functional model and is how the layers actually work. There are seven OSI layers compared to the four TCP/IP layers. The OSI model was made by the International Organization for Standardization as a conceptual model.

OSI Model

The best way to think about the OSI Model is to break it down into layers. These are from the bottom to the top and starts with layer 1 which is the Physical layer, layer two is the Data Link layer, the Network layer, Transport layer, Session, Presentation and layer 7 which is the Application layer. By using the Please Do Not Throw Sausage Pizza Away mnemonic you can remember these layers.

The Physical layer is the actual hardware, cabling, and wireless mediums and uses encapsulation to go to the Data Link layer which are frames. The Network layer uses packets and encapsulates the frames into packets. By the fourth layer, the Transport layer, the packets are encapsulated by ports.

With the Session layer, the ports are encapsulated by sessions which interact with layer six to allow for encryption and then the Application layer which is by that point data. By understanding these layers, you can understand more about what the TCP/IP Model is about and why it is easier to troubleshoot with the OSI model. The OSI model is also used by vendors that create hardware and software to be interoperable.

TCP/IP Model

In the TCP/IP Model there are four layers which are the Network Access layer that corresponds to Layer 1 and 2 of the OSI Model, the Internet layer for Layer 3, Transport layer for layer 4, and the Application layer which corresponds with layers 5, 6, and 7 of the OSI Model. This model was developed by the Department of Defense and is a practical standard for internet communications.

Conclusion

By learning more about the OSI and TCP/IP models you can understand how to troubleshoot more effectively. There are some encapsulation and decapsulation items going up and down the TCP/IP stack at the same time. This allows for effective communication across systems. When you understand this at a deeper level you can go for more advanced certifications like the CCNP or even the CCNA.

NAT Types

 Network Address Translation

There are three different types of NAT which are Static NAT, Dynamic NAT, and also Port-Address Translation which is also known as NAT Overload. Static NAT is a one-to-one mapping of an internal private address into a public address. These types of NAT are some of the main types and there are some others like gaming types of NAT that I will not go over in this blog post.

Dynamic NAT is a one-to-many mapping with one private address and many public addresses. The Port Address Translation is used with a single public address and multiple private addresses. PAT, also known as NAT overload, is used mostly by home routers and is the most common type. PAT is done using port numbers for each session that is connected by each IP address.

Static and Dynamic NAT

The static NAT type is used mostly by people hosting a server in a private network behind a firewall or router. The dynamic NAT type of Network Address Translation is used by companies to map their IP addresses. This results in a one private IP to multiple public IP addresses. This is most commonly done by companies with larger networks.

Knowledge Byte

There are some things to work on regarding computer networking certifications. The certifications that this will help with the most are the CCST Networking and the Network+ certification. Certification study is one of the best things that you can do for your career and will help you get better jobs over time along with some education.

In order to understand a book or course you would want to section off the information in a study plan and be consistent in order to finish the study plan before taking one of these exams. With a study plan there is built in consistency, and you will want to keep pace with your study sessions. This is in order to pass the exam or class that you are in. If you stick to your plan, you can make it better or do better things with it next time.

Conclusion

These types of NAT are the main types and will help you out on exam day if you can put in a solid study plan along with some reading. I do have the CCST Networking and the CCNA along with other certifications and this information has helped me with those exams. When working on a study plan it should include some reading, practice, and thorough online course study.

RAID Types and Uses

There are different types of RAID which is Redundant Array of Inexpensive Discs. The more common ones include RAID 0, which is striping, RAID 1 which is mirroring, RAID 5 which is distributed parity, and RAID 6 which is dual parity. There are also combinations including RAID 10, RAID 50, and RAID 60. More combinations are used, however RAID 2, 3, and 4 are considered obsolete in favor of RAID 5 and 6.

RAID 0

RAID 0 is also called striping and is where data can be split between drives and can improve Read/ Write functionality. This provides better performance. This is something that doesn’t have redundancy just better read/ write speeds for things like cache or temporary data.

RAID 1

RAID 1 is mirroring which allows for some redundancy and clones the data providing higher levels of redundancy. There are some things that it works best on like databases, and critical drives. With a minimum of two drives needed it provides the highest security of critical systems. Although there is a reduction of 50% storage capacity.

RAID 5

This RAID is used for distributed parity where the data is in a good amount of speed and storage capability. The best use for this is for file servers and any storage that is needed. With three drives needed at a minimum there is an allowance of 1 drive failure that can be tolerated. This provides the best balance of any RAID type. 

RAID 6

RAID 6 is also known as double parity where there are four minimum disks that can be used for RAID 6. This improves on the RAID 5 and is used more for higher protection on larger systems. There are two failures allowed on this RAID type.

RAID 10, RAID 50, and RAID 60

The RAID 10 type has been done mainly for both the striping and mirroring capabilities, high performance and high redundancy. This is helpful for enterprise databases and servers. RAID 50 and 60 are both used to provide high performance and either distributed parity or double parity.

Conclusion

Using RAID is something that you will learn in the A+ exam training materials and is for the computer hardware and virtualization modules. Choosing your RAID type is something that is per the situation that the company has and the policies for choosing the RAID level. It is also what is best for the equipment. The main thing is remembering the different types of RAID and what situations they are used for.

Cloud Concepts

 Cloud Concepts

There are three main types of cloud computing services. These are IaaS, PaaS, and SaaS which are Infrastructure as a Service, Platform as a Service, and Software as a Service. There are also different types of cloud computing platforms. These platforms are generally put into Private Cloud, Public Cloud, Community Cloud, Hybrid Cloud and Multi-Cloud types.

IaaS, PaaS and SaaS

Infrastructure as a Service is characterized as the service for people who want to control their operating system, applications, security, and any data that they have while letting the cloud provider handle all of the physical security, firmware updates, networking and cabling and things like that. Platform as a Service is used generally for an application development platform provided by a cloud provider.

In a PaaS solution, the cloud provider handles the operating system, operating system patches, security issues and all of the IaaS components that are below the operating system. This essentially leaves the application, application security, and data up to the developer. In a SaaS environment, there is essentially everything except for the data and some application security issues that the cloud provider takes care of.

Cloud Platform Types

Private Cloud is a type of cloud platform where the company owns the cloud infrastructure and hosts an internal cloud that is private. Public Cloud is where a company has infrastructure and services on a public cloud service provider like AWS, Azure or GCP. In a public cloud the infrastructure is shared with multiple tenants.

Community Cloud is where there is an industry or some common community of companies that use cloud infrastructure or services. Hybrid Cloud is a cloud platform type that uses more than one type of cloud platform like public and private cloud. The multi-cloud is where there are two or more cloud providers or cloud platform types available.

Conclusion

Knowing how the cloud is structured will help you with your studies of cloud computing. There are multiple cloud providers like Amazon Web Services, Microsoft Azure and Google Cloud Platform. Knowing more about them can help in getting certain cloud certifications like the AZ-900 or the AWS Certified Cloud Practitioner certifications.

These cloud concepts can help on any cloud related certification exam. The way that you can calm some of the anxiety around studying for certification exams is by knowing the material through diligent and consistent practice. Other things like diet, exercise and sleep play a role in the study plan completion. I currently hold the AZ-900 exam and am going for my AWS Certified Cloud Practitioner certification later in March 2026. This will be my tenth IT certification, so I am excited about it. Use the certifications that you want to go for as steppingstones on the way to your career goals.