Introduction to System Administration
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System Administration is one of the core disciplines of Information Technology and Business Infrastructure and maybe easily be considered to be the core discipline as without systems, there is nothing on which to build anything else; it is foundational to everything that we do in IT. System Admins maybe have had many names over the years, such as "computer operators", "sys ops", or similar but the core discipline has always been the same: the care and feeding of the computer systems.
There is an important distinction which must be made between physical systems and logical ones. Physical systems are the hardware of a computer. Logical systems are the operating systems that run on top of that hardware. Originally computer systems and their operating systems were effectively always one to one and inseparable, so differentiating between the two was pointless. Today, however, the two are wildly different. Today it is not uncommon for system admins to also have some role in maintaining the physical hardware on which their systems run, but this itself is not a system admin task. The "system" in "system admin" is a reference to the operating system, not the hardware. If a system admin also maintains the hardware, that is another hat to wear. In many environments it would be expected that system admins would never see, touch or gain access to the physical systems which they support.
Also worth noting at the highest level that system admin does not differentiate between server and client systems. Desktops, laptops and so forth have operating systems that need to be maintained just like servers do. In fact, one could even attempt to abstract the end user system and consider it a server that is dedicated to the local needs of a single user, in a sense. Tools and techniques used on servers apply to end user client systems as well. But abstracting the concepts properly, applying proper rules of thumb to each, and understanding how concepts apply broadly can be confusing as the two are so often considered separate entities. Also the technology of one tends to trail the other significantly and some standard rules make assumptions about one or the other environment. In this text I will strive to be as inclusive as possible and present concepts in such a way so that they will apply to both or note when they do not. But importantly, the administration of end user systems is as much as part of system administration as a discipline as maintaining servers is.
System administration is easily the most key of all IT roles because it is the most unavoidable. For many years, organizations existed without the concept of networking, but always with systems. Databases are not always used, but when they are there is always a system underneath. Organizations may even exist without servers, but never without at least end user devices and these, of course, are systems.
System admins will come in all shapes and sizes, and work with a broad range of technologies, exist in every market vertical and companies of every size and will merge, blend or bump up against a myriad of other roles. Systems are not going anywhere and while the role of the system admin is always changing, it is also always staying the same. System administration has been around for more than seventy years and will continue to be around for a long time to come. It is a widely varied, exciting and demanding discipline and is both one of the most common, as well as the most potentially challenging, in IT.
The core skills of the system administrator are the same across all platforms and technologies. While most system administrators will spend much of their careers focused on just one or two key operating systems, the majority of job experience and skill will cross nearly seamlessly between different underlying products.
In this book I hope to establish the basic foundation of what it means to be a system administrator, identify the skills and aptitudes that are needed for the whole and explore the fundamentals of the practice without becoming mired in technology specifics. System administration, even at a higher level, however continues to evolve as at only seven decades old there is still much time for techniques and paradigms to arise and evolve. Even system administration has much maturing to do.
