Red Hat RHCSA, RHCE & RHCA
Oracle Linux OCA & OCP
Beyond the Top 5: More Linux Certs
Certifications for IT professionals working in Linux server environments include an interesting mix of vendor-neutral and distribution-specific credentials from Red Hat, Novell, Oracle and more. Here are the five of the best Linux certs for 2015 .
A Brief History of Linux
Though the birth of Linux didn't occur until 1991, when Finnish college student Linus Torvalds started work on a new and free operating system, its roots go all the way back to the late 1960s at an archetypal research and development facility still known and revered as Bell Labs. Taking a break from building a massive, complex and powerful multi-user OS called MULTICS, Ken Thompson (and later Dennis Ritchie and eventually a host of others) started working on a simple, minimal OS so he could use it to run a favorite computer game of his at the time, known as Space Travel.
Ultimately, Brian Kernighan (another then-unsung luminary also working at Bell Labs at the time) jokingly referred to Thompson's toy OS as UNICS to contrast its minimal simplicity against the massive complexity of MULTICS. Soon after, it became known as UNIX, and it would set the standard for minicomputer (and even microcomputer) operating systems throughout the 1970s and 1980s, until the PC revolution drove different OS designs beneath the UNIX architecture and design philosophy.
But even by the 1990s, when Torvalds got started on Linux, there were plenty of more serious computing needs for multi-tasking, parallel processing, high-volume computing and so forth, that microcomputer OSes simply couldn't handle. At the same time, it still remained too expensive to invest in the hardware and software required to do industrial scale computing. Richard Stallman's efforts with Hurd (a GPL licensed patchwork OS that fell shy of completion) failed to reach critical mass, so nobody ever used that platform much, either.
From the 1970s to the 1990s, AT&T tied up many of the major computer makers of the day in litigation based on patents taken out on UNIX, as it moved into System V releases and beyond. Though the famous Berkeley Software Distribution (aka BSD) did much to open up UNIX and make its inner workings visible, intelligible, and infinitely customizable, those same lawsuits ultimately strangled development and adoption of BSD before the end of the twentieth century.
In short, Torvalds had lots of good reason to assemble and promulgate a free and open operating
system, and every reason to expect that creditable and usable work in this arena would be rewarded by large-scale participation from other developers, and broad adoption from legions of computer users eager to run a powerful, multi-tasking operating system. And of course, Torvalds understood very well that the implementation had to be new, so that there could be no grounds for AT&T to come at him with its legal artillery blazing away. Wikipedia attributes this crucial move to Torvalds: ". if either the GNU or 386BSD kernels were available at the time, he likely would not have written his own. But they weren't, so he did write his own kernel, and called it Linux."
Today, twenty-odd years later, Linux has become a genuine force in the computing industry. While Linux is not widely used on desktops (comprising only 1.25 percent the overall desktop operating system market share in November 2014, according to NetMarketShare ), it is extraordinarily strong on the web server side, where it enjoys a market share of around 54.4 percent (W3Techs ). And it holds a near-monopoly on supercomputers, where its share for November 2014 was 76.7 percent (Top500.org ).
Because IT holds more sway over servers than it sometimes does over desktops, IT professionals tend to invest more of themselves into learning about server computing for everything from installation, configuration, maintenance, virtualization, to application support and so forth. And perforce, this also means that many IT professionals are working with and around Linux operating systems on a daily basis, often alongside Windows and various actual UNIX OS brands as well.
It should come as no surprise that the best of the Linux certifications vie for considerable mindshare among IT professionals, and present an interesting mix of distribution (or brand) agnostic credentials alongside some pretty formidable vendor-specific credentials as well. Nor should anyone be surprised that there are multiple well-elaborated certification ladders available to those interested in devoting long-term time and effort into learning, using, and mastering the Linux operating system environment and all the many bells and whistles it so cheerfully supports.
In Table 1, you'll find the results of a job search we conducted on several popular job boards to see which Linux certifications employers are looking for when hiring new employees. While the results vary from day to day (and job board to job board), this should provide you with some idea of the Linux-related certifications employers were seeking as we wrote this update.
Table 1: Job Board Survey Results