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systems HP-UX, IBM z Series, and others that are difficult to port to commodity hardware (and probably should
not be ported!). Some hardware is almost fault-tolerant, and that is quintessential for some critical workloads. IBM
mainframes for example provide very high reliability
In summary, specialized hardware has its place in the IT landscape, and it would not be wise trying to replace
these. There is only so much evangelism to be done, and anyone who tells you that your special requirement can
be processed with another system should be challenged to prove the assumption. On the other hand, purchasing
a mainframe system just to virtualize apache instances does not seem to be the best value for the money. Most of
today's workloads can be processed by the dual-socket server based on Intel's x86-64 architecture, and there seems to
be a clear trend towards that platform.
The Linux operating (eco-) system
The choice of operating system for the consolidation platform is very relevant, and has a great many implications.
Most companies already have an existing set of supported platforms, and it takes a while for them to change. While
Linux has almost immediately taken off with smaller, dynamic companies right from the start, it had a hard time
getting into larger organizations, and it took longer to find widespread adoption. This certainly changed when the big
players in the Linux market started to provide customers with Enterprise distributions and good support models. This
countered the uncertainty, partly supported by the established UNIX vendors, whether or not Linux installations were
actually fit for enterprise use. Also, large vendors of business-relevant software started to port applications to Linux;
most notably IBM, Informix, and Oracle among many others. This sent a signal to the world: if these heavyweights
support Linux, then it must have reached a state of maturity justifying further investigation into it.
When Linux was in its early days, different ideas about software started to become more visible. Eric S. Raymond
famously brought the ideas of Open Source to the wider public's attention when publishing his essay “The Cathedral
and the Bazaar.” Since then, Linux has come a long way and some of the ideals appear to have been lost over time.
Let's look at Linux, how it started, and why it has become so popular.
A little bit of (UNIX) history
Speaking in greatly simplified terms, Linux is the result of a computer science student's experiment, which has been
continuously improved by a large number of mostly nonpaid volunteers. Most people consider a Linux distribution
as “Linux,” but there is a subtle distinction to be made. Linux is only really the operating system's kernel. The kernel
includes the low-level drivers to address the hardware, and presents an operating environment to the rest of the
ecosystem. Most of the utilities we like, such as bash, tar, and most other GNU tools were ported. Since it is impossible
to explain the success of Linux without going even further back in time to its cousin, Unix, a little wider explanation
needs to be made.
UNIX was written when operating systems were still in their infancy. Multi-user and multi-tasking support,
which are taken for granted today, were certainly not the norm. UNIX meant to change this when Ken Thompson and
many others developed it in 1969 as members of the Bell Laboratories. A child of its time, UNIX was entirely written in
assembly code. This changed a few years later when it was ported to the C language. This was a great step ahead since
it allowed the code to be ported to a larger number of platforms.
One particularly notable element of UNIX was that it (including the sources) was easily available to universities.
This not only included the right to use it, but also the kernel and utilities. Like Linux today, that made for an excellent
academic research object. For a nominal fee, tapes containing the operating system could be obtained and used.
This unique feat is owed to the fact that AT&T, owning Bell Labs at the time, was not allowed to commercially engage
businesses other than telecommunication. Many universities made use of the early UNIX and some even created
their own derivative. A notable example is the Berkeley Software Distribution (BSD) of the University of California,
Berkeley.
The legal requirement not to distribute UNIX commercially was lifted for AT&T when Bell was removed from
the AT&T world in the early 1980s in what will turn out to be a very fortunate event for the UNIX community. This
sounds paradox, but the commercialization as System V (SysV) of the UNIX code prompted researchers to think
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