IBM had a very solid mythology built around it - but it was exactly that, mythology. There was technical myth, but the software technology was second rate, even if they did build solid hardware. According to Edsger Dijkstra:
"In my Turing Lecture I described the week that I studied the specifications of the 360, it was [laughter] the darkest week in my professional life. In a NATO Conference on Software Engineering in 1969 in Rome, I characterized the Russian decision to build a bit-compatible copy of the IBM 360 as the greatest American victory in the Cold War."
http://cacm.acm.org/magazines/2010/8/96632-an-interview-with-edsger-w-dijkstra/fulltext
(In this article it is clear there is a difference between European computing and American. European computing is about software and building machines to support software, American computing is about building electronic hardware and inflicting its foibles on software people.)
IBM would do business at any cost:
https://en.wikipedia.org/wiki/IBM_and_the_Holocaust
That is just one specific period of history. For a more general history of IBM from its start with Thomas Watson senior at NCR (where he picked up very unethical practices) through to all its market domineering, monopolistic anti-trust practices read Richard DeLamarter "Big Blue: IBM's Use and Abuse of Power"
https://www.amazon.com/Big-Blue-IBMs-Abuse-Power/dp/0396085156
but this book is very hard to find.
On the following page I review three books about IBM:
http://ianjoyner.name/IBM_Books.html
The three books are
“In Search of Excellence” by Peters and Waterman (1982 Harper & Row)
“Beyond IBM” by Mobley and McKeown (1989 Penguin)
“Big Blue, IBM’s Use and Abuse of Power” by Richard DeLamarter (1986 Pan books)
IBM was built on a myth, not a solid foundation. What it is undergoing now exposes what it always was.