I've been looking into the history of computing. I'm just wondering if Mainframes & Minicomputers are still in use? I mean now a days PC's are very many times faster than mainframes in 90s. Even http://en.wikipedia.org/wiki/Google_platform doesn't say anything about mainframes. They also use PCs as their servers.
I've no idea about Cloud Computing.
According to this article, mainframes were definitely alive 2008, and I don't think the situation has changed much since then.
Yes, banks, businesses, and especially government institutions still use mainframes. (Heck, they still use COBOL).
The cool ones are now called "Supercomputers".
But, companies like IBM still sell more mundane mainframes.
I was a mainframe programmer until about 3 years ago, and my former colleagues in my former department still work with those machines. They serve vital roles in the reservations and check-in processing for some large airlines.
Something interesting to note is that, while languages and other tools have arisen that allow developers to create very complex software, this has also raised the complexity of the task and customers' expectations. Also, modern management seems to be all about cost-cutting.
Given overly complex tasks and unrealistic time and budget constraints, very often development teams these days fail to successfully complete projects. Thus, while successfully executed modern projects may have much more functionality and "coolness factor," project success rates haven't improved since the 1970s.
As a result, a lot of old mainframe systems are still in operation because one or more projects intended to replace them failed. The revamping of the US national Air Traffic Control system, meanwhile (I think) successful, was for many years a nice example of such failure.
Until a few weeks ago I was an architect at a bank; they have 2x IBM 390 mainframes, and they will have them for a very long time to come.
Reason is the applications they run are core banking applications which were written over a 15-20 year period using Natural (that's a programming language) and Adabas (a database that uses the organisational concept of Files, rather than Tables).
They have such a massive investment in these applications that it is going to take them a very long time to move to something else. I'm not just talking code and data, but big teams of mainframe people that 'know the business'.
Given that these are core banking systems and have been very reliable, they have little appetite to move to emulation, or another platform.
Drawbacks of mainframes today are primarily exorbitant support and maintenance fees, and a dwindling skills base in the market.
They also still run VMS, so that's kind of a minicomputer.
Hope that helps.
Another example: German Telekom uses a Mainframe-based system named KONTES designed in the 1970s to manage data about phone lines and customer data. Some auxillary systems have been replaced by more modern architectures, but the core systems are still Mainframes, so huge and complex that no company has felt up to the task of replacing them.
Some banking systems still run in more or less the same configuration in which they were build decades ago. It's not broken so they don't feel the need to upgrade.