why was the mainframe invented?

Answer 1

It was the only computer of its kind at that time. First it was for experimental purposes, then it was used to develop trajectory information for artillery pieces, and eventually it found its way into business usage.

I've heard that roughly half of the world's IT work is still done on mainframes. They are still around today because, even though they're not sexy and sleek and trendy like network systems are, they are still workhorses that can process huge amounts of data in a hurry.

There are legacy systems that were written to run on these platforms that have worked nearly flawlessly for literally decades. At the institution where I work, I am sure I could find code that was written in the 1980's that is still in use today.

Answer 2

Because it was the first computer and all the circuits were using tubes, so it had to be built on standard frame and panel electronic hardware, like radar or controls for a steel mill. From the time of WWII to the mid-60's all computers were mainframes, then transistors, running cooler permitted mini-computers in the office with dedicated air conditioning ducts and in the mid-70's, integrated circuits allowed desktop computers without special cooling requirements.
Mainframes remain in use because if you dedicate serious cooling you can run very, very fast and deal with huge amounts of data to do bigger problems in the same amount of time (or even in a person's lifetime.)

Answer 3

It was developed as a centralized repository of resoures. The original data server and such.

Answer 4

For many reasons - one of which being the challenge!

http://en.wikipedia.org/wiki/Mainframe_computer