The first real computer was by Charles Babbage, known as the
"computing engine", a system of numerical gears in 1822.
http://www.livescience.com/common/media/video.php?aid=19205
Now if you're discussion pertains to modern computers, it was
during World War II, at Bletchey Park in the UK, and you can read
it here:
http://www.cs4fn.net/history/colossus.php
However, if your discussion is about the history of the first handheld
computer, then follow this timeline:
http://www.islandnet.com/~kpolsson/handheld/
The first computer with a hard drive:
http://kobnet.net/misc/www.cedmagic.com/history/ibm-305-ramac.html
The first computer with a solid state drive?
http://en.wikipedia.org/wiki/Solid-state_drive
The first computer with a 4Terabyte(4T) solid state drive:
http://news.cnet.com/8301-13924_3-10028216-64.html
The first computer to use a graphical user interface (GUI):
http://www.britannica.com/EBchecked/topic-art/130429/19724/The-first-graphical-user-interface-The-Xerox-Alto-was-the#tab=active~checked%2Citems~checked AND,
http://en.wikipedia.org/wiki/History_of_the_GUI
Oh sorry, got kinda carried away.