Questions

The First Generation Computers size was very large. 

Since the First generation computers used 1000s of vacuum tubes that required lot of space made them gigantic in size. Single transistor could replace 1000 vacuum tubes and a single IC chip replaced 1000s of transistors made computers smaller and more speedy.

It is obvious that computers developed with more power, reliability, speed and smaller sizes due to the enhancement of technology.

A bug leakage results when a bug is detected which should have been detected in earlier builds/versions of the application.

A defect which exists during testing yet unfound by the tester which is eventually found by the tester/end-user is also called bug leakage.

A bug release is when a particular version of s/w is released with a set of known bug(s)/defect(s). These bugs are usually low severity and/or low priority bugs. It is done when the company can afford the existence of bug in the released s/w rather than the time/cost for fixing it in that particular version. These bugs are usually mentioned in the Release Notes.