The context of these two texts is one that is used to shape so much of the theme, plot and character of the two texts. Orwell's classic is set very firmly in the year 1984, though, as Winston reflects, it is unsure as to whether this is the actual year, or whether time itself has been mutilated and adapted by the Party for its own purposes. Note what Winston tells the reader about the context of the novel, however:
This, he thought with a sort of vague distaste--this was London, chief city of Airstrip One, itself the third most populous of the provinces of Oceania. He tried to squeeze out some childhood memory that should tell him whether london had always been quite like this.
London in this novel has therefore been transformed to a grey, bleak, dilapidated city with plenty of signs of bombing and destruction. The context is one of massive fear, as Winston and other characters are shown to live in a world where they may be watched at any moment and nobody is safe.
The context of The Matrix is again some future time, except the changes in the context compared to the present are much more drastic. Human civilisation as we know it has completely ended, and anything resembling our world has vanished. Humans are merely farmed and kept in a state where their heat and electrical activity can be used by the computers that control them as an energy source. The only free humans that remain live as rebels, deep under the surface of the earth, and the rest live under complete control of the computers, who create a digital world that they are inserted into in order so that they do not become aware of their true state.