What are some typical questions one might be asked in a Computer Science PhD Viva? I know that you are likely to suggest "Ask your supervisor. He/She will know best.". 

While that is obviously true, I would like to know from your personal experience either as the PhD candidate or as the examiner: What should I expect in my viva?

For example:


Should I expect to be asked about the history of my topic? 
About the research cited in my thesis (i.e references - will they ask me about them? I have over 100...)?
About methods used?
About justifications for my conclusions?
etc


What should one expect, in general, to be asked? I am PhD student in the UK.
There is one critical question that is asked in every Phd viva, be it either directly or indirectly, that is "what is the original contribution of your thesis to knowledge". To be awarded a Phd the result of the research must be to contribute something new to the planetary or disciplines store of knowledge. You must have done something new and know what that thing is.

It is the very purpose of a viva to discover if you know that. Saying "I do not know" to this question can result in a Phd failure.

Other questions will seek to discover if you really understand the works you are citing in your bibliography; have you actually read and understood them and do you know how they relate to your work.

The third aspect of a viva is to resolve any ambiguity that the examiners read into your writing. Which of the possible interpretations of the words and conclusions did you actually mean. You might not have realised that your thesis contained ambiguity but the examiners will certainly find it. They will also seek to expand on or explore elements that are not clearly explained and get you to clarify them.

The answers to all these questions will determine if you have to make corrections to the thesis to resolve these ambiguities or make clarification, or even conduct more research to resolve those matters.

This is written from the perspective of a Phd examiner, both internal and external and experience as an independent chair of such vivas.