Relevance of Questions
Being one of those labelled as having a "superior attitude" and having had my post removed I would simply ask "What is the question actually asking"?
Flight at FL430 is given and it is stated "there were cabin altitude alert but sometimes it was alright". "Is it relate to pressure around there or not"? "How can I know that there would be cabin altitude"?
Not knowing anything about the B777 I am unsure of what triggers a cabin altitude alert, however I would assume that a differential pressure which allows the cabin altitude to reach 10000' would. Why do we have insufficient differential? Well, any number of reasons relating to either air supply or flow control, be it pack flow in or conditioned air flow out, cabin pressure control problems. As for the last part of the question I am unsure of what is being asked, however I guess it relates to an indication of actual cabin altitude on a cabin altitude altimeter.
The Tech Log should not be made inaccessible to any legitimate questioner Mr Moderator, but it does loose some relevance with questions worded in such a way as the one which started this thread.