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Summative Exams are designed not to have a dynamic end time based on when the student started, but instead to have a common end time for the cohort based on what computer lab they are in. Exam timing is initiated on the Invigilator screens. It is designed so that different labs can have different end times. It is possible that in a situation where the same exam is split over multiple labs that some of the labs may not start at exactly the same time. Thus, each lab will have its own record in the log_lab_end_time table. Student client computers know which lab they are in by looking up IP address or machine name in the client_identifiers table and linking this to a lab in the labs table.
Database tables: log_lab_end_time, labs and client_identifiers
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