28 06 16 1

Pagina 1

Politecnico di Milano FACOLTÀ DI INGEGNERIA DELL’INFORMAZIONE Advanced Operating Systems A.A. 2015-2016 – Exam date: 28 June 2016 Prof. William FORNACIARI Surname (readable)........................................ Name (readable)............................ Matr................................................................. Signature........................................ Q1 Q2 Q3 TOT NOTES It is forbidden to refer to texts or notes of any kind as well as interact with their neighbors. Anyone found in possession of documents relating to the course, although not directly relevant to the subject of the examination will cancel the test. It is not allowed to leave during the first half hour, the task must still be returned, even if it is withdrawn. The presence of the writing (not delivered) implies the renunciation of any previous ratings. Question Q1 Describe the main algorithms for the scheduling of a single CPU with a discussion on the response time to events and their implementation complexity. 1/7 Question Q2 Assume we have a library called Logger. The main purpose of the library is to allow external programs to safely and concurrently write into a system log file (located at “/var/log/mysystem.log”). Here below it is shown an example of log file content: <Fri Jun 24 10:52:12 2016> [E] chrome: Plugin not found <Fri Jun 24 10:52:41 2016> [I] audio­frm: Loading driver... <Fri Jun 24 10:53:11 2016> [I] audio­frm: Driver successfully loaded <Fri Jun 24 10:54:09 2016> [W] installer: Found missing repositories <Fri Jun 24 10:57:54 2016> [D] myprog: Checking input data... As shown in the example each line includes: 1. the current date and time 2. the logging level (D=DEBUG, I=INFO, W=WARNING, E=ERROR) 3. the program producing the log message 4. the log message The…