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Politecnico di Milano FACOLTÀ DI INGEGNERIA DELL ’INFORMAZIONE Advanced Operating Systems A.A. 2014-2015 – Exam date: 9 September 2015 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 It is not allowed to leave during the first half hour, the task must still be returned, even if it is withdrawn.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 two following schedule strategies, Rate Monotonic and Earliest Deadline First, showing also their possible weaknesses and value. 1/10 Question Q2 A 16 bit microcontroller has an 8 bit GPIO port, controlled through the following registers: Bit access modes:  rw = software reading and writing is allowed PORTA_DIR: Address: 0x01a0, Initial value upon reset: 0xff This is an 8 bit register used to configure a pin as input or output. 7 6 5 4 3 2 1 0 D7 D6 D5 D4 D3 D2 D1 D0 rw rw rw rw rw rw rw rw  Dx: Set this bit to 1 to make the corresponding GPIO an input, set it to 0 to configure it as an output PORTA_PIN: Address: 0x01a2, Initial value upon reset: undefined This is an 8 bit register used to write to output pins and read input pins. 7 6 5 4 3 2 1 0 IO7 IO6 IO5 IO4 IO3 IO2 IO1 IO0 rw rw rw rw rw rw rw rw  IOx: If the corresponding pin is configured as input writes are ignored, while reads reflct the GPIO…