Real-Time Kernels and Systems Master Degree in Computer Science University of Padova, a.y. 2020/2021 Instructor: Tullio Vardanega

(Latest update: 23 May 2021, 15:05)
[published material of lecture 23]

Outline of course

Learning outcomes

This course aims to familiarize students with the application requirements, the hardware and software architecture, and the principles of execution of real-time systems. As their name suggests, the principal trait of such systems is that their operation is subject to stringent execution-time constraints, and their design and implementation must be proven able to satisfy them.  

The origin of real-time systems theory and practice dates back to the early 1970s, seeking to enable computer-based automation of the real-time control procedures of industrial engines, equipment, and plants. The digitalization of modern service infrastructures has much amplified the need for software-driven real-time control, and consequently the demand for solid education in this field.

The course lectures take the student across the hardware and software internals of real-time systems, to appreciate how concurrency works, how preemption relates to scheduling, how interrupts occur and are serviced, what access control protocols warrant safe and sound concurrent use of shared resources.

Useful reading

1. Real-Time Systems
   Jane W.S. Liu
   Prentice Hall ISBN 0-13-099651-3 (2000)
   
2. Analysable Real-Time Systems - Programmed in Ada
   Alan Burns and Andy Wellings
   CreateSpace Independent Publishing Platform, Amazon Books (2016)
3. Scientific literature
   (see under: "Resources")

Thematic resources

• IEEE Technical Committee on Real-Time Systems
• Real-time for the real world (E. Douglas Jensen)

Ada-specific resources

• GNAT Community Edition 2020 (supplied by AdaCore)
• Ada e-learning course ware

Lecture schedule

Week	Date	Lecture #	Lecture topic	Reading refs
1	01 March	1	Introduction Self-study: Dependability (2.§3)	1.§1-3
	04 March	2
2	08 March	3	Scheduling basics Resources: A model of cyclic scheduling executive	1.§4-6
	11 March	4
3	15 March	5	Fixed Priority Scheduling Resources: Response time analysis	2.§5
	18 March	6
4	22 March	7	Resource sharing Resources: Priority inheritance protocols Resources: Stack-based resource allocation policy	1.§8-9
	25 March	8
5	29 March	9	Recap exercises and further model extensions Resources: A practical implementation of deferred preemption Resources: Generalized fixed-priority scheduling with limited preemptions	1.§6.8,12
	01 April	10
7	12 April	11	Programming real-time systems (in Ada) Resources: ISO/IEC TR 24718:2018 Resources: An example Ravenscar application	2.§16-17
	15 April	12
8	19 April	13	A look under the hood Resources: On the dynamic semantics and the timing behavior of Ravenscar kernels	2.§15
	22 April	14
9	26 April	15	Distributed real-time systems Resources: Worst-Case Dynamic Offsets with Priority Schemes Resources: ARTIST2 video seminars
	29 April	16	Analysis of end-to-end response time & of worst-case execution time
Evaluation questionnaire
10	3 May	17	Enter multicore processors	BJ2000 1.§9.1,3
	6 May	18
11	10 May	19	Seeking the lost optimality	DP-Fair RUN original implementation
	13 May	20
12	17 May	21	Global resource sharing
	20 May	22	Mixed-criticality systems
13	24 May	23	Exam themes and requirements
	27 May	24	Closing seminar: The challenge of predictable parallelism

Hall assignment and Zoom links

The hall assignment for the lectures in the schedule is reported in the relevant UNIPD portal. The corresponding Zoom links will be communicated via the Moodle page of this course.

Appointments with students

Students are welcome to request personal or group appointments with the instructor, who will offer either a face-to-face or a Zoom-based meeting as the circumstances will allow.

Exam requirements

In the second-half of the lecture series, the instructor will single out themes that the students shall be invited to select as their exam study topic. The students, whether individually or collaboratively (in groups of 2-3 individuals), shall review the state of the art on the selected topic, and implement a software demonstrator that highlights aspects of interest in keeping with the course focus (hence the runtime involvement in the realization of advanced concurrency or distribution features).

The exam will consist in the student(s)' first submitting a technical report on the main findings of the said effort (including the highlights of the software demonstrator), and then, in an oral presentation and discussion of the same.

Should students not feel sufficiently engaged by the themes as proposed, they will be allowed to negotiate elective alternative topics of pertinence with the instructor.

Exam schedule

The students ready to make their own oral presentation shall request an appointment with the instructor. Pass grades will be entered in Uniweb at the date in the official exam schedule closest to said appointment.