Operating Systems A - L

Knowledge and understanding

Upon completion of the course, the students will have acquired: knowledge of the basic concepts inherent to the design of operating systems; ability to write programs using the system calls in the Linux / UNIX environment; knowledge of the operating system structure, of the relevant project issues and of the policies for resource (CPU, main memory, mass storage, peripherals) virtualization and management; understanding of the process concept, of the thread concept, and knowledge about their management; knowledge of management techniques of mutually exclusive resources.


Applying knowledge and understanding

At the end of the course the students will be able to develop applications using the Linux system calls for the: creation and management of processes; signal handling; interaction and communication between processes; concurrency on shared resources; creation of multithreaded applications. Moreover, the students will be able to apply the acquired knowledge for the selection of both the SW component and Linux APIs suitable for the problem to be solved.
Making judgements.

On completion of the course, the students will be able to choose a suitable operating system for the design problem to deal with. Moreover, an appropriate software solution based on the Linux API for each of the topics covered in the course. This ability is improved through the exercises carried out during the course and with appropriate programming questions assigned at the final exam.


Communication skills.

On completion of the course, the students will have acquired the operating system technical terminology, and therefore they will be able to make recommendations about the design and use of the operating systems and to explain, in a clear and unambiguous way, to both a specialist and a non-specialist audience the rationale behind the design choices made.


Learning skills.

On completion, the students will be able to improve their operating systems knowledge by studying the reference textbooks and specialized journals. The students will also be able to learn the new functionalities and features developed on Linux operating system by consulting the relevant manuals and official documentation.

The course is essentially based on lectures, which include the development of exercises by the teachers. The proposed exercises are addressed by the teachers through the use of computer connected to the projector. The course also includes practical exercises carried out by the students. These exercises are carried out in the University's multimedia rooms. Each student is assigned a task that must be performed on the computer. The teachers supervise the work of the students by providing the explanations and teaching aids necessary to complete the assigned tasks. The methods of carrying out the teaching described above allow the achievement of the pre-established training objectives, which include the acquisition of knowledge and the ability to apply knowledge.

Should teaching be carried out in mixed mode or remotely, it may be necessary to introduce changes with respect to previous statements, in line with the program planned out in the syllabus.

Requirements necessary to successfully reach the course goals:

-    Basic general knowledge of the computer architecture, in particular: CPU, interrupts, registers, memories, multiprocessor architectures, I /0 devices.

-    Programming skills and knowledge of ANSI C language, with particular reference to:

"use of argc and argv parameters in the main() function", 

"use of pointers, vectors and dynamic allocation", 

"use of structures", 

"use of functions and relative use of parameters by value and by reference".

-    Knowledge of the main data structures: lists, stacks, queues, hash tables, and their implementation in ANSI C language.

Asterisks (*) indicate the minimum skills.

Operating Systems Introduction (*)

Operating systems concepts. Kernel. (*)

History and classification of operating systems. GNU/Linux.

Operating systems structures: monolythic, microkernel, hybrid, client/server. (*)

The POSIX standard. (*)

System calls. (*)

Operating systems structure.  (*)

Multiprocessor OS structure.

Virtualization. Virtual machines.  Hypervisors: level 1 and 2.  (*)

Linux shell commands.         (*)

Shell programming (brief hints).

Processes, Threads. (*)

Signals and signal handling.(*)

Thread implementation. POSIX threads. The pthread.h library. (*)

Scheduling. (*)

Real-time systems scheduling. (brief hints) (*)

Linux scheduling. Completely Fair Scheduler. (brief hints)

Concurrency. Critical regions. Race conditions. Mutual exclusion. Busy waiting. Semaphores and Mutexes. Program examples. (*)

Interprocess Communications. Message queues, Shared memory. Classical IPC problems. Program examples. (*)

File Systems. File. Directories.  (*)

Client/server model. Sockets. (*)

Deadlocks. Characterization, detection, prevention, avoidance. (*)

Case Studies

Linux (*)

1) Theory:

Andrew S. Tanenbaum, H. Bos, “Modern operating systems 5/Ed.", 2023, Pearson, ISBN 9788891931955.

(Alternative option for theory: Abraham Silberschatz, Peter Baer Galvin, Greg Gagne, “Sistemi Operativi, Concetti e esempi”, 10th Edition, Pearson, ISBN 9788891904553), 2019.

2) Programming part:

R. Stones, N. Matthew, “Beginning Linux Programming”, 4th edition, Wrox Press, Wiley Publishing, Inc. 2007. Available online.

LEARNING ASSESSMENT PROCEDURES
The exams are fixed in agreement with the CdS in compliance with the procedures established by the academic calendar.
Reservations are required through the University portal. The closing date for reservations is usually fixed a few days before the exam, in order to allow the teacher to book the computer rooms of adequate capacity for the number of registered students.
The exam consists of a written test and an oral test.
The written test is made up by two sections. One section is relevant to the development of one or more programs in C language using the system calls studied in the course; for this reason, it requires the use of a computer made available to the students by the university. The other section consists of one or more theoretical open-ended questions. The section relevant to the C language program development allows to achieve a total mark of 18/30 points; the theoretical section allows to achieve a total mark of 12 /30 points. The written test, 3 hours long, is passed if the sum of the two marks is greater than or equal to 18/30. On the corse website available on Studium (www.studium.it) a template of the written test that specifies both the types of sections and the relative marks is available.
The oral test is optional and can only be held in the same session in which the written test was passed. The oral exam focuses on the theoretical topics addressed in the classes.
The assessment can also be carried out on-line, should the conditions require it.

System call for process and signal management.

Difference between thread and process.

Thread implementations.

Pthread library.

Mutual exclusion and relevant solutions.

InterProcess Communication mechanisms.