Real-time operating system

A real-time operating system is an operating system intended to serve real-time applications that process data as it comes in without buffer delays. Processing time requirements are measured in shorter increments of time. A real-time system is a time bound system. Processing must be done within the defined constraints or the system will fail, they either are time sharing. Event driven systems switch between tasks based on their priorities while time sharing systems switch the task based on clock interrupts. Most RTOSs use a pre-emptive scheduling algorithm. A key characteristic of an RTOS is the level of its consistency concerning the amount of time it takes to accept and complete an application's task. A'hard' real-time operating system has less jitter than a'soft' real-time operating system; the chief design goal is not high throughput, but rather a guarantee of a soft or hard performance category. An RTOS that can or meet a deadline is a soft real-time OS, but if it can meet a deadline deterministically it is a hard real-time OS.

An RTOS has an advanced algorithm for scheduling. Scheduler flexibility enables a wider, computer-system orchestration of process priorities, but a real-time OS is more dedicated to a narrow set of applications. Key factors in a real-time OS are minimal interrupt latency and minimal thread switching latency. See the comparison of real-time operating systems for a comprehensive list. See the list of operating systems for all types of operating systems; the most common designs are: Event-driven – switches tasks only when an event of higher priority needs servicing. Time-sharing – switches tasks on a regular clocked interrupt, on events. Time sharing designs switch tasks more than needed, but give smoother multitasking, giving the illusion that a process or user has sole use of a machine. Early CPU designs needed many cycles to switch tasks during which the CPU could do nothing else useful. For example, with a 20 MHz 68000 processor, task switch times are 20 microseconds. In contrast, a 100 MHz ARM CPU switches in less than 3 microseconds.

Because switching took so long, early OSes tried to minimize wasting CPU time by avoiding unnecessary task switching. In typical designs, a task has three states: Running. Most tasks are blocked or ready most of the time because only one task can run at a time per CPU; the number of items in the ready queue can vary depending on the number of tasks the system needs to perform and the type of scheduler that the system uses. On simpler non-preemptive but still multitasking systems, a task has to give up its time on the CPU to other tasks, which can cause the ready queue to have a greater number of overall tasks in the ready to be executed state; the data structure of the ready list in the scheduler is designed to minimize the worst-case length of time spent in the scheduler's critical section, during which preemption is inhibited, and, in some cases, all interrupts are disabled, but the choice of data structure depends on the maximum number of tasks that can be on the ready list. If there are never more than a few tasks on the ready list a doubly linked list of ready tasks is optimal.

If the ready list contains only a few tasks but contains more the list should be sorted by priority. That way, finding the highest priority task to run does not require iterating through the entire list. Inserting a task requires walking the ready list until reaching either the end of the list, or a task of lower priority than that of the task being inserted. Care must be taken not to inhibit preemption during this search. Longer critical sections should be divided into small pieces. If an interrupt occurs that makes a high priority task ready during the insertion of a low priority task, that high priority task can be inserted and run before the low priority task is inserted; the critical response time, sometimes called the flyback time, is the time it takes to queue a new ready task and restore the state of the highest priority task to running. In a well-designed RTOS, readying a new task will take 3 to 20 instructions per ready-queue entry, restoration of the highest-priority ready task will take 5 to 30 instructions.

In more advanced systems, real-time tasks share computing resources with many non-real-time tasks, the ready list can be arbitrarily long. In such systems, a scheduler ready list implemented; some used RTOS scheduling algorithms are: Cooperative scheduling Preemptive scheduling Rate-monotonic scheduling Round-robin scheduling Fixed priority pre-emptive scheduling, an implementation of preemptive time slicing Fixed-Priority Scheduling with Deferred Preemption Fixed-Priority Non-preemptive Scheduling Critical section preemptive scheduling Static time scheduling Earliest Deadline First approach Stochastic digraphs with multi-threaded graph traversal A multitasking operating system like Unix is poor at real-time tasks. The scheduler gives the highest priority to jobs with the lowest demand on the computer, so there is no way to ensure that a time-critical job will have access to enough resources. Multitasking systems must manage sharing data and hardware resources among multiple tasks, it is un

Tommaso Cucchietti

Tommaso Cucchietti is an Italian football player. He plays for Südtirol on loan from Torino. Cucchetti is a youth product of Torino youth team, he made several appearances on the bench for the entire 2016–17 season, but he never appear on the field. On 13 July 2017, Cucchietti was loaned to Serie C club Reggina on a season-long loan deal. On 2 September he made his professional debut for Reggina in Serie C in a 1–0 away defeat against Catanzaro. On 23 September he kept his first clean sheet for the team in a 1–0 away win over Fondi. Three weeks on 14 October, he kept his second clean sheet for the club in a 2–0 home win over Fidelis Andria and, three more weeks on 4 November, he kept his third clean sheet in a 0–0 away draw against Casertana. On 26 March 2018, Cucchietti kept his 10th clean sheet of the season for Reggina in a 0–0 away draw against Siracusa. Cucchietti ended his loan to Reggina with 34 appearances, 11 clean sheets and 36 goals conceded. On 28 July 2018, Cucchietti was signed by Serie C side Alessandria on a season-long loan.

One day on 29 July, he made his debut for the club in a 1–0 home defeat against Giana Erminio in the first round of Coppa Italia. On 16 September he made his Serie C debut for Alessandria in a 2–1 away win over Juventus U23. Two weeks on 30 September, Cucchietti kept his first clean sheet in a 0–0 home draw against Lucchese. One more week on 7 October, he kept his second consecutive clean sheet, a 0–0 away draw against Pisa and, ten days on 17 October, he kept his third clean sheet, another 0–0 draw against Olbia. Cucchietti ended his loan to Alessandria with 32 appearances, 42 goals conceded and 8 clean sheets. On 26 July 2019, Cuccchietti was loaned to Serie C club Südtirol on a season-long loan deal. One week on 4 August, he made his debut for the club in a 4–2 home win over Città di Fasano in the first round of Coppa Italia. On 25 August, Cucchietti made. On 21 September he kept his first clean sheet for the club in a 1–0 away win against Arzignano Valchiampo. Four days on 25 September, he kept his second clean sheet in a 3–0 home win over Fermana and four more days on 29 September, his third consecutive in a 2–0 away win over Alma Juventus Fano.

Cucchietti represented Italy from Under-16 to Under-19 level. On 11 March 2014 he made his debut at Under-16 level in a 2–1 away win over Croatia U-16, one month he kept his first clean sheet at this level in a 3–0 home win over Poland U-16. On 27 August 2014, Cucchietti made his debut and kept his clean sheet at Under-17 level in a 0–0 away draw against Portugal U-17. Cucchetti, with Italy U-17, played 2 matches in the 2015 UEFA European Under-17 Championship qualification against Slovakia U-17 and Germany U-17. On 16 September 2015 he made his debut at U-18 level in a 3–2 away defeat against Czech Republic U-18. On 11 August 2016, Cucchietti made his debut at U-19 level, as a substitute replacing Mattia Del Favero in a 1–0 away defeat against Croatia U-19; as of 26 December 2019 Torino Primavera Supercoppa Primavera: 2015 Tommaso Cucchietti at Soccerway

Zaban Sambhal Ke

Zaban Sambhal Ke is a 2018 Hindi web series sitcom created by Rajiv Mehra for Ekta Kapoor's video on demand platform ALTBalaji. The series stars Sumeet Raghvan as the protagonist, the head master of Hindi speaking institute; the idea for the plot has been taken from the British sitcom from the late'70s. The series revolves around the hilarious miscommunication between the students due to language barriers; the series is available for streaming on the ALT Balaji App and its associated websites since its release date. The comedy series centres on a Hindi-learning class which has students from different nationalities and ethnicities. Sumeet Raghavan Shoma Anand Tarranum Khan Bakhtiyaar Irani Ashwin Mushran Rupali Bhosle Pipa Hughes Mishka Sharma Hemant Kumar Bhawsheel Singh Jimmy Moses Meenakshi Chand Nyra Bannerjee Rakesh Shrivastav Watch Zaban Sambhal Ke on ALT Balaji website