Module 1 Flashcards

(15 cards)

1
Q

What is a real time system? (4, 3)

A

A system
whose logical correctness
depends on the correctness of the outputs
as well as their timeliness

A system
which must satisfy bounded response time constraints
or risk severe consequences

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is a response time? (3)

A

Le temps entre la présentation des données au système
et la réalisation du comportement attendu
y compris la disponsibilité de toutes les sorties correspondantes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is an embedded system?

A

A system which contains one or more computer parts that are central to the functioning of the system, but the system itself is not called a computer.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is a system failure? (2)

A

A system that cannot meet one or more of the requirements

outlined in the SRS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Distinguish the configuration of a typical embedded system from a conventional operating system? (2)

A

User programs are combined with OS elements

instead of being in separate layers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Distinguish soft (2) , firm (2), and hard (1) real time systems with respect to missing a deadline in response time

A

Soft
when, missing several deadlines performance is degraded
but not failing completely

Firm
missing a few does not lead to complete failure
missing many will lead to complete failure

Hard
missing a single response time can lead to complete failur

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is a good rule of thumb for building a cost-effective and robust real-time system? (2)

A

process everything as slowly as the requirements allow it

repeat tasks as seldom as the requirements allow it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is an event? (2)

A

A change in flow of control

An occurence that causes the program counter to change nonsequentially

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

When can a system be said to be determinstic? (2)

A

For each possible state and set of inputs

a unique set of outputs and next state of the system can be determined

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is event determinism? (2)

A

For each set of inputs triggering an event

the next state and outputs are known

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is temporal determinism?

A

A system in which the response time for every set of outputs is known

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Doit considérer la nature du temps dans les systèmes de temps car les échéances sont des instants de temps. D’où viennent les échéances? (1)

A

Les échéances découlent des phénomènes physiques du système sous contrôle.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Donnez des valeurs d’utilisation commun ou acceptable pour 1) un nouveau produit, 2) un système sans croissance attendue, 3) valeur découlant de la recherche des systèmes.

A

1) un nouveau produit: 50%
2) un système sans croissance attendue: 80%
3) valeur découlant de la recherche des systèmes en temps réel ou les tâches sont périodiques et indépendantes: 69%.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Quel est le facteur global d’utilisation d’UCT de l’exemple de l’ascenseur?

Un contrôleur individuel d’ascenseur dans une série d’ascenseurs contient les tâches de logiciels suivantes avec les périodes d’exécution pi et les pires temps d’exécution ei, i  { 1, 2, 3, 4 }.
◦Tâche 1: Communication avec le répartiteur de groupe (débit de 19.2 kBits/s avec un protocole de communication propriétaire); p1 = 500 ms, e1 = 17 ms
◦Tâche 2: Mise à jour de la position de l’ascenseur et la gestion de déplacement, ainsi que contrôle des portes; p2 = 25 ms, e2 = 4ms
◦Tâche 3: Enregistrement et annulation des appels à l’ascenseur; p3 = 75 ms, e3 = 1 ms
◦Tâche 4: Supervision divers du système; p4 = 200 ms, e4 = 20 ms

A

30.7%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Name 2x3 examples of events

A

http://prntscr.com/iieuug

How well did you know this?
1
Not at all
2
3
4
5
Perfectly