What makes a good RTOS - Abstract
What is a real-time operating system (RTOS)? There are a lot of misconceptions
on the topic of real-time. Following reflects the opinion of Real-time
Consult on what makes a good RTOS. We will examine techniques that can
be found in general purpose operating systems (GPOS) and explain why they
can or cannot be used in real-time operating systems (RTOS).
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A. Abstract
B. Table of Contents
C. Table of Figures
A. Abstract
A lot of misconceptions exist on the topic of real-time. This paper
reflects the opinion of Real-time Consult on what is necessary in an operating
system (OS) to become a real-time operating system (RTOS).
B. Table of contents
|
|
Page |
| 1 |
Introduction |
3 |
| 2 |
Real-time systems & real-time operating systems |
4 |
| 3 |
System architecture |
5 |
| 3.1 |
OS structures |
5 |
| 3.1.1 |
Monolithic operating system |
5 |
| 3.1.2 |
Layered operating system |
6 |
| 3.1.3 |
Client-server operating system |
8 |
| 3.2 |
Process - Thread - Task model |
8 |
| 3.3 |
Scheduling & Priorities & Interrupts |
9 |
| 4 |
Basic system facilities |
10 |
| 4.1 |
Tasking Model |
10 |
| 4.1.1 |
General |
10 |
| 4.1.2 |
Categories |
11 |
| 4.2 |
Memory |
14 |
| 4.3 |
Interrupts |
19 |
| 4.3.1 |
General |
19 |
| 5 |
API richness |
23 |
| 5.1 |
General |
23 |
| 5.1.1 |
Purpose |
23 |
| 5.1.2 |
POSIX |
23 |
| 5.2 |
Categories |
26 |
| 5.2.1 |
Task management |
26 |
| 5.2.2 |
Clock and timer |
26 |
| 5.2.3 |
Memory management |
26 |
| 5.2.4 |
Interrupt handling |
27 |
| 5.2.5 |
Synchronization and exclusion objects |
28 |
| 5.2.6 |
Communication and message passing |
28 |
| 5.2.7 |
Waiting list length |
28 |
| 6 |
Conclusion |
30 |
C. Table of figures
|
|
Page |
| Figure 1 |
Monolithic operating system |
5 |
| Figure 2 |
MS-DOS system architecture 1 |
6 |
| Figure 3 |
MS-DOS system architecture 2 |
7 |
| Figure 4 |
Client/Server operating system |
8 |
| Figure 5 |
Process states & transitions |
13 |
| Figure 6 |
Memory protection & dynamic relocation |
15 |
| Figure 7 |
Paging hardware |
15 |
| Figure 8 |
Associated map limitations |
16 |
| Figure 9 |
Virtual memory mechanism |
17 |
| Figure 10 |
Context definition |
19 |
| Figure 11 |
Context switch |
20 |
| Figure 12 |
Context switch timing |
21 |
| Figure 13 |
Interrupt-to-task run |
22 |
| Figure 14 |
Features versus profiles |
24 |
| Figure 15 |
Problems with POSIX 1003.13 |
25 |
| Figure 16 |
Extended POSIX 1003.13 by RTConsult |
25 |
| Figure 17 |
Naming in RTOSs |
27 |
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