How VxWorks handles process scheduling and memory management in comparison to QNX
How VxWorks handles process scheduling and memory management in comparison to QNX
Patrik Alnefelt – patal533@student.liu.se
Marcus Svensson – marsv024@student.liu.se
INDEX
1. Abstract 3
2. Introduction 3 Process Scheduling 4
2.1. QNX 4
2.2. VxWorks 5
2.3. Comparison 5
3. Memory Management 6
3.1. QNX 6
3.2. VxWorks 7
3.3. Comparison 8
4. Conclusion 9
1. Abstract
The purpose of this report is to state the differences and similarities between the two real time operative systems QNX and VxWorks in how they handle Process Scheduling and Memory Management. The goal is to get a better understanding of real time operative systems and how they work. The main conclusion we have drawn from the comparison made is that the two systems are equivalent when it comes to system performance and features. The biggest difference between them is how they are implemented.
2. Introduction
In this report we first start looking at Process Scheduling for QNX and then for VxWorks. When the both OS have been presented, a comparison is made between the two stating differences and similarities. The next thing we look at is Memory Management in first QNX and then VxWorks followed by another comparison. In the last chapter we draw conclusions from what previous sections have discussed.
Process Scheduling
2.1. QNX1
QNX is a microkernel real-time operating system, from now on referred to as an RTOS. A microkernel RTOS is special in the way that the OS is built up with a number of small services which each handle a specific task, this is basically a set of system calls which is available to the developer. These services only implement low-level communication over network and between processes, process scheduling and interrupt handling. Other OS functions as file-system and device drivers are deployed as user processes outside the kernel. In contrast most other OS use a monolithic kernel. In that case all kernel functions reside in
Patrik Alnefelt – patal533@student.liu.se
Marcus Svensson – marsv024@student.liu.se
INDEX
1. Abstract 3
2. Introduction 3 Process Scheduling 4
2.1. QNX 4
2.2. VxWorks 5
2.3. Comparison 5
3. Memory Management 6
3.1. QNX 6
3.2. VxWorks 7
3.3. Comparison 8
4. Conclusion 9
1. Abstract
The purpose of this report is to state the differences and similarities between the two real time operative systems QNX and VxWorks in how they handle Process Scheduling and Memory Management. The goal is to get a better understanding of real time operative systems and how they work. The main conclusion we have drawn from the comparison made is that the two systems are equivalent when it comes to system performance and features. The biggest difference between them is how they are implemented.
2. Introduction
In this report we first start looking at Process Scheduling for QNX and then for VxWorks. When the both OS have been presented, a comparison is made between the two stating differences and similarities. The next thing we look at is Memory Management in first QNX and then VxWorks followed by another comparison. In the last chapter we draw conclusions from what previous sections have discussed.
Process Scheduling
2.1. QNX1
QNX is a microkernel real-time operating system, from now on referred to as an RTOS. A microkernel RTOS is special in the way that the OS is built up with a number of small services which each handle a specific task, this is basically a set of system calls which is available to the developer. These services only implement low-level communication over network and between processes, process scheduling and interrupt handling. Other OS functions as file-system and device drivers are deployed as user processes outside the kernel. In contrast most other OS use a monolithic kernel. In that case all kernel functions reside in
References: QNX Software Systems Ltd. (2003), System Architecture guide [www] Laszlo, Zoltan, Wind River Systems Inc. (2005), Memory Allocation in VxWorks 6.0 [www] Nagarajan, Shiv; Craig, Robert QNX Software Systems Ltd. (2005), Porting Legacy Systems from VxWorks to QNX Neutrino RTOS [www] Wind River Systems Inc. (2006), VxWorks kernel programmer’s guide 6.3