- Data objects are a special type of shared resources.
- When jobs are scheduled preemptively, their accesses to data object may be interleaved.
- To ensure data integrity it is common to require that reads and writes be serializable.
- A sequence of reads and writes by a set of jobs is serializable if the effect produced by the sequence on all the data objects shared by the jobs is the same as the effect produced by a serial sequence.
- Two phase locking protocol is used to access the data objects. It is :
- A way to ensure serializability
- A job never requests any lock once it releases some lock
- Introduction
- Hard versus Soft Real-Time Systems
- Reference Model of Real-Time Systems
- Approaches to Real-Time Scheduling
- Clock-Driven Scheduling
- Priority-Driven Scheduling of Periodic Tasks
-
Scheduling Aperiodic and Sporadic Jobs in Periodic-Driven Systems
- Deferrable Server:
- Sporadic Server:
- Constant Utilization Server:
- Total Bandwidth Server:
- Weighted Fair Queuing Server:
- Slack Stealing in Fixed priority System (Optimality Criterion and Design Consideration):
- Model of Scheduling Sporadic Jobs:
- Real Time Performance of Jobs with Soft Timing Constraints- Traffic Models:
- Assumptions and Approaches:
-
Resources and Resource Access Control
- Assumptions on Resources and their Usage
- Effects of Resource Contention and Resource Access Control
- Non-Preemptive Critical Section:
- Basic-Priority Inheritance Protocol:
- Priority Ceiling Protocol:
- Difference between Priority Inheritance and Priority Ceiling Protocols:
- Use of Priority Ceiling Protocol in Dynamic Priority Systems:
- Stack based Priority Ceiling Protocol:
- Controlling Access to Multiple unit Resources:
- Controlling Concurrent Access to Data Objects:
- Multiprocessor Scheduling, Resource Access Control and Synchronization
- Real-Time Communication
- Other Specifics
Controlling Concurrent Access to Data Objects:
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