Real-Time and Embedded Systems ? - Chapter 1 & 2 -
Definition is not clear!
Let's take a look at "examples"
Cell phones, PDAs Digital cameras Microwave ovens Network adaptor box (e.g., ISDN adaptor) Multimedia systems such as DVR, VOD server, et
QoS-Driven Optimal Resource Management
Chang-Gun Lee Seoul National University
Resource Assignment Problem
Resources: CPU, Bandwidth, etc. Resource Assignment Problem: How much resource should be assigned to real-time tasks?
Always satisfy minim
Scheduling of Aperiodic and Sporadic Jobs in Priority-Driven Systems - Chapter 7 (Fixed-Priority Framework)
Types of Aperiodic Requests
The jobs of an aperiodic task have random release times
Soft aperiodic tasks:
random arrivals such as a Poiss
Scheduling of Aperiodic and Sporadic Jobs in Priority-Driven Systems - Chapter 7 (Dynamic Priority Framework)
Dynamic priority servers
We focused on fixed priority servers so far. Such servers can be used along with RM. Now, we will focus on dyna
What are real-time embedded systems?
Cell phones, PDAs Digital cameras Microwave ovens Multimedia systems such as DVR, VOD server, etc Factory process control Radar systems Avionics
Most of e
This workbook contains VBA code that uses the ChartSeries class module
The ChartSeries class module makes it easy to work with chart data using VBA.
The class module may be exported and then imported into any project.
Click the sheet tabs to access the de
Traditional DIY approach
Do everything by yourself
CPU, Peripherals I/O and Memory address mapping
ROM Bios or Monitor program Interrupt processing Application functions In charge of entire CPU
NOT necessarily responsible everything A big system can be partitioned into multiple functions running simultaneously One person can focus on only one function RTOS thread help this
Priority-Driven Scheduling of Periodic Tasks (2) - Chapter 6 -
Schedulable utilization bound
Simpler method for the schedulabiity check
A periodic task's utilization Ui of an active resource is the ratio between its execution time
Real-Time Task Model - Chapter 3 -
"Monolithic approach" Good enough?
For a complex system, it is really hard to design a single superloop Really hard to validate cross-related temporal requirements
So, we need a more structured way to look
Priority-Driven Scheduling of Periodic Tasks - Chapter 6 (Dynamic Priority (2)
All of the above schedulability check works only under limited conditions
Preemptable at any time Context switch overhead is negligible Scheduling decision i
Objected-Oriented Real-Time System Design
Next-Generation real-time systems become
Complicated Distributed Networked
Military unmanned command/control system City-wide disaster monitoring and management system Hospital
Real-Time Ubiquitous System: A Case Study
"Combined Scheduling of Sensing and Communication for Real-Time Indoor Tracking in Assisted Living" RealLiving"
M.-Y. Nam M.CS Dept. UIUC
M. Z. Al-Sabbagh C.-G. Lee, J. Kim, M. Yoon AlC.ECE Dept. Ohio State
Inter-process communication (FIFO and Shared Memory)
NOT necessarily responsible everything RTOS system calls
pthread_create pthread_setschedparam/ pri. sched pthread_make_periodic_np pthread_wait_np pthread_delete_np
Power Aware Scheduling
PDAs and Pocket PCs
Display, processor, hard disk, and wireless LAN card are main sources of power consumption Processor may consume up to 25% of the system power for laptop computers Technology advance in proc
Overview of Commonly used Approaches to Real-Time Scheduling - Chapter 4 -
Overview of Chapter 4 topics
The nature of the "game" Overview of common approaches
Clock-Driven Approach Weighted Round-Robin Approach Priority-Driven Approach