Advances in Large-scale Advances in Large-scale

Distributed, Distributed,

Real-time, & Embedded Systems Real-time, & Embedded Systems Douglas C. Schmidt

d.schmidt@vanderbilt.edu

Professor of EECS Vanderbilt University Nashville, Tennessee

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The Evolution of DRE Systems

• Stringent quality of service (QoS) demands• e.g., latency, jitter, footprint

• Resource constrained

• Stringent quality of service (QoS) demands• e.g., latency, jitter, footprint

• Resource constrained

The Past

• Network-centric & larger-scale• Stringent simultaneous quality of service (QoS) demands• e.g., availability, security, throughput, scalability

• Part of larger systems• Dynamic context

• Network-centric & larger-scale• Stringent simultaneous quality of service (QoS) demands• e.g., availability, security, throughput, scalability

• Part of larger systems• Dynamic context

The Future

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Evolution of DRE System Development

Technology ProblemsDRE systems have

historically tended to be:StovepipedProprietary

Brittle & non-adaptiveExpensiveVulnerable

Historically, mission-critical DRE applications were built directly atop hardware

• Tedious• Error-prone• Costly over lifecycles

IOM

IOM

IOM

IOM

IOM

IOM

IOM

IOM

IOM

IOM

IOM

IOM

IOM

IOM

IOM

IOM

IOM

IOM

BSE

BSE

BSE

BSE

BSE

BSE

BSEBSE

BSE

AirFrame

AP

Nav HUD

GPS IFF

FLIR

Cyclic Exec

CLI

SS7

SM CM

RX TX

IP

RTOS

4

Technology ProblemsDRE systems have

historically tended to be:StovepipedProprietary

Brittle & non-adaptiveExpensiveVulnerable

Historically, mission-critical apps were built directly atop hardware

• Tedious• Error-prone• Costly over lifecycles

IOM

IOM

IOM

IOM

IOM

IOM

IOM

IOM

IOM

IOM

IOM

IOM

IOM

IOM

IOM

IOM

IOM

IOM

BSE

BSE

BSE

BSE

BSE

BSE

BSEBSE

BSE

Middleware

MiddlewareServices

DRE Applications

Operating Sys& Protocols

Hardware & Networks

Middleware

MiddlewareServices

DRE Applications

Operating Sys& Protocols

Hardware & Networks

•Middleware has effectively factored out many reusable mechanisms & services from what was traditionally DRE application responsibility

•Middleware is no longer primary DRE system performance bottleneck

Evolution of DRE System Development

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Middleware

MiddlewareServices

DRE Applications

Operating Sys& Protocols

Hardware & Networks

DRE Systems: The Challenges Ahead

•There is a limit to how much application functionality can be factored into broadly reusable COTS middleware

•System infrastructure has become extremely complicated to use, configure, & provision statically & dynamically

•There are now multiple middleware technologies to choose from

IntServ + Diffserv

RTOS + RT Java

RT/DP CORBA + DRTSJ

Load BalancerFT CORBA

Network latency & bandwidth

Workload & Replicas

CPU & memory

Connections & priority bands

CORBA

CORBAServices

CORBAApps

J2EE

J2EEServices

J2EEApps

.NET

.NETServices

.NETApps

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•e.g., standard technologies are emerging that can:1. Model2. Analyze3. Synthesize & optimize4. Provision & deploy

multiple layers of QoS-enabled middleware & applications

•These technologies are guided by patterns & implemented by component frameworks

•Partial specialization is essential for inter-/intra-layer optimization

Promising Approach: Model Driven Middleware

Middleware

MiddlewareServices

DRE Applications

Operating Sys& Protocols

Hardware & Networks

<CONFIGURATION_PASS> <HOME> <…> <COMPONENT> <ID> <…></ID> <EVENT_SUPPLIER> <…events this component supplies…> </EVENT_SUPPLIER> </COMPONENT> </HOME></CONFIGURATION_PASS>

<CONFIGURATION_PASS> <HOME> <…> <COMPONENT> <ID> <…></ID> <EVENT_SUPPLIER> <…events this component supplies…> </EVENT_SUPPLIER> </COMPONENT> </HOME></CONFIGURATION_PASS>

Distributedsystem

Goal is not to replace programmers per se – it is to provide higher-level domain-specific languages for middleware developers & users

Solution approach: Integrate model-based software technologies with QoS-enabled component middleware