Embedded Software Course Notes On-Line

I'm just wrapping up my first semester teaching a new course on embedded system software. It covers code quality, safety, and security. Below is table of lecture handouts.

NOTE: there is an update here:
     https://users.ece.cmu.edu/~koopman/lectures/index.html#642
which includes newer course notes and quite a few YouTube videos of these lectures.
You should use that URL instead of this blog post, but I've left this post as-is for Fall 2017.

18-642 Embedded System Software Engineering
Prof. Philip Koopman, Carnegie Mellon University, Fall 2017

	Slides	Topics
1	Course Introduction	Software is eating the world; embedded applications and markets; bad code is a problem; coding is 0% of software; truths and management misconceptions
2	Software Development Processes	Waterfall; swiss cheese model; lessons learned in software; V model; design vs. code; agile methods; agile for embedded
3	Global Variables	Global vs. static variables; avoiding and removing globals
4	Spaghetti Code	McCabe Cyclomatic Complexity (MCC); SCC; Spaghetti Factor (SF)
5	Unit Testing	Black box testing; white box testing; unit testing strategies; MCDC coverage; unit testing frameworks (cunit)
6	Modal Code/Statecharts	Statechart elements; statechart example; statechart implementation
7	Peer Reviews	Effective code quality practices, peer review efficiency and effectiveness; Fagan inspections; rules for peer review; review report; perspective-based reviews; review checklist; case study; economics of peer review
8	Code Style/Humans	Making code easy to read; good code hygiene; avoiding premature optimization; coding style
9	Code Style/Language	Pitfalls and problems with C; language use guidelines and analysis tools; using language wisely (strong typing); Mars Climate Orbiter; deviations & legacy code
10	Testing Quality	Smoke testing, exploratory testing; methodical test coverage; types of testing; testing philosophy; coverage; testing resources
11	Requirements	Ariane 5 flight 501; rules for good requirements; problematic requirements; extra-functional requirements; requirements approaches; ambiguity
12	System-Level Test	First bug story; effective test plans; testing won't find all bugs; F-22 Raptor date line bug; bug farms; risks of bad software
13	SW Architecture	High Level Design (HLD); boxes and arrows; sequence diagrams (SD); statechart to SD relationship; 2011 Health Plan chart
14	Integration Testing	Integration test approaches; tracing integration tests to SDs; network message testing; using SDs to generate unit tests
15	Traceability	Traceability across the V; examples; best practices
16	SQA isn't testing	SQA elements; audits; SQA as coaching staff; cost of defect fixes over project cycle
17	Lifecycle CM	A400M crash; version control; configuration management; long lifecycles
18	Maintenance	Bug fix cycle; bug prioritization; maintenance as a large cost driver; technical debt
19	Process Key Metrics	Tester to developer ratio; code productivity; peer review effectiveness
33	Date Time Management	Keeping time; time terminology; clock synchronization; time zones; DST; local time; sunrise/sunset; mobility and time; date line; GMT/UTC; leap years; leap seconds; time rollovers; Zune leap year bug; internationalization.
21	Floating Point Pitfalls	Floating point formats; special values; NaN and robots; roundoff errors; Patriot Missile mishap
23	Stack Overflow	Stack overflow mechanics; memory corruption; stack sentinels; static analysis; memory protection; avoid recursion
25	Race Conditions	Therac 25; race condition example; disabling interrupts; mutex; blocking time; priority inversion; priority inheritance; Mars Pathfinder
27	Data Integrity	Sources of faults; soft errors; Hamming distance; parity; mirroring; SECDED; checksum; CRC
20	Safety+Security Overview	Challenges of embedded code; it only takes one line of bad code; problems with large scale production; your products live or die by their software; considering the worst case; designing for safety; security matters; industrial controls as targets; designing for security; testing isn't enough Fiat Chrysler jeep hack; Ford Mytouch update; Toyota UA code quality; Heartbleed; Nest thermostats; Honda UA recall; Samsung keyboard bug; hospital infusion pumps; LIFX smart lightbulbs; German steel mill hack; Ukraine power hack; SCADA attack data; Shodan; traffic light control vulnerability; hydroelectric plant vulnerability; zero-day shopping list
22	Dependability	Dependability; availability; Windows 2000 server crash; reliability; serial and parallel reliability; example reliability calculation; other aspects of dependability
24	Critical Systems	Safety critical vs. mission critical; worst case and safety; HVAC malfunction hazard; Safety Integrity Levels (SIL); Bhopal; IEC 61508; fleet exposure
26	Safety Plan	Safety plan elements; functional safety approaches; hazards & risks; safety goals & safety requirements; FMEA; FTA; safety case (GSN)
28	Safety Requirements	Identifying safety-related requirements; safety envelope; Doer/Checker pattern
29	Single Points of Failure	Fault containment regions (FCR); Toyota UA single point failure; multi-channel pattern; monitor pattern; safety gate pattern; correlated & accumulated faults
30	SIL Isolation	Isolating different SILs, mixed-SIL interference sources; mitigating cross-SIL interference; isolation and security; CarShark hack
31	Redundancy Management	Bellingham WA gasoline pipeline mishap; redundancy for availability; redundancy for fault detection; Ariane 5 Flight 501; fail operational; triplex modular redundancy (TMR) 2-of-3 pattern; dual 2-of-2 pattern; high-SIL Doer/Checker pattern; diagnostic effectiveness and proof tests
32	Safety Architecture Patterns	Supplemental lecture with more detail on patterns: low SIL; self-diagnosis; partitioning; fail operational; voting; fail silent; dual 2-of-2; Ariane 5 Flight 501; fail silent patterns (low, high, mixed SIL); high availability mixed SIL pattern
34	Security Plan	Security plan elements; Target Attack; security requirements; threats; vulnerabilities; mitigation; validation
35	Cryptography	Confusion & diffusion; Caesar cipher; frequency analysis; Enigma; Lorenz & Colossus; DES; AES; public key cryptography; secure hashing; digital signatures; certificates; PKI; encrypting vs. signing for firmware update
36	Security Threats	Stuxnet; attack motivation; attacker threat levels; DirectTV piracy; operational environment; porous firewalls; Davis Besse incident; BlueSniper rifle; integrity; authentication; secrecy; privacy; LG Smart TV privacy; DoS/DDos; feature activation; St. Jude pacemaker recall
37	Security Vulnerabilities	Exploit vs. attack; Kettle spambot; weak passwords; master passwords; crypto key length; Mirai botnet attack; crypto mistakes; LIFX revisited; CarShark revisited; chip peels; hidden functionality; counterfeit systems; cloud connected devices; embedded-specific attacks
38	Security Mitigation Validation	Password strength; storing passwords & salt/pepper/key stretching; Adobe password hack; least privilege; Jeep firewall hack; secure update; secure boot; encryption vs. signing revisited; penetration testing; code analysis; other security approaches; rubber hose attack
39	Security Pitfalls	Konami code; security via obscurity; hotel lock USB hack; Kerckhoff's principle; hospital WPA setup hack; DECSS; Lodz tram attack; proper use of cryptography; zero day exploits; security snake oil; realities of in-system firewalls; aircraft infotainment and firewalls; zombie road sign hack

Note that in Spring 2018 these are likely to be updated, so if want to see the latest also check the main course page:  https://www.ece.cmu.edu/~ece642/   For other lectures and copyright notes, please see my general lecture notes & video page: https://users.ece.cmu.edu/~koopman/lectures/index.html

Embedded System Dependability (Preview)

Here's a summary video on Embedded System Dependability.


Dependability Tutorial Preview [ECR]

Other pointers on this topic (my blog posts unless otherwise noted):

• The Grand Challenge of Embedded System Dependability
• Is your software dependable enough?
• Reliability calculation tools

Other pointers

• Avizienis, Laprie, Randell & Landwehr, "Basic Concepts and Taxonomy of Dependable and Secure Computing," Jan 2004, (authoritative terminology reference).
• Dependable Systems & Networks conference (DSN)
• IFIP WG 10.4 dependability workshop presentation slides

For more about Edge Case Research and how to subscribe to our video training channel, please see this Blog posting.

Safety Requirements for Embedded Systems (Preview)

Here's a summary video on Embedded System Safety Requirements.


Safety Requirements Preview [ECR]

Other pointers on this topic (my blog posts unless otherwise noted):

• Don't require perfection
• Testing failsafe mechanisms
• Doer/Checker (monitor/actuator) design pattern

For more about Edge Case Research and how to subscribe to our video training channel, please see this Blog posting.

Embedded Software Safety Plan (Preview)

Here's a summary video on creating an embedded Software Safety Plan.   (See additional pointers below.)

Safety Plan Preview [ECR]

Other pointers on this topic (my blog posts unless otherwise noted):

• How a Risk Table works
• Go beyond just system testing to ensure safety
• Why creating a software safety plan is challenging for an autonomous vehicle
• Your embedded system might be safety critical

Other pointers:

• Medical device regulatory environment (Micrium blog)
• Software safety standards and guidebooks system-safety.org
• International safety standards via law.resource.org (e.g., look for IEC 61508 in their industrial safety standards) -- very useful for teaching access to actual international standards, although sometimes older versions

For more about Edge Case Research and how to subscribe to our video training channel, please see this Blog posting.

Embedded System Safety Overview (Preview)

Here's a summary overview video on Embedded System Safety.  (See additional pointers below.)

https://youtu.be/Ul0tN_EUnqY

Other pointers on this topic (my blog posts unless otherwise noted):

• Safety culture
• Toyota Unintended Acceleration case study
• Layered defenses for safety critical systems
• Therac 25 summary

On-line resources:

• UK MOD, An Introduction to System Safety Management in the MOD, January 2011.

• RISKS Digest (archive of discussions on computing risks)
• Safety critical mailing list (international safety experts discuss almost everything; includes on-line archives)

John Knight's book: Fundamentals of Dependable Computing for Software Engineers (2012) is an excellent current book on software dependability and safety.

Nancy Leveson has some great publications in the area of software safety, and is credited for developing this as an academic field. Anyone doing software safety should read at least these:

• Software Safety: why, what, and how (a shorter, earlier version of the material in the Safeware book); pay to download from ACM, or sometimes you can find a free copy on-line if you don't have a subscription (1986)
• The Therac-25 Accidents (1993)
• High-Pressure Steam Engines and Computer Software (1992)
• Safeware (book on amazon; 1995) 
• Engineering a safer world (free on-line book) (2011)

For more about Edge Case Research and how to subscribe to our video training channel, please see this Blog posting.

Avoiding Embedded System Stack Overflow (Preview)

Here's a summary video on avoiding Stack Overflow. 

Stack Overflow Preview [ECR]


Other pointers on this topic (my blog posts unless otherwise noted):

• Don't Overflow the Stack blog post

Other useful pointers:

• Nigel Jones / Barr Group One hour webinar on stack overflow

For more about Edge Case Research and how to subscribe to our video training channel, please see this Blog posting.

Embedded System Security Pitfalls Tutorial (Preview)

Here's a summary video on Security Pitfalls.  (Hint: security via obscurity doesn't make you secure!)

Security Pitfalls Preview [ECR] 

Other pointers on this topic (my blog posts unless otherwise noted):

• A list of 16 Embedded Security Pitfalls
• Why encryption is often the wrong approach for embedded system security

Other useful pointers:

• Bruce Schneier: Security Pitfalls in Cryptography
• Schneier on Security

For more about Edge Case Research and how to subscribe to our video training channel, please see this Blog posting.

Spaghetti Code and Complexity Tutorial

Here's a preview video on Spaghetti Code and Cyclomatic Complexity.  There is also a full version of this video available for free from the Edge Case Research video library (see below for details).

Notes:

• Also see my blog posting on avoiding high cyclomatic complexity (Blog)
• Toyota Unintended Acceleration and the Big Bowl of “Spaghetti” Code (Safety Research & Strategies Blog)

Spaghetti Code Preview [ECR] .

Full tutorial video: https://vimeo.com/185732981

For more about Edge Case Research and how to subscribe to our video training channel, please see this Blog posting.

Security Plan Tutorial

Here's a preview video on creating a Security Plan.  There is also a full version of this video available for free from the Edge Case Research video library (see below for details).

You might also find these pointers useful:

• MITRE Commone Weakness Enumeration (security)

Embedded System Security Plan Preview [ECR].

Full tutorial video: https://vimeo.com/185255673

For more about Edge Case Research and how to subscribe to our video training channel, please see this Blog posting.

Peer Review Tutorial

Here's a preview video on Peer Review (about 1 minute of content, plus leader/trailer stuff).  There is also a full version of this video available for free from the Edge Case Research video library (see below for details).

Notes:

• Peer review finds half the defects for 10% of the project cost. (Blog)
• But they only work if you actually do the reviews! (Blog)
• If you're finding more than 50% of your defects in test instead of peer review, then your peer reviews are broken. It's as simple as that. (Blog)
• Here's a peer review checklist to get you started. (Blog) You should customize it to your needs.

Peer Review Tutorial Overview [ECR].

Full tutorial video: https://vimeo.com/181433327

For more about Edge Case Research and how to subscribe to our video training channel, please see this Blog posting.

Training Video Series

Summary: My startup company is launching a series of training videos.  Here's an overview.

-------------------------
(This blog posting is an ad for my startup company ... but it also has links to free training videos!)

• Here's a page with a list of the currently available videos

Edge Case Research:

I have a startup company that has built a brisk business in design reviews, robustness testing, and software safety.  We're building on the 20 years and 200 design reviews I've done working with industry partners on a variety of embedded systems. We're also building on my long collaboration with my co-founder Mike Wagner and others at the National Robotics Engineering Center doing autonomy validation and safety.

We do a lot of work with autonomous systems (robots, self-driving cars), but also with consumer electronics and industrial controls. In general the idea is that we have a dedicated team of embedded system experts who can help companies with both the technical aspects of their product and their software development processes. Our strengths are:

• Identifying risk areas in embedded products
• Best-practice assessments & technical practice benchmarking across dozens of risk areas that have been a problem for other project teams
• Autonomous system safety (self-driving vehicles and other robots, but also non-robot systems)
• Robustness testing and improvement
• Hands-on training based on your current project in both technology and just-the-right-weight software development process

If we can help you with your embedded product just let us know!

Free Training Videos:

One of the things we have found is that there are a number of common areas in which our customers (and probably many others) could use some help with in terms of updating technical and process skills.  Thus, we're launching a video training series to help with the topics we most commonly see as we review projects.

To access the full videos for free, visit our video library page here.  If this is successful we'll add more videos over time, possibly requiring registration and/or a subscription for the full library.  But the ones there now are free, and I expect that these particular videos will stay free indefinitely.  Please respect our copyright and substantial investment in creating them by pointing people there to view them instead of trying to download the full length videos.

We also have a YouTube channel with just the previews that you can subscribe to if you want notification of new videos as they come out.

Hope you enjoy these!