[SystemSafety] Agile methods

Mon Sep 2 18:40:29 CEST 2013

All,
I have personal experience using Agile, and personal experience doing safety-critical development (DO-178B), but not personal experience doing agile development for a safety critical system. Instead of being polarizing and claiming "it can't be done", I'll simply say that I believe that it is possible to do it—it could just end up being very costly to do so. The worst case would be developing the code for the system in an truly agile way, and then looping back and re-developing it with the necessary safety analysis, etc. in place using more traditional processes.

All that said, I have a report titled, "AAMI TIR45: 2012 Technical Information Report      Guidance on the use of AGILE practices in the development of medical device software". AAMI is the "Association for the Advancment of Medical Instrumentation" and they're based at
4301 N. Fairfax Drive, Suite 301
Arlington, VA   USA    22203-1633
www.aami.org

The report abstract states, "Over the past several years, AGILE software development has become an accepted method for developing software products. There have been questions from both manufacturers and regulators as to whether (or which) AGILE practices are appropriate for developing medical device software. Enough medical device manufacturers have implemented AGILE practices in their software development so that answers to these questions can be documented. Having clear guidance of which practices have been found to be appropriate will be very useful for all developers of medical device software. This TIR will provide recommendations for complying with international standards and U.S. Food and Drug Administration (FDA) guidance documents when using AGILE practices to develop medical device software."

A preview copy is at:
http://marketplace.aami.org/eseries/scriptcontent/docs/Preview%20Files/TIR45_1208_preview.pdf

I have a licensed copy, but it's copyrighted material and can't be shared. If you're really interested in the content, you'll have to get a copy on your own (sorry).

Having said that, three comments about all this:

1) I don't know what sort of status AAMI has with respect to FDA policy on medical device software development. In other words, I don't know if the FDA has actually agreed to this, or it's simply AAMI's suggestion on how one might approach it.

2) The AAMI approach talks about agile development in a way that's very consistent with how most competent people would characterize agile development.

3) I took a look at the Bruce Douglass report that Geoffrey Biggs mentioned (Thanks, Geoffrey)
http://www.ibm.com/developerworks/rational/library/agile-analysis-practices-safety-critical-development/
I've worked with Bruce before, and I have a lot of respect for his work. However, I'd be willing to bet that most people who really understand what agile development is could easily argue that the Harmony method discussed by Bruce would not be considered agile. It's clearly iterative, but iteration alone does not constitute true agility. *I* wouldn't consider the Harmony method described by Bruce to be truly agile.

-- steve

From: René Senden <rene.senden at gmail.com<mailto:rene.senden at gmail.com>>
Date: Monday, September 2, 2013 8:32 AM
To: 'M Mencke' <menckem at gmail.com<mailto:menckem at gmail.com>>
Cc: "systemsafety at techfak.uni-bielefeld.de<mailto:systemsafety at techfak.uni-bielefeld.de>" <systemsafety at techfak.uni-bielefeld.de<mailto:systemsafety at techfak.uni-bielefeld.de>>
Subject: Re: [SystemSafety] Agile methods

Myriam,

You are right about my initial question being somewhat polarizing, perhaps because I tacitly assumed that anyone who’d answer this question with “Yes”, would also include some
of the corresponding experiences … Regarding experience with reconciliation of agile environments with typical/common/… (software) safety standards, I am very interested in the
development processes and corresponding results/evidence/outputs, all this should be auditable. Is it (at all) possible to harmonize these very different worlds, or would any such
attempt result in compromising either? Transparency, auditability, documentation, and safety specific processes such as analyses are examples that, to me, seem to be particularly
difficult to address in an agile environment, let’s take “scrum” as an example of a popular agile approach.

Rene

From: systemsafety-bounces at lists.techfak.uni-bielefeld.de<mailto:systemsafety-bounces at lists.techfak.uni-bielefeld.de> [mailto:systemsafety-bounces at lists.techfak.uni-bielefeld.de] On Behalf Of M Mencke
Sent: maandag 2 september 2013 14:39
To: Jon Davies
Cc: systemsafety at techfak.uni-bielefeld.de<mailto:systemsafety at techfak.uni-bielefeld.de>
Subject: Re: [SystemSafety] Agile methods

René,

I have come across a situation in the railway field where an organization was required by the customer to comply with a safety standard which has specific requirements on the software development process, in this case, EN 50128, where this was previously not required.

It seems to me that this type of situation typically arises in industries/products where the SIL concept has traditionally not been applied, or is being introduced. The customer creates a “SIL requirement” as a type of marketing argument, where the SIL is understood by the customer as applying to equipment rather than to a function (in order to be able to state “This equipment is SIL X” in commercial scenarios).

Regarding your question, “Have you encountered a situation, in industrial practice, in which an organization developing software following an agile methodology has to comply with a safety standard which has specific requirements on the software development process?”

This is a polar question, which can only be answered with a yes/no.

If you are interested in practical experience, it might be useful to add to this question which aspect(s) of such a situation you are interested in. For example, if the answer is “yes”, was the project actually a success? Which measures/procedures were implemented in the company to approach this problem and reconcile the development process with such requirements?, etc.
Depending on the type of information you are seeking, it may not be possible to provide particular details regarding such a state of affairs, as this information may be company-specific.
Regards,
Myriam.

2013/9/2 Jon Davies <jdavies at theiet.org<mailto:jdavies at theiet.org>>
On 30 August 2013 18:02, René Senden <rene.senden at gmail.com<mailto:rene.senden at gmail.com>> wrote:
> Dear all,
>
> Do any of you have practical experience with reconciling established agile
> software development with software safety requirements (e.g. IEC-61508 or
> DO-178..) ?
Yes, and we usually end up throwing away the software developed using
"agile" methods, and starting again properly.

I'm taking "agile software development" as meaning the development of
software using processes consistent with the agile manifesto:
http://agilemanifesto.org/ - to quote the relevant part:
"...we value... working software over comprehensive documentation"

this is fundamentally in conflict with many of the things we know
about building high integrity software, and so "agile" methods are
fundamentally in conflict with developing software for safety critical
systems.

There's plenty to learn from agile development methods that might be
useful in high integrity software development, but that's a whole
different discussion.  Every time we discuss agile development here,
we end up back at the need to use a development process that builds in
correctness - we can't test exhaustively, so we need a process that
builds integrity in.  Agile methods don't do this.

Jon
_______________________________________________
The System Safety Mailing List
systemsafety at TechFak.Uni-Bielefeld.DE<mailto:systemsafety at TechFak.Uni-Bielefeld.DE>

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.techfak.uni-bielefeld.de/mailman/private/systemsafety/attachments/20130902/1d5020ee/attachment-0001.html>