Software in Medical Devices, by MD101 Consulting - Tag - critical software - CommentsBlog about software medical devices and their regulatory compliance. Main subjects are software validation, IEC 62304, ISO 13485, ISO 14971, CE mark 93/42 directive and 21 CFR part 820.2024-03-27T15:32:28+01:00Cyrille Michaudurn:md5:9c06172e7cd5ed0f5b192883b657eabbDotclearProbability of occurence of a software failure - Aliurn:md5:7e8227ed3f3475cabe2387a313d05a9f2022-02-16T14:50:24+01:002022-02-16T14:50:24+01:00Ali<p>Thank you for this informative post. But I think, in some places you calculated the total probability by multiplication (if the events be dependent, you have to calculate the total probability by conditional probability formulas).</p>En route to Software Verification: one goal, many methods - part 2 - Mitchurn:md5:fb0b14f8979d67678a47fc779f0ae3032020-03-18T11:26:30+01:002020-03-18T11:27:41+01:00MitchHi Sebastien,
I'd say why not, IEC 62304 doesn't require to have automated tests. You should however be prepared to answer to auditor's questions about the rationale of having only static code analysis and code reviews.En route to Software Verification: one goal, many methods - part 2 - Sébastienurn:md5:b2587c315fe331429bc0e6d434c4c7942020-03-05T17:27:15+01:002020-03-18T11:24:08+01:00SébastienHello Cyrille,
Can static code analysis or code review be considered sufficient methods of verification of software units for a DM class B?Probability of occurence of a software failure - Mitchurn:md5:a8cd1f727b7ae1df5ba1cbe98ce59d932018-02-17T17:02:42+01:002018-02-17T17:03:32+01:00Mitch<p>Hi Hans,</p>
<p>You're right :-) That's the purpose of IEC 62034. But ISO 14971 is there to force you to find mitigation actions specific to your software with top priority for "safety by design".</p>Class A, B and C. Is it possible to reduce the documentation of detailed design of software medical devices? - Mitchurn:md5:731139c74309320a3eb0df0e780646422018-02-17T16:56:02+01:002018-02-17T16:56:02+01:00Mitch<p>Hi Murielle,</p>
<p>The hardware risk control is required to downgrade form C to B or B to A without isolation/segregation. But according to 4.3.d, the segregation can be software/logical or hardware/physical. But you shall bring strong rationale for a logical segregation. Usually, it is better admitted to have logical separation between classes A and B, and physical between C and B.</p>
<p>Bye.</p>Probability of occurence of a software failure - Hansurn:md5:8afac24eedf6e1eb87b65ff13adc1d272018-02-16T22:26:22+01:002018-02-16T22:26:22+01:00Hans<p>Thanks for the article.</p>
<p>Where you wrote "The main mitigation action of risks linked to software failures generated by defects is applying the IEC 62304 standard," I was wondering if "Software developed using IEC 62304" would be documented as the risk control on the hazard analysis.</p>
<p>It seems like this would end up being a risk control for all software-related hazards because all the software would be written to IEC 62304.</p>Class A, B and C. Is it possible to reduce the documentation of detailed design of software medical devices? - Murielleurn:md5:540bfc56fcd2f03177a8bde98a5469162018-01-26T15:06:19+01:002018-02-17T16:49:05+01:00Murielle<p>Thank you for this post<br />
I have a question<br />
You write that the "The isolation may also be physical". So I assume that the interface may be done by software (for exemple with mutex, queue if using an OS).<br />
But when I read EN62304:2006 4.3.a, there is only hardware risk control measure which can reduce the software safety classification.<br />
So the interface can be only physical with consequence to run software items on separate hardware or I'm wrong in comprehension?<br />
Thanks for your response</p>Class A, B and C. Is it possible to reduce the documentation of detailed design of software medical devices? - Mitchurn:md5:ebe4d8e4190f037be2f7e08ff14a4cf62017-12-08T16:00:41+01:002017-12-08T16:00:41+01:00Mitch<p>Thanks for your feedback.</p>
<p>Yes, it's possible to downgrade from class C to class A with two mitigation actions.</p>Class A, B and C. Is it possible to reduce the documentation of detailed design of software medical devices? - Mathieu Febvayurn:md5:09a67e0aebfc23cfe2a5d1cded2130112017-12-05T17:16:57+01:002017-12-05T17:16:57+01:00Mathieu Febvay<p>Thank you for this trick !</p>
<p>However, when you isolate your software like you did, is the interface manager mandatory class B ?</p>
<p>Is it possible to switch from class C item to class A with risk mitigation measures (CRC and another hardware/software checks the class C item) ? (EN62304:2006 4.3.a explains that is possible to switch from class C to class B AND from class B to class A)</p>
<p>Again, thank you for all your valuable informations.</p>
<p>Mathieu.</p>Probability of occurence of a software failure - Martinurn:md5:e210fd6ce3faf4e3e0314c966020aa802012-12-05T16:06:07+01:002012-12-05T16:06:07+01:00Martin<p>We had the exact same discussion in one of our projects the other day. I usually read new posts on your blog, but I must have missed this one...</p>
<p>btw. I always recommend your blog to people I work with. It's often easier to get them to read this instead of looking into IEC/ISO documents =)</p>