[SystemSafety] The States and Modes debate

[Prof. Dr. Peter Bernard Ladkin]

On 2026-05-22 01:27 , Les Chambers wrote:
>
> In these contexts, synonyms abominate the functional Safety countryside. They must be hunted down 
> and eliminated with extreme prejudice - along with the “qualitative state machine(s)” they rode in 
> on.
>
First, it seems silly to me to renounce synonyms. In the 61508 context, it would be ridiculous to 
insist people say/write Equipment Under Control when they can write EUC and even more ridiculous to 
insist they say/write Equipment Under Control Control System when they can say/write EUCCS.

Second, you seem to have a prejudice for working with numbers when it comes to state machines. 
That's fine, I guess, as a personal preference. But if you perform any system development using 
formal methods (which 61508 now says is "highly recommended" for any safety function) you will very 
quickly have to get used to manipulating state machines which work on symbols which are not numbers. 
For almost all formal verification techniques for the last 57 years use them or some equivalent.

PBL

Prof. Dr. Peter Bernard Ladkin
Causalis Limited/Causalis IngenieurGmbH, Bielefeld, Germany
Tel: +49 (0)521 3 29 31 00