[Phpgroupware-developers] Should and Shall in standards

[Andrew M Cohill]

>     It uses the words "you should not inlcude GIF's in..." it does *not* say
>     "you cannot" or "you shall not". It says "should not", which implies an
>     option.
>
> It is a requirement, not an option.  This file always states
> requirements with "should not", never "cannot" or "shall not".  The
> file uses "cannot" only for factual statements about what is possible,
> and never uses "shall" at all.

 I was a member of the ANSI Standards Committee HFES-200 (Software 
Ergonomics) for more than 10 years.

All ANSI standards  use "should" and "shall" in this way:

Should-- strongly encouraged to do it, but it is not required.

Shall--to be in compliance with the standard, you must do it.

We also were part of the ISO 9241 Standards Committee, and the 
Europeans also followed this practice.

Andrew
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Andrew Michael Cohill, Ph.D.
Director, Blackburg Electronic Village
address@hidden    http://www.bev.net/