Program logic bugs vs input/environmental errors

[Kagamin via Digitalmars-d]

On Friday, 31 October 2014 at 20:33:54 UTC, H. S. Teoh via 
Digitalmars-d wrote:
> You are misrepresenting Walter's position. His whole point was 
> that once
> a single component has detected a consistency problem within 
> itself, it
> can no longer be trusted to continue operating and therefore 
> must be
> shutdown. That, in turn, leads to the conclusion that your 
> system design
> must include multiple, redundant, independent modules that 
> perform that
> one function. *That* is the real answer to system reliability.

In server software such component is a transaction/request. They 
are independent.

> Pretending that a failed component can somehow fix itself is a 
> fantasy.

Traditionally a failed transaction is indeed rolled back. It's 
more a business logic requirement because a partially completed 
operation would confuse the user.