What is a good antonym for "redundant" (engineering)?

What is a good antonym for redundant?

The definition I am looking to find an antonym for is:

Source: Dictionary.com

Redundant

adjective

  1. Engineering.
    ...
    d. (of a device, circuit, computer system, etc.) having excess or duplicate parts that can continue to perform in the event of malfunction of some of the parts.

Wikipedia has a page that uses this definition. Wikipedia defines this kind of redundancy as "duplication of critical components".

Used in a paragraph, "A software product can be installed redundantly or [non-redundantly]. The purpose of installing the product redundantly would be to allow for high availability. If one side goes down, then the other side immediately takes over. This is common practice in hardware and software industry."

I prefer a single word, but a phrase is also acceptable. I also prefer neutral or positive connotations. "Low availability" has negative connotations.


Solution 1:

Just negate the term with non- to form non-redundant (or nonredundant). As with redundant itself, an engineering context directs the reader or hearer to understand the term in the engineering sense.

Wiktionary gives primacy to the closed spelling; OED offers only the hyphenated one, with examples but no definition (since defining the negation of redundant would be redundant).

Solution 2:

That missile is a single point of failure device, which is why it's not man rated.