In my opinion it's all MontaVista's fault! The problem began when they announced a "fully preemptable hard real-time Linux kernel."



Then came the debate about whether their kernel was or was not fully preemptable, and whether or not it was truly hard real-time. But that's not where the debate ends. Nobody thought of questioning another aspect of MontaVista's release -- namely: had they spelled "preemptable" correctly?

You'd think we could all at least agree on a simple thing like how to spell a word! Some words, though, seem destined for controversy. Some challenge even the experts -- perhaps, even their inventors. This can easily occur when a word is coined to describe some new situation, category, or technology.

We all know what it is to preempt something. We understand the concept of preemption, as the act of preempting. But what word do you use to describe something (like software) which is able to be preempted?

"Preemptable," of course. Or . . . is it "preemptible"?

Putting it to a "vote"

You'd think something this simple would be easy to determine. Nevertheless, I failed to find either version of the word in any of my dictionaries or spell checkers. So, why not simply put it to a vote? How about searching on the 'net to see which spelling is more widely used?

That I did (using Linux-powered Google, of course), and here is what I found . . .

• Preemptable -- 2590 occurrences
  
• Preemptible -- 1260 occurrences

So, on the basis of usage frequency, the winner appears to be "preemptable".

But is popularity really the best measure of what's right?

Enter, the "experts"

In search of a more intelligent approach, I put the question to half a dozen companies that specialize in real-time (preemptable?) operating systems. Surely they must know how to spell a simple word like preemptable (preemptible?).

Here's what I learned . . .

• Phil Wilshire (of Lineo Industrial Solutions, formerly Zentropix): I voted for "ible" until I saw this. Now I am a firm "able" fan!
  
  
• Dr. Douglas Locke (VP Technology of TimeSys): You'll be amused that a couple of us have actually had this discussion recently, and we didn't completely agree. The word seems not to be used outside the field of computers at all. Personally, I have consistently used "preemptible" in my writing for years, but I really can't make a claim for authority here.
  
  
• Srini Vasan (CEO of TimeSys): I prefer "able". But then, Doug prefers "ible". Guess you could use either!
  
  
• Myron Zimmerman (Founder and CTO of VenturCom): IBM, Microsoft and VenturCom generally use "ible". But you will find occasional docs from these organizations to the contrary. Another question, is whether there is a hyphen in real-time or not. (Good question, Myron!)
  
  
• Steve Furr (Senior Software Architect and "closet linguist", QNX): Interesting question. I think either is acceptable. I lean towards "ible", but I suspect QNX tech writers have their own corporate standard. I suspect that my leaning is because I have probably seen it more in the literature, and it feels right to me.
  
  The Phonological View: The real difference is probably both dialectal and idiolectal due to differing pronunciation based on obscure phonological rules particular to the dialect or individual. I suspect for me, I have become accustomed to using -ible -- which has a higher vowel -- in most cases where it follows a stressed syllable, as in forcible, terrible, possible. Many English dialects, however, have experienced a shift to laxer vowels in such situations, so the schwa sees more common use (i.e. suggesting -able in more situations).
  
  The Pragmatic View: Since English is a living language, I think that more people also prefer to use -able today as it is more commonly applied. Note that -able in modern English is extended to verbs of all conjugations, including verb phrases, unlike -ible forms or traditional prescriptive English grammar. In other words, the flexibility of -able wins out in the shift to simpler patterns in English in a kind of Darwinian selection, with the exception of -ible words in common usage.
  
  Conclusion: Pick one and stick with it. I suspect more American English speakers will be comfortable with the -able form for the reason above. Sorry you asked? ;-)
  
  
• Bill Weinberg (Director of Marketing and "closet linguist", MontaVista): Definitely preemptible. Both Word's spelling checker and the dictionary agree (although my mail program likes neither).
  
  The etymology determines the correct spelling: Preemptible is a derivative of preempt, which is a back formation from preemption, derived from Latin pre- (before) and emere (to buy, e.g., emporium, caveat emptor) and originally meant to "buy first", or "prepurchase".
  
  From American Heritage . . .
  
  1. a. The right to purchase something before others, especially the right to
  purchase public land that is granted to one who has settled on that land. b. A
  purchase made by such a right. 2. Prior seizure of, appropriation of, or claim
  to something, such as property.
  
  Latin verbs ending in -ere and -ire take i-base suffixes. QED: preemptible, not preemptable.

OK, that settles it. Sort of.

I decided to go with the advice of the (amateur) linguists, and use "preemptible" from now on. But before completely settling on that spelling, I decided to check on one more thing, namely: what's the correct spelling of "interruptable"?

Here, we have a word that benefits from being a long-time member of our language. Thankfully, my monster dictionary did contain an "ible vs. able" opinion on that one -- and it's "ible". Interruptible, that is.

That settled it for me! From now on, I'll spell preemptable "preemptible". On the other hand, given the amount of disagreement among the experts, you're probably safe spelling it which ever way you prefer!

By the way . . . how do you spell "real-time"? ;)

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