pronunciation - How should the first "o" in "operator" be pronounced?

I've always been taught that a vowel before a double consonant following another vowel should have a short sound. Conversely, there are many situations where a vowel preceding a single consonant and vowel gets a long sound.

Short Sounds:

Mississippi    - All I's except the last get short sound
Communication  - First O gets short sound
Oppose         - First O gets short sound where second O gets long

Long Sound:

Ape            - A gets long sound
Popery         - O gets long sound
Oppose         - First O gets short sound where second O gets long

Yet, I hear people use a short O in "operator" when using the word. Is this the correct pronunciation?

Answer

Indeed, it is. 'Operator' is pronounced ˈɒpəreɪtə (IPA), with the o- sound of 'offense' or 'orange'.

Most spellings as we use them today were standardized in the late 18th century on a fairly arbitrary basis. Most choices were based in common transliteration habits, but others followed historical convention. In this case, 'operator' had been historically spelled with a single p thanks to its root the Latin 'operari', and so the habit stuck.

Edit: I'm aware our American cousins have some regional variations, but these accents evolved more recently.