All the apostrophes look like a little nine: in contractions like it's, and the possessive 's.
That's the character that was included in the American Standard Code for Information Interchange.
Image: http://www.worldpowersystems.com/J/codes/X3.4-1963/page5.JPG
The glyph appearing in the standard looks like a little 9. It is denoted as "APOS" in parentheses. A reference to it is made in A6.8, calling it "apostrophe".
Wikipedia's (https://en.wikipedia.org/wiki/Apostrophe) page refers to a vertical notch glyph as a "typewriter apostrophe". The normal non-typewriter apostrophe looks like a comma.
Okina? That indicates a glottal stop in some languages none of which are English, and so which were understandably not represented in the American Standard Code.
