I am using MacOSX Snow Leopard.
How do I achieve page-up and page-down?
If you have a full keyboard you can use the pgup and pgdown keys on your keyboard, near the numpad.
If you are not using a full keyboard, function, labeled fn on your keyboard, plus the up and down arrow keys will give you a page up and down.
It's true that the hardware keyboard on Macintosh machines has:
Fn + ← = Home
So these "keys" fully exist already. This is apparent if you run Linux/Windows natively on your Mac.
However, OS X applications are responsible for handling these functions as they see fit, which is not something most of us expect. And the OSX Terminal application needs some tweaking to use them as we all expect.
I guess OS X follows an old school Unix tradition where
ctrl + a = Home
I now use this routinely, but my terminal-reflexes still demand a proper home,end,pg-up,pg-down...
Edit OS X's Terminal Keyboard Binding Settings to match
I tend to get this entered by copying a similar entry that already exists and then using that delete a character button to remove the different bits before typing in the rest.
Overall, this will look along these lines:
This meets all my expectations for how this should work. It works in vim and through ssh.
I'm somewhat fascinated how this remains an OSX issue, though I also understand that there's a purist Unix thing going on here. Just, most of us kids aren't coming from old-school Unix-land, but rather Linux.. But I digress.
If you use KeyRemap4Macbook app, check under "Change Arrrow Up/Down/Left/Right" keys.
When you have this set up, Page Up and Page Down will work with irrsi – I log-on remotely to another linux host for that – you only need to press Shift + Page Up or Page Down will work for that window (as opposed to scrolling pages of OS X terminal window).
Successfully tested on my brand new MBPro retina !