How to find which swap in use?

[Timothy Murphy]

A very old (11 years?) but much loved desktop
has developed a nasty habit of stopping me editing
because the file, it says, is Read-only.

I suspect this is because the swap partition
(on an even older SCSI disk) is not functioning.

How does one find which swap device or devices is in use?
("top" says there is 2GB swap space, but 0k in use.)

And is there any other likely cause of the Read-only disease?

-- 
Timothy Murphy  
e-mail: gayleard /at/ eircom.net
tel: +353-86-2336090, +353-1-2842366
s-mail: School of Mathematics, Trinity College, Dublin 2, Ireland