Computing device mainly provides means of summarising information (5)
I believe the answer is:
table
'means of summarising information' is the definition.
(eg a table of statistics)
'computing device mainly' is the wordplay.
'computing device' becomes 'tablet' (eg an iPad).
'mainly' means to remove the last letter.
'tablet' with its last letter taken off is 'TABLE'.
'provides' acts as a link.
(Other definitions for table that I've seen before include "Statistical chart" , "Horizontal furniture" , "shelf" , "Index" , "Submit for consideration" .)