At base, a computer has a bulk equal to its tier squared. Computers with light bulk or negligible bulk can be worn easily on the wrist or clipped to communications devices and used without having to hold them in a hand. Any computer with a bulk of 1 or more must be held or set on a sturdy surface to be used. (Example: Tier 2 Computer would equal 4 Bulk {2x2=4}).
Under Upgades/Miniturization: Treat your computer as 1 tier lower when calculating its bulk, to a minimum of tier –1. A tier-0 computer has light bulk, and a computer of tier –1 has negligible bulk. You can buy this upgrade multiple times. Each time it costs 10% of the base price
of the computer. So would the example tier 2 become a tier 1 (1x1=1) for bulk? Or would you reduce the bulk of 4 to a 3?
It reduces the effective tier of the computer, so you apply the reduction before squaring. If it just reduced the bulk of the computer by one, it would say so.