I use a Rolodex. Yes, I trust the (inanimate) thing, and yet, I do keep it under lock and key. The entries are hand written ... so no printing effort, so no files of entries exist on any computer. The handwritten entries are not literal, and disproportionally filled with e's and i's. It is transportable in that is is reasonably compact. It travels well but is somewhat 'fragile'. It has no electronics, no batteries, no chargers, no software and no electronic connections.