This research performs a literature survey of remote user authentication researches based on smart card and external memory. The main security confidence of smart card based schemes is temper-resistance property. Other reasons are small physical size, portability, convenience of non-volatile memory, and security provided by a single chip computer embedded in a plastic card. The most efficient schemes are those that used hash function or ECC. The high cost of the cards and readers and their deployment remains a burden to issuers or users. This is what motivates the use of external memory instead of smart card. But the problem of non-temper resistance property associated with external memory limited researches in that direction. There are also, absence of other activities that are essential in user authentication such as forgot/reset password and re-registration in case the external memory or smart card is stolen or lost in all the reviewed researches.