Description:

The term 'lokin' was borrowed during the early or middle period from the English 'log in'. It existed in a number of forms until the early modern period when the AXZ standardised its spelling, pronunciation and meaning.

Be careful about making assumptions about its usage based on its English etymology, because it has become something of a false friend. The modern base meaning is something like 'access', and it is no longer specific to the domain of computers. 

Verb:

In a verbal context, lokin is a transitive skurun verb the takes an ergative subject that is the entity gaining access and an absolutive direct object which is the thing accessed. The object can refer to the actual material accessed or to the repository where the material resides. It is not periphrastic, as the English origin would lead you to expect - saying something like, 'Je tene lokin a lenatrop,' 'I have logged in to the server,' or 'I have accessed the server' can feel a bit weird to English speakers - the latter idea is a better way to think about it.

Noun:

As a noun, 'lokin' can refer either to an instance of gaining access or access as a generality. It is reasonable to say something like, 'Je te sif a lokin na lenatrop,' meaning 'I have the ability to access the server'. The driver term 'lokinysyn' refers to access as an abstraction.

Referring to having access to something is as shown above, Common expresses it more like having access of something, using the null preposition construction.

Modifier:

The derived form 'lokinys' can have the sense of 'accessible' when applied to something you might want to access, or when applied to an agent like a person, had a vague sense that this person has a lot of control and access to things of interest (that sense could be conveyed less ambiguously with 'lokincas')