Most places use the terms interchangeably. And most of us probably do a little of both. I think in the purest form:
- Engineer: Mostly design and integration work.
High-level understanding of implementation and operations.
More knowledge of business practices and goals from a technical POV. Maybe even his career is tied to a certain industry.
His sh*t rolls down hill to the admins.
Not concerned with hardware/software/programming language/shell selections, as long as it conforms to predefined standards and will perform to the needed spec.
Not on an on-call rotation, although could be called in off-hours if a **really** big problem occurs.
- Admin: keeps the systems running.
Intimate understanding of implementation and operations.
More flexible in job selection (for most admins it doesn't matter if they are working for a shoe company or a finance company) although the amount of pressure will vary from industry to industry.
On-call duties.
His sh*t rolls down hill to the NOC and the Help Desk.
Very concerned with hardware/shell/software/language selections.
If there is a clear differentiation between the two levels, both should have influence on the other. (or else the admin positions will turn over frequently).