+-----------------------------------------------+
| Flag | Meaning | Possible values |
|------+-----------------+----------------------|
| E | Error | Space, R, I |
|------+-----------------+----------------------|
| I | Installed State | Space, *, -, U, C, I |
|------+-----------------+----------------------|
| O | Old Mark | *, -, =, _, n |
|------+-----------------+----------------------|
| M | Mark | *, -, =, _, n |
+-----------------------------------------------+

Rather than spell all this out here, I refer you to the Help screens where
all is revealed. One example, though.

You enter dselect and find a line like this:

EIOM Pri Section Package Description

** Opt misc loadlin a loader (running under DOS) for LINUX

This is saying that loadlin was selected when you last ran dselect and
that it is still selected, but it is not installed. Why not? The answer
must be that the loadlin package is not physically available. It is
missing from your mirror.

The information that dselect uses to get all the right packages installed
is buried in the packages themselves. Nothing in this world is perfect,
and it does sometimes happen that the dependencies built into a package
are incorrect, which means that dselect simply cannot resolve the