> I get that error when I just logon to the console normally.  I haven't had
> any time to look into it, though.  A search through groups.google.com turned
> up a suggestion to do a "ps -axf" to see what your process structure looks
> like.  Mine looks like this:

There has been at least one bug on older 2.4 kernels where the initial
console session ends up not being the "controlling terminal" for the session

In the general case the getty (mingetty whatever) should have done the work

For the list in general

Traditional unix terminals:

/sbin/init runs all the time. It uses /etc/inittab as a guide to what should
be running. So

1:2345:respawn:/sbin/mingetty tty1

is a task (identified as 1) which is to run /sbin/mingetty on tty1, and if
it goes away to make more of them.


The getty process waits for a login name to be entered (and in many cases
before that also does modem management). When it gets a name it passes the
control on to another program (normally login). In the olden days this was
very useful because getty is small and login may not be. Getty sits around
all the time so it was important it was small.

Login decides what to do with the username. Normally ask for a password.
Having received a valid login/password it logs various things (for
last, lastlog, who and friends),  it makes the user the owner of the
terminal, and it runs their login shell. The shell is run with a "-" at the
start of the name to indicate it is a login shell.


Originally unix just used a password file /etc/passwd. Then people like Sun
added Yellow Pages which became NIS (due to trademarks I believe). Others
added shadow passwords, LDAP, SQL based lookups, kerberos, hesiod ...

After a while login ceased to be pretty code. The PAM loadable modules allow
the authentication to be seperated from the programs using it. If for example
you have a user database in your own strange format (eg a non UNIX VM session)
you can go off and write a new PAM module and _all_ the system tools
will now suport it. PAM modules have been written for things as unusual as
fingerprint scanners.

Alan

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