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Date:      Fri, 19 May 1995 11:02:52 -0400
From:      Garrett Wollman <wollman@halloran-eldar.lcs.mit.edu>
To:        sven@stack.urc.tue.nl (Sven Berkvens)
Cc:        freebsd-questions@FreeBSD.org, unix@stack.urc.tue.nl
Subject:   Lots of questions (retry - sorry!)
Message-ID:  <9505191502.AA24815@halloran-eldar.lcs.mit.edu>
In-Reply-To: <199505190910.LAA16095@zen.stack.urc.tue.nl>
References:  <199505190910.LAA16095@zen.stack.urc.tue.nl>

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<<On Fri, 19 May 1995 11:10:26 +0200 (MET DST), sven@stack.urc.tue.nl (Sven Berkvens) said:

> I mention the above because it may have something to do with my qeustion:
> when I type 'arp -a' to view the ARP cache, all it says (on all three
> machines) is:

> ? (0.0.0.0) at (incomplete)

This is a fairly clear indication that your `arp' binary doesn't match
the kernel.  Other route-related binaries use a different interface to
the kernel and would return an error if they were out of date, but
`arp' just reads the routing table and prints out those entries that
are related to the Ethernets.

> Also, I cannot query a host for its ARP address:

> Turtle: /home/sven> arp zen
> zen (131.155.140.130) -- no entry

All this does is look up the entry in the routing table, and as we've
already established, your `arp' binary isn't capable of doing that.

> When ELM does a read(2) to check for terminal input, read(2) returns
> 0 (I guess as an EOF condition).

Actually, it returns -1 (an error) with errno set to EIO because of a
bug.

> ELM interprets this wrong (so does TIN for example) and does not see
> this as an error; even worse, these programs interpret it as a
> keystroke.

Yes.  These programs are broken.  This used to be a big problem with
`vi'.  Terry Lambert will claim that this is a job control problem; I
don't believe that.

> Why does the tty/pty immediate get chown(2)'ed back to root (and more
> important: who does this??) instead of leaving it behind as it was and
> then chown(2)-ing it to another user when necessary (like on SVR4)?

Security.  This greatly reduces the opportunity for someone to
``capture'' a PTY before some unsuspecting (and broken) program tries
to open it.  As to who does it, that's the responsibility of the
exiting telnetd, rlogind, or xterm.

> Another question: is there a stat-daemon available for FreeBSD?

Meaning what?

> Will the new version of FreeBSD be able to handle bad sectors on disks and
> harddisks? 

Yes.

> And what about bad sectors in the swap partition?

It's part of the `disk'.

> And why isn't
> it (yet) possible to swap out of a file?

Because it's not important enough for someone to have implemented it.
You can kluge around this by configuring a `vn' device into your
kernel (read vn(4) and vnconfig(8)), and then enabling swapping on it.

-GAWollman

--
Garrett A. Wollman   | Shashish is simple, it's discreet, it's brief. ... 
wollman@lcs.mit.edu  | Shashish is the bonding of hearts in spite of distance.
Opinions not those of| It is a bond more powerful than absence.  We like people
MIT, LCS, ANA, or NSA| who like Shashish.  - Claude McKenzie + Florent Vollant



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