Seagate HD not detected by FreeBSD

[Ted Mittelstaedt]

> -----Original Message-----
> From: owner-freebsd-questions at freebsd.org
> [mailto:owner-freebsd-questions at freebsd.org]On Behalf Of Svein Halvor
> Halvorsen
> Sent: Sunday, May 29, 2005 4:49 AM
> To: Ted Mittelstaedt
> Cc: Ulf Magnusson; freebsd-questions at freebsd.org
> Subject: RE: Seagate HD not detected by FreeBSD
>
>
>
> * Ted Mittelstaedt [2005-05-29 00:05 -0700]
> >  Wrong.  Each IDE cable can have 2 devices a master and a
> slave.  So if
> >  you have 2 IDE controllers you can have master, slave,
> master, slave
> >  for a total of 4 drives.
> >
> >  It is not master on ide cable 1, slave on ide cable 2.
>
>
> There's nothing wrong with having a primary master and a
> secondary slave,
> just as much as there is nothing wrong with the setup you proposes.
> _______________________________________________
>



According to the UDMA/66/100/133 standard, which REQUIRES an 80-pin
cable, a
SINGLE drive on the bus MUST BE connected to the BLACK end connector NOT
to
the GREY slave connector, OR to the BLUE motherboard connector.  On this
setup
the BLUE end connector MUST BE connected to the motherboard.  The only
time it
is permissible to connect a drive to the GREY slave connector is when
there
are TWO DRIVES on the cable.

This requirement is because of cable termination issues - at high speed,
an
unterminated black connector with a terminated grey connector causes huge
amount of noise and can disrupt high speed transfers.  This is the same
issue
as SCSI cables, by the way.

According to the Microsoft's PC97 AND the ATA Plug and Play standard,
(ATA-2
and ATA-3) drive cables all must follow the Cable Select standard, AS
MUST
hard drives.  CS removes pin 28 on the SLAVE connector.

So on a correctly setup modern system, BOTH DRIVES have the CS jumper
set,
and if the drive is plugged into the black master connector it is
automatically
selected as master, and if the drive is unplugged from that connector and
plugged to the grey connector it is automatically setup as a slave. Since
the standard requires a single drive on the controller to be plugged into
the end of the cable - for termination reasons - with CS set, by default
the
standard requires a single drive to be master.

So yes, there is something wrong with a primary master and a secondary
slave.  Just because it works on a lot of motherboards, and just because
it
worked in the past on old incorrectly manufactured IDE cables, running
in PIO mode, doesen't make it per-standard, and definitely doesen't make
it
right electrically if using CS, as per the standard.  As I said already,
motherboards take a lot of shortcuts and do a lot of non-standard things.

Ted