What is ata2 ?

[Joel]

> >>I'm running FreeBSD on a range of PCs, from
> >> Pentium-1 (60 MHz) to Pentium-4 (2.60GHz), though
> >> none but one has a 'ata2' line in the dmesg output:
> >>
> >> ata0: channel #0 on atapci0
> >> ata1: channel #1 on atapci0
> >> ...
> >> ata2: <Generic ESDI/IDE/ATA controller> at port
> >>       0x36e-0x36f,0x168-0x16f irq 10 on isa0
> >> ad0: 6149MB <QUANTUM FIREBALL EX6.4A/A0A.0D00>
> >>      [13328/15/63] at ata0-master UDMA33
> >> ad1: 4892MB <QUANTUM FIREBALL EL5.1A/A08.1100>
> >>      [10602/15/63] at ata0-slave UDMA33
> >> acd0: CDROM <GCR-8521B/1.02> at ata1-master PIO4
> >>
> >>What is so special about this particular PC, that
> >>it has an ata2, unlike all other PCs I have?
> >>
> >>Can I add more than 4 disks (2 masters + 2 slaves)
> >>to this PC? Or is this ata2 for something else?
> > 
> > From here, with the limited information you've
> > provided, I'm guessing you can, if you have the
> > cables and the spare power connectors.
> 
> I'm quite keen on trying to understand this.

yeah, yeah

> So let me try to provide more information below.
> 
> As above lines show, the ata2 controller is on
> interrupt 10:
> 
>  # vmstat -i
>  interrupt                          total       rate
>  irq0: clk                       10392173        100
>  irq1: atkbd0                           1          0
>  irq3: sio1                           219          0
>  irq4: sio0                             1          0
>  irq8: rtc                       13301014        128
>  irq11: rl0 uhci0                  187119          1
>  irq13: npx0                            1          0
>  irq14: ata0                       491426          4
>  irq15: ata1                           46          0
>  Total                           24372000        234
> 
> But interrupt 10 is not there !?!

You were expecting interrupts on irq10? Where would they come from?

>  # atacontrol list
>  ATA channel 0:
>     Master:  ad0 <QUANTUM FIREBALL EX6.4A/A0A.0D00>
>              ATA/ATAPI revision 4
>     Slave:   ad1 <QUANTUM FIREBALL EL5.1A/A08.1100>
>              ATA/ATAPI revision 4

I count two hard disks on the primary channel of your first ATA
controller, which is probably on the motherboard itself. Not to unusual,
although very few controllers allow you to access both drives
concurrently.

>  ATA channel 1:
>     Master: acd0 <GCR-8521B/1.02> ATA/ATAPI revision 0
>     Slave:       no device present

I count one CD drive on the secondary channel of your first ATA
controller. That's standard, since mixing CD-drives and HD drives on the
same controller tends to produce less than satisfying results.

If you look at the motherboard, you should see two sockets grouped
together, with ribbon cables trailing off to the drives. One cable will
have two hard drives plugged into it, the other should have the end
plug plugged into the CD drive and the middle plug empty.

>  ATA channel 2:
>     Master:      no device present
>     Slave:       no device present

As has been suggested, this may be on the motherboard, but it might be
an SATA connector instead of an ATA connector. It's also been suggested
that this may be on a multifunction card, which would typically be a
multimedia card. The reason that they are suggesting that it is not a
regular ATA controller card would be that there is only one channel
shown. Most regular ATA controller cards would give you two more
channels, primary and secondary.

> ----------------------
> 
> You also mentioned USB possibility:
>  # grep -i usb /var/run/dmesg.boot
>  uhci0: <Intel 82371AB/EB (PIIX4) USB controller>
>      port 0xe000-0xe01f irq 11 at device 7.2 on pci0
>  usb0: <Intel 82371AB/EB (PIIX4) USB controller>
>      on uhci0
>  usb0: USB revision 1.0
> 
> 
> What would you conclude from this?

Not much. 

However, I'm trying to remember if ATA over USB generally tends to
pretend to be SCSI, and if that's the case, I'd likely guess that it's
not USB.

Anyway, it's hard to see inside your box from here. 

> Is this ata2 another IDE controller, so that I can
> add 6 (instead of the normal 4) harddisks/cdroms etc.
> to this computer?

You're the closest to the box, I think. What's the box look like inside?

Incidentally, and as has been mentioned, there are performance
advantages to not using the slave.

--
Joel Rees   <rees at ddcom.co.jp>
digitcom, inc.   株式会社デジコム
Kobe, Japan   +81-78-672-8800
** <http://www.ddcom.co.jp> **