I thought SATA did away with the master/slave ugliness of PATA.
no.
SATA and PATA both present the same ATA interface to the
system, the only difference is how the chips are connected
to the hard drive.
The ATA interface is backwards compatible all the way back
to the original IBM x86 BIOS that supported only 1 MFM
controller with a maximum of 2 drives on it that used the
Task File interface. When the PC architecture went to
IDE drives from MFM, they didn't want to rewrite their
motherboard BIOS code because MS-DOS was what everyone ran,
and DOS depended on the BIOS code for accessing the disks.
This is why today you can still boot MS-DOS on a SATA
motherboard.
All of the newer stuff like DMA transfers and such, are a
superset laid on top of the original IDE interface, but
that software interface is still present in ATA.
If you don't like it, buy a SATA RAID card.
It would be possible for a SATA chip to be designed to
use separate controllers and unique busses to each SATA
disk. For example that is how the HP Proliant servers
work, every SATA port is a Master. Each
SATA port comes up as a separate atapci, ie atapci0,
atapci1, atapci2, etc. And, although each atapci has
2 channels on it, the second channel has no port on it
and cannot have anything plugged into it.
Your
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] Behalf Of Dane Miller
Sent: Thursday, March 06, 2008 4:12 PM
To: freebsd-questions@freebsd.org
Subject: Re: sata slave on intel ICH7
Anyone have thoughts on this? If I'm missing salient details or posting
to the wrong list, please point me in the right direction.
On Wed, 2008-03-05 at 13:54 -0800, Dane Miller wrote:
Hi,
FreeBSD 6.3-RELEASE detects one of my three SATA disks as ata2-slave.
I thought SATA did away with the master/slave ugliness of PATA.
Thinking maybe this was misleading output from FreeBSD, I did some
concurrent writes using dd. Sure enough, I see poor performance on
concurrent writes to ad4 and ad5 (ata2-master and ata2-slave), while I
see good performance on concurrent writes to ad4 and ad6 (ata2-master,
ata3-master). I can provide more details on the write tests I
performed, but I'm more interested in *why* FreeBSD detects one of my
SATA disks as a slave...
Here are some details:
6.3-RELEASE FreeBSD 6.3-RELEASE #0 i386
Motherboard: Intel S3000AH
BIOS: SATA Mode is set to Enhanced (as opposed to Legacy)
# atacontrol list
ATA channel 0:
Master: no device present
Slave: no device present
ATA channel 1:
Master: no device present
Slave: no device present
ATA channel 2:
Master: ad4 WDC WD2500KS-00MJB0/02.01C03 Serial ATA II
Slave: ad5 WDC WD2500KS-00MJB0/02.01C03 Serial ATA II
ATA channel 3:
Master: ad6 WDC WD2500KS-00MJB0/02.01C03 Serial ATA II
Slave: no device present
# grep -i ata /var/run/dmesg.boot
atapci0: Intel ICH7 UDMA100 controller port
0x1f0-0x1f7,0x3f6,0x170-0x177,0x376,0x30b0-0x30bf irq 18 at device 31.1
on pci0
ata0: ATA channel 0 on atapci0
ata1: ATA channel 1 on atapci0
atapci1: Intel ICH7 SATA300 controller port
0x30c8-0x30cf,0x30e4-0x30e7,0x30c0-0x30c7,0x30e0-0x30e3,0x30a0-0x30af
mem 0x8820-0x882003ff irq 19 at device 31.2 on pci0
ata2: ATA channel 0 on atapci1
ata3: ATA channel 1 on atapci1
ad4: 238475MB WDC WD2500KS-00MJB0 02.01C03 at ata2-master SATA150
ad5: 238475MB WDC WD2500KS-00MJB0 02.01C03 at ata2-slave SATA150
ad6: 238475MB WDC WD2500KS-00MJB0 02.01C03 at ata3-master SATA150
Any guidance on this would be greatly appreciated. Thanks,
Dane
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