atapi_ide - Interface for ATAPI or IDE (PC) devices
PCI bus CMD/Acer ATAPI/IDE adapter:
bus pci0 at *
bus ata0 at *
controller scsi0 at ata0 slot 0
controller scsi1 at ata0 slot 1
PCI bus Cypress ATAPI/IDE adapter:
bus pci0 at *
bus ata0 at *
bus ata1 at *
controller scsi0 at ata0 slot 0
controller scsi1 at ata1 slot 0
PCMCIA bus ATA/IDE disk card:
bus pcmcia0 at *
bus ata0 at pcmcia?
controller scsi0 at ata0
Devices commonly known for their use on PC devices as ATA
or IDE devices are supported using the SCSI CAM device
driver. The ATA standard has also been expanded to
include what are known as ATAPI devices. The SCSI CAM
device driver is also used for those disks and CD-ROM
devices. These devices may also be known under the names
EIDE, ATA-2, Fast-ATA, or Ultra-ATA.
Beacuse the ATA/IDE standard was not developed until after
many of the devices that used this standard were produced,
there are many devices which do not strictly comply with
the standard. While it is possible some industry standard
devices may appear to work, it is also possible they will
cause hang or data corruption cases when used under more
stressful situations. For this reason, it is recommended
that only the supported devices be used. These devices
have been tested and are certified for correct operation.
ATAPI/IDE controllers allow the connection of two devices.
These two devices are known as the master device and the
slave device. If only one device is connected, that
device must be the master (slave-only configurations are
not supported). When used by the SCSI CAM device driver,
the IDE master device is assigned SCSI id 0 for that controller.
The slave device is assigned SCSI id 1 for that
controller. No other SCSI ids are assigned on that controller.
Most ATAPI/IDE adapters contain two channels
(known as the primary and secondary). Each of these channels
may contain their own master and slave devices.
Therefore, a dual channel ATAPI/IDE controller may contain
up to 4 devices (a master and slave pair on each channel).
These 4 devices are then accessed as SCSI id 0 and 1 on
each channel.
Many SCSI operations translate perfectly for use on IDE.
For example, read and write operations are the same. However,
many SCSI disk mode pages are emulated by the IDE
device driver. For example, you can display the SCSI
inquiry mode pages using the following command:
% scu show inq pages
pages are created by the device driver to contain the long
(full IDE) form of the device name, serial number, revision,
and the operational modes of the device. Only a
shortened version of this information is available with
the standard SCSI inquiry command. Note also that the
following command:
% scu show pages
Shows that the SCSI mode pages contain only partial information.
Only that information (such as geometry) that the
drive reports to the system is able to be reformatted into
these emulated SCSI mode pages. Much of the information
(such as RPM) is simply not available from the drive, and
therefore not accurately reported.
ATAPI devices are much more closely related to SCSI
devices, and as such contain their own mode pages. Therefore,
for these devices, the mode page values reported are
those from the device, and no emulation is involved.
ATAPI tape devices are not supported at this time.
/dev/disk/dsk???
/dev/disk/dsk???
SCSI(7), rz(7), and disklabel(8)
atapi_ide(7)
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