SANsurfer iSCSI HBA Manager User’s Guide
Management Tool for QLogic iSCSI Host Bus Adapters
Glossary-2
IS0054602-00 B
S
device
A computer subsystem, such an HBA
card, which mediates data in a computer
network. The term “device” is used inter-
changeably with “
target
” and “target
device.”
DHCP
Dynamic Host Configuration Protocol is
used by networked devices (clients) to
obtain various parameters necessary for
the clients to operate in an Internet
Protocol (
IP
) network.
driver
Software that interfaces between the file
system and a physical data storage device
or network media.
The level structure for Windows drivers is
as follows:
Class driver
is the highest driver level.
There is a separate class for disk,
Ethernet, etc. This level handles all
generic aspects of operations for that
class.
Port driver
is the middle driver level,
which handles aspects of the operation
specific to the port type; for example,
there is a port driver for SCSI.
Miniport driver
is the lowest driver
level and device specific. This level is
usually supplied by the manufacturer
as a companion to a physical device.
Monolithic driver
level combines the
functions of different driver levels in the
same driver to increase performance.
Adjunct driver
level works along side
a driver at the same level to increase
performance.
In NetWare, the required drivers include:
Host Adapter Module (HAM)
is the
driver component associated with the
host adapter hardware. It provides the
functionality to route requests to the
bus where a specified device is
attached.
Custom Device Module (CDM)
is the
drive component associated with
storage devices. It provides the
functionality to build device-specific
commands from I/O messages
received from NetWare's Media
Manager.
In Red Hat/SUSE Linux, the driver layers
include:
SCSI Upper Layer
is the device
management layer. It handles
device-dependent tasks for devices,
such as disks and tapes.
SCSI Middle Layer
is the SCSI traffic
handling layer. It directs requests
between the kernel and the SCSI.
SCSI Lower Layer
is the SCSI HBA
driver. It communications directly to the
SCSI HBA.
The structure for Solaris SPARC/x86
drivers includes:
Nexus drivers
provide bus mapping
and translation services to subordinate
nexus and leaf devices. These include
drivers for PCI-to-PCI bridges,
PCMCIA adapters, and SCSI HBAs.
Leaf drivers
provide the traditional
character and block driver interfaces
for reading and writing data to storage
and communication devices. These
include drivers for peripheral devices,
including QLA2
xxx
HBAs, disks, tapes,
network HBAs, and frame buffers.
