Fibre Channel Adapter for VMware ESX User’s Guide
Glossary-2
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L2 cache
—Secondary (larger) cache.
Either on the processor chip or
external to the processor.
device
A target, typically a disk drive. Hardware
such as a disk drive, tape drive, printer, or
keyboard that is installed in or connected
to a system. In FC, a
target
device.
driver
The software that interfaces between the
file system and a physical data storage
device or network media.
The level structure for Windows XP
Professional/2000/Windows Server 2003
drivers is as follows:
Class Driver
. The highest driver level.
There is a separate class for disk,
Ethernet, and so forth. This level
handles all generic aspects of opera-
tions for that class.
Port Driver
. The middle driver level,
which handles aspects of the operation
specific to the port type; for example,
there is a port driver for SCSI.
In Red Hat/SUSE Linux, the driver layers
include:
SCSI Upper Layer.
This is the device
management layer. It handles
device-dependent tasks for devices,
such as disks and tapes.
SCSI Middle Layer.
This is the SCSI
traffic handling layer. It directs requests
between the kernel and the SCSI.
SCSI Lower Layer.
This is the SCSI
adapter driver. It communications
directly to the SCSI adapter.
The structure for Solaris SPARC drivers
includes:
Nexus Drivers.
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
adapters.
Leaf Drivers.
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
QLA200/QLA2
xxx
adapters, disks,
tapes, network adapters, and frame
buffers.
Miniport Driver
. The lowest driver level
and device specific. This level is
usually supplied by the manufacturer
as a companion to a physical device.
Monolithic Driver
. This level combines
the functions of different driver levels in
the same driver to increase perfor-
mance.
A
djunct Driver
. This level works along
side a driver at the same level to
increase performance.
In NetWare, the required drivers include:
Host Adapter Module (HAM)
. 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)
. 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.
