D-16
Understanding Drive Arrays
Writer: Pamela King Project: SMART-2DH Array Controller Reference Guide Comments: 295469-002
File Name: K-APPD.DOC Last Saved On: 2/27/98 12:06 PM
COMPAQ CONFIDENTIAL - NEED TO KNOW REQUIRED
Consider the following example. The SMART-2DH Controller receives a
request for a physical drive that is not currently active. The controller
schedules the request immediately ahead of previously received requests
already queued to other active drives within the array. This request
management process operates concurrently with drive operations. The benefits
of optimized request management increase as greater demands are made on
the drive subsystem.
Bus Master Data Transfers
The SMART-2DH Controller is a bus master device that takes control of the
PCI bus during high-speed transfers. This allows the system processor to
handle application processing or other types of tasks. Data transfer occurs at
rates of up to 133 megabytes/sec. for the PCI bus. Bus master high-speed
transfers are particularly important when the supported models are used in
conjunction with multiple expansion boards such as network interface
controllers (NICs).
Expanding Storage Capacity
The SMART-2DH Array Controller allows the configuration of one or more
separate logical drives into a single drive array. An existing drive array can be
expanded by adding one or more logical drives to the array. To create the
room for the additional logical drives, more physical drives must be added.
See Figure D-10.
