Use the latest Atto driver

4 Maximizing Performance with your ExpressPCI HBA

If you are getting less performance than you expect, there are several things you can do such as making sure you are using the latest ATTO driver, setting the registry entry for large block transfers, using ATTO ExpressRAID for setting up RAID groups, increasing transfer size, and analyzing your system’s I/Os.

While the factory settings on your ExpressPCI host adapter should provide excellent performance for a wide range of applications, you may improve performance by modifying some of the system factors which affect your ExpressPCI host adapter.

For example, the ATTO driver can transfer well over a megabyte with one SCSI command.

NOTE You must use an ATTO driver when using ATTO ExpressRAID software.

Determine which drive is currently in use, then install the latest ATTO driver found at www.attotech.com.

Windows NT

1Open My Computer

2Open Control Panel

3Open SCSI Adapters

4Examine the Driver tab for your SCSI adapter. If the driver is not express.sys, install the express.sys driver.

5Either remove the previously-installed driver or disable it using the Devices applet. If the system has a built in Symbios or LSI adapter, do not disable the driver for that adapter.

Windows 2000 and XP

1Using the Device Manager, select SCSI & RAID Controllers

2Examine the Driver tab for your SCSI adapter. If the driver is not express.sys, install the express.sys driver.

3Either remove the previously-installed driver or disable it using the Devices applet. If the system has a built in Symbios or LSI adapter, do not disable the driver for that adapter.

Set registry for large block transfers

If your application requires large block transfers, set the registry entry correctly for the MaximumSGList keyword. Several files supplied with the device driver download package can set this value to any one of the following sizes: 64Kb, 128KB, 256Kb, 512KB, 1MB and NT default (64KB). The files are ASCII text files and can be viewed with any suitable editor. The files also explain the registry setting and how to change the setting.

The ExpressPCI adapter can have a maximum transfer size from 64KB to 1MB. If the registry value is set to a number higher than 0xff, the driver will reduce the setting to 0xff. The driver installation process will set the default value to 0xff.

Set up RAID groups with ATTO

ExpressRAID

Instead of using the RAID functionality built into Windows OS, use the ATTO ExpressRAID software for the most efficient performance.

ATTO ExpressRAID requires one less level of driver through which commands must pass and fewer commands are required to pass through the driver hierarchy.

Other advantages of ATTO ExpressRAID striping:

❖You can boot your system off striped drives

❖Stripe sets created with ExpressRAID are recognizable by DOS and Windows

❖You can stripe removable-media drives with ExpressRAID.

If you have purchased the striping option, additional information about ExpressRAID is

15 ATTO Technology ExpressPCI Ultra/WIDE SCSI Host Adapters Installation and Operation Manual

ATTO ExpressPCI Ultra/WIDE SCSI Host Adapters Express PCI PSC: Single-Channel Single-Ended Ultra/WIDE ExpressPCI DC: Dual-Channel Single-Ended Ultra/WIDE specifications

ATTO Technology is a leading provider of cutting-edge storage connectivity solutions, and their line of ATTO ExpressPCI Ultra/WIDE SCSI Host Adapters has showcased the company’s commitment to performance and reliability for demanding data applications. Specifically, the ExpressPCI PSC (Single-Channel Single-Ended Ultra/WIDE) and the ExpressPCI DC (Dual-Channel Single-Ended Ultra/WIDE) models cater to different user needs while maintaining industry standards.

The ATTO ExpressPCI PSC is designed for environments where a single channel is sufficient to meet the connectivity demands. This single-ended adapter supports Ultra/WIDE SCSI technology, enabling data transfer rates of up to 40 MB/s. The PSC is perfect for users who require efficient storage solutions without the complexity of handling multiple channels. With its robust design, this adapter excels in various applications, from small business servers to high-performance workstations, offering reliability in demanding environments.

On the other hand, the ATTO ExpressPCI DC doubles the capability with its dual-channel architecture. This feature allows for two independent SCSI buses, effectively doubling the potential data throughput. By utilizing ultra/WIDE SCSI technology, the DC can achieve a combined throughput of 80 MB/s, making it an optimal choice for users needing higher performance for tasks such as video editing, data intensive applications, and backups. The dual-channel configuration provides advantages in multitasking, enabling the simultaneous operation of multiple drives or devices.

Both models incorporate advanced technologies such as automatic bus termination and active negation, ensuring optimal signal integrity and reliability. Additionally, ATTO’s exclusive Advanced Data Flow Management technology enhances performance by intelligently managing data transfer to optimize bandwidth utilization, which is key in environments where data transfer speed and reliability are crucial.

Another noteworthy characteristic is the high compatibility with various operating systems and SCSI devices, making the ExpressPCI Ultra/WIDE SCSI Host Adapters versatile and easy to incorporate into existing systems. They support a wide range of SCSI drives and peripherals, ensuring that users can leverage their investment in both current and future technologies. In summary, the ATTO ExpressPCI Ultra/WIDE SCSI Host Adapters—PSC and DC—represent robust solutions that blend speed, reliability, and flexibility, catering to the diverse needs of businesses and advanced users alike. With their proven performance, these adapters continue to be an important asset in high-demand data environments, showcasing ATTO's dedication to innovation in the storage connectivity realm.