Description
Description
PCI Bus Interface
The i960 Processor/Memory System
Battery Backup Module
Controller BIOS
Controller Firmware
SCSI Bus Interface
Operating Systems Supported
Quick Start
The DAC960PL disk array controller is a caching PCI SCSI disk array controller card. Its key components include:
 PCI Bus Interface
Intel� i960 32-bit RISC processor
On-board cache memory using standard SIMM
EEPROM for system BIOS
Flash EEPROM for system firmware
Two Independent Fast/Wide SCSI channels utilizing NCR 53C720 32-bit RISC SCSI controllers
Two internal 68-pin SCSI connectors
Fault management connector
Cache memory battery backup module
Automatic PCI configuration
Disk failure detection
Disk media error management
Online drive replacement (�hot swap�)
Automatic rebuild to standby drives (�hot spare�)
Block Diagram of a Basic Disk Array Subsystem
PCI Bus Interface
The DAC960PL disk array controller interfaces to its host system through the PCI bus interface. The PCI bus is a 32-bit, high-speed, processor-independent local bus.
The PCI Bus allows 32-bit high-speed transfers, which can burst data at a rate of over 130 MB per second.
The i960 Processor/Memory System
The CPU of the DAC960PL disk array controller is a 32-bit Intel i960JF RISC microprocessor. The CPU controls all functions of the controller including SCSI bus transfers, PCI bus transfers, RAID processing, controller configuration, data striping, error recovery, and drive rebuilding.
The standard cache memory subsystem is configured with 4 MB of cache, depending on the type of memory modules being used.
Battery Backup Module
The cache battery-backup module provides battery backup to the standard cache memory subsystem in the event of power loss to the system.
Controller BIOS
The DAC960PL disk array controller has an AT-compatible BIOS. The BIOS allows a PCI-based host system to boot the Microsoft MS-DOS� operating system or other operating systems that use the system BIOS for disk service without special software or auxiliary device drivers. For running other operating systems, the DAC960PL requires a device driver to access the disk array.
Controller Firmware
The DAC960PL disk array controller firmware contains the programs that are executed by the i960 CPU; they reside in a flash EEPROM on the controller. This type of memory device retains information even after power off, and it can also be rewritten when new firmware becomes available. This allows the system firmware to be upgraded without replacing any hardware.
In addition to the BIOS and firmware, the flash EEPROM also stores information on the current configuration of the controller and hard-disk drives. As the disk configurations change (for example, when a drive fails), the flash EEPROM keeps a record of the changes.
SCSI Bus Interface
The SCSI bus is used to connect hard-disk drives to the DAC960PL disk array controller. It has two independent SCSI channels, each using a separate SCSI I/O RISC processor. This allows the system to read or write data on several drives simultaneously. Up to seven drives can be connected and controlled by each channel. Striping data across the drives and channels of the DAC960PL can result in system performance of several times the throughput of any single drive.
The SCSI channels on the DAC960PL support the Fast/Wide SCSI-2 standard, which is backward compatible with earlier SCSI standards.
Operating Systems Supported
Dell supports use of the following operating systems with the DAC960PL controller:
Novell� NetWare� versions 3.12 and 4.1
Novell NetWare version 4.1 SMP
Microsoft Windows NT Server version 3.51
Quick Start
1. Install the DAC960PL disk array controller card.
2. Connect the SCSI hard-disk drives to the controller.
3. Configure the DAC960PL controller for the server.
4. Configure the RAID subsystem, including the packs and system drives.
5. Save the configuration.
6. Initialize the system drives.
7. Install the target operating system on the system drive(s). See also Supported Operating Systems.
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