Principles of Operation

Functional Description

 

 

2.2PRINCIPLES OF OPERATION

The Zeus SSD comprises three primary functional blocks—the ATA (IDE) interface connector, Zeus SSD controller and NAND flash memory. A description of each drive component is provided in “Zeus SSD Functional Blocks” on page 13.

All read/write data transfer requests are initiated by the host via the ATA (IDE) bus interface. Once received, the Zeus controller, under the control of the SSD’s microcontroller, processes the request.

The SSD’s microcontroller is responsible for initiating and controlling all activity within the Zeus controller—including bad block mapping and executing the wear-leveling algorithms.

The Zeus controller decodes an incoming host command, and sets up the appropriate interrupts and status for the local microprocessor to handle various ATA commands. For read and write transfer commands, the hardware can handle the initial handshake with the host automatically. If firmware enables full auto mode, read and write transfers can be fully handled by hardware with minimum firmware support.

Commands that do not require data to be read from or written to the flash memory controller are typically handled by the Zeus controller. Some commands may require the Zeus controller to use external circuitry (for example, Intelligent Destructive Purge™), which do not involve the flash memory controller.

When a write operation is requested and data is received, the Zeus controller uses integrated DMA controllers to transfer the data from host memory to the SSD’s flash memory controller. Through a standard ATA (IDE) interface, the flash memory controller transfers the data from the Zeus controller to available locations in the SSD’s local flash memory. Depending on drive configuration, Zeus SSD storage capacity can range between from 2GB to 128GB, with internal IDE transfer rates ranging from 10 to 60 MB per second. After the write operation completes, the Zeus controller notifies the host.

If a read request is received, the Zeus controller retrieves the data from the local flash memory via the flash memory controller. If the Zeus controller is responding to a PIO read operation, it presents the data to the ATA bus. If it is responding to a UDMA read request, the Zeus controller writes the data directly to system memory on the host. Regardless of the type of operation (PIO or UDMA), the Zeus controller notifies the host when the data is ready for transmission.

Zeus Ultra DMA Solid State Drives

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