Sunday, January 04, 2009

The Brains and Bones of my NAS

I've just found this article on AnalogZone featuring the custom ASIC (IT3107) of my Netgear ReadyNAS Duo, which contains a SPARC-based core along wth integrated NAS circuitry. Apparently the IT3107 supports 4 SATA controllers (argh, I should have gotten a 4-bay NAS instead, but the cost would be prohibitive at this stage).

Here is an excerpt from the article on some of its major features (I didn't know this before):

Infrant's basic concept is to integrate all the functions required to support a small RAID array with the electronics required to put the data on a 10/100/1000BaseT network, and to throw in a print server function for good measure. They've already rolled out a product to address the higher-priced SMB-level market which supports up to eight SATA drives. They're now introducing the ExpandaNAS IT3107, a consumer-grade device with half the SATA drives for the SoHo and consumer market. Depending on what works best for your needs, Infrant will happily sell you either the raw chip or a complete OEM-able board that only requires a case, power supply and disks. And power won't be too much of a problem since power consumption for the IT307 is only 5 W.

Powered by a 32-bit SPARC-based RISC core (with several extensions that we'll look at shortly) the chip supports RAID 0/1/5 operation for up to four SATA drives. Its network connection is a single Gbit Ethernet port. A PCI host interface and a pair of USB interfaces for supporting peripherals such as printers complete the I/O complement.

Rather than pass disc data through the CPU, its disc interface bypasses the PCI bus and uses DMA to shove blocks of data from the drives to the on-chip 64 bit DRAM controller. This leaves most of the SPARC's processing power available to manage the disks, handle the print serve tasks, and support its GbE connection at full rate. Infrant has also enhanced the chip's performance by beefing up the SPARC processor's instruction set. While its instruction set is still SPARC v8-compatible, the processor has had the way it executes several instructions optimized to keep critical segments in the fast lane. They also equipped the CPU with additional hardware logic including a hardware table walk-through for lookups, a lock-down cache, and a 3DES encryption core.

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