SCSIDE adapter, card and box save expense

Acard Technology Corp of Taiwan has designed an SCSIDE adapter capable of interfacing IDE hard disk drives (HDDs) to SCSI I/O. The idea is that applications, and in particular, mass data storage, can enjoy all the benefits of SCSI I/O—including bandwidth and connectivity for several devices on one port—without being committed to the expense of dedicated SCSI hard disk drives.

The basic SCSIDE adapter chip, part ARC 765, integrates two controllers. On the SCSI side, one controller supports LVD (low-voltage differential) SCSI III, for data throughput at up to 160 Mbytes/s. On the IDE side, there is support for ATA 133, with throughput at up to 133 Mbytes/s (see photo). This adapter also integrates a DMA controller, an 8-bit 80-MHz RISC processor with associated SRAM (2 Kbytes), plus internal ROM (60 Kbytes) and flash ROM. The internal ROM moves data into the RISC processor, with RISC operations cached in SRAM. The flash ROM allows for some adjustment of compatibility with external devices such as IDE HDDs and optical devices.


Acard has designed a controller card, the AEC 8001, that supports two of the adapter chips. On-card, the adapter chip used is part ARC 766. This part does not differ from the ARC 765 in terms of basic architecture. However, it is packaged in such a way that it will support two SCSI channels, with on-card support for Ultra 2 LVD SCSI, delivering up to 80 Mbytes/s.


This card enables SCSI interfacing with four ATA 133 IDE HDDs, on one SCSI cable/port. Maximum storage capacity per disk is currently 160 Gbytes, for a combined total capacity of 640 Gbytes. Under JBOD, similar to RAID in concept, and deriving its terminology from “just a bunch of disks,” the four disks can be aggregated as two drives, rather than four.


Controller card AEC 8001 can be accommodated, along with four IDE HDDs, in Acard’s disk box, model ARS 3010. Seven boxes can be stacked, via SCSI daisy chaining, for a maximum of 28 disks, allowing a maximum storage capacity of 4.48 Tbytes. This is a 1U rack-mount box, incorporating an ATX power supply. Alternatively, power can be supplied by a standard 5/12V connector on card AEC 8001.


The box is priced at US$450, which includes cost of the card at US$280, in quantities of 500. The adapter chip is not sold as a discrete component, but Acard can custom design cards that will support 8 or 16 drives.


Acard Technology Corp
Fax (886) 8512 2548
www.acard.com