Should hard drives do parallel I/O

Introduction

A document from a Phil White of ECC Tek came into my hands. It was sent to Seagate and advances the idea of multiple, single platter HDAs (head disk assemblies) hard disk drives (HDDs) with one or two read-write heads per platter. They would operate in parallel and deliver, he asserts, several benefits as well as speeding up I/O. Specifically there would be built-in backup, obviating the need for separate RAID arrays.

The executive summary of the document is reproduced below. The full (33-page) document can be downloaded here.

Executive summary

ECC Tek proposes that the disk drive industry develop an entirely new class of disk storage products called parallel-transfer Hard Disk Drives (pHDDs). pHDDs would have much higher transfer rates than conventional HDDs and a variable level of automatic, built-in backup. pHDDs would contain a number of Head-Disk Assemblies (HDAs) and a custom controller chip as components.

All of the HDAs in a pHDD would be written and read simultaneously. The disks within all of the HDAs would be synchronized so that a pHDD would appear to be a conventional HDD but with higher performance and automatic, built-in backup which is impossible in a conventional HDD.

To summarize, ECC Tek believes pHDDs should be developed into commercial products for the following reasons:

• pHDDs could significantly increase revenues and profits at disk drive companies because fewer types of components would need to be manufactured, fewer employees would be needed, and a higher percentage of manufactured media could be used in pHDD products than can be used in conventional HDDs because of the increased power of the ECC system used in pHDDs.

• pHDDs would have much higher transfer rates and a much higher overall performance than conventional HDDs.

• pHDDs would have automatic, built-in backup eliminating the expense, nuisance and need for RAID controller boards, extra drives and backup software.

• pHDDs which use tiny HDAs as components would have higher performance, consume less space and less power than equivalent capacity conventional HDDs.

• pHDDs would enable disk drive companies to make many unique types of pHDD models while only manufacturing a few types of HDAs increasing economies of scale and driving down the cost of HDAs.

• pHDDs would allow the use of media that is unusable in conventional HDDs because the pHDD ECC system operates on a two dimensional array of data instead of a one dimensional array as is done in conventional HDDs.

• pHDDs have features that are highly desirable and commercially valuable but impossible with conventional HDDs.

• pHDDs have more commercial value than conventional HDDs and therefore they can be priced higher and offer more profit potential than conventional HDDs.