Single disk emulation interface for an array of synchronous spindle disk drives

• US 5,128,810 A
• Filed: 07/03/1991
• Issued: 07/07/1992
• Est. Priority Date: 08/02/1988
• Status: Expired due to Term

• Current Assignee: Silicon Graphics International Corporation (Hewlett-Packard Enterprise Company)
• Original Assignee: CRAY Incorporated (Hewlett-Packard Enterprise Company)
• Inventors: Halford, Robert J.
• Primary Examiner(s): Canney, Vincent P.
• Application Number:
  US07/727,282
• Time in Patent Office: 370 Days
• Field of Search: 360/39
• US Class Current: 360/39
• CPC Class Codes: G06F 3/0601 Interfaces specially adapted for storage systems
• CPC Class Codes: G06F 3/0673 Single storage device
• CPC Class Codes: G11B 19/28 Speed controlling, regulating, or indicating G11B19/24 takes precedence
• CPC Class Codes: G11B 20/1252 for discontinuous data, e.g. digital information signals, computer programme data
• CPC Class Codes: G11B 2020/183 wherein at least one additional attempt is made to read or write the data when a first attempt is unsuccessful

Abstract

A multiple disk drive array storage device is described which emulates the operation of a single disk drive so that the handshaking and protocol between the array storage device and the host computer appears to the host computer to be that of a single disk drive. The array storage device includes a plurality of individual disk drives, each of which having its spindle synchronized to the other disk drives using a master clock synchronization. Digital data words are received by the array storage device controller which divides the words into subparts and writes each subpart to a different disk drive within the storage device. The buffering and formatting of the digital data for reading and writing from the individual disk drives is accomplished by the controller transparent to the host computer.

Claims

1. A high speed disk array for emulating the operation of a single disk drive, comprising:

a data input/output interface means for connecting to a computer for receiving/transmitting digital data, said input/output interface comprising a first speed matching buffer coupled to a bidirectional data bus;

a plurality of disk storage devices, each having spindles synchronized with each other by a master clock signal that is broadcast to each of said plurality of disk storage devices;

a common controller connected to said interface means and connected for controlling each of said disk storage device for performing the steps of;

(a) receiving said digital data from said data interface means;

(b) dividing said digital data into subparts;

(c) assigning error detection codes to said subparts;

(d) formatting said subparts into a plurality of fixed sector format subparts; and

(e) simultaneously writing each fixed sector format subpart to one of said plurality of disk storage devices;

said common controller comprising;

(a) a second speed matching buffer coupled to said bidirectional data bus; and

(b) a plurality of third speed matching buffers coupled one each to said plurality of disk storage devices; and

said plurality of disk storage devices coupled together in a daisy chain configuration wherein said disk storage devices are coupled together by a plurality of control cables in a continuous unbroken chain, one and only one of said plurality of disk storage devices further coupled to said common controller by another control cable.

2. The disk array according to claim 1 wherein said common controller is further operable for performing the steps of:

(f) simultaneously reading each fixed sector format subpart from each of said plurality of disk storage devices;

(g) unformatting said subparts from each fixed sector format subpart;

(h) reassembling said digital data from said unformatted subparts; and

(i) transmitting said reconstructed digital data to said data interface.