Redundant array of removable cartridge disk drives

• US 5,752,257 A
• Filed: 07/29/1994
• Issued: 05/12/1998
• Est. Priority Date: 07/29/1994
• Status: Expired due to Fees

• Current Assignee: EMC Corporation (Dell Technologies Inc.)
• Original Assignee: Nomai SA (Lenovo Group Ltd.)
• Inventors: Janon, Frederic, Ripoll, Jean-Louis, Frouin, Marc
• Primary Examiner(s): Swann, Tod R.
• Assistant Examiner(s): Chow, Christopher S.
• Application Number:
  US08/283,094
• Time in Patent Office: 1,383 Days
• Field of Search: 395/441, 395/439, 395/182.05, 395/442, 395/182.03, 395/182.04
• US Class Current: 711/114
• CPC Class Codes: G06F 11/006 Identification G06F11/2289 takes precedence
• 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 20/1833 by adding special lists or symbols to the coded information G11B20/1806, G11B20/1866 take precedence

Abstract

A memory system comprises an array of parallel removable hard disk cartridges and matching drives. Each cartridge is recorded with an array position signature so that an array can be programmatically reconstructed each time the cartridges are loaded in their drives without regard to the original physical associations of cartridges to drives.

Claims

1. A computer data storage memory system (10), comprising:

a plurality of removable cartridge disk drives (33-37) for reading and writing data on interchangeable hard disk cartridges, wherein one of the plurality of removable cartridge disk drives is limited to reading and writing error correction and detection data;

a peripheral controller connected to each of the removable cartridge disk drives;

a host interface (28, 66,

     70) having a host data input/output (I/O) port (30,

     80) and connected to the peripheral controller;

data parsing means (96,

     106) connected to the peripheral controller and the host interface for accepting data from said host data I/O port and for parsing, distributing and recombining said data amongst the plurality of removable cartridge disk drives according to a signature code recorded on a plurality of interchangeable hard disk cartridges then present in the plurality of removable cartridge disk drives;

a plurality of interchangeable hard disk cartridges (33-37) for loading into respective ones of the plurality of removable cartridge disk drives and each having a unique one of said signature codes;

signature assignment means (10, 28, 96, 106,

     114) connected to the peripheral interface controller for recognizing the absence of a signature code in the plurality of interchangeable hard disk cartridges loaded into respective ones of the plurality of removable cartridge disk drives and for writing a unique one of said signature codes on respective ones of said hard disk cartridges;

first error detection and correction means (112) connected to the plurality of removable cartridge disk drives for generating correction codes for data received from said host data I/O port on the plurality of interchangeable hard disk cartridges;

second error detection and correction means (112) connected to the plurality of removable cartridge disk drives for reading data and correction codes received from the plurality of interchangeable hard disk cartridges and for correcting and rebuilding data that is forwarded to said host data I/O port; and

a computer-implemented program (96) for verifying which set of the plurality of interchangeable hard disk cartridges are loaded in particular ones of the plurality of removable cartridge disk drives such that the sequence and order of data contained in each interchangeable hard disk cartridge is electronically manipulated and shuffled for reconstruction of the whole data as it had been originally presented to said host data I/O port.

2. A memory system (10), comprising:

a host interface (28, 66,

     70) that presents the appearance of a single very large capacity hard disk storage drive;

a first through n-th group of drive controller interfaces (22-26, 60-64) connected to the host interface (28,

     66);

a first through n-th group of removable media cartridge drives (33-37);

a plurality of unique signatures written on respective ones of each cartridge in a group of removable hard disk cartridges (33-37) to identify the position of each cartridge in a redundant array of the group of removable media cartridge drives (33-37), and initially each drive with a freshly formatted cartridge can have an array position identity arbitrarily assigned and once data is written to a group of cartridges comprising a particular array, the order and sequence of the data distributed amongst the cartridges is preserved by a program (96) that verifies which cartridges are loaded in each drive such that the sequence and order of data contained in each cartridge can then be manipulated and shuffled for reconstructing a copy of the original data file as it had been presented at the host interface (28);

wherein all the unique signatures in each group of interchangeable hard disk cartridges (33-37) are required to be present and all the interchangeable hard disk cartridges (33-37) in each group are identified by their respective signatures and provide for the communication of recovery information associated with a data file; and

wherein, the exact physical distribution of the interchangeable hard disk cartridges (33-37) amongst the removable media hard disk drives need not be repeated for complete data file recovery as a consequence of the signatures which are written on each cartridge being able to provide array-position reconstruction information for the recovery of said data file.

3. The memory system of claim 2, wherein:

the drive controller and host interfaces (22-26 and

     28) support block oriented data transfers and a memory space represented by the storage capacity of any particular disk drive is divided into a string of sequentially numbered blocks and block-identified traffic is converted to a cylinder, surface, track and sector format, wherein sectors, tracks or surfaces with hard defects are mapped out of said sequence of blocks and sequentially numbered blocks skip past any identified defective recording areas; and

the host interface (28) has a data transfer rate that is substantially increased by a parsing of a series of blocks amongst the drive controller interfaces (22-26) such that data accepted by a host interface program (106) is parsed into separate blocks according to said signatures, and sent out to each drive through the controllers (60-64) by a peripheral interface program (70);

wherein, the rate that data is accepted by the host interface (28) is essentially equal to the sum of the individual transfer rates of the individual drive controller interfaces (22-26), and data read and data write operations are both commanded in near parallel within the controllers (60-64).