Mass computer storage system having both solid state and rotating disk types of memory

• US 5,778,418 A
• Filed: 08/08/1994
• Issued: 07/07/1998
• Est. Priority Date: 09/27/1991
• Status: Expired due to Term

• Current Assignee: SanDisk Technologies LLC (Western Digital Corporation)
• Original Assignee: SanDisk Corporation (Western Digital Corporation)
• Inventors: Harari, Eliyahou, Auclair, Daniel L.
• Primary Examiner(s): Swann, Tod R.
• Assistant Examiner(s): PEIKARI, BEHZAD
• Application Number:
  US08/287,107
• Time in Patent Office: 1,429 Days
• Field of Search: 395/425, 395/833, 395/497.01, 395/497.04, 395/430, 395/439, 395/500, 395/550, 364/DIG. 1, 365/185, 365/104, 365/189.01, 711/101, 711/4, 711/103, 711/111, 711/112, 711/153, 711/202
• US Class Current: 711/101
• CPC Class Codes: G06F 3/0625 Power saving in storage systems
• CPC Class Codes: G06F 3/0634 by changing the state or mode of one or more devices
• CPC Class Codes: G06F 3/068 Hybrid storage device
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

Solid-state flash electrically erasable and programmable read-only-memory ("flash EEPROM") system is combined with a rotating disk drive memory to provide mass program and data storage in a computer system. A common memory controller directs system generated memory addresses in a disk format to either the EEPROM system or disk memory. The blocks of data handled by the EEPROM system have the same size and other attributes as sectors of data handled by the disk system, thereby making it transparent to the computer system processor as to whether it is accessing the EEPROM or disk portion of the storage system. A particular program or data file may then be stored in the portion of the memory system best suited to handle it, and thus take advantage of the different features and characteristics of EEPROM and magnetic media disk memory.

Claims

1. A method of configuring and operating a mass storage system as part of a computer system that also includes a central processor connected to communicate with the mass storage system over a common system bus, wherein the central processor is programmed to address data within individual sectors in an entire memory space of the mass storage system over said bus with a given disk drive format, comprising the steps of:

providing as the mass storage system both a rotating disk drive memory and a solid-state flash electrically erasable and programmable read only memory that are connected through a controller to the common system bus to receive addresses from the central processor,

partitioning each of the disk drive and solid-state memory into individually addressable sectors that each store a given amount of data,

designating within the controller first and second non-overlapping portions of the mass memory address space, the first portion being implemented by the disk drive memory and the second portion being implemented by the solid state memory,

causing the controller to access a data sector within the disk drive when an address received in said given disk drive format from the central processor over the system bus is within said first address space portion, and

causing the controller to access a data sector within the solid state memory when an address received in said given disk drive format from the central processor over the system bus is within said second address space portion, including a step of translating the address from the central processor within the second address space portion into a physical address of a data sector of the solid state memory.

2. The method according to claim 1 wherein the step of designating portions of the address space includes the step of designating substantially all memory space addresses within one logical disk drive to be within either said first portion or said second portion but not both.

3. The method according to claim 1 wherein the step of designating portions of the address space includes the step of designating addresses within at least one logical disk drive within both of the first and second address portions.

4. The method according to claim 1 wherein the central processor is further programmed to address sectors of data in the mass storage system by drive, head, and cylinder locations.

5. The method according to claim 1 wherein said sectors of data are individually substantially 512 bytes in size.

6. The method according to claim 1 which comprises the additional step, prior to the step of causing the controller to access a data sector of the disk drive, of causing the controller to initiate power to the disk drive memory in response to receiving an address within the first address space portion.

7. The method according to claim 1 which comprises the additional step, prior to the step of causing the controller to access a data sector of the solid state memory, of causing the controller to initiate power to the solid state memory in response to receiving an address within the second address space portion.

8. A mass storage system adapted to operate as part of a computer system by connection through a system bus to a central processor that is programmed to address the entire memory space of the mass storage system over said bus by specifying at least one sector of data at a time in a disk drive format, comprising:

a rotating disk drive memory partitioned into individually addressable sectors that individually store a given amount of data,

a solid-state flash electrically erasable and programmable read only memory partitioned into individually addressable sectors that individually store said given amount of data,

a controller connected to both of the disk drive and solid-state memories for communicating between said memories and the central processor over the system bus,

means within the controller for accessing at least one of the data sectors within the disk drive when an address received in said disk drive format from the central processor over the system bus is within a first portion of the mass memory address space, and

means within the controller for accessing at least one of the data sectors within the solid state memory when an address received in said disk drive format from the central processor over the system bus is within a second portion of the mass memory address space, said first and second portions of the mass memory address space being non-overlapping.

9. A method of operating a mass storage system having an address space, comprising:

utilizing as the mass storage system both a rotating disk drive memory, a solid-state flash EEPROM array and a controller common to both the disk drive and the solid-state array, each of the disk drive and the solid-state array being partitioned into separately addressable sectors that individually store a given amount of data,

operating the mass storage system as part of a computer system that also includes a central processor connected to communicate with the mass storage system,

accessing at least one data sector within the disk drive when an address received by the controller in a disk drive format from the central processor is within a first portion of the mass storage system address space,

accessing at least one data sector within the solid state memory when an address received by the controller in the disk drive format from the central processor is within a second portion of the mass storage system address space, said first and second address space portions being distinct and non-overlapping,

translating the address from the central processor within the second address space portion into a physical address of a data sector of the solid state array, and

generating from the central processor and sending to the controller an address in the disk drive format of at least one sector within the mass storage system address space without regard for whether the address is within the first or second portions of the mass storage system address space.

10. The method according to claim 9 wherein generating the address from the central processor includes doing so with a format that designates drive, head, and cylinder locations.

11. The method according to claim 9 wherein said given amount of data stored in the sectors of the disk drive and solid-state array includes 512 bytes of user data.

12. The method according to claim 9 which comprises the additional step, prior to the step of causing the controller to access a data sector of the disk drive, of causing the controller to initiate power to the disk drive memory in response to receiving an address within the first address space portion.

13. The method according to claim 9 which comprises the additional step, prior to the step of causing the controller to access a data sector of the solid state memory, of causing the controller to initiate power to the solid state memory in response to receiving an address within the second address space portion.

14. A memory system, comprising:

a rotating disk drive memory partitioned into sectors of a given amount of data,

a solid-state flash EEPROM array partitioned into sectors of said given amount of data, and

a memory system controller connected to both the disk drive and the solid-state array, and responsive to receipt of an address of one or more memory sectors in a common disk drive format to access a corresponding one or more sectors of the disk drive when the received address is within a first range of addresses and to access a corresponding one or more sectors of the solid-state array when the received address is within a second range of addresses, said first and second ranges of received addresses being distinct and non-overlapping.

15. The memory system of claim 14, wherein the memory system controller is additionally responsive to receipt of the address within the second range of addresses to translate the received address into a physical address of one or more sectors of the solid-state memory.

16. The memory system of claim 14, wherein the memory system controller is responsive to the common disk drive address format that includes drive, head and cylinder locations.

17. The memory system of claim 14, wherein the given amount of data stored by individual sectors of both the disk drive and solid-state array includes 512 bytes of user data.

18. The memory system of claim 14, wherein the controller additionally includes means responsive to receipt of an address within either of the first or second address ranges for initiating power to a respective one of either the disk drive or solid-state array.