MEMORY SYSTEM WITH ROBUST BACKUP AND RESTART FEATURES AND REMOVABLE MODULES

摘要

A Flash-based memory system comprises a plurality of Flash memory devices, a Flash controller communicating independently with each Flash memory device to perform memory operations, a power circuit providing power the Flash memory devices, and a CPU configured to perform a controlled powering down procedure upon detecting a power failure. In some embodiments, the Flash-based memory system includes a backup power source having a charge storage device and charging circuitry, the CPU configured to perform one or more test procedures on the charge storage device to provide an indication of a charge storage capacity of the charge storage device. A plurality of Flash-based memory systems may be mounted on a Flash-based memory card, and multiple such Flash-based memory cards may be combined into a Flash-based memory module. A number of Flash-based memory modules may then be removably mounted in a rack-mountable housing to form unitary Flash-based memory unit.

主权项

1. A method of backing up and recovering data in a nonvolatile memory system, comprising:
performing memory operations on a plurality of nonvolatile memory devices in the nonvolatile memory system, each nonvolatile memory device having a physical memory space that is divided into blocks, each block being further divided into pages, each page representing an individually addressable memory location on which memory operations are performed, multiple memory locations being erased at the same time in one-block groupings; accessing a logical-to-physical translation table that associates a logical address of a memory operation with a physical address of a memory location; detecting a power failure in the nonvolatile memory system; performing a controlled powering down procedure upon detecting the power failure, the controlled powering down procedure comprising: determining whether the nonvolatile memory system was in normal operation when the power failure is detected; removing power from the nonvolatile memory devices without backing up data upon determining that the nonvolatile memory system was not in normal operation when the power failure is detected; and removing power from the nonvolatile memory devices after backing up selected data upon determining that the nonvolatile memory system was in normal operation when the power failure is detected, wherein the backing up of selected data comprises:
storing the logical-to-physical translation table in predefined memory locations in the nonvolatile memory devices; andstoring system data in a nonvolatile backup memory of a central processing unit, the system data including data reflecting bad blocks within the nonvolatile memory devices, a pointer pointing to the predefined memory locations in the nonvolatile memory devices where the logical-to-physical translation table is stored, and error correction information associated with the system data.