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Index cache tree

An indexing and memory technology, applied in the field of memory mapping, can solve the problem of no longer storing data, and achieve the effect of reducing the average time and increasing the number of

Active Publication Date: 2012-05-23
APPLE INC
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  • Summary
  • Abstract
  • Description
  • Claims
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AI Technical Summary

Problems solved by technology

Unfortunately, flash memory suffers from two limitations
First, bits can only be cleared by erasing large blocks of memory
Second, each block can only withstand a limited number of erasures, after which it can no longer reliably store data

Method used

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Examples

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Embodiment Construction

[0016] System Overview

[0017] Figure 1A is a block diagram illustrating an example memory mapping architecture 100 for mapping logical sectors into physical pages using lookup tables and index cache trees. In some implementations, the look-up table 102 in volatile memory (eg, RAM) holds the location (eg, physical address) of the look-up table 106 in non-volatile memory (eg, flash memory). Lookup table 106 holds the physical addresses of data pages 108 . In some implementations, a cache 104 in non-volatile memory holds the physical addresses of recently written, read or accessed logical sectors to allow faster readout. In the example shown, lookup table 102 is also referred to as index TOC 102 , lookup table 106 is also referred to as index table 106 or index page, and cache 104 is also referred to as index table cache 104 .

[0018] In architecture 100, index TOC 102 and index table cache 104 enable at least a portion of index table 106 to be stored in non-volatile memor...

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Abstract

Memory mapping techniques for non-volatile memory are disclosed where logical sectors are mapped into physical pages using data structures in volatile and non-volatile memory. In some implementations, a first lookup table in non-volatile memory maps logical sectors directly into physical pages. A second lookup table in volatile memory holds the location of the first lookup table in non-volatile memory. An index cache tree in volatile memory holds the physical addresses of the most recently written or accessed logical sectors in a compressed format.

Description

[0001] Cross References to Related Applications [0002] This application claims priority to US Application Serial No. 12 / 509,267, filed July 24, 2009. technical field [0003] This topic relates generally to memory mapping. Background technique [0004] Flash memory is a type of Electrically Erasable Programmable Read-Only Memory (EEPROM). Because flash memory is non-volatile and relatively dense, they are used to store files and other data in handheld computers, mobile phones, digital cameras, portable music players, and many other devices where other storage solutions such as magnetic disks are not suitable. persistent object. Unfortunately, flash memory suffers from two limitations. First, bits can only be cleared by erasing large blocks of memory. Second, each block can only withstand a limited number of erasures, after which it can no longer store data reliably. Because of these limitations, complex data structures and algorithms are often required to use flash m...

Claims

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Application Information

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IPC IPC(8): G06F9/26
CPCG06F12/0246G06F12/1009G06F2212/7201G06F12/06G06F12/08
Inventor 丹尼尔·杰弗里·波斯特尼尔·雅各布·瓦卡拉特威蒂姆·克梅尔尼特斯基
Owner APPLE INC
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