Compression solution for embedded devices and systems
View Patent ↗An embedded device is hibernated by storing state data of the embedded device to a non-volatile data storage medium, and powering off the embedded device. The embedded device is later woken up in response to the detection of a wakeup event from a wakeup source. The state data stored in the RAM of the embedded device comprises one or more registers of a Central Processing Unit (CPU) of the embedded device, one or more registers of a system-on-chip (SOC) of the embedded device, and the system and applications code and data. Waking the embedded device comprises loading, from the non-volatile data storage medium, initial memory sections that are used to run a kernel of the embedded device. State data that is stored in the RAM of a system is compressed by dividing the RAM into a plurality of sections and independently choosing, for each section in the plurality of sections, a compression arithmetic. For each section, a compression arithmetic that has a high decompression speed is selected. The selected compression arithmetic is used to compress data in the section.
1. A method of compressing data in a RAM of an embedded device, comprising:
dividing the RAM into a plurality of sections;
for each section in the plurality of sections, performing the steps of:
selecting a first compression arithmetic;
generating a set of compression data, the set of compression data comprising data in the each section compressed using the first compression arithmetic;
in response to determining that the set of compressed data does not meet a compression-ratio requirement, performing the steps of:
selecting a second compression arithmetic; and
regenerating the set of compression data, the set of compression data comprising data in the each section compressed using the second compression arithmetic;
storing information that indicates an association between a compression arithmetic used to generate the set of compressed data and the each section; and
storing the set of compressed data to a non-volatile data storage medium.
2. The method of claim 1 , wherein the first compression arithmetic has a higher decompression speed than the second compression arithmetic.
3. The method of claim 1 , further comprising:
powering off the device.
4. The method of claim 1 , further comprising:
waking the device.
5. The method of claim 4 , wherein waking the device comprises:
for each section in the plurality of sections, performing the steps of:
selecting, based on information that indicates an association between the compression arithmetic used to generate the set of compressed data for the each section, a decompression arithmetic; and
decompressing the set of compressed data for the each section using the decompression arithmetic.
6. The method of claim 1 , wherein the data stored in the RAM of the device comprises data in one or more registers of a Central Processing Unit (CPU) of the device.
7. The method of claim 1 , wherein the data stored in the RAM of the device comprises data in one or more registers of a system-on-chip (SOC) of the device.
8. The method of claim 1 , wherein the RAM is an SDRAM.
9. The method of claim 1 , wherein the non-volatile storage is one of: a hard drive, an SD card, an MMC memory, and a flash memory.
10. An embedded device comprising a RAM and a non-volatile data storage medium, the embedded device further comprising:
means for dividing the RAM into a plurality of sections;
each section in the plurality of sections, comprising:
means for selecting a first compression arithmetic;
means for generating a set of compression data, the set of compression data comprising data in the each section compressed using the first compression arithmetic;
means for determining whether the set of compressed data meets a compression-ratio requirement;
means for selecting a second compression arithmetic if it is determined that the set of compressed data does not meet a compression-ratio requirement; and
means for regenerating the set of compression data, the set of compression data comprising data in the each section compressed using the second compression arithmetic;
means for storing information that indicates an association between a compression arithmetic used to generate the set of compressed data and the each section; and
means for storing the set of compressed data to a non-volatile data storage medium.
11. The embedded device of claim 10 , wherein the embedded device comprises a GPS receiver.
12. The embedded device of claim 10 , wherein the data stored in the RAM of the device comprises data in one or more registers of a Central Processing Unit (CPU) of the device.
13. The embedded device of claim 10 , wherein the data stored in the RAM of the device comprises data in one or more registers of a system-on-chip (SOC) of the device.
14. The embedded device of claim 10 , wherein the RAM is an SDRAM.
15. The method of claim 10 , wherein the non-volatile storage is one of: a hard drive, an SD card, an MMC memory, and a flash memory.