1. A method of managing data for at least one wireless communication network, the method comprising:
determining at least one free space metric for at least one data storage device;
comparing the at least one determined free space metric for the at least one data storage device to at least one threshold value; and
if the at least one determined free space metric for the at least one data storage device exceeds the at least one threshold value:
identifying data object groups represented by data objects stored within the at least one data storage device;
determining a retention priority value for each identified data object group;
determining at least one data object group for which to retire data objects based at least partly on the determined retention priority values; and
retiring data objects within the determined at least one data object group from the at least one data storage device.
2. The method of claim 1, wherein the free space metric comprises at least one of:
a proportional free space metric; and
an absolute free space metric.
3. The method of claim 1, wherein the retention priority value for an identified data object group is calculated based at least partly on a minimum retention period value for the respective data object group.
4. The method of claim 1, wherein the retention priority value for an identified data object group is calculated based at least partly on a time period for which data objects within the respective data object group are stored.
5. The method of claim 1, wherein the retention priority value for an identified data object group is calculated based at least partly on a ratio of: (TS_old\u2212TS_new)T_min.
6. The method of claim 1, wherein the method comprises determining at least one data object group for which to retire data objects based at least partly on a data object group comprising an extreme retention priority value.
7. The method of claim 1, wherein the method comprises retiring data objects within the determined at least one data object group from the at least one data storage device comprising a timestamp value older than a retirement cut-off time value.
8. The method of claim 7, wherein the retirement cut-off time value equals a timestamp value for an oldest data object within the determined at least one data object group+a data removal period value.
9. The method of claim 8, wherein the retirement cut-off time value equals a timestamp value for an oldest data object within the determined at least one data object group+a data object group specific data removal period value.
10. The method of claim 1, wherein the method comprises retiring data objects within the determined at least one data object group from the at least one data storage device as long as:
TS_new\u2212(TS_old+R_period)<T_min.
11. The method of claim 1, wherein data objects are data object grouped based at least partly on one or more of:
air interface technology;
type of data;
categories of subscribers;
geographic locations;
user equipment device types (models) or manufacturers;
12. The method of claim 1, wherein the method comprises determining free space metrics for a plurality of data storage devices;
comparing the determined free space metrics for the plurality of data storage devices to at least one threshold value; and
if at least one determined free space metric for at least one data storage device exceeds the at least one threshold value:
identifying data object groups represented by data objects stored within at least the data storage device for which the free space metric exceeds the at least one threshold value;
determining a retention priority value for each identified data object group;
determining at least one data object group for which to retire data objects based at least partly on the determined retention priority values; and
retiring data objects within the determined at least one data object group from at least the data storage device for which the free space metric exceeds the at least one threshold value.
13. The method of claim 12, wherein the method comprises retiring data objects within the determined at least one data object group from all of the data storage devices.
14. The method of claim 12, wherein the method comprises comparing the determined free space metrics for the plurality of data storage devices to data storage device specific threshold values.
15. The method of claim 1, wherein the method comprises retiring data objects within the determined at least one data object group with a timestamp earlier than TS_old+R_period.
16. The method of claim 1, wherein the method is arranged to be automatically initiated periodically.
17. A data management system comprising at least one data processing module arranged to:
determine at least one free space metric for at least one data storage device;
compare the at least one determined free space metric for the at least one data storage device to at least one threshold value; and
if the at least one determined free space metric for the at least one data storage device exceeds the at least one threshold value:
identify data object groups represented by data objects stored within the at least one data storage device;
determine a retention priority value for each identified data object group;
determine at least one data object group for which to retire data objects based at least partly on the determined retention priority values; and
retire data objects within the determined at least one data object group from the at least one data storage device.
18. A wireless communication system incorporating the data management system of claim 17.
19. A non-transitory computer program product having computer-readable code stored thereon for programming a data processing module to perform a method of managing data for at least one wireless communication network, the code operable for:
determining at least one free space metric for at least one data storage device;
comparing the at least one determined free space metric for the at least one data storage device to at least one threshold value; and
if the at least one determined free space metric for the at least one data storage device exceeds the at least one threshold value:
identifying data object groups represented by data objects stored within the at least one data storage device;
determining a retention priority value for each identified data object group;
determining at least one data object group for which to retire data objects based at least partly on the determined retention priority values; and
retiring data objects within the determined at least one data object group from the at least one data storage device.
20. The non-transitory computer program product of claim 19, wherein the non-transitory computer program product comprises at least one of: a hard disk, a CD-ROM, an optical storage device, a magnetic storage device, a Read Only Memory (ROM), a Programmable Read Only Memory (PROM), an Erasable Programmable Read Only Memory (EPROM), an Electrically Erasable Programmable Read Only Memory (EEPROM), and a Flash memory
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An error symbol detecting apparatus comprising:
an equalizer to equalize a signal transmitted to a channel using a channel equalization characteristic that is suitable for a corresponding system;
a data detector to detect data from a signal output from the equalizer;
a modeling tool having a same characteristic as a partial response (PR) target polynomial applied to the system with respect to the signal transmitted to the channel;
a correlation evaluation information generating unit to generate correlation evaluation information based on a correlation degree between the signal output of the equalizer and a target output of the modeling tool; and
an error symbol determination unit to determine an order of probability of error generation of one or more symbols based on the correlation evaluation information, and to determine a predetermined number of symbols having a high probability of generating one or more errors corresponding to the order of probability of error generation as one or more error generating symbols, the error symbol determination unit having:
a serial-parallel transducer to output the correlation evaluation information of the symbol unit generated by the correlation evaluation information generating unit in a sector unit in parallel;
a comparator to determine the order of the probability of error generation of the one or more symbols according to a magnitude of the correlation evaluation information output from the serial-parallel transducer; and
an error symbol determiner to determine the predetermined number of symbols as the one or more error symbols according to the order of the probability of error generation of the one or more symbols, and to output the determination result to an error correction decoder;
wherein the equalizer comprises a FIR filter.
2. The apparatus of claim 1, wherein the modeling tool comprises:
a finite impulse response (FIR) filter having a response characteristic corresponding to a factor obtained by resolving the PR target polynomial according to the signal;
a modeling filter connected to the FIR filter in series, and corresponding to remaining factors obtained by resolving the PR target polynomial except for the factor realized by the FIR filter; and
a first delay to delay an output of the modeling filter in order to synchronize the data output from the equalizer to be used in a correlation evaluation with data output from the modeling filter.
3. The apparatus of claim 1, wherein the data detector comprises a Viterbi detector.
4. The apparatus of claim 1, wherein the correlation evaluation information generating unit comprises:
a matched filter to receive the data detected by the data detector, and to calculate a correlation value of the input data corresponding to the PR target polynomial of the system;
a second delay to delay the output of the equalizer in order to synchronize the data output from the matched filter with the data output from the equalizer;
a first subtracter to calculate a difference between a signal output from the matched filter and a signal output from the second delay;
a second subtracter to calculate a difference between the signal output from the matched filter and the target output from the modeling tool; and
a multiply-accumulation calculator to generate correlation evaluation information by multiplying the output of the first subtracter with the output of the second subtracter and accumulating the multiplied values by a symbol unit.
5. The apparatus of claim 4, wherein a magnitude of the correlation evaluation information represents a determination that the error is likely to occur.
6. An error symbol detecting method comprising:
generating correlation evaluation information based on an output of an equalizer corresponding to a channel characteristic and a target output of a modeling tool having a same characteristic as a partial response (PR) target polynomial applied to the equalizer by generating a correlation value correspondinq to the PR target polynomial from the output signal of the equalizer;
determining an order of probability of error generation of one or more symbols with a sector unit according to a magnitude of the correlation evaluation information; and
determining a predetermined number of symbols having a high probability of generating errors corresponding to the order of probability of error generation as one or more error symbols;
wherein the equalizer comprises an FIR filter.
7. The method of claim 6, wherein the generating of the correlation evaluation information comprises:
generating the output signal of the equalizer having a response characteristic corresponding to the PR target polynomial that is suitable for the corresponding channel characteristic;
calculating a first subtracted value that corresponds to a difference between the output signal of the equalizer and the correlation value corresponding to the output signal;
generating a target output signal using a modeling tool corresponding to the PR target polynomial;
calculating a second subtracted value that corresponds to a difference between the target output signal of the modeling tool and the correlation value corresponding to the output signal; and
generating correlation evaluation information that is obtained by multiplying the first subtracted value with the second subtracted value and accumulating the multiplied values by symbol units.
8. A computer readable recording medium having embodied thereon a computer program to execute a method, the method comprising:
generating correlation evaluation information based on an output of an equalizer corresponding to a channel characteristic and a target output of a modeling tool having a same characteristic as a partial response (PR) target polynomial applied to the equalizer by generating a correlation value corresponding to the PR target polynomial from the output signal of the equalizer;
determining an order of probability of error generation of one or more symbols with a sector unit according to a magnitude of the correlation evaluation information; and
determining a predetermined number of symbols having a high probability of generating errors corresponding to the order of probability of error generation as one or more error symbols;
wherein the equalizer comprises a FIR filter.
9. A disk drive comprising:
a disk to store information;
a transducer to read the information from the disk;
an amplifier to change a gain of a signal detected by the transducer and to amplify the signal to a target level;
an analogdigital transducer to convert the amplified signal to a digital signal;
an equalizer to receive the digital signal that is converted by the analogdigital transducer and to equalize the digital signal to have a channel equalizing characteristic suitable for a corresponding system;
a data detector to detect data from the signal output from the equalizer;
a modeling tool corresponding to a partial response (PR) target polynomial that is applied to the system;
a correlation evaluation information generating unit to generate correlation evaluation information based on a correlation between the signal output of the equalizer and a target output of the modeling tool; and
an error symbol determination unit to determine an order of probability of error generation of one or more symbols based on the correlation evaluation information, and to determine a predetermined number of symbols corresponding to the order of probability of error generation as one or more error symbols the error symbol determination unit having:
a serial-parallel transducer to output the correlation evaluation information of the symbol unit generated by the correlation evaluation information generating unit in a sector unit in parallel;
a comparator to determine an order of the probability of error generation of the one or more symbols according to a magnitude of the correlation evaluation information output from the serial-parallel transducer; and
an error symbol determiner to determine the predetermined number of symbols as the one or more error symbols according to the order of the probability of error generation of the one or more symbols, and to output the determination result to an error correction decoder.
10. The disk drive of claim 9, wherein the correlation evaluation information generating unit comprises:
a matched filter to receive the data detected by the data detector, and to calculate correlation value of the input data corresponding to the PR target polynomial of the system;
a first delay to delay the output of the equalizer in order to synchronize data output from the matched filter with the data output from the equalizer;
a first subtracter to calculate a difference between a signal output from the matched filter and a signal output from the first delay;
a second subtracter to calculate a difference between the signal output from the matched filter and the target output from the modeling tool; and
a multiply-accumulation calculator to generate the correlation evaluation information by multiplying output of the first subtracter with output of the second subtracter and accumulating the multiplied values by a symbol unit.
11. The disk drive of claim 9, wherein the modeling tool comprises:
an FIR filter having a response characteristic corresponding to a factor obtained by resolving a PR target polynomial;
a modeling filter connected to the FIR filter in series, and designed to correspond to remaining factors obtained by resolving the PR target polynomial except for the factor realized by the FIR filter; and
a second delay to delay an output of the modeling filter to synchronize the data output from the equalizer to be used in a correlation evaluation with the target output from the modeling filter.
12. The disk drive of claim 9, wherein the data detector comprises a Viterbi detector.
13. The disk drive of claim 9, wherein the equalizer comprises an FIR filter.
14. A method of detecting errors in a data storage device, the method comprising:
generating a first signal corresponding to a partial response (PR) polynomial;
generating a second signal corresponding to the PR polynomial;
generating correlation evaluation information based on the first signal and the second signal;
determining an order of probability of error generation of one or more symbols corresponding to the correlation evaluation information; and
determining at least one symbol having a high probability of generating errors corresponding to the order of probability of error generation of one or more symbols;
wherein the PR polynomial corresponds to a channel characteristic of the data storage device,
wherein the determining the order of the probability of error generation further comprises ranking the one or more symbols with respect to each other based on a value associated with each of the one or more symbols in a manner that a symbol associated with a greater value can be ranked higher than an other symbol associated with a lesser value.
15. The method of claim 14, wherein the first signal is a signal output from an equalizer.
16. The method of claim 14, wherein the second signal is a target output of a modeling tool.
17. The method of claim 14, wherein the determining the at least one symbol of the one or more symbols further comprises selecting a predetermined number of the highest ranked symbols.
18. The method of claim 14, wherein the determining the at least one symbol of the plurality of symbols further comprises selecting at least one symbol based on the value of the at least one symbol being equal to or greater than a predetermined value.