US5388083A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Flash memory mass storage architecture
Assignee: Micron Technology Inc
•
Filing: 1993-03-26
•
Granted: 1995-02-07
•
Expires: 2013-03-26
Abstract
Abstract A semiconductor mass storage system and architecture can be substituted for a rotating hard disk. The system and architecture avoid an erase cycle each time information stored in the mass storage is changed. (The erase cycle is understood to include, fully programming the block to be erased, and then erasing the block.) Erase cycles are avoided by programming an altered data file into an empty mass storage block rather than over itself as hard disk would. Periodically, the mass storage will need to be cleaned up. Secondly, all blocks in the mass storage are used evenly. These advantages are achieved through the use of several flags, a map to correlate a logical address of a block to a physical address of that block and a count register for each block. In particular, flags are provided for defective blocks, used blocks, old version of a block, a count to determine the number of times a block has been erased and written and erase inhibit flag.
Inventors
- 👤 Mahmud Assar
- 👤 Siamack Nemazie
- 👤 Petro Estakhri
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:11
CPC Classifications
G; G11; G11C; G11C16/00; G11C16/02; G11C16/06; G11C16/34; G11C16/349; G11C16/3495; G06; G06F; G06F3/00; G06F3/06; G06F3/0601; G11C16/10; G11C16/102; G06F3/0628; G06F3/0662; G06F3/0664
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
63 words
A non-volatile semiconductor mass storage device comprising: a. a plurality of non-volatile storage blocks, wherein each block is selectively programmable to store data and is selectively erasable and further wherein each block has a finite number of erase cycle lifetimes; and b. means for ensuring no block is subjected to more than a predetermined larger number of erase cycles than any other block.
Claim 2
Dependent Claim
63 words
A non-volatile semiconductor mass storage device comprising: a. a plurality of non-volatile storage blocks, wherein each block is selectively programmable to store data and is selectively erasable and further wherein each block has a finite number of erase cycle lifetimes; and b. means for ensuring no block is subjected to more than a predetermined larger number of erase cycles than any other block.
Claim 3
Dependent Claim
29 words
The device according to claim 1 wherein the means for ensuring comprises a counter for each block for counting each erase cycle to which that block has been subjected.
Claim 4
Dependent Claim
18 words
The device according to claim 2 wherein the counter includes a plurality of bits programmed by binary counting.
Claim 5
Dependent Claim
33 words
The device according to claim 2 wherein the counter includes a plurality of bits programmed by sequentially programming each bit, one at a time, wherein each programmed bit represents a count of one.
Claim 6
Dependent Claim
53 words
The device according to claim 2 further comprising means for setting a maximum count value which applies to all blocks, and further an erase inhibit flag having a set condition and an unset condition for each block for preventing further erases to a block having its erase inhibit flag in the set condition.
Claim 7
Dependent Claim
72 words
The device according to claim 5 further comprising: a. means for determining whether the counter for any erased block is equal to the maximum count value; b. means for finding a block having a count value less than the maximum count value; and c. means for moving the block having a count value less than the maximum count value into an erased block having its counter equal to the maximum count value.
Claim 8
Dependent Claim
36 words
The device according to claim 6 further comprising means for finding a block having a then least count value and moving that block into the erased block having its counter equal to the maximum count value.
Claim 9
Dependent Claim
20 words
The device according to claim 5 wherein the blocks, the counter and the flag are formed of flash memory cells.
Claim 10
Dependent Claim
21 words
The device according to claim 5 wherein the blocks, the counter and the flag are formed of E 2 PROM cells.
Claim 11
Dependent Claim
64 words
A non-volatile semiconductor mass storage device comprising: a. a plurality of non-volatile storage blocks, wherein each block is selectively programmable to store data and is selectively erasable and further wherein each block has a finite number of erase cycle lifetimes; and b. a controller to ensure no block is subjected to more than a predetermined larger number of erase cycles than any other block.
Claim 12
Dependent Claim
64 words
A non-volatile semiconductor mass storage device comprising: a. a plurality of non-volatile storage blocks, wherein each block is selectively programmable to store data and is selectively erasable and further wherein each block has a finite number of erase cycle lifetimes; and b. a controller to ensure no block is subjected to more than a predetermined larger number of erase cycles than any other block.
Claim 13
Dependent Claim
27 words
The device according to claim 10 wherein the controller comprises a counter for each block for counting each erase cycle to which that block has been subjected.
Claim 14
Dependent Claim
18 words
The device according to claim 11 wherein the counter includes a plurality of bits programmed by binary counting.
Claim 15
Dependent Claim
33 words
The device according to claim 11 wherein the counter includes a plurality of bits programmed by sequentially programming each bit, one at a time, wherein each programmed bit represents a count of one.
Claim 16
Dependent Claim
53 words
The device according to claim 11 further comprising means for setting a maximum count value which applies to all blocks, and further an erase inhibit flag having a set condition and an unset condition for each block for preventing further erases to a block having its erase inhibit flag in the set condition.
Claim 17
Dependent Claim
77 words
The device according to claim 12 further comprising: a. a first circuit to determine whether the counter for any erased block is equal to the maximum count value; b. a searcher to find a block having a count value less than the maximum count value; and c. a second circuit to move the block having a count value less than the maximum count value into an erased block having its counter equal to the maximum count value.
Claim 18
Dependent Claim
36 words
The device according to claim 15 further comprising means for finding a block having a then least count value and moving that block into the erased block having its counter equal to the maximum count value.
Claim 19
Dependent Claim
20 words
The device according to claim 12 wherein the blocks, the counter and the flag are formed of flash memory cells.
Claim 20
Dependent Claim
21 words
The device according to claim 12 wherein the blocks, the counter and the flag are formed of E 2 PROM cells.
Claim 21
Dependent Claim
155 words
A non-volatile semiconductor mass storage device comprising: a. a plurality of non-volatile storage blocks, wherein each block is selectively programmable to store data and is selectively erasable and further wherein each block has a finite number of erase cycle lifetimes; b. a plurality of counters, one counter for each block, to count each time its associated block is erased, wherein a programmable maximum value is applied to all the blocks; c. a plurality of erase inhibit flags, each flag having a set condition and an unset condition, one flag for each block, wherein the flag for a block having a count value equal to the maximum value is set to prevent further erasing of that block; d. a controller to switch data in a block having a relatively small count value into a block having the maximum value; and e. an erase element to clear all counters and all flags once all flags are set.
Claim 22
Dependent Claim
155 words
A non-volatile semiconductor mass storage device comprising: a. a plurality of non-volatile storage blocks, wherein each block is selectively programmable to store data and is selectively erasable and further wherein each block has a finite number of erase cycle lifetimes; b. a plurality of counters, one counter for each block, to count each time its associated block is erased, wherein a programmable maximum value is applied to all the blocks; c. a plurality of erase inhibit flags, each flag having a set condition and an unset condition, one flag for each block, wherein the flag for a block having a count value equal to the maximum value is set to prevent further erasing of that block; d. a controller to switch data in a block having a relatively small count value into a block having the maximum value; and e. an erase element to clear all counters and all flags once all flags are set.
Claim 23
Dependent Claim
72 words
The device according to claim 19 further comprising: a. means for determining whether the counter for any erased block is equal to the maximum count value; b. means for finding a block having a count value less than the maximum count value; and c. means for moving the block having a count value less than the maximum count value into an erased block having its counter equal to the maximum count value.
Claim 24
Dependent Claim
36 words
The device according to claim 20 further comprising means for finding a block having a then least counter value and moving that block into the erased block having its counter equal to the maximum count value.
Claim 25
Dependent Claim
20 words
The device according to claim 21 wherein the blocks, the counter and the flag are formed of flash memory cells.
Claim 26
Dependent Claim
21 words
The device according to claim 21 wherein the blocks, the counter and the flag are formed of E 2 PROM cells.
Claim 27
Independent Claim
131 words
A method of maintaining parity of erase cycles amongst storage blocks in a non-volatile semiconductor mass storage device having a plurality of non-volatile storage blocks, wherein each block is selectively programmable to store data and is selectively erasable and further wherein each block has a finite number of erase cycle lifetimes, the method comprising; a. counting and maintaining a count value for each block representing each time it is erased; b. setting a predetermined maximum value; c. preventing an erase cycle from being performed on a block having a count value equal to the maximum value; d. switching data from a block having a smallest count value into a block having the maximum value; and e. erasing the count values once all blocks have been erased the maximum value of times.
Claim 28
Independent Claim
131 words
A method of maintaining parity of erase cycles amongst storage blocks in a non-volatile semiconductor mass storage device having a plurality of non-volatile storage blocks, wherein each block is selectively programmable to store data and is selectively erasable and further wherein each block has a finite number of erase cycle lifetimes, the method comprising; a. counting and maintaining a count value for each block representing each time it is erased; b. setting a predetermined maximum value; c. preventing an erase cycle from being performed on a block having a count value equal to the maximum value; d. switching data from a block having a smallest count value into a block having the maximum value; and e. erasing the count values once all blocks have been erased the maximum value of times.
References Cited (Backward Citations)
JPS5945695A
Cited
JPS62283496A
Cited
JPS62283497A
Cited
US4943962A
Cited
US5053990A
Cited
US5168465A
Cited
US5095344A
Cited
US5043940A
Cited
US5034926A
Cited
US5155705A
Cited
US5163021A
Cited
US5172338B1
Cited
US5172338A
Cited
US5138580A
Cited
US5065364A
Cited
EP0424191A2
Cited
US5134589A
Cited
US5303198A
Cited
EP0489204A1
Cited
EP0501289A2
Cited
US5270979A
Cited
EP0509330A2
Cited
EP0509184A1
Cited
DE4214184A1
Cited
JPH04332999A
Cited
DE4215063A1
Cited
US5341368A
Cited
US5341339A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-02-06 | 1998-08-08 | 1999-02-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-02-06 | 2002-08-08 | 2003-02-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-02-06 | 2006-08-08 | 2007-02-07 | $7700.00 | Window Closed / Lapsed |