Data formater/converter for use with solid-state disk memory using storage devices with defects
Abstract
Abstract A computer system includes a main memory that is able to make use of DRAM memory devices having a relatively high level of bad cells (hard faults). An EDC circuit is provided which uses combinatorial logic to perform a BCH code type of error detection and correction. A primary feature is the recognition that due to use of high density integrated circuits-gate arrays-it is no longer necessary to use sequential logic to decode the multiple-bit error correcting codes. An EDC with 128-bits of data and a check bit field 41-bits wide, using a BCH code, constructed in ASIC sea-of-gates technology using about 87,000 logic gates, can correct 5-bits in error and can detect 6-bits in error. By using multiple-bit EDC in the controller for main memory, it is no longer necessary that all DRAM devices be ostensibly "perfect." A certain density of non-functional memory cells can be tolerated, yet the memory system will still return perfect data. The added cost of multiple-bit EDC, including the added cost of extra storage for the check bits and the EDC circuit itself, is more than compensated by reduced cost of the DRAMs. In a addition the computer system includes a solid-state disk type memory for a computer system is able to make use of DRAM memory devices having a relatively high level of bad cells (hard faults). An EDC circuit is employed to perform a Reed-Solomon code type of error detection and correction. A primary feature is the recognition that it is no longer necessary that all DRAM devices be ostensibly "perfect." A certain density of non-functional memory cells can be tolerated, yet the memory system will still return perfect data. The added cost of multiple-bit EDC, including the added cost of extra storage for the check bits and the EDC circuit itself, is more than compensated by reduced cost of the DRAMs. A preferred data formatter circuit to convert between symbol and word data is also described.
Inventors
- 👤 Charles Cassidy
- 👤 Paul Kemp
Bibliographic Details
Claims Analysis
Total Claims: 7References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-08-29 | 1998-02-28 | 1998-08-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-08-29 | 2002-02-28 | 2002-08-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-08-29 | 2006-02-28 | 2006-08-30 | $7700.00 | Window Closed / Lapsed |