Electrical computers and digital data processing systems: input/ – Input/output data processing – Direct memory accessing
Patent
1997-09-30
2000-11-21
Lee, Thomas C.
Electrical computers and digital data processing systems: input/
Input/output data processing
Direct memory accessing
714 1, 714 5, 714 6, 714801, G06F 1314
Patent
active
061516414
ABSTRACT:
A DMA controller including an XOR FIFO buffer and XOR circuitry for computation of parity. The DMA controller resides within a RAID controller and establishes a direct data connection from host memory to subsystem local memory in order allow the CPU to perform other functions. The DMA controller accesses data segments from host memory corresponding to blocks of data within a disk stripe. As the data is transferred from host memory to subsystem local memory, the XOR circuitry simultaneously computes the parity corresponding to the successive data segments. Computing parity substantially simultaneously with the DMA data transfer reduces memory bandwidth utilization on the memory bus of the RAID controller. The parity is stored in the XOR buffer. Once parity is computed for a portion of data segments corresponding to a data stripe, the parity is transferred to local memory for retention. These steps are repeated until the full stripe is read into local memory and a parity value is computed for the entire data stripe. Once the RAID controller is ready to post the data to disk, the data is transferred from local memory to disk. The DMA controller of the present invention may also be advantageously applied when performing partial stripe writes by reducing the memory bandwidth utilization required to compute partial parity values.
REFERENCES:
patent: 4052699 (1977-10-01), Micka et al.
patent: 4996690 (1991-02-01), George et al.
patent: 5191584 (1993-03-01), Anderson
patent: 5206943 (1993-04-01), Callison et al.
patent: 5257391 (1993-10-01), DuLac et al.
patent: 5373512 (1994-12-01), Brady
patent: 5390327 (1995-02-01), Lubbers et al.
patent: 5471640 (1995-11-01), McBride
patent: 5594862 (1997-01-01), Winkler et al.
patent: 5742752 (1998-04-01), DeKoning
patent: 5787463 (1998-07-01), Gajjar
patent: 5798750 (1998-08-01), Ozaki
patent: 5838892 (1998-11-01), Wilson
Elamin Abdelmoniem
Lee Thomas C.
LSI Logic Corporation
LandOfFree
DMA controller of a RAID storage controller with integrated XOR does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with DMA controller of a RAID storage controller with integrated XOR , we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and DMA controller of a RAID storage controller with integrated XOR will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1266921