Method and apparatus for using CRC for data integrity in on-chip memory

A disc drive comprising:

• a rotatable disc;
• a transducer in transducing relationship to the rotating disc;
• a channel node having a first port and a second port, each port supporting a fibre-channel arbitrated-loop communications channel, each communications channel including a cyclic-redundancy code within data transmissions on the communications channel, the channel node operatively coupled to the transducer to communicate data;
• an on-chip frame memory located on-chip in the channel node that receives a frame and the received frame's associated CRC from the communications channel;
• and
• an integrity apparatus that uses the received associated CRC for data-integrity checking of the received frame that is in the on-chip frame memory.

A communications method comprising steps of:

• (a) supporting a fibre-channel arbitrated-loop communications channel on each of a first port and a second port of a first channel node;
• (b) receiving a frame from the communications channel, the received frame including a cyclic-redundancy code that is based on other data in the received frame;
• (c) storing the received frame, including the cyclic-redundancy code, into a frame buffer;
• (d) moving the received frame to a memory that is separate from the frame buffer;
• and
• (e) checking the received frame for accuracy by verifying the cyclic-redundancy code (CRC) while moving the received frame to the separate memory.

A communications channel system comprising:

• a channel node having a first port and a second port, each port supporting a fibre-channel arbitrated-loop communications channel, each communications channel including a cyclic-redundancy code within data transmissions on the communications channel;
• a buffer that receives, from the channel node, a frame that includes a cyclic-redundancy code;
• an off-chip memory separate from the buffer;
• means for moving the received frame from the buffer to the off-chip memory and checking the received frame for accuracy by verifying the cyclic-redundancy code (CRC) while moving the received frame to the off-chip memory.