Endec

Abstract: A sampled amplitude read channel is disclosed for writing data to and reading data from a disk storage medium. A first channel encoder encodes a first j-k bits of a j-bit data block to generate first encoded data, and an ECC encoder encodes the first encoded data and a remaining k-bits of the data block to generate ECC redundancy symbols comprising a plurality of bits. A second channel encoder encodes the remaining k-bits of the data block and the ECC redundancy symbols to generate second encoded data. The first encoded data and the second encoded data are then output as channel data written to the disk storage medium.

Abstract: A rate 16/17 ENDEC is disclosed which encodes 16 bit input data words into 17 bit codewords according to at least one predetermined code constraint, such as an RLL (d,k) constraint. The encoder encodes the high and low byte of the input data word using the same mapping circuitry which reduces its cost and complexity. The codewords are transferred through a communication channel, such as a computer disc storage device, and upon reception (or readback) the first 8 bits of the 17 bit codeword are decoded independent from the last 8 bits which prevents error propagation. That is, the first 8 bits of the codeword are decoded into a high byte of the decoded data word, and the last 8 bits of the codeword are decoded into a low byte of the decoded data word independent from one another. Thus, errors that occur in the received data sequence which affect only the first 8 bits of the codeword will not propagate to the decoded low byte, and errors affecting only the last 8 bits of the codeword will not propagate to the decoded high byte. Furthermore, the decoder uses the same mapping circuitry to decode the low and high byte of the output data words, thereby reducing its cost and complexity.

Abstract: Methods and apparatus for interconnecting Serial Attached SCSI (SAS) or Serial Advanced Technology Attachment (SATA) devices using either an electrical communication medium or an optical communication medium. Each device includes an out of band (OOB) encoder/decoder (endec) logic component to translate between standard OOB signals used by the devices and digitally encoded OOB signals exchanged over the communication medium. Thus the devices may be coupled using either optical or electrical cabling. The digitally encoded OOB signals may also be scrambled to reduce electromagnetic interference (EMI) generated during OOB communications using the digitally encoded OOB signals. The scrambled digitally encoded OOB signals may comprise information regarding capabilities of the device that generated the underlying OOB signal. Such information may indicate to the other high speed device certain capabilities of the transmitting device—the information to be used in establishing logical connections between devices.

Abstract: A system is disclosed that provides for the proper decoding of data information in an Encoder-Decoder ENDEC receiver in a Fiber Distributed Data Interface FDDI network. The system decouples the receiver from the data information when idle signals are provided thereto. In so doing "fragment bytes" associated with such transmission are not decoded.