Decoding method for shortened fire codes and its application to VLSI processor

Abstract

the hard disc, where the burst error-correcting code is frequently employed to im-The disc system is one of the areas of prove the reliability of the data. In the applications for the error-correcting code.implementation of the burst error-correct-For this purpose, a Fire code with the gener-ing code function in the VLSI chip for a c hard disc controller, the following pointsfrequently used. This paper considers the shortened Fire code, where the length of the code can be reduced according to the length of the record used. A decoding method suitable for VLSI is proposed. It is noted that the content of the feedback shift register with p(;c) as the divider returns to the original pattern when it is shifted by must be taken into consideration: (1) Scale of the hardware (chip area), (2) decoding time, (3) Frequency of utilization, and ( 4 ) easiness of design (logic, circuit and layout). for more than one information scale (record lengths), it is necessary to utilize ( 5 ) the decoding algorithm with the expandability.Especially, when a chip is utilized the period e of p ( x ) , and the speed is improved by ignoring the integer multiple shifts of e . This decoding method requires less hardware (i.e., shift registers and counters), and has the merits of easiness in design and expandability, according to the record length. The principle is expanded to the general cyclic code. The proposed decoding method is implemented on the hard disc controller (peripheral LSI for HDC 16 bit microcomputers). A 32-bit Fire code is used. For a typical record length of 512 bits in the disc system, the speed was comparable to that of the high-speed decoding.The error-correcting part is composed of 6700 Tr, which is 5.2% of the whole system (129 kTr). This figure demonstrates the practical usefulness of the proposed method in VLSI design.