پروژه ارشد درس معماری ذخیره سازی

A Tutorial on Reed-Solomon Coding for Fault-Tolerance in RAID-like Systems

It is well-known that Reed-Solomon codes may be used to provide error correction for multiple failures in RAIDlike systems. The coding technique itself, however, is not as well-known. To the coding theorist, this technique is a

straightforward extension to a basic coding paradigm and needs no special mention. However, to the systems programmer with no training in coding theory, the technique may be a mystery. Currently, there are no references that describe how to perform this coding that do not assume that the reader is already well-versed in algebra and coding theory.

This paper is intended for the systems programmer. It presents a complete specification of the coding algorithm plus details on how it may be implemented. This specification assumes no prior knowledge of algebra or coding theory. The goal of this paper is for a systems programmer to be able to implement Reed-Solomon coding for reliability in RAID-like systems without needing to consult any external references

بخشی از کدهای فایل ورد

#include

#include

#include

#include

#include

#include

#define prim_poly_16 0210013

typedef unsigned short unit;

typedef struct {

int *condensed_matrix;

int *row_identities;

} Condensed_Matrix;

extern void gf_modar_setup();

extern int gf_single_multiply(int a, int b);

extern int gf_single_divide(int a, int b);

extern void gf_fprint_matrix(FILE *f, int *m, int rows, int cols);

extern void gf_fast_add_parity(void *to_add, void *to_modify, int size);

extern void gf_add_parity(void *to_add, void *to_modify, int size);

extern void gf_mult_region(void *region, int size, int factor);

extern int gf_log(int value);

extern int *gf_make_vandermonde(int rows, int cols);

extern int *gf_make_dispersal_matrix(int rows, int cols);

extern Condensed_Matrix *gf_condense_dispersal_matrix(

int *disp,

int *existing_rows,

int rows,

intcols);

extern int *gf_invert_matrix(int *mat, int rows);

extern int *gf_matrix_multiply(int *a, int *b, int rows);

extern void gf_write_matrix(FILE *f, int *a, int rows, int cols);

extern int *gf_read_matrix(FILE *f, int *rows, int *cols);

static int gf_already_setup = 0;

static int Modar_w = 16;

static int Modar_nw = 65536;

static int Modar_nwm1 = 65535;

static int Modar_poly = prim_poly_16;

static int *B_TO_J;

static int *J_TO_B;

static int Modar_M;

static int Modar_N;

static int Modar_Iam;

int gf_single_multiply(int xxx, int yyy)

{