ALPHA_BOOT_BLOCK_OFFSET
rv = pread(params->fsfd, &bb, sizeof(bb), ALPHA_BOOT_BLOCK_OFFSET);
rv = pwrite(params->fsfd, &bb, sizeof(bb), ALPHA_BOOT_BLOCK_OFFSET);
rv = pread(params->fsfd, &bb, sizeof(bb), ALPHA_BOOT_BLOCK_OFFSET);
startblock = ALPHA_BOOT_BLOCK_OFFSET /
rv = pwrite(params->fsfd, &bb, sizeof(bb), ALPHA_BOOT_BLOCK_OFFSET);