_sbuf_info
struct _sbuf_info;
_sbuf_info *fRel; /* next buf to be released */
_sbuf_info *fFreeBuffers;
_sbuf_info *fOldestBuffer; /* first in line */
_sbuf_info *fNewestBuffer; /* fNewest->fNext = NULL */
_sbuf_info *fAcq; /* next buf to be acquired */
_sbuf_info fBuffers[B_MAX_BUFFER_COUNT];
_sbuf_info *fNext; /* next "newer" buffer in the chain */