--- ray/src/hd/holofile.c	1998/09/15 14:26:23	3.24
+++ ray/src/hd/holofile.c	2003/05/15 05:13:35	3.45
@@ -1,9 +1,6 @@
-/* Copyright (c) 1998 Silicon Graphics, Inc. */
-
 #ifndef lint
-static char SCCSid[] = "$SunId$ SGI";
+static const char	RCSid[] = "$Id: holofile.c,v 3.45 2003/05/15 05:13:35 greg Exp $";
 #endif
-
 /*
  * Routines for managing holodeck files
  *
@@ -13,33 +10,46 @@ static char SCCSid[] = "$SunId$ SGI";
 #include "holo.h"
 
 #ifndef CACHESIZE
-#define CACHESIZE	16	/* default cache size (Mbytes, 0==inf) */
+#ifdef SMLMEM
+#define CACHESIZE	5
+#else
+#define CACHESIZE	17	/* default cache size (Mbytes, 0==inf) */
 #endif
+#endif
 #ifndef FREEBEAMS
-#define FREEBEAMS	1024	/* maximum beams to free at a time */
+#define FREEBEAMS	1500	/* maximum beams to free at a time */
 #endif
 #ifndef PCTFREE
 #define PCTFREE		15	/* maximum fraction to free (%) */
 #endif
-#ifndef MAXFRAG
-#define MAXFRAG		32767	/* maximum fragments/file to track (0==inf) */
+#ifndef MAXFRAGB
+#define MAXFRAGB	16	/* fragment blocks/file to track (0==inf) */
 #endif
+#ifndef FF_DEFAULT
+				/* when to free a beam fragment */
+#define FF_DEFAULT	(FF_WRITE|FF_KILL)
+#endif
+#ifndef MINDIRSEL
+				/* minimum directory seek length */
+#define MINDIRSEL	(4*BUFSIZ/sizeof(BEAMI))
+#endif
 
 #ifndef BSD
 #define write	writebuf	/* safe i/o routines */
 #define read	readbuf
 #endif
 
-#define FRAGBLK		256	/* number of fragments to allocate at a time */
+#define FRAGBLK		512	/* number of fragments to allocate at a time */
 
+int	hdfragflags = FF_DEFAULT;	/* tells when to free fragments */
 unsigned	hdcachesize = CACHESIZE*1024*1024;	/* target cache size */
-unsigned long	hdclock;	/* clock value */
+unsigned long	hdclock;		/* clock value */
 
 HOLO	*hdlist[HDMAX+1];	/* holodeck pointers (NULL term.) */
 
 static struct fraglist {
 	short	nlinks;		/* number of holodeck sections using us */
-	short	writerr;	/* write error encountered */
+	short	writable;	/* 0 read-only, <0 write error encountered */
 	int	nfrags;		/* number of known fragments */
 	BEAMI	*fi;		/* fragments, descending file position */
 	long	flen;		/* last known file length */
@@ -48,24 +58,78 @@ static struct fraglist {
 static int	nhdfragls;	/* size of hdfragl array */
 
 
-hdattach(fd)		/* start tracking file fragments for some section */
+HOLO *
+hdalloc(hproto)		/* allocate and set holodeck section based on grid */
+HDGRID	*hproto;
+{
+	HOLO	hdhead;
+	register HOLO	*hp;
+	int	n;
+				/* copy grid to temporary header */
+	bcopy((void *)hproto, (void *)&hdhead, sizeof(HDGRID));
+				/* compute grid vectors and sizes */
+	hdcompgrid(&hdhead);
+				/* allocate header with directory */
+	n = sizeof(HOLO)+nbeams(&hdhead)*sizeof(BEAMI);
+	if ((hp = (HOLO *)malloc(n)) == NULL)
+		return(NULL);
+				/* copy header information */
+	copystruct(hp, &hdhead);
+				/* allocate and clear beam list */
+	hp->bl = (BEAM **)malloc((nbeams(hp)+1)*sizeof(BEAM *)+sizeof(BEAM));
+	if (hp->bl == NULL) {
+		free((void *)hp);
+		return(NULL);
+	}
+	bzero((void *)hp->bl, (nbeams(hp)+1)*sizeof(BEAM *)+sizeof(BEAM));
+	hp->bl[0] = (BEAM *)(hp->bl+nbeams(hp)+1);	/* set blglob(hp) */
+	hp->fd = -1;
+	hp->dirty = 0;
+	hp->priv = NULL;
+				/* clear beam directory */
+	bzero((void *)hp->bi, (nbeams(hp)+1)*sizeof(BEAMI));
+	return(hp);		/* all is well */
+}
+
+
+char *
+hdrealloc(ptr, siz, rout)	/* (re)allocate memory, retry then error */
+char	*ptr;
+unsigned	siz;
+char	*rout;
+{
+	register char	*newp;
+					/* call malloc/realloc */
+	if (ptr == NULL) newp = (char *)malloc(siz);
+	else newp = (char *)realloc((void *)ptr, siz);
+					/* check success */
+	if (newp == NULL && rout != NULL) {
+		hdfreecache(25, NULL);	/* free some memory */
+		errno = 0;		/* retry */
+		newp = hdrealloc(ptr, siz, NULL);
+		if (newp == NULL) {	/* give up and report error */
+			sprintf(errmsg, "out of memory in %s", rout);
+			error(SYSTEM, errmsg);
+		}
+	}
+	return(newp);
+}
+
+
+hdattach(fd, wr)	/* start tracking file fragments for some section */
 register int	fd;
+int	wr;
 {
 	if (fd >= nhdfragls) {
-		if (nhdfragls)
-			hdfragl = (struct fraglist *)realloc((char *)hdfragl,
-					(fd+1)*sizeof(struct fraglist));
-		else
-			hdfragl = (struct fraglist *)malloc(
-					(fd+1)*sizeof(struct fraglist));
-		if (hdfragl == NULL)
-			error(SYSTEM, "out of memory in hdattach");
-		bzero((char *)(hdfragl+nhdfragls),
+		hdfragl = (struct fraglist *)hdrealloc((char *)hdfragl,
+				(fd+1)*sizeof(struct fraglist), "hdattach");
+		bzero((void *)(hdfragl+nhdfragls),
 				(fd+1-nhdfragls)*sizeof(struct fraglist));
 		nhdfragls = fd+1;
 	}
 	hdfragl[fd].nlinks++;
-	hdfragl[fd].flen = lseek(fd, 0L, 2);	/* get file length */
+	hdfragl[fd].writable = wr;		/* set writable flag */
+	hdfragl[fd].flen = lseek(fd, (off_t)0L, 2);	/* get file length */
 }
 
 
@@ -78,28 +142,13 @@ register int	fd;
 	if (fd < 0 | fd >= nhdfragls || !hdfragl[fd].nlinks)
 		return;
 	if (!--hdfragl[fd].nlinks && hdfragl[fd].nfrags) {
-		free((char *)hdfragl[fd].fi);
+		free((void *)hdfragl[fd].fi);
 		hdfragl[fd].fi = NULL;
 		hdfragl[fd].nfrags = 0;
 	}
 }
 
 
-markdirty(hp)			/* mark holodeck section directory dirty */
-register HOLO	*hp;
-{
-	static BEAMI	smudge = {0, -1};
-
-	if (hp->dirty)		/* already marked? */
-		return;
-	hp->dirty = 1;
-	if (lseek(hp->fd, biglob(hp)->fo+(nbeams(hp)-1)*sizeof(BEAMI), 0) < 0
-			|| write(hp->fd, (char *)&smudge,
-					sizeof(BEAMI)) != sizeof(BEAMI))
-		error(SYSTEM, "seek/write error in markdirty");
-}
-
-
 HOLO *
 hdinit(fd, hproto)	/* initialize a holodeck section in a file */
 int	fd;			/* corresponding file descriptor */
@@ -107,11 +156,12 @@ HDGRID	*hproto;		/* holodeck section grid */
 {
 	long	rtrunc;
 	long	fpos;
+	int	writable;
 	register HOLO	*hp;
 	register int	n;
 					/* prepare for system errors */
 	errno = 0;
-	if ((fpos = lseek(fd, 0L, 1)) < 0)
+	if ((fpos = lseek(fd, (off_t)0L, 1)) < 0)
 		error(SYSTEM, "cannot determine holodeck file position");
 	if (hproto == NULL) {		/* assume we're loading it */
 		HDGRID	hpr;
@@ -126,9 +176,20 @@ HDGRID	*hproto;		/* holodeck section grid */
 		if (read(fd, (char *)(hp->bi+1), n) != n)
 			error(SYSTEM, "failure loading holodeck directory");
 						/* check that it's clean */
-		if (hp->bi[nbeams(hp)].fo < 0)
-			error(WARNING, "dirty holodeck section");
-	} else {			/* assume we're creating it */
+		for (n = nbeams(hp); n > 0; n--)
+			if (hp->bi[n].fo < 0) {
+				hp->bi[n].fo = 0;
+				error(WARNING, "dirty holodeck section");
+				break;
+			}
+						/* check writability */
+		if (fd < nhdfragls && hdfragl[fd].nlinks)
+			writable = hdfragl[fd].writable;
+		else
+			writable = lseek(fd, (off_t)fpos, 0) == fpos &&
+				write(fd, (char *)hp, sizeof(HDGRID)) ==
+							sizeof(HDGRID);
+	} else {			/* else assume we're creating it */
 		if ((hp = hdalloc(hproto)) == NULL)
 			goto memerr;
 						/* write header and skeleton */
@@ -137,18 +198,19 @@ HDGRID	*hproto;		/* holodeck section grid */
 					sizeof(HDGRID) ||
 				write(fd, (char *)(hp->bi+1), n) != n)
 			error(SYSTEM, "cannot write header to holodeck file");
+		writable = 1;
 	}
 	hp->fd = fd;	
 	hp->dirty = 0;
 	biglob(hp)->fo = fpos + sizeof(HDGRID);
 					/* start tracking fragments */
-	hdattach(fd);
+	hdattach(fd, writable);
 					/* check rays on disk */
 	fpos = hdfilen(fd);
 	biglob(hp)->nrd = rtrunc = 0;
 	for (n = hproto == NULL ? nbeams(hp) : 0; n > 0; n--)
 		if (hp->bi[n].nrd)
-			if (hp->bi[n].fo + hp->bi[n].nrd > fpos) {
+			if (hp->bi[n].fo+hp->bi[n].nrd*sizeof(RAYVAL) > fpos) {
 				rtrunc += hp->bi[n].nrd;
 				hp->bi[n].nrd = 0;
 			} else
@@ -171,6 +233,57 @@ memerr:
 }
 
 
+hdmarkdirty(hp, i)		/* mark holodeck directory position dirty */
+register HOLO	*hp;
+int	i;
+{
+	static BEAMI	smudge = {0, -1};
+	int	mindist, minpos;
+	register int	j;
+
+	if (!hp->dirty++) {			/* write smudge first time */
+		if (lseek(hp->fd, (off_t)(biglob(hp)->fo+(i-1)*sizeof(BEAMI)), 0) < 0
+				|| write(hp->fd, (char *)&smudge,
+					sizeof(BEAMI)) != sizeof(BEAMI))
+			error(SYSTEM, "seek/write error in hdmarkdirty");
+		hp->dirseg[0].s = i;
+		hp->dirseg[0].n = 1;
+		return;
+	}
+						/* insert into segment list */
+	for (j = hp->dirty; j--; ) {
+		if (!j || hp->dirseg[j-1].s < i) {
+			hp->dirseg[j].s = i;
+			hp->dirseg[j].n = 1;
+			break;
+		}
+		copystruct(hp->dirseg+j, hp->dirseg+(j-1));
+	}
+	do {				/* check neighbors */
+		mindist = nbeams(hp);		/* find closest */
+		for (j = hp->dirty; --j; )
+			if (hp->dirseg[j].s -
+					(hp->dirseg[j-1].s + hp->dirseg[j-1].n)
+					< mindist) {
+				minpos = j;
+				mindist = hp->dirseg[j].s -
+					(hp->dirseg[j-1].s + hp->dirseg[j-1].n);
+			}
+						/* good enough? */
+		if (hp->dirty <= MAXDIRSE && mindist > MINDIRSEL)
+			break;
+		j = minpos - 1;			/* coalesce neighbors */
+		if (hp->dirseg[j].s + hp->dirseg[j].n <
+				hp->dirseg[minpos].s + hp->dirseg[minpos].n)
+			hp->dirseg[j].n = hp->dirseg[minpos].s +
+					hp->dirseg[minpos].n - hp->dirseg[j].s;
+		hp->dirty--;
+		while (++j < hp->dirty)		/* close the gap */
+			copystruct(hp->dirseg+j, hp->dirseg+(j+1));
+	} while (mindist <= MINDIRSEL);
+}
+
+
 int
 hdsync(hp, all)			/* update beams and directory on disk */
 register HOLO	*hp;
@@ -190,13 +303,16 @@ int	all;
 			hdsyncbeam(hp, j);
 	if (!hp->dirty)			/* directory clean? */
 		return(0);
-	errno = 0;
-	if (lseek(hp->fd, biglob(hp)->fo, 0) < 0)
-		error(SYSTEM, "cannot seek on holodeck file");
-	n = nbeams(hp)*sizeof(BEAMI);
-	if (write(hp->fd, (char *)(hp->bi+1), n) != n)
-		error(SYSTEM, "cannot update holodeck section directory");
-	hp->dirty = 0;
+	errno = 0;			/* write dirty segments */
+	for (j = 0; j < hp->dirty; j++) {
+		if (lseek(hp->fd, (off_t)(biglob(hp)->fo +
+				(hp->dirseg[j].s-1)*sizeof(BEAMI)), 0) < 0)
+			error(SYSTEM, "cannot seek on holodeck file");
+		n = hp->dirseg[j].n * sizeof(BEAMI);
+		if (write(hp->fd, (char *)(hp->bi+hp->dirseg[j].s), n) != n)
+			error(SYSTEM, "cannot update section directory");
+	}
+	hp->dirty = 0;			/* all clean */
 	return(1);
 }
 
@@ -239,10 +355,10 @@ int	fd;
 	if (fd < 0)
 		return(-1);
 	if (fd >= nhdfragls || !hdfragl[fd].nlinks) {
-		if ((fpos = lseek(fd, 0L, 1)) < 0)
+		if ((fpos = lseek(fd, (off_t)0L, 1)) < 0)
 			return(-1);
-		flen = lseek(fd, 0L, 2);
-		lseek(fd, fpos, 0);
+		flen = lseek(fd, (off_t)0L, 2);
+		lseek(fd, (off_t)fpos, 0);
 		return(flen);
 	}
 	return(hdfragl[fd].flen);
@@ -284,22 +400,20 @@ int	nr;			/* number of new rays desired */
 	RAYVAL	*p;
 	int	n;
 
-	if (nr <= 0)
-		return(NULL);
-	if (i < 1 | i > nbeams(hp))
-		error(CONSISTENCY, "bad beam index given to hdnewrays");
+	if (nr <= 0) return(NULL);
+	CHECK(i < 1 | i > nbeams(hp),
+			CONSISTENCY, "bad beam index given to hdnewrays");
 	if (hp->bl[i] != NULL)
 		hp->bl[i]->tick = hdclock;	/* preempt swap */
 	if (hdcachesize > 0 && hdmemuse(0) >= hdcachesize)
 		hdfreecache(PCTFREE, NULL);	/* free some space */
-	errno = 0;
 	if (hp->bl[i] == NULL) {		/* allocate (and load) */
 		n = hp->bi[i].nrd + nr;
-		if ((hp->bl[i] = (BEAM *)malloc(hdbsiz(n))) == NULL)
-			goto memerr;
+		hp->bl[i] = (BEAM *)hdrealloc(NULL, hdbsiz(n), "hdnewrays");
 		blglob(hp)->nrm += n;
-		if (n = hp->bl[i]->nrm = hp->bi[i].nrd) {
-			if (lseek(hp->fd, hp->bi[i].fo, 0) < 0)
+		if ((n = hp->bl[i]->nrm = hp->bi[i].nrd)) {
+			errno = 0;
+			if (lseek(hp->fd, (off_t)hp->bi[i].fo, 0) < 0)
 				error(SYSTEM, "seek error on holodeck file");
 			n *= sizeof(RAYVAL);
 			if (read(hp->fd, (char *)hdbray(hp->bl[i]), n) != n)
@@ -307,20 +421,17 @@ int	nr;			/* number of new rays desired */
 				"error reading beam from holodeck file");
 		}
 	} else {				/* just grow in memory */
-		hp->bl[i] = (BEAM *)realloc( (char *)hp->bl[i],
-				hdbsiz(hp->bl[i]->nrm + nr) );
-		if (hp->bl[i] == NULL)
-			goto memerr;
+		hp->bl[i] = (BEAM *)hdrealloc((char *)hp->bl[i],
+				hdbsiz(hp->bl[i]->nrm + nr), "hdnewrays");
 		blglob(hp)->nrm += nr;
 	}
+	if (hdfragflags&FF_ALLOC && hp->bi[i].nrd)
+		hdfreefrag(hp, i);		/* relinquish old fragment */
 	p = hdbray(hp->bl[i]) + hp->bl[i]->nrm;
 	hp->bl[i]->nrm += nr;			/* update in-core structure */
-	bzero((char *)p, nr*sizeof(RAYVAL));
-	hp->bl[i]->tick = hdclock;		/* update LRU clock */
-	blglob(hp)->tick = hdclock++;
+	bzero((void *)p, nr*sizeof(RAYVAL));
+	blglob(hp)->tick = hp->bl[i]->tick = hdclock++;	/* update LRU clock */
 	return(p);				/* point to new rays */
-memerr:
-	error(SYSTEM, "out of memory in hdnewrays");
 }
 
 
@@ -331,25 +442,25 @@ register int	i;
 {
 	register int	n;
 
-	if (i < 1 | i > nbeams(hp))
-		error(CONSISTENCY, "bad beam index given to hdgetbeam");
+	CHECK(i < 1 | i > nbeams(hp),
+			CONSISTENCY, "bad beam index given to hdgetbeam");
 	if (hp->bl[i] == NULL) {		/* load from disk */
 		if (!(n = hp->bi[i].nrd))
 			return(NULL);
 		if (hdcachesize > 0 && hdmemuse(0) >= hdcachesize)
 			hdfreecache(PCTFREE, NULL);	/* get free space */
-		errno = 0;
-		if ((hp->bl[i] = (BEAM *)malloc(hdbsiz(n))) == NULL)
-			error(SYSTEM, "cannot allocate memory for beam");
+		hp->bl[i] = (BEAM *)hdrealloc(NULL, hdbsiz(n), "hdgetbeam");
 		blglob(hp)->nrm += hp->bl[i]->nrm = n;
-		if (lseek(hp->fd, hp->bi[i].fo, 0) < 0)
+		errno = 0;
+		if (lseek(hp->fd, (off_t)hp->bi[i].fo, 0) < 0)
 			error(SYSTEM, "seek error on holodeck file");
 		n *= sizeof(RAYVAL);
 		if (read(hp->fd, (char *)hdbray(hp->bl[i]), n) != n)
 			error(SYSTEM, "error reading beam from holodeck file");
+		if (hdfragflags&FF_READ)
+			hdfreefrag(hp, i);	/* relinquish old frag. */
 	}
-	hp->bl[i]->tick = hdclock;	/* update LRU clock */
-	blglob(hp)->tick = hdclock++;
+	blglob(hp)->tick = hp->bl[i]->tick = hdclock++;	/* update LRU clock */
 	return(hp->bl[i]);
 }
 
@@ -383,11 +494,12 @@ int	(*bf)();		/* callback function (optional) */
 	register BEAM	*bp;
 	register int	i;
 					/* precheck consistency */
+	if (n <= 0) return;
 	for (i = n; i--; )
-		if (hb[i].h == NULL || hb[i].b < 1 | hb[i].b > nbeams(hb[i].h))
+		if (hb[i].h==NULL || hb[i].b<1 | hb[i].b>nbeams(hb[i].h))
 			error(CONSISTENCY, "bad beam in hdloadbeams");
 					/* sort list for optimal access */
-	qsort((char *)hb, n, sizeof(HDBEAMI), hdfilord);
+	qsort((void *)hb, n, sizeof(HDBEAMI), hdfilord);
 	bytesloaded = 0;		/* run through loaded beams */
 	for ( ; n && (bp = hb->h->bl[hb->b]) != NULL; n--, hb++) {
 		bp->tick = hdclock;	/* preempt swap */
@@ -417,20 +529,22 @@ int	(*bf)();		/* callback function (optional) */
 }
 
 
-hdfreefrag(fd, bi)			/* free a file fragment */
-int	fd;
-register BEAMI	*bi;
+int
+hdfreefrag(hp, i)			/* free a file fragment */
+HOLO	*hp;
+int	i;
 {
+	register BEAMI	*bi = &hp->bi[i];
 	register struct fraglist	*f;
 	register int	j, k;
 
-	if (bi->nrd == 0)
-		return;
-#ifdef DEBUG
-	if (fd < 0 | fd >= nhdfragls || !hdfragl[fd].nlinks)
-		error(CONSISTENCY, "bad file descriptor in hdfreefrag");
-#endif
-	f = &hdfragl[fd];
+	if (bi->nrd <= 0)
+		return(0);
+	DCHECK(hp->fd < 0 | hp->fd >= nhdfragls || !hdfragl[hp->fd].nlinks,
+			CONSISTENCY, "bad file descriptor in hdfreefrag");
+	f = &hdfragl[hp->fd];
+	if (!f->writable)
+		return(0);
 	if (f->nfrags % FRAGBLK == 0) {	/* delete empty remnants */
 		for (j = k = 0; k < f->nfrags; j++, k++) {
 			while (f->fi[k].nrd == 0)
@@ -443,18 +557,25 @@ register BEAMI	*bi;
 		f->nfrags = j;
 	}
 	j = f->nfrags++;		/* allocate a slot in free list */
-#if MAXFRAG
-	if (j >= MAXFRAG-1)
-		f->nfrags--;
+#if MAXFRAGB
+	if (j >= MAXFRAGB*FRAGBLK) {
+		f->nfrags = j--;	/* stop list growth */
+		if (bi->nrd <= f->fi[j].nrd)
+			return(0);	/* new one no better than discard */
+	}
 #endif
-	if (j % FRAGBLK == 0) {		/* more free list space */
+	if (j % FRAGBLK == 0) {		/* more (or less) free list space */
+		register BEAMI	*newp;
 		if (f->fi == NULL)
-			f->fi = (BEAMI *)malloc(FRAGBLK*sizeof(BEAMI));
+			newp = (BEAMI *)malloc((j+FRAGBLK)*sizeof(BEAMI));
 		else
-			f->fi = (BEAMI *)realloc((char *)f->fi,
+			newp = (BEAMI *)realloc((void *)f->fi,
 					(j+FRAGBLK)*sizeof(BEAMI));
-		if (f->fi == NULL)
-			error(SYSTEM, "out of memory in hdfreefrag");
+		if (newp == NULL) {
+			f->nfrags--;	/* graceful failure */
+			return(0);
+		}
+		f->fi = newp;
 	}
 	for ( ; ; j--) {		/* insert in descending list */
 		if (!j || bi->fo < f->fi[j-1].fo) {
@@ -479,38 +600,62 @@ register BEAMI	*bi;
 			}
 			break;
 		}
+	biglob(hp)->nrd -= bi->nrd;		/* tell fragment it's free */
+	bi->nrd = 0;
+	bi->fo = 0L;
+	hdmarkdirty(hp, i);			/* assume we'll reallocate */
+	return(1);
 }
 
 
+int
+hdfragOK(fd, listlen, listsiz)	/* get fragment list status for file */
+int	fd;
+int	*listlen;
+register int4	*listsiz;
+{
+	register struct fraglist	*f;
+	register int	i;
+
+	if (fd < 0 | fd >= nhdfragls || !(f = &hdfragl[fd])->nlinks)
+		return(0);		/* listless */
+	if (listlen != NULL)
+		*listlen = f->nfrags;
+	if (listsiz != NULL)
+		for (i = f->nfrags, *listsiz = 0; i--; )
+			*listsiz += f->fi[i].nrd;
+#if MAXFRAGB
+	return(f->nfrags < MAXFRAGB*FRAGBLK);
+#else
+	return(1);			/* list never fills up */
+#endif
+}
+
+
 long
 hdallocfrag(fd, nrays)		/* allocate a file fragment */
 int	fd;
 unsigned int4	nrays;
 {
 	register struct fraglist	*f;
-	register int	j, k;
+	register int	j;
 	long	nfo;
 
 	if (nrays == 0)
 		return(-1L);
-#ifdef DEBUG
-	if (fd < 0 | fd >= nhdfragls || !hdfragl[fd].nlinks)
-		error(CONSISTENCY, "bad file descriptor in hdallocfrag");
-#endif
+	DCHECK(fd < 0 | fd >= nhdfragls || !hdfragl[fd].nlinks,
+			CONSISTENCY, "bad file descriptor in hdallocfrag");
 	f = &hdfragl[fd];
-	k = -1;				/* find closest-sized fragment */
-	for (j = f->nfrags; j-- > 0; )
-		if (f->fi[j].nrd >= nrays &&
-				(k < 0 || f->fi[j].nrd < f->fi[k].nrd))
-			if (f->fi[k=j].nrd == nrays)
-				break;
-	if (k < 0) {			/* no fragment -- extend file */
+	for (j = f->nfrags; j-- > 0; )	/* first fit algorithm */
+		if (f->fi[j].nrd >= nrays)
+			break;
+	if (j < 0) {			/* no fragment -- extend file */
 		nfo = f->flen;
 		f->flen += nrays*sizeof(RAYVAL);
 	} else {			/* else use fragment */
-		nfo = f->fi[k].fo;
-		f->fi[k].fo += nrays*sizeof(RAYVAL);
-		f->fi[k].nrd -= nrays;
+		nfo = f->fi[j].fo;
+		f->fi[j].fo += nrays*sizeof(RAYVAL);
+		f->fi[j].nrd -= nrays;
 	}
 	return(nfo);
 }
@@ -521,29 +666,28 @@ hdsyncbeam(hp, i)		/* sync beam in memory with beam on
 register HOLO	*hp;
 register int	i;
 {
+	int	fragfreed;
 	unsigned int4	nrays;
 	unsigned int	n;
 	long	nfo;
 					/* check file status */
-	if (hdfragl[hp->fd].writerr)
-		return(-1);
-#ifdef DEBUG
-	if (i < 1 | i > nbeams(hp))
-		error(CONSISTENCY, "bad beam index in hdsyncbeam");
-#endif
+	if (hdfragl[hp->fd].writable <= 0)
+		return(hdfragl[hp->fd].writable);
+	DCHECK(i < 1 | i > nbeams(hp),
+			CONSISTENCY, "bad beam index in hdsyncbeam");
 					/* is current fragment OK? */
 	if (hp->bl[i] == NULL || (nrays = hp->bl[i]->nrm) == hp->bi[i].nrd)
 		return(0);
-	if (hp->bi[i].nrd)		/* relinquish old fragment */
-		hdfreefrag(hp->fd, &hp->bi[i]);
+					/* relinquish old fragment? */
+	fragfreed = hdfragflags&FF_WRITE && hp->bi[i].nrd && hdfreefrag(hp,i);
 	if (nrays) {			/* get and write new fragment */
 		nfo = hdallocfrag(hp->fd, nrays);
 		errno = 0;
-		if (lseek(hp->fd, nfo, 0) < 0)
+		if (lseek(hp->fd, (off_t)nfo, 0) < 0)
 			error(SYSTEM, "cannot seek on holodeck file");
 		n = hp->bl[i]->nrm * sizeof(RAYVAL);
 		if (write(hp->fd, (char *)hdbray(hp->bl[i]), n) != n) {
-			hdfragl[hp->fd].writerr++;
+			hdfragl[hp->fd].writable = -1;
 			hdsync(NULL, 0);	/* sync directories */
 			error(SYSTEM, "write error in hdsyncbeam");
 		}
@@ -552,7 +696,8 @@ register int	i;
 		hp->bi[i].fo = 0L;
 	biglob(hp)->nrd += nrays - hp->bi[i].nrd;
 	hp->bi[i].nrd = nrays;
-	markdirty(hp);			/* section directory now out of date */
+	if (!fragfreed)
+		hdmarkdirty(hp, i);		/* need to flag dir. ent. */
 	return(1);
 }
 
@@ -570,19 +715,21 @@ register int	i;
 			nchanged += hdfreebeam(hdlist[i], 0);
 		return(nchanged);
 	}
-	if (hdfragl[hp->fd].writerr)	/* check for file error */
+	if (hdfragl[hp->fd].writable < 0)	/* check for file error */
 		return(0);
 	if (i == 0) {			/* clear entire holodeck */
+		if (blglob(hp)->nrm == 0)
+			return(0);		/* already clear */
 		nchanged = 0;
 		for (i = nbeams(hp); i > 0; i--)
 			if (hp->bl[i] != NULL)
 				nchanged += hdfreebeam(hp, i);
+		DCHECK(blglob(hp)->nrm != 0,
+				CONSISTENCY, "bad beam count in hdfreebeam");
 		return(nchanged);
 	}
-#ifdef DEBUG
-	if (i < 1 | i > nbeams(hp))
-		error(CONSISTENCY, "bad beam index to hdfreebeam");
-#endif
+	DCHECK(i < 1 | i > nbeams(hp),
+			CONSISTENCY, "bad beam index to hdfreebeam");
 	if (hp->bl[i] == NULL)
 		return(0);
 					/* check for additions */
@@ -590,7 +737,7 @@ register int	i;
 	if (nchanged)
 		hdsyncbeam(hp, i);		/* write new fragment */
 	blglob(hp)->nrm -= hp->bl[i]->nrm;
-	free((char *)hp->bl[i]);		/* free memory */
+	free((void *)hp->bl[i]);		/* free memory */
 	hp->bl[i] = NULL;
 	return(nchanged);
 }
@@ -601,7 +748,6 @@ hdkillbeam(hp, i)		/* delete beam from holodeck */
 register HOLO	*hp;
 register int	i;
 {
-	static BEAM	emptybeam;
 	int	nchanged;
 
 	if (hp == NULL) {		/* clobber all holodecks */
@@ -611,30 +757,33 @@ register int	i;
 		return(nchanged);
 	}
 	if (i == 0) {			/* clobber entire holodeck */
+		if (biglob(hp)->nrd == 0 & blglob(hp)->nrm == 0)
+			return(0);		/* already empty */
 		nchanged = 0;
+		nchanged = 0;
 		for (i = nbeams(hp); i > 0; i--)
 			if (hp->bi[i].nrd > 0 || hp->bl[i] != NULL)
 				nchanged += hdkillbeam(hp, i);
-#ifdef DEBUG
-		if (biglob(hp)->nrd != 0 | blglob(hp)->nrm != 0)
-			error(CONSISTENCY, "bad beam count in hdkillbeam");
-#endif
+		DCHECK(biglob(hp)->nrd != 0 | blglob(hp)->nrm != 0,
+				CONSISTENCY, "bad beam count in hdkillbeam");
 		return(nchanged);
 	}
-#ifdef DEBUG
-	if (i < 1 | i > nbeams(hp))
-		error(CONSISTENCY, "bad beam index to hdkillbeam");
-#endif
+	DCHECK(i < 1 | i > nbeams(hp), CONSISTENCY,
+			"bad beam index to hdkillbeam");
+	DCHECK(!hdfragl[hp->fd].writable, CONSISTENCY,
+			"hdkillbeam called on read-only holodeck");
 	if (hp->bl[i] != NULL) {	/* free memory */
 		blglob(hp)->nrm -= nchanged = hp->bl[i]->nrm;
-		free((char *)hp->bl[i]);
+		free((void *)hp->bl[i]);
+		hp->bl[i] = NULL;
 	} else
 		nchanged = hp->bi[i].nrd;
-	if (hp->bi[i].nrd) {		/* free file fragment */
-		hp->bl[i] = &emptybeam;
-		hdsyncbeam(hp, i);
+	if (hp->bi[i].nrd && !(hdfragflags&FF_KILL && hdfreefrag(hp,i))) {
+		biglob(hp)->nrd -= hp->bi[i].nrd;	/* free failed */
+		hp->bi[i].nrd = 0;
+		hp->bi[i].fo = 0L;
+		hdmarkdirty(hp, i);
 	}
-	hp->bl[i] = NULL;
 	return(nchanged);
 }
 
@@ -680,6 +829,11 @@ register HOLO	*honly;			/* NULL means check all */
 	int	freetarget;
 	int	n;
 	register int	i;
+#ifdef DEBUG
+	unsigned	membefore;
+
+	membefore = hdmemuse(0);
+#endif
 						/* compute free target */
 	freetarget = (honly != NULL) ? blglob(honly)->nrm :
 			hdmemuse(0)/sizeof(RAYVAL) ;
@@ -700,6 +854,12 @@ register HOLO	*honly;			/* NULL means check all */
 			break;
 	}
 	hdsync(honly, 0);	/* synchronize directories as necessary */
+#ifdef DEBUG
+	sprintf(errmsg,
+	"%dK before, %dK after hdfreecache (%dK total), %d rays short\n",
+		membefore>>10, hdmemuse(0)>>10, hdmemuse(1)>>10, freetarget);
+	wputs(errmsg);
+#endif
 	return(-freetarget);	/* return how far past goal we went */
 }
 
@@ -712,7 +872,7 @@ register HOLO	*hp;		/* NULL means clean up all */
 	if (hp == NULL) {		/* NULL means clean up everything */
 		while (hdlist[0] != NULL)
 			hddone(hdlist[0]);
-		free((char *)hdfragl);
+		free((void *)hdfragl);
 		hdfragl = NULL; nhdfragls = 0;
 		return;
 	}
@@ -727,6 +887,6 @@ register HOLO	*hp;		/* NULL means clean up all */
 				i++;
 			break;
 		}
-	free((char *)hp->bl);		/* free beam list */
-	free((char *)hp);		/* free holodeck struct */
+	free((void *)hp->bl);		/* free beam list */
+	free((void *)hp);		/* free holodeck struct */
 }