diff --git a/archive/pc_archive.c b/archive/pc_archive.c
index d3f89fa..c6be1f7 100644
--- a/archive/pc_archive.c
+++ b/archive/pc_archive.c
@@ -91,6 +91,121 @@ static struct arc_list_state {
 
 pthread_mutex_t nftw_mutex = PTHREAD_MUTEX_INITIALIZER;
 
+/*
+ * Archive writer callback routines for archive creation operation.
+ */
+static int
+creat_open_callback(struct archive *arc, void *ctx)
+{
+	pc_ctx_t *pctx = (pc_ctx_t *)ctx;
+
+	sem_init(&(pctx->read_sem), 0, 0);
+	sem_init(&(pctx->write_sem), 0, 0);
+	pctx->arc_buf = NULL;
+	pctx->arc_buf_pos = 0;
+	pctx->arc_buf_size = 0;
+	return (ARCHIVE_OK);
+}
+
+static int
+creat_close_callback(struct archive *arc, void *ctx)
+{
+	pc_ctx_t *pctx = (pc_ctx_t *)ctx;
+
+	pctx->arc_closed = 1;
+	if (pctx->arc_buf) {
+		sem_post(&(pctx->read_sem));
+	} else {
+		pctx->arc_buf_pos = 0;
+	}
+	return (ARCHIVE_OK);
+}
+
+static ssize_t
+creat_write_callback(struct archive *arc, void *ctx, const void *buf, size_t len)
+{
+	uchar_t *buff = (uchar_t *)buf;
+	pc_ctx_t *pctx = (pc_ctx_t *)ctx;
+	size_t remaining;
+
+	if (pctx->arc_closed) {
+		archive_set_error(arc, ARCHIVE_EOF, "End of file when writing archive.");
+		return (-1);
+	}
+
+	if (!pctx->arc_writing) {
+		sem_wait(&(pctx->write_sem));
+	}
+
+	if (pctx->arc_buf == NULL || pctx->arc_buf_size == 0) {
+		archive_set_error(arc, ARCHIVE_EOF, "End of file when writing archive.");
+		return (-1);
+	}
+	pctx->arc_writing = 1;
+
+	remaining = len;
+	while (remaining && !pctx->arc_closed) {
+		uchar_t *tbuf;
+
+		tbuf = pctx->arc_buf + pctx->arc_buf_pos;
+		if (remaining > pctx->arc_buf_size - pctx->arc_buf_pos) {
+			size_t nlen = pctx->arc_buf_size - pctx->arc_buf_pos;
+			memcpy(tbuf, buff, nlen);
+			remaining -= nlen;
+			pctx->arc_buf_pos += nlen;
+			buff += nlen;
+			pctx->arc_writing = 0;
+			sem_post(&(pctx->read_sem));
+			sem_wait(&(pctx->write_sem));
+			pctx->arc_writing = 1;
+		} else {
+			memcpy(tbuf, buff, remaining);
+			pctx->arc_buf_pos += remaining;
+			remaining = 0;
+			if (pctx->arc_buf_pos == pctx->arc_buf_size) {
+				pctx->arc_writing = 0;
+				sem_post(&(pctx->read_sem));
+			}
+			break;
+		}
+	}
+
+	return (len - remaining);
+}
+
+int64_t
+archiver_read(void *ctx, void *buf, uint64_t count)
+{
+	pc_ctx_t *pctx = (pc_ctx_t *)ctx;
+
+	if (pctx->arc_closed)
+		return (0);
+
+	if (pctx->arc_buf != NULL) {
+		log_msg(LOG_ERR, 0, "Incorrect sequencing of archiver_read() call.");
+		return (-1);
+	}
+
+	pctx->arc_buf = buf;
+	pctx->arc_buf_size = count;
+	pctx->arc_buf_pos = 0;
+	sem_post(&(pctx->write_sem));
+	sem_wait(&(pctx->read_sem));
+	pctx->arc_buf = NULL;
+	return (pctx->arc_buf_pos);
+}
+
+int
+archiver_close(void *ctx)
+{
+	pc_ctx_t *pctx = (pc_ctx_t *)ctx;
+
+	pctx->arc_closed = 1;
+	sem_post(&(pctx->write_sem));
+	sem_post(&(pctx->read_sem));
+	return (0);
+}
+
 /*
  * Comparison function for sorting pathname mambers. Sort by name/extension and then
  * by size.
@@ -172,6 +287,10 @@ read_next_path(pc_ctx_t *pctx, char *fpath)
 			srt = srt->next;
 		}
 
+		/*
+		 * If we are not using mmap then seek to the position of the current entry, otherwise
+		 * just note the entry position.
+		 */
 		if (pctx->temp_mmap_len == 0) {
 			if (lseek(pctx->archive_members_fd, mem1->file_pos, SEEK_SET) == (off_t)-1) {
 				log_msg(LOG_ERR, 1, "Error seeking in archive members file.");
@@ -209,10 +328,10 @@ do_mmap:
 			munmap(pctx->temp_mmap_buf, pctx->temp_mmap_len);
 			adj = pctx->temp_file_pos % pctx->pagesize;
 			pctx->temp_mmap_pos = pctx->temp_file_pos - adj;
-			pctx->temp_mmap_len = pctx->archive_temp_size - pctx->temp_file_pos;
+			pctx->temp_mmap_len = pctx->archive_temp_size - pctx->temp_mmap_pos;
 
 			if (pctx->temp_mmap_len > TEMP_MMAP_SIZE)
-				pctx->temp_mmap_len = TEMP_MMAP_SIZE;
+				pctx->temp_mmap_len = TEMP_MMAP_SIZE ;
 			pctx->temp_mmap_buf = mmap(NULL, pctx->temp_mmap_len, PROT_READ,
 			    MAP_SHARED, pctx->archive_members_fd, pctx->temp_mmap_pos);
 			if (pctx->temp_mmap_buf == NULL) {
@@ -225,6 +344,12 @@ do_mmap:
 		buf = pctx->temp_mmap_buf + (pctx->temp_file_pos - pctx->temp_mmap_pos);
 		namelen = U32_P(buf);
 		pctx->temp_file_pos += 2;
+
+		/*
+		 * If length of pathname entry exceeds current mmap region, repeat mmap
+		 * at the entry offset. Only one repeat attempt is made. If there is a
+		 * failure then we give up.
+		 */
 		if (pctx->temp_mmap_len - (pctx->temp_file_pos - pctx->temp_mmap_pos) < namelen) {
 			if (!retried) {
 				pctx->temp_file_pos -= 2;
@@ -243,6 +368,9 @@ do_mmap:
 		return (namelen);
 	}
 
+	/*
+	 * This code is used if mmap is not being used for the pathlist file.
+	 */
 	if ((rbytes = Read(pctx->archive_members_fd, &namelen, sizeof(namelen))) != 0) {
 		if (rbytes < 2) {
 			log_msg(LOG_ERR, 1, "Error reading archive members file.");
@@ -386,7 +514,7 @@ int
 setup_archiver(pc_ctx_t *pctx, struct stat *sbuf)
 {
 	char *tmpfile, *tmp;
-	int err, fd, pipefd[2];
+	int err, fd;
 	uchar_t *pbuf;
 	struct archive *arc;
 	struct fn_list *fn;
@@ -510,28 +638,16 @@ setup_archiver(pc_ctx_t *pctx, struct stat *sbuf)
 	sbuf->st_gid = getegid();
 	sbuf->st_mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH;
 
-	/*
-	 * Generate a pipe. The archiver writes to one end of the pipe and the
-	 * compression stages read from the other end. This allowed plugging in
-	 * archiving with the minimum of changes to the rest of Pcompress.
-	 */
-	if (pipe(pipefd) == -1) {
-		log_msg(LOG_ERR, 1, "Unable to create archiver pipe.\n");
-		close(fd);  unlink(tmpfile);
-		return (-1);
-	}
-
-	pctx->uncompfd = pipefd[0]; // Read side
-	pctx->archive_data_fd = pipefd[1]; // Write side
 	arc = archive_write_new();
 	if (!arc) {
 		log_msg(LOG_ERR, 1, "Unable to create libarchive context.\n");
-		close(fd); close(pipefd[0]); close(pipefd[1]);
+		close(fd);
 		unlink(tmpfile);
 		return (-1);
 	}
 	archive_write_set_format_pax_restricted(arc);
-	archive_write_open_fd(arc, pctx->archive_data_fd);
+	archive_write_open(arc, pctx, creat_open_callback,
+			   creat_write_callback, creat_close_callback);
 	pctx->archive_ctx = arc;
 	pctx->archive_members_fd = fd;
 	pctx->temp_mmap_len = TEMP_MMAP_SIZE;
@@ -542,6 +658,7 @@ setup_archiver(pc_ctx_t *pctx, struct stat *sbuf)
 		pctx->temp_mmap_len = 0;
 	}
 	pctx->temp_mmap_pos = 0;
+	pctx->arc_writing = 0;
 
 	return (0);
 }
diff --git a/archive/pc_archive.h b/archive/pc_archive.h
index c0c83a2..5fe657e 100644
--- a/archive/pc_archive.h
+++ b/archive/pc_archive.h
@@ -45,6 +45,8 @@ int setup_archiver(pc_ctx_t *pctx, struct stat *sbuf);
 int start_archiver(pc_ctx_t *pctx);
 int setup_extractor(pc_ctx_t *pctx);
 int start_extractor(pc_ctx_t *pctx);
+int64_t archiver_read(void *ctx, void *buf, uint64_t count);
+int archiver_close(void *ctx);
 
 #ifdef	__cplusplus
 }
diff --git a/pcompress.c b/pcompress.c
index 4dfa971..c2fb648 100644
--- a/pcompress.c
+++ b/pcompress.c
@@ -1901,12 +1901,6 @@ start_compress(pc_ctx_t *pctx, const char *filename, uint64_t chunksize, int lev
 				log_msg(LOG_ERR, 0, "Setup archiver failed.");
 				return (1);
 			}
-
-			/*
-			 * This is a pipe between the libarchive based archiving process and
-			 * the rest of the compression stuff.
-			 */
-			uncompfd = pctx->uncompfd;
 		}
 
 		/*
@@ -2292,9 +2286,12 @@ start_compress(pc_ctx_t *pctx, const char *filename, uint64_t chunksize, int lev
 		rctx = create_dedupe_context(chunksize, 0, pctx->rab_blk_size, pctx->algo, &props,
 		    pctx->enable_delta_encode, pctx->enable_fixed_scan, VERSION, COMPRESS, 0, NULL,
 		    pctx->pipe_mode, nprocs);
-		rbytes = Read_Adjusted(uncompfd, cread_buf, chunksize, &rabin_count, rctx);
+		rbytes = Read_Adjusted(uncompfd, cread_buf, chunksize, &rabin_count, rctx, pctx);
 	} else {
-		rbytes = Read(uncompfd, cread_buf, chunksize);
+		if (pctx->archive_mode)
+			rbytes = archiver_read(pctx, cread_buf, chunksize);
+		else
+			rbytes = Read(uncompfd, cread_buf, chunksize);
 	}
 
 	while (!bail) {
@@ -2386,6 +2383,7 @@ start_compress(pc_ctx_t *pctx, const char *filename, uint64_t chunksize, int lev
 					COMP_BAIL;
 				}
 			}
+
 			/* Signal the compression thread to start */
 			sem_post(&tdat->start_sem);
 			++(pctx->chunk_num);
@@ -2400,9 +2398,12 @@ start_compress(pc_ctx_t *pctx, const char *filename, uint64_t chunksize, int lev
 			 * buffer is in progress.
 			 */
 			if (pctx->enable_rabin_split) {
-				rbytes = Read_Adjusted(uncompfd, cread_buf, chunksize, &rabin_count, rctx);
+				rbytes = Read_Adjusted(uncompfd, cread_buf, chunksize, &rabin_count, rctx, pctx);
 			} else {
-				rbytes = Read(uncompfd, cread_buf, chunksize);
+				if (pctx->archive_mode)
+					rbytes = archiver_read(pctx, cread_buf, chunksize);
+				else
+					rbytes = Read(uncompfd, cread_buf, chunksize);
 			}
 		}
 	}
@@ -2425,6 +2426,8 @@ comp_done:
 	 */
 	if (!pctx->pipe_mode) {
 		if (uncompfd != -1) close(uncompfd);
+		if (pctx->archive_mode)
+			archiver_close(pctx);
 	}
 
 	if (pctx->t_errored) err = pctx->t_errored;
diff --git a/pcompress.h b/pcompress.h
index e2d9d54..dcd965a 100644
--- a/pcompress.h
+++ b/pcompress.h
@@ -202,24 +202,33 @@ typedef struct pc_ctx {
 	int verbose;
 	int enable_archive_sort;
 	int pagesize;
+	int uncompfd, compfd;
+
+	/*
+	 * Archiving related context data.
+	 */
 	char archive_members_file[MAXPATHLEN];
 	int archive_members_fd, archive_data_fd;
 	uint32_t archive_members_count;
 	void *archive_ctx, *archive_sort_buf;
 	pthread_t archive_thread;
-	int uncompfd, compfd;
 	char archive_temp_file[MAXPATHLEN];
 	int archive_temp_fd;
-	uint64_t archive_temp_size;
+	uint64_t archive_temp_size, archive_size;
 	uchar_t *temp_mmap_buf;
 	uint64_t temp_mmap_pos, temp_file_pos;
 	uint64_t temp_mmap_len;
+	struct fn_list *fn;
+	sem_t read_sem, write_sem;
+	uchar_t *arc_buf;
+	uint64_t arc_buf_size, arc_buf_pos;
+	int arc_closed, arc_writing;
+
 	unsigned int chunk_num;
 	uint64_t largest_chunk, smallest_chunk, avg_chunk;
-	uint64_t chunksize, archive_size;
+	uint64_t chunksize;
 	const char *algo, *filename;
 	char *to_filename;
-	struct fn_list *fn;
 	char *exec_name;
 	int do_compress, level;
 	int do_uncompress;
diff --git a/utils/utils.c b/utils/utils.c
index 0f76107..a73de5c 100644
--- a/utils/utils.c
+++ b/utils/utils.c
@@ -42,6 +42,7 @@
 #include <rabin_dedup.h>
 #include <cpuid.h>
 #include <xxhash.h>
+#include <pc_archive.h>
 
 #include <sys/sysinfo.h>
 
@@ -211,19 +212,27 @@ Read(int fd, void *buf, uint64_t count)
  * after the previous rabin boundary.
  */
 int64_t
-Read_Adjusted(int fd, uchar_t *buf, uint64_t count, int64_t *rabin_count, void *ctx)
+Read_Adjusted(int fd, uchar_t *buf, uint64_t count, int64_t *rabin_count, void *ctx, void *pctx)
 {
         uchar_t *buf2;
         int64_t rcount;
         dedupe_context_t *rctx = (dedupe_context_t *)ctx;
 
-        if (!ctx) return (Read(fd, buf, count));
+        if (!ctx) {
+		if (pctx)
+			return (archiver_read(pctx, buf, count));
+		else
+			return (Read(fd, buf, count));
+	}
         buf2 = buf;
         if (*rabin_count) {
                 buf2 = buf + *rabin_count;
                 count -= *rabin_count;
         }
-	rcount = Read(fd, buf2, count);
+	if (pctx)
+		rcount = archiver_read(pctx, buf2, count);
+	else
+		rcount = Read(fd, buf2, count);
         if (rcount > 0) {
                 rcount += *rabin_count;
 		if (rcount == count) {
diff --git a/utils/utils.h b/utils/utils.h
index fdfa3a7..a506f83 100644
--- a/utils/utils.h
+++ b/utils/utils.h
@@ -238,7 +238,7 @@ extern int parse_numeric(int64_t *val, const char *str);
 extern char *bytes_to_size(uint64_t bytes);
 extern int64_t Read(int fd, void *buf, uint64_t count);
 extern int64_t Read_Adjusted(int fd, uchar_t *buf, uint64_t count,
-	int64_t *rabin_count, void *ctx);
+	int64_t *rabin_count, void *ctx, void *pctx);
 extern int64_t Write(int fd, const void *buf, uint64_t count);
 extern void set_threadcounts(algo_props_t *props, int *nthreads, int nprocs,
 	algo_threads_type_t typ);