diff --git a/write.c b/write.c
index 773189d..0d4b3a5 100644
--- a/write.c
+++ b/write.c
@@ -24,6 +24,8 @@ struct io_block_t {
 
 #pragma mark GLOBALS
 
+#define DEBUG 0
+
 static size_t gNumEncodeThreads = 0;
 static pthread_t *gEncodeThreads = NULL;
 static pthread_t gReadThread;
@@ -45,6 +47,12 @@ static size_t gFileIndexBufPos = 0;
 
 #pragma mark FUNCTION DECLARATIONS
 
+#if DEBUG
+    #define debug(str, ...) fprintf(stderr, str "\n", ##__VA_ARGS__)
+#else
+    #define debug(...)
+#endif
+
 static void *read_thread(void *data);
 static void *encode_thread(void *data);
 static void block_queue_free(int type, void *p);
@@ -70,6 +78,7 @@ static void write_file_index_buf(lzma_action action);
 #pragma mark FUNCTION DEFINITIONS
 
 int main(int argc, char **argv) {
+    debug("launch");
     if (argc != 3)
         die("Need two arguments");
     if (!(gInFile = fopen(argv[1], "r")))
@@ -104,9 +113,10 @@ int main(int argc, char **argv) {
     if (pthread_create(&gReadThread, NULL, &read_thread, NULL))
         die("Error creating read thread");
     for (int i = 0; i < gNumEncodeThreads; ++i) {
-        if (pthread_create(&gEncodeThreads[i], NULL, &encode_thread, NULL))
+        if (pthread_create(&gEncodeThreads[i], NULL, &encode_thread, (void*)(uintptr_t)i))
             die("Error creating encode thread");
     }
+    debug("writer: start");
     
     // pre-block setup: header, index
     if (!(gIndex = lzma_index_init(NULL, NULL)))
@@ -122,6 +132,7 @@ int main(int argc, char **argv) {
         if (msg == MSG_STOP)
             break;
         
+        debug("writer: received %zu", ib->seq);
         write_blocks(&seq, &ibs, ib);
     }
     
@@ -136,6 +147,7 @@ int main(int argc, char **argv) {
     fclose(gOutFile);
     
     // thread cleanup
+    debug("writer: cleaning up reader");
     if (pthread_join(gReadThread, NULL))
         die("Error joining read thread");
     queue_free(gEncodeQ);
@@ -143,6 +155,7 @@ int main(int argc, char **argv) {
     queue_free(gReadQ);
     free(gEncodeThreads);
     
+    debug("exit");
     return 0;
 }
 
@@ -150,6 +163,8 @@ int main(int argc, char **argv) {
 #pragma mark READING
 
 static void *read_thread(void *data) {
+    debug("reader: start");
+    
     struct archive *ar = archive_read_new();
     archive_read_support_compression_none(ar);
     archive_read_support_format_tar(ar);
@@ -176,11 +191,13 @@ static void *read_thread(void *data) {
     // write last block, if necessary
     if (gReadBlock) {
         // if this block had only one read, and it was EOF, it's waste
+        debug("reader: handling last block %zu", gReadBlock->seq);
         queue_push(gReadBlock->insize ? gEncodeQ : gReadQ, MSG_BLOCK, gReadBlock);
         gReadBlock = NULL;
     }
     
     // stop the other threads
+    debug("reader: cleaning up encoders");
     for (int i = 0; i < gNumEncodeThreads; ++i) {
         queue_push(gEncodeQ, MSG_STOP, NULL);
     }
@@ -190,6 +207,7 @@ static void *read_thread(void *data) {
     }
     queue_push(gWriteQ, MSG_STOP, NULL);
     
+    debug("reader: end");
     return NULL;
 }
 
@@ -198,6 +216,7 @@ static ssize_t tar_read(struct archive *ar, void *ref, const void **bufp) {
         queue_pop(gReadQ, (void**)&gReadBlock);
         gReadBlock->insize = 0;
         gReadBlock->seq = gBlockNum++;
+        debug("reader: reading %zu", gReadBlock->seq);
     }
     
     size_t space = gBlockInSize - gReadBlock->insize;
@@ -212,6 +231,7 @@ static ssize_t tar_read(struct archive *ar, void *ref, const void **bufp) {
     *bufp = buf;
     
     if (gReadBlock->insize == gBlockInSize) {
+        debug("reader: sending %zu", gReadBlock->seq);
         queue_push(gEncodeQ, MSG_BLOCK, gReadBlock);
         gReadBlock = NULL;
     }
@@ -272,19 +292,23 @@ static void block_queue_free(int type, void *p) {
 
 #pragma mark ENCODING
 
-static void *encode_thread(void *vp) {
+static void *encode_thread(void *arg) {
+    int thnum = (uintptr_t)arg;
+    
     while (true) {
         io_block_t *ib;
         int msg = queue_pop(gEncodeQ, (void**)&ib);
         if (msg == MSG_STOP)
             break;
         
+        debug("encoder %d: received %zu", thnum, ib->seq);
         block_init(&ib->block);
         ib->outsize = 0;
         if (lzma_block_buffer_encode(&ib->block, NULL, ib->input, ib->insize,
                 ib->output, &ib->outsize, gBlockOutSize) != LZMA_OK)
             die("Error encoding block");
         
+        debug("encoder %d: sending %zu", thnum, ib->seq);
         queue_push(gWriteQ, MSG_BLOCK, ib);
     }
     
@@ -321,6 +345,8 @@ static void stream_edge(lzma_vli backward_size) {
 }
 
 static void write_block(io_block_t *ib) {
+    debug("writer: writing %zu", ib->seq);
+
     // Does it make sense to chunk this?
     size_t written = 0;
     while (ib->outsize > written) {
@@ -336,6 +362,8 @@ static void write_block(io_block_t *ib) {
             lzma_block_unpadded_size(&ib->block),
             ib->block.uncompressed_size) != LZMA_OK)
         die("Error adding to index");
+
+    debug("writer: writing %zu complete", ib->seq);
 }
 
 static void write_blocks(size_t *seq, io_block_t **ibs, io_block_t *ib) {