diff --git a/src/cache.h b/src/cache.h
index 5b1947b..797279c 100644
--- a/src/cache.h
+++ b/src/cache.h
@@ -69,9 +69,6 @@ struct Cache {
 
     /** \brief the FUSE filesystem path to the remote file*/
     char *fs_path;
-
-    /** Transfer struct for the streaming cache */
-    TransferStruct *ts;
 };
 
 /**
diff --git a/src/link.c b/src/link.c
index e7e98fe..eb0e105 100644
--- a/src/link.c
+++ b/src/link.c
@@ -41,8 +41,7 @@ static Link *Link_new(const char *linkname, LinkType type)
     /*
      * remove the '/' from linkname if it exists
      */
-    char *c =
-        &(link->linkname[strnlen(link->linkname, MAX_FILENAME_LEN) - 1]);
+    char *c = &(link->linkname[strnlen(link->linkname, MAX_FILENAME_LEN) - 1]);
     if (*c == '/') {
         *c = '\0';
     }
diff --git a/src/log.h b/src/log.h
index 75fee30..3ea7b26 100644
--- a/src/log.h
+++ b/src/log.h
@@ -13,7 +13,8 @@ typedef enum {
     link_lock_debug = 1 << 5,
     network_lock_debug = 1 << 6,
     cache_lock_debug = 1 << 7,
-    libcurl_debug = 1 << 8,
+    ramcache_debug = 1 << 8,
+    libcurl_debug = 1 << 9,
 } LogType;
 
 /**
diff --git a/src/ramcache.c b/src/ramcache.c
index 1750ce2..7c9a62f 100644
--- a/src/ramcache.c
+++ b/src/ramcache.c
@@ -1,6 +1,7 @@
 #include "ramcache.h"
 
 #include "log.h"
+#include "util.h"
 
 #include <stdlib.h>
 #include <string.h>
@@ -11,6 +12,12 @@ size_t write_memory_callback(void *recv_data, size_t size, size_t nmemb,
     size_t recv_size = size * nmemb;
     TransferStruct *ts = (TransferStruct *) userp;
 
+    if (ts->bg_transfer) {
+        lprintf(ramcache_debug, "ramcache: thread %x: locking;\n",
+                pthread_self());
+    }
+    PTHREAD_MUTEX_LOCK(&ts->lock);
+
     ts->data = realloc(ts->data, ts->curr_size + recv_size + 1);
     if (!ts->data) {
         /*
@@ -22,5 +29,49 @@ size_t write_memory_callback(void *recv_data, size_t size, size_t nmemb,
     memmove(&ts->data[ts->curr_size], recv_data, recv_size);
     ts->curr_size += recv_size;
     ts->data[ts->curr_size] = '\0';
+    if (ts->bg_transfer) {
+        lprintf(ramcache_debug, "ramcache: thread %x: unlocking;\n",
+                pthread_self());
+    }
+    PTHREAD_MUTEX_UNLOCK(&ts->lock);
     return recv_size;
-}
\ No newline at end of file
+}
+
+TransferStruct *TransferStruct_bg_transfer_new()
+{
+    TransferStruct *ts = CALLOC(1, sizeof(TransferStruct));
+    if (pthread_mutexattr_init(&ts->lock_attr)) {
+        lprintf(fatal, "lock_attr initialisation failed!\n");
+    }
+
+    if (pthread_mutexattr_setpshared(&ts->lock_attr,
+                                     PTHREAD_PROCESS_SHARED)) {
+        lprintf(fatal, "could not set lock_attr!\n");
+    }
+
+    if (pthread_mutex_init(&ts->lock, &ts->lock_attr)) {
+        lprintf(fatal, "lock initialisation failed!\n");
+    }
+
+    ts->bg_transfer = 1;
+
+    return ts;
+}
+
+void TransferStruct_bg_transfer_free(TransferStruct *ts)
+{
+    if (ts->bg_transfer) {
+        if (pthread_mutex_destroy(&ts->lock)) {
+            lprintf(fatal, "could not destroy lock!\n");
+        }
+
+        if (pthread_mutexattr_destroy(&ts->lock_attr)) {
+            lprintf(fatal, "could not destroy lock_attr!\n");
+        }
+    }
+
+    /* free(NULL) does nothing */
+    free(ts->data);
+    FREE(ts);
+}
+
diff --git a/src/ramcache.h b/src/ramcache.h
index 33cada1..e688fb3 100644
--- a/src/ramcache.h
+++ b/src/ramcache.h
@@ -26,12 +26,32 @@ struct TransferStruct {
     Link *link;
     /** \brief The minium requested size */
     size_t min_req_size;
-    /** \brief Whether we have sent off the minimally requested data*/
-    int min_data_sent;
+    /** \brief mutex for background transfer */
+    pthread_mutex_t lock;
+    /** \brief attribute associated with the mutex */
+    pthread_mutexattr_t lock_attr;
+    /** \brief Whether this TransferStruct was used for background transfer */
+    int bg_transfer;
+    /** \brief The cache file used for background transfer */
+    Cache *cf;
+    /** \brief The ID of the segment being downloaded */
+    off_t seg_id;
 };
 
-/** \brief callback function for file transfer */
+/**
+ * \brief Callback function for file transfer
+ */
 size_t write_memory_callback(void *contents, size_t size, size_t nmemb,
                              void *userp);
 
+/**
+ * \brief Create a TransferStruct for background transfer
+ */
+TransferStruct *TransferStruct_bg_transfer_new();
+
+/**
+ * \brief Free a TransferStruct used for background transfer
+ */
+void TransferStruct_free(TransferStruct *ts);
+
 #endif
\ No newline at end of file
diff --git a/src/util.c b/src/util.c
index be9adec..1ad431b 100644
--- a/src/util.c
+++ b/src/util.c
@@ -142,7 +142,6 @@ void FREE(void *ptr)
 {
     if (ptr) {
         free(ptr);
-        ptr = NULL;
     } else {
         lprintf(fatal, "attempted to double free a pointer!\n");
     }