diff --git a/io/io_createfile.c b/io/io_createfile.c
index a58dfb4..453d77b 100644
--- a/io/io_createfile.c
+++ b/io/io_createfile.c
@@ -6,11 +6,8 @@
 int io_createfile(int64* d,const char* s) {
   long fd=open(s,O_WRONLY|O_CREAT|O_TRUNC,0600);
   if (fd != -1) {
-    if (io_fd(fd)) {
-      *d=fd;
-      return 1;
-    }
-    close(fd);
+    *d=fd;
+    return 1;
   }
   return 0;
 }
diff --git a/io/io_readfile.c b/io/io_readfile.c
index 177502b..7b262d5 100644
--- a/io/io_readfile.c
+++ b/io/io_readfile.c
@@ -6,11 +6,8 @@
 int io_readfile(int64* d,const char* s) {
   long fd=open(s,O_RDONLY);
   if (fd != -1) {
-    if (io_fd(fd)) {
-      *d=fd;
-      return 1;
-    }
-    close(fd);
+    *d=fd;
+    return 1;
   }
   return 0;
 }
diff --git a/io/iob_addbuf.c b/io/iob_addbuf.c
new file mode 100644
index 0000000..3963555
--- /dev/null
+++ b/io/iob_addbuf.c
@@ -0,0 +1,15 @@
+#include "iob_internal.h"
+
+int iob_addbuf(io_batch* b,void* buf,uint64 n) {
+  io_entry* e=array_allocate(&b->b,sizeof(io_entry),
+			     array_length(&b->b,sizeof(io_entry)));
+  if (!e) return 0;
+  e->type=FROMBUF;
+  e->fd=-1;
+  e->buf=buf;
+  e->n=n;
+  e->offset=0;
+  b->bytesleft+=n;
+  ++b->bufs;
+  return 1;
+}
diff --git a/io/iob_addfile.c b/io/iob_addfile.c
new file mode 100644
index 0000000..4daf2e5
--- /dev/null
+++ b/io/iob_addfile.c
@@ -0,0 +1,15 @@
+#include "iob_internal.h"
+
+int iob_addfile(io_batch* b,int64 fd,uint64 off,uint64 n) {
+  io_entry* e=array_allocate(&b->b,sizeof(io_entry),
+			     array_length(&b->b,sizeof(io_entry)));
+  if (!e) return 0;
+  e->type=FROMFILE;
+  e->fd=fd;
+  e->buf=0;
+  e->n=n;
+  e->offset=off;
+  b->bytesleft+=n;
+  ++b->files;
+  return 1;
+}
diff --git a/io/iob_new.c b/io/iob_new.c
new file mode 100644
index 0000000..f4036f9
--- /dev/null
+++ b/io/iob_new.c
@@ -0,0 +1,17 @@
+#include <stdlib.h>
+#include "iob_internal.h"
+
+io_batch* iob_new(int hint_entries) {
+  io_batch* b=(io_batch*)malloc(sizeof(io_batch));
+  if (!b) return 0;
+  if (hint_entries) {
+    if (!array_allocate(&b->b,sizeof(io_entry),hint_entries)) {
+      free(b);
+      return 0;
+    }
+    array_trunc(&b->b);
+  }
+  b->next=b->bufs=b->files=0;
+  b->bytesleft=0;
+  return b;
+}
diff --git a/io/iob_reset.c b/io/iob_reset.c
new file mode 100644
index 0000000..b5caa07
--- /dev/null
+++ b/io/iob_reset.c
@@ -0,0 +1,7 @@
+#include <stdlib.h>
+#include "iob_internal.h"
+
+void iob_reset(io_batch* b) {
+  array_reset(&b->b);
+  free(b);
+}
diff --git a/io/iob_send.c b/io/iob_send.c
new file mode 100644
index 0000000..06c2507
--- /dev/null
+++ b/io/iob_send.c
@@ -0,0 +1,83 @@
+#if defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__NetBSD__)
+#define BSD_SENDFILE
+#endif
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/uio.h>
+#include <errno.h>
+#include <alloca.h>
+
+#include "iob_internal.h"
+
+int64 iob_send(int64 s,io_batch* b) {
+  io_entry* e,* last;
+  struct iovec* v;
+  int64 sent;
+  long i;
+  long headers;
+#ifdef BSD_SENDFILE
+  long trailers;
+#endif
+
+  if (b->bytesleft==0) return 0;
+  last=array_start(&b->b)+array_bytes(&b->b);
+  if (!(e=array_get(&b->b,sizeof(io_entry),b->next)))
+    return -1;		/* can't happen error */
+  v=alloca(b->bufs*sizeof(struct iovec));
+#ifdef BSD_SENDFILE
+  /* BSD sendfile can send headers and trailers.  If we run on BSD, we
+   * should try to exploit this. */
+  headers=trailers=0;
+#endif
+  for (i=0; e+i<last; ++i) {
+    if (e[i].type==FROMFILE) break;
+    v[i].iov_base=e[i].buf+e[i].offset;
+    v[i].iov_len=e[i].n-e[i].offset;
+  }
+  headers=i;
+#ifdef BSD_SENDFILE
+  if (e[i].type==FROMFILE) {
+    off_t sbytes;
+    struct sf_hdtr hdr;
+    int r;
+    for (++i; e+i<last; ++i) {
+      if (e[i].type==FROMFILE) break;
+      v[i-1].iov_base=e[i].buf+e[i].offset;
+      v[i-1].iov_len=e[i].n-e[i].offset;
+      ++trailers;
+    }
+    hdr.headers=v; hdr.hdr_cnt=headers;
+    hdr.trailers=v+headers; hdr.trl_cnt=trailers;
+    r=sendfile(e[headers].fd,s,e[headers].off,nbytes,&hdr,&sbytes,0);
+    if (r==0)
+      sent=b->bytesleft;
+    else if (r==-1 && errno==EAGAIN)
+      sent=sbytes;
+    else
+      sent=-1;
+  } else
+    sent=writev(s,v,headers);
+#else
+  if (headers)
+    sent=writev(s,v,headers);
+  else
+    sent=io_sendfile(s,e->fd,e->offset,e->n);
+#endif
+  if (sent==b->bytesleft)
+    b->bytesleft=0;
+  else if (sent>0) {
+    int64 rest=sent;
+    b->bytesleft-=rest;
+    for (i=0; e+i<last; ++i) {
+      if (e[i].n-e[i].offset<rest) {
+	rest-=e[i].n-e[i].offset;
+	++b->next;
+      } else {
+	e[i].offset+=rest;
+	break;
+      }
+    }
+  }
+  return sent;
+}
diff --git a/iob.h b/iob.h
new file mode 100644
index 0000000..d0a49b8
--- /dev/null
+++ b/iob.h
@@ -0,0 +1,14 @@
+#ifndef _IOB_H
+#define _IOB_H
+
+#include "io.h"
+
+typedef struct io_batch io_batch;
+
+io_batch* iob_new(int hint_entries);
+int iob_addbuf(io_batch* b,void* buf,uint64 n);
+int iob_addfile(io_batch* b,int64 fd,uint64 off,uint64 n);
+int64 iob_send(int64 s,io_batch* b);
+void iob_reset(io_batch* b);
+
+#endif
diff --git a/iob_internal.h b/iob_internal.h
new file mode 100644
index 0000000..fdabc35
--- /dev/null
+++ b/iob_internal.h
@@ -0,0 +1,15 @@
+#include "iob.h"
+#include "array.h"
+
+struct io_batch {
+  array b;
+  uint64 bytesleft;
+  long next,bufs,files;
+};
+
+typedef struct io_entry {
+  enum { FROMBUF, FROMFILE } type;
+  int64 fd;
+  char* buf;
+  uint64 offset,n;
+} io_entry;