diff --git a/src/os/aix/aix_sigar.c b/src/os/aix/aix_sigar.c
index 2bc0d5bb..ca6d5935 100644
--- a/src/os/aix/aix_sigar.c
+++ b/src/os/aix/aix_sigar.c
@@ -763,8 +763,8 @@ int sigar_proc_disk_io_get(sigar_t *sigar, sigar_pid_t pid,
     if (status != SIGAR_OK) {
         return status;
     }
-    proc_disk_io->bytes_read = 0;
-    proc_disk_io->bytes_written = 0;
+    proc_disk_io->bytes_read = SIGAR_FIELD_NOTIMPL;
+    proc_disk_io->bytes_written =  SIGAR_FIELD_NOTIMPL;
     proc_disk_io->bytes_total = pinfo->pi_ioch;
 
     return SIGAR_OK;
diff --git a/src/os/hpux/hpux_sigar.c b/src/os/hpux/hpux_sigar.c
index e2ec906a..0d5bbf92 100644
--- a/src/os/hpux/hpux_sigar.c
+++ b/src/os/hpux/hpux_sigar.c
@@ -317,9 +317,9 @@ int sigar_proc_disk_io_get(sigar_t *sigar, sigar_pid_t pid,
     if (status != SIGAR_OK) {
         return status;
     }
-    proc_disk_io->bytes_read =  pinfo->pst_inblock;
-    proc_disk_io->bytes_written = pinfo->pst_oublock;
-    proc_disk_io->bytes_total =  pinfo->pst_inblock + pinfo->pst_oublock;
+    proc_disk_io->bytes_read = SIGAR_FIELD_NOTIMPL; 
+    proc_disk_io->bytes_written = SIGAR_FIELD_NOTIMPL; 
+    proc_disk_io->bytes_total =  pinfo->pst_ioch;
 
 
    return SIGAR_OK;
diff --git a/src/os/solaris/solaris_sigar.c b/src/os/solaris/solaris_sigar.c
index 5083eac7..35a9d7df 100644
--- a/src/os/solaris/solaris_sigar.c
+++ b/src/os/solaris/solaris_sigar.c
@@ -727,8 +727,8 @@ int sigar_proc_disk_io_get(sigar_t *sigar, sigar_pid_t pid,
    if ((status = sigar_proc_usage_get(sigar, &usage, pid)) != SIGAR_OK) {
         return status;
    }
-   proc_disk_io->bytes_read = usage.pr_inblk;
-   proc_disk_io->bytes_written = usage.pr_oublk;
+   proc_disk_io->bytes_read = SIGAR_FIELD_NOTIMPL;
+   proc_disk_io->bytes_written = SIGAR_FIELD_NOTIMPL;
    proc_disk_io->bytes_total =  usage.pr_ioch;
 
     return SIGAR_OK;