diff --git a/autotest/utils_tests.py b/autotest/utils_tests.py
index 9074982a..62e59b42 100644
--- a/autotest/utils_tests.py
+++ b/autotest/utils_tests.py
@@ -3279,15 +3279,72 @@ def gpr_zdt1_ppw():
     os.chdir("..")
 
 
+def pestpp_runstorage_file_test(tmp_path):
+    import os
+    import numpy as np
+    import pandas as pd
+    import pyemu
 
+    org_rns_file = os.path.join("utils","runstor.rns")
+    rns_file = os.path.join(tmp_path,"runstor.rns")
+    if os.path.exists(rns_file):
+        os.remove(rns_file)
+    shutil.copy2(org_rns_file,rns_file)
+    rs = pyemu.helpers.RunStor(rns_file)
+    header,par_names,obs_names = rs.file_info(rns_file)
+    cols = ["n_runs","run_size","p_name_size","o_name_size","run_start"]
+    for col in cols:
+        assert col in header
+        assert header[col] > 0
+    df = rs.get_data()
+    assert "run_status_label" in df.columns
+    assert np.all(df.run_pos.values>0)
+
+    for entry in df.info_txt:
+        assert len(str(entry)) > 0
+        assert "realization:" in entry
+        assert "da_cycle:-9999" in entry
+    assert df.run_status.sum() == 0
+    org_df = df.copy()
+    df["run_status"] = -100
+    df.loc[:,par_names[0]] = -111
+    df.loc[:,obs_names[-1]] = -222
+    df["buffer_status"] = 1
+    #df.loc[0,par_names] = -1111
+    rs.update(df)
+    rs2 = pyemu.helpers.RunStor(rns_file)
+    header,par_names,obs_names = rs.file_info(rns_file)
+    #print(header)
+    df2 = rs2.get_data()
+    #print(df2.shape)
+    assert df.shape == df2.shape
+    #print(df2.run_status_label)
+    assert np.all(df2.run_status.values == -100)
+
+    print(df2.loc[:,par_names[0]])
+    assert np.all(df2.loc[:,par_names[0]].values == -111)
+    print(df2.loc[:, obs_names[-1]])
+    assert np.all(df2.loc[:,obs_names[-1]].values == -222)
+    print(df2.buffer_status)
+    #buffer status should always be 0 no matter what values are put in the dataframe
+    assert df2.buffer_status.sum() == 0
+    rs2.update(org_df)
+    p1,o1,meta = pyemu.helpers.read_pestpp_runstorage(rns_file,irun="all", with_metadata=True)
+
+    p2 = pd.read_csv(os.path.join("utils","runstor.0.par.csv"),index_col=0)
+
+    diff = np.abs(p1.loc[:,p2.columns].values - p2.values)
+    print(diff.max())
+    assert diff.max() < 1.0e-7
 
 
 if __name__ == "__main__":
+    pestpp_runstorage_file_test(".")
     #geostat_draws_test('.')
     #fac2real_wrapped_test('.')
     #maha_pdc_test('.')
     #ppu_geostats_test(".")
-    pypestworker_test()
+    #pypestworker_test()
     #gpr_zdt1_test()
     #gpr_compare_invest()
     #gpr_constr_test()
diff --git a/pyemu/utils/helpers.py b/pyemu/utils/helpers.py
index 7b24c4b9..e5e10d48 100644
--- a/pyemu/utils/helpers.py
+++ b/pyemu/utils/helpers.py
@@ -1366,6 +1366,200 @@ def pst_from_parnames_obsnames(
     )
 
 
+class RunStor(object):
+
+    def __init__(self,filename):
+        """access to the pest++ run storage file.  Can be used to support
+        usage of the pest++ external run manager
+
+        Args:
+            filename (str): the name of a pest++ run storage file (ie pest.rns)
+
+        Example::
+
+            rns = pyemu.helpers.RunStor("pest.rns")
+            # get a dataframe of both parameter and observation
+            # values for all runs in the file.
+            df = rns.get_data()
+            # a function that processes the runs stored
+            # in df; the observation values in df should
+            # be updated "in place"
+            failed_idxs = process_my_model_runs(df)
+            #mark the failed runs
+            df.run_status.iloc[failed_idxs] = -99
+            #update the parameter and observation values
+            # stored in the rns file
+            rns.update(df)
+
+        """
+        assert os.path.exists(filename)
+        self.filename = filename
+        self.info_txt_size = 1001
+
+    @staticmethod
+    def header_dtype():
+        """the numpy header dtype of the file
+        """
+        return np.dtype(
+                [
+                ("n_runs", np.int64),
+                ("run_size", np.int64),
+                ("p_name_size", np.int64),
+                ("o_name_size", np.int64),
+                ]
+            )
+
+    @staticmethod
+    def file_info(filename):
+        """get information about whats stored in the file
+
+        Args:
+            filename (str): the run storage file name
+
+        Returns:
+            header (dict): the file header
+            par_names (list): parameter names ordered as they occur in the file
+            obs_names (list): observation names ordered as they occur in the file
+        """
+
+        with open(filename,"rb") as f:
+            header = np.fromfile(f, dtype=RunStor.header_dtype(), count=1)
+            header = {name: header[name][0] for name in RunStor.header_dtype().names}
+            p_name_size, o_name_size = header["p_name_size"], header["o_name_size"]
+            par_names = (
+                struct.unpack("{0}s".format(p_name_size), f.read(p_name_size))[0]
+                .strip()
+                .lower()
+                .decode()
+                .split("\0")[:-1]
+            )
+            obs_names = (
+                struct.unpack("{0}s".format(o_name_size), f.read(o_name_size))[0]
+                .strip()
+                .lower()
+                .decode()
+                .split("\0")[:-1]
+            )
+            run_start = f.tell()
+        header["run_start"] = run_start
+        return header, par_names, obs_names
+
+    @staticmethod
+    def status_str(r_status):
+        """convert the run status string to a txt label
+
+        Args:
+            r_status (int): the int run status from the file
+
+        Returns:
+            status (str): run status label
+
+        """
+        if r_status == 0:
+            return "not completed"
+        if r_status == 1:
+            return "completed"
+        if r_status == -100:
+            return "canceled"
+        if r_status == "-99":
+            return "failed"
+        else:
+            return "failed"
+
+
+    def _read_run(self,f,npar,nobs):
+        """private method to read a run from the file
+
+        Args:
+            f (file): the open file handle
+            npar (int): number of parameters
+            nobs (int): number of observations
+
+        Returns:
+            r_status (int): run status
+            info_txt (str): run information
+            buf_status (int): status of the write buffer (not really used...)
+            par_vals (np.ndarray): the parameter values for the run
+            obs_vals (np.ndarray): the observation values for the run
+
+        """
+        r_status = np.fromfile(f, dtype=np.int8, count=1)
+        info_txt = struct.unpack("{0}s".format(self.info_txt_size), f.read(self.info_txt_size))[0].strip().lower().decode()
+        info_txt = info_txt.replace("\x00","")
+        info_val = np.fromfile(f, dtype=np.float64, count=1)[0]
+        par_vals = np.fromfile(f, dtype=np.float64, count=npar)
+        obs_vals = np.fromfile(f, dtype=np.float64, count=nobs)
+        buf_status = np.fromfile(f, dtype=np.int8, count=1)[0]
+        return r_status, info_txt, buf_status, par_vals, obs_vals
+
+    def get_data(self):
+        """read the contents of the file into a dataframe
+
+        Returns:
+            df (pd.DataFrame): the file contents
+
+        """
+        header, par_names, obs_names = RunStor.file_info(self.filename)
+        with open(self.filename,'rb') as f:
+            f.seek(header["run_start"])
+            rstats, infos, par_vals, obs_vals = [],[],[],[]
+            run_poss,bstats = [],[]
+            for irun in range(header["n_runs"]):
+                run_pos = header["run_start"] + (irun*header["run_size"])
+                f.seek(run_pos)
+                try:
+                    r_status, info_txt, buf_status, par_val, obs_val = self._read_run(f,len(par_names),len(obs_names))
+                except Exception as e:
+                    raise Exception("error reading run {0}: {1}".format(irun,str(e)))
+                rstats.append(r_status[0])
+                infos.append(info_txt)
+                par_vals.append(par_val)
+                obs_vals.append(obs_val)
+                run_poss.append(run_pos)
+                bstats.append(buf_status)
+        df = pd.DataFrame({"run_status":rstats,"run_pos":run_poss,"info_txt":infos,"buffer_status":bstats})
+        df["run_status"] = df.run_status.astype(int)
+        df["run_status_label"] = df.run_status.apply(RunStor.status_str)
+        par_vals = np.array(par_vals)
+        obs_vals = np.array(obs_vals)
+        df = pd.concat([df,pd.DataFrame(par_vals,columns=par_names),pd.DataFrame(obs_vals,columns=obs_names)],axis=1)
+        return df
+
+    def update(self,df):
+        """update the parameter and observation values
+
+        Args:
+            df (pd.DataFrame) : file contents to update.  Should be derived from the get_data() method
+                to maintain dtypes and required information.  The parameter and observation values for each
+                run are updated "in place" in the file, as is the run_status int flag; this flag should be set to
+                -99 for any runs that "failed".
+
+        """
+        header, par_names, obs_names = RunStor.file_info(self.filename)
+        if header["n_runs"] != df.shape[0]:
+            raise Exception("number of runs implied by df nrows {0} != n_runs in file {1}".format(df.shape[0],header["n_runs"]))
+        par_vals = df.loc[:,par_names].values
+        obs_vals = df.loc[:,obs_names].values
+        run_status = df.run_status.astype(np.int8).values
+        run_pos = df.run_pos.values
+        offset =  1 + self.info_txt_size
+        with open(self.filename,"r+b") as f:
+            f.seek(header["run_start"])
+            for irun,(rstat,rpos) in enumerate(zip(run_status,run_pos)):
+                f.seek(rpos)
+                run_status[irun].tofile(f,sep="")
+
+                f.seek(rpos+offset)
+                #write the unused info val
+                np.float64(-999.).tofile(f, sep="")
+                par_vals[irun,:].tofile(f,sep="")
+                obs_vals[irun, :].tofile(f, sep="")
+                #the buffer status flag - 0 means the write was completed
+                np.int8(0).tofile(f, sep="")
+
+
+
+
 def read_pestpp_runstorage(filename, irun=0, with_metadata=False):
     """read pars and obs from a specific run in a pest++ serialized
     run storage file (e.g. .rns/.rnj) into dataframes.