diff --git a/Benchmark/System/Process.hs b/Benchmark/System/Process.hs
index 64a6bc08..945289ea 100644
--- a/Benchmark/System/Process.hs
+++ b/Benchmark/System/Process.hs
@@ -13,12 +13,12 @@ import System.IO
     , openFile
     , hClose
     )
-import System.Process (proc, createProcess, waitForProcess, callCommand)
 
 import qualified Streamly.Data.Fold as FL
 import qualified Streamly.FileSystem.Handle as FH
 import qualified Streamly.Prelude as S
 import qualified Streamly.System.Process as Proc
+import qualified Streamly.Internal.System.Command as Cmd
 
 -- Internal imports
 import qualified Streamly.Internal.FileSystem.Handle
@@ -71,16 +71,12 @@ largeByteFile = "./largeByteFile"
 generateByteFile :: IO ()
 generateByteFile = do
     ddPath <- which "dd"
-    let procObj = proc ddPath [
-                "if=" ++ devRandom,
-                "of=" ++ largeByteFile,
-                "count=" ++ show ddBlockCount,
-                "bs=" ++ show ddBlockSize
-            ]
-
-    (_, _, _, procHandle) <- createProcess procObj
-    _ <- waitForProcess procHandle
-    return ()
+    Cmd.toStdout
+        $ ddPath
+            ++ " if=" ++ devRandom
+            ++ " of=" ++ largeByteFile
+            ++ " count=" ++ show ddBlockCount
+            ++ " bs=" ++ show ddBlockSize
 
 -------------------------------------------------------------------------------
 -- Create a file filled with ascii chars
@@ -112,7 +108,7 @@ trToStderrContent =
 createExecutable :: IO ()
 createExecutable = do
     writeFile trToStderr trToStderrContent
-    callCommand ("chmod +x " ++ trToStderr)
+    Cmd.toStdout ("chmod +x " ++ trToStderr)
 
 -------------------------------------------------------------------------------
 -- Create and delete the temp data/exec files
diff --git a/default.nix b/default.nix
index 550cba8d..f6dcc745 100644
--- a/default.nix
+++ b/default.nix
@@ -47,7 +47,7 @@ let haskellPackages =
                         #  } {})
                         (let src = fetchGit {
                             url = "git@github.com:composewell/streamly.git";
-                            rev = "1ee11e87ec920df66e6bb1299ab000948df90ae5";
+                            rev = "4bb8b7c950ffeee9d5c9c3ca23c65be93ca34f0b";
                         }; in super.callCabal2nix "streamly" src {})
                         (old:
                           { librarySystemDepends =
@@ -62,7 +62,7 @@ let haskellPackages =
                       nixpkgs.haskell.lib.overrideCabal
                         (let src = fetchGit {
                             url = "git@github.com:composewell/streamly.git";
-                            rev = "cbccb7777792cb4bf8dd8716929f4e28ea6cf718";
+                            rev = "4bb8b7c950ffeee9d5c9c3ca23c65be93ca34f0b";
                         }; in super.callCabal2nix "streamly-core" "${src}/core" {})
                         (old:
                           { librarySystemDepends =
diff --git a/src/Streamly/Internal/System/Command.hs b/src/Streamly/Internal/System/Command.hs
index cd8af967..b45900fe 100644
--- a/src/Streamly/Internal/System/Command.hs
+++ b/src/Streamly/Internal/System/Command.hs
@@ -61,7 +61,7 @@ where
 import Control.Monad.Catch (MonadCatch)
 import Data.Char (isSpace)
 import Data.Word (Word8)
-import Streamly.Data.Array.Foreign (Array)
+import Streamly.Data.Array.Unboxed (Array)
 import Streamly.Data.Fold (Fold)
 import Streamly.Internal.Data.Parser (Parser)
 import Streamly.Prelude (MonadAsync, SerialT)
diff --git a/src/Streamly/Internal/System/Process.hs b/src/Streamly/Internal/System/Process.hs
index 1d305655..51077d03 100644
--- a/src/Streamly/Internal/System/Process.hs
+++ b/src/Streamly/Internal/System/Process.hs
@@ -93,28 +93,27 @@ module Streamly.Internal.System.Process
     )
 where
 
--- #define USE_NATIVE
-
+import Control.Exception (Exception(..), catch, throwIO)
+import Control.Monad (void, unless)
 import Control.Monad.Catch (MonadCatch, throwM)
 import Control.Monad.IO.Class (MonadIO, liftIO)
+import Control.Concurrent (forkIO, forkOS, runInBoundThread)
+import Control.Concurrent.MVar
 import Data.Function ((&))
 import Data.Word (Word8)
-import Streamly.Data.Array.Foreign (Array)
+import Foreign.C.Error (Errno(..), ePIPE)
+import GHC.IO.Exception (IOException(..), IOErrorType(..))
+import Streamly.Data.Array.Unboxed (Array)
 import Streamly.Data.Fold (Fold)
 import Streamly.Prelude (MonadAsync, parallel, IsStream, adapt, SerialT)
 import System.Exit (ExitCode(..))
 import System.IO (hClose, Handle)
 
 #ifdef USE_NATIVE
-import Control.Exception (Exception(..), catch, throwIO, SomeException)
+import Control.Exception (SomeException)
 import System.Posix.Process (ProcessStatus(..))
 import Streamly.Internal.System.Process.Posix
 #else
-import Control.Concurrent (forkIO)
-import Control.Exception (Exception(..), catch, throwIO)
-import Control.Monad (void, unless)
-import Foreign.C.Error (Errno(..), ePIPE)
-import GHC.IO.Exception (IOException(..), IOErrorType(..))
 import System.Process
     ( ProcessHandle
     , CreateProcess(..)
@@ -126,7 +125,7 @@ import System.Process
     )
 #endif
 
-import qualified Streamly.Data.Array.Foreign as Array
+import qualified Streamly.Data.Array.Unboxed as Array
 import qualified Streamly.Data.Fold as Fold
 import qualified Streamly.Prelude as Stream
 
@@ -185,6 +184,13 @@ mkConfig _ _ = Config False
 
 pipeStdErr :: Config -> Config
 pipeStdErr (Config _) = Config True
+
+inheritStdin :: Config -> Config
+inheritStdin (Config _) = Config True
+
+inheritStdout :: Config -> Config
+inheritStdout (Config _) = Config True
+
 #else
 newtype Config = Config CreateProcess
 
@@ -288,7 +294,11 @@ cleanupException :: MonadIO m =>
     (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle) -> m ()
 cleanupException (Just stdinH, Just stdoutH, stderrMaybe, ph) = liftIO $ do
     -- Send a SIGTERM to the process
+#ifdef USE_NATIVE
+    terminate ph
+#else
     terminateProcess ph
+#endif
 
     -- Ideally we should be closing the handle without flushing the buffers so
     -- that we cannot get a SIGPIPE. But there seems to be no way to do that as
@@ -298,7 +308,11 @@ cleanupException (Just stdinH, Just stdoutH, stderrMaybe, ph) = liftIO $ do
     whenJust hClose stderrMaybe
 
     -- Non-blocking wait for the process to go away
+#ifdef USE_NATIVE
+    void $ forkIO (void $ wait ph)
+#else
     void $ forkIO (void $ waitForProcess ph)
+#endif
 
     where
 
@@ -343,6 +357,14 @@ createProc' modCfg path args = do
 
     Config cfg = modCfg $ mkConfig path args
 
+createProc'' ::
+       (Config -> Config) -- ^ Process attribute modifier
+    -> FilePath                         -- ^ Executable path
+    -> [String]                         -- ^ Arguments
+    -> IO (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)
+createProc'' modCfg path args =
+    runInBoundThread $ createProc' modCfg path args
+
 {-# INLINE putChunksClose #-}
 putChunksClose :: (MonadIO m, IsStream t) =>
     Handle -> t m (Array Word8) -> t m a
diff --git a/src/Streamly/Internal/System/Process/Posix.hs b/src/Streamly/Internal/System/Process/Posix.hs
index 4903a545..fe87360a 100644
--- a/src/Streamly/Internal/System/Process/Posix.hs
+++ b/src/Streamly/Internal/System/Process/Posix.hs
@@ -1,3 +1,4 @@
+-- {-# LANGUAGE Safe #-}
 -- |
 -- Module      : Streamly.Internal.System.Process.Posix
 -- Copyright   : (c) 2020 Composewell Technologies
@@ -17,6 +18,7 @@ module Streamly.Internal.System.Process.Posix
     , newProcess
     , wait
     , getStatus
+    , terminate
 
     -- * IPC
     , mkPipe
@@ -33,15 +35,19 @@ import Data.Tuple (swap)
 import GHC.IO.Device (IODeviceType(..))
 import GHC.IO.Encoding (getLocaleEncoding)
 import GHC.IO.Handle.FD (mkHandleFromFD)
-import System.IO (IOMode(..), Handle)
+import System.IO (IOMode(..), Handle, hPutStrLn, stderr)
 import System.IO.Error (isDoesNotExistError)
 import System.Posix.IO (createPipe, dupTo, closeFd)
-import System.Posix.Process (forkProcess, executeFile, ProcessStatus)
+import System.Posix.Process (forkProcess, executeFile, ProcessStatus, getProcessID)
 import System.Posix.Types (ProcessID, Fd(..), CDev, CIno)
+import System.Posix.Signals (signalProcess, sigTERM)
 import System.Posix.Internals (fdGetMode)
+import qualified Streamly.Internal.FileSystem.Dir as Dir
+import qualified Streamly.Prelude as Stream
 
 import qualified GHC.IO.FD as FD
 import qualified System.Posix.Process as Posix
+import Data.List (intercalate)
 
 -------------------------------------------------------------------------------
 -- Utilities to create stdio handles
@@ -51,13 +57,13 @@ import qualified System.Posix.Process as Posix
 -- We have to put the FDs into binary mode on Windows to avoid the newline
 -- translation that the CRT IO library does.
 setBinaryMode :: FD.FD -> IO ()
-#if defined(mingw32_HOST_OS)
-setBinaryMode fd = do
-    _ <- setmode (FD.fdFD fd) True
-    return ()
-#else
+
+
+
+
+
 setBinaryMode _ = return ()
-#endif
+
 
 -- See Posix.fdToHandle and GHC.IO.Handle.FD.fdToHandle
 -- See stdin, stdout, stderr in module GHC.IO.Handle.FD
@@ -109,9 +115,18 @@ mkPipeDupChild :: Direction -> Fd -> IO (Fd, (IO (), IO (), IO ()))
 mkPipeDupChild direction childFd = do
     let setDirection = if direction == ParentToChild then id else swap
     (child, parent) <- fmap setDirection createPipe
+    pid <- getProcessID
     let parentAction = closeFd child
         childAction =
-            closeFd parent >> void (dupTo child childFd) >> closeFd child
+            hPutStrLn stderr ("closing parent fd" ++ show parent) >>
+            closeFd parent >>
+            hPutStrLn stderr ("closed parent fd" ++ show parent) >>
+            hPutStrLn stderr ("duplicating child to fd" ++ show (child, childFd)) >>
+            void (dupTo child childFd) >>
+            hPutStrLn stderr ("duplicated child to fd" ++ show (child, childFd)) >>
+            hPutStrLn stderr ("closing child" ++ show child) >>
+            closeFd child >>
+            hPutStrLn stderr ("closed child" ++ show child)
         failureAction = closeFd child >> closeFd parent
     return (parent, (parentAction, childAction, failureAction))
 
@@ -141,7 +156,15 @@ mkStdioPipes pipeStdErr = do
     -}
 
     let parentAction = inpParent >> outParent >> errParent -- >> excParent
-        childAction = inpChild >> outChild >> errChild -- >> excChild
+        childAction =
+            hPutStrLn stderr "child input action doing"
+            >> inpChild
+            >> hPutStrLn stderr "child input action done"
+            >> hPutStrLn stderr "child output action doing"
+            >> outChild
+            >> hPutStrLn stderr "child output action done"
+            >> errChild -- >> excChild
+        -- childAction = inpChild >> outChild >> errChild -- >> excChild
         failureAction = inpFail >> outFail >> errFail -- >> excFail
 
     inpH <- toHandle WriteMode inp
@@ -235,6 +258,7 @@ newProcess ::
     -> IO Process
 newProcess action path args env = do
     pid <- forkProcess exec
+    hPutStrLn stderr ("parent process " ++ show pid)
     pidToProcess pid Nothing
 
     where
@@ -243,7 +267,12 @@ newProcess action path args env = do
     -- to the parent and clean up the parent fds. We can send the exceptions
     -- via a pipe like we do for threads.
     --
-    exec = action >> executeFile path True args env
+    exec = do
+        pid <- getProcessID
+        hPutStrLn stderr ("child process " ++ show pid)
+        fds <- Stream.toList . Stream.unfold Dir.readFiles $ ("/proc/" ++ show pid ++ "/fd")
+        hPutStrLn stderr (intercalate ", " fds)
+        action >> executeFile path True args env
 
 newtype ProcessDoesNotExist = ProcessDoesNotExist ProcessID deriving Show
 
@@ -315,3 +344,6 @@ getStatus proc@(Process pid _ procStatus) = do
         if isDoesNotExistError e
         then return (Nothing, Nothing)
         else throwIO e
+
+terminate :: Process -> IO ()
+terminate (Process pid _ _) = signalProcess sigTERM pid
diff --git a/src/Streamly/System/Process.hs b/src/Streamly/System/Process.hs
index e022ad3d..92c09eeb 100644
--- a/src/Streamly/System/Process.hs
+++ b/src/Streamly/System/Process.hs
@@ -134,7 +134,7 @@ import Streamly.Internal.System.Process
 -- >>> import Data.Char (toUpper)
 -- >>> import Data.Function ((&))
 -- >>> import qualified Streamly.Console.Stdio as Stdio
--- >>> import qualified Streamly.Data.Array.Foreign as Array
+-- >>> import qualified Streamly.Data.Array.Unboxed as Array
 -- >>> import qualified Streamly.Data.Fold as Fold
 -- >>> import qualified Streamly.Prelude as Stream
 -- >>> import qualified Streamly.System.Process as Process
diff --git a/stack.yaml b/stack.yaml
index ecfb9263..be790b09 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -5,9 +5,9 @@ packages:
 extra-deps:
 - unicode-data-0.3.0
 - git: https://github.com/composewell/streamly
-  commit: "1ee11e87ec920df66e6bb1299ab000948df90ae5"
+  commit: "4bb8b7c950ffeee9d5c9c3ca23c65be93ca34f0b"
 - git: https://github.com/composewell/streamly
-  commit: "1ee11e87ec920df66e6bb1299ab000948df90ae5"
+  commit: "4bb8b7c950ffeee9d5c9c3ca23c65be93ca34f0b"
   subdirs:
     - core
 
diff --git a/streamly-process.cabal b/streamly-process.cabal
index ca5529df..7c9ae4cf 100644
--- a/streamly-process.cabal
+++ b/streamly-process.cabal
@@ -48,17 +48,26 @@ flag use-gauge
   manual: True
   default: False
 
+flag use-native
+  description: Do not depend on the process package
+  manual: True
+  default: False
+
 common compile-options
   default-language: Haskell2010
   ghc-options:
-    -Wall
-    -Wcompat
-    -Wunrecognised-warning-flags
-    -Widentities
-    -Wincomplete-record-updates
-    -Wincomplete-uni-patterns
-    -Wredundant-constraints
-    -Wnoncanonical-monad-instances
+    -Weverything
+    -Wno-implicit-prelude
+    -Wno-missing-deriving-strategies
+    -Wno-missing-exported-signatures
+    -Wno-missing-import-lists
+    -Wno-missing-local-signatures
+    -Wno-missing-safe-haskell-mode
+    -Wno-missed-specialisations
+    -Wno-all-missed-specialisations
+    -Wno-monomorphism-restriction
+    -Wno-prepositive-qualified-module
+    -Wno-unsafe
 
 common optimization-options
   ghc-options:
@@ -66,6 +75,8 @@ common optimization-options
     -fdicts-strict
     -fspec-constr-recursive=16
     -fmax-worker-args=16
+  if flag(use-native)
+    cpp-options: -DUSE_NATIVE
 
 library
   import: compile-options, optimization-options
@@ -74,18 +85,20 @@ library
     Streamly.System.Process
     Streamly.Internal.System.Process
     Streamly.Internal.System.Command
-  if !os(windows)
+  if flag (use-native) && !os(windows)
     exposed-modules:
       Streamly.Internal.System.Process.Posix
   build-depends:
       base              >= 4.8   && < 5
     , exceptions        >= 0.8   && < 0.11
-    , process           >= 1.0   && < 1.7
     -- Uses internal APIs
     , streamly          == 0.9.0.*
-  if !os(windows)
-    build-depends:
-      unix              >= 2.5   && < 2.8
+  if !flag(use-native)
+    build-depends: process >= 1.0 && < 1.7
+  else
+     if !os(windows)
+       build-depends:
+         unix >= 2.5 && < 2.8
 
 -------------------------------------------------------------------------------
 -- Benchmarks
@@ -106,7 +119,6 @@ benchmark Benchmark.System.Process
       streamly-process
     , base              >= 4.8   && < 5
     , directory         >= 1.2.2 && < 1.4
-    , process           >= 1.0   && < 1.7
     -- Uses internal APIs
     , streamly          == 0.9.0.*
 
@@ -136,7 +148,6 @@ test-suite Test.System.Process
     , directory         >= 1.2.2 && < 1.4
     , exceptions        >= 0.8   && < 0.11
     , hspec             >= 2.0   && < 3
-    , process           >= 1.0   && < 1.7
     , QuickCheck        >= 2.10  && < 2.15
     -- Uses internal APIs
     , streamly          == 0.9.0.*
diff --git a/test/Streamly/System/Process.hs b/test/Streamly/System/Process.hs
index a7440978..01d7d6c5 100644
--- a/test/Streamly/System/Process.hs
+++ b/test/Streamly/System/Process.hs
@@ -1,6 +1,6 @@
 {-# LANGUAGE CPP #-}
 
-module Main where
+module Main (main) where
 
 import Data.Function ((&))
 import Data.List ((\\))
@@ -71,18 +71,12 @@ minBlockCount = 1
 maxBlockCount :: Int
 maxBlockCount = 100
 
-minNumChar :: Int
-minNumChar = 1
-
-maxNumChar :: Int
-maxNumChar = 100 * 1024
-
 arrayChunkSize :: Int
 arrayChunkSize = 100
 
 interpreterFile :: FilePath
 interpreterArg :: String
-#if mingw32_HOST_OS == 1
+#ifdef mingw32_HOST_OS
 interpreterFile = "cmd.exe"
 interpreterArg = "/c"
 #else
@@ -91,21 +85,21 @@ interpreterArg = "sh"
 #endif
 
 executableFile :: FilePath
-#if mingw32_HOST_OS == 1
+#ifdef mingw32_HOST_OS
 executableFile = "./test/data/writeTrToError.bat"
 #else
 executableFile = "./test/data/writeTrToError.sh"
 #endif
 
 executableFileFail :: FilePath
-#if mingw32_HOST_OS == 1
+#ifdef mingw32_HOST_OS
 executableFileFail = "./test/data/failExec.bat"
 #else
 executableFileFail = "./test/data/failExec.sh"
 #endif
 
 executableFilePass :: FilePath
-#if mingw32_HOST_OS == 1
+#ifdef mingw32_HOST_OS
 executableFilePass = "./test/data/passExec.bat"
 #else
 executableFilePass = "./test/data/passExec.sh"