diff --git a/.babelrc b/.babelrc
index ba11916..b8a0eba 100644
--- a/.babelrc
+++ b/.babelrc
@@ -6,7 +6,10 @@
     "stage-2",
   ],
   "plugins": [
+    "transform-async-to-generator",
     "transform-class-properties",
+    "transform-es2015-classes",
     "transform-function-bind",
+    "transform-object-rest-spread",
   ]
 }
diff --git a/.eslintrc.js b/.eslintrc.js
index b10fd46..c1e1590 100644
--- a/.eslintrc.js
+++ b/.eslintrc.js
@@ -1,6 +1,12 @@
 module.exports = {
   extends: 'eslint-config-airbnb',
+  parser: 'babel-eslint',
+  parserOptions: {
+    sourceType: 'module',
+    ecmaVersion: 8,
+  },
   rules: {
+    'react/sort-comp': 0,
     'import/extensions': 0,
     'import/no-extraneous-dependencies': 0,
     'import/no-unresolved': [2, {ignore: ['electron']}],
diff --git a/package.json b/package.json
index 388c2e7..65462a3 100644
--- a/package.json
+++ b/package.json
@@ -50,6 +50,7 @@
     "@commitlint/travis-cli": "^8.0.0",
     "@semantic-release/github": "^5.4.0",
     "babel-cli": "^6.26.0",
+    "babel-eslint": "10.0.2",
     "babel-plugin-transform-async-to-generator": "^6.24.1",
     "babel-plugin-transform-class-properties": "^6.24.1",
     "babel-plugin-transform-es2015-classes": "^6.24.1",
diff --git a/src/app.jsx b/src/app.jsx
index 3ad109c..f153a6d 100644
--- a/src/app.jsx
+++ b/src/app.jsx
@@ -1,17 +1,21 @@
 import Container from '@material-ui/core/Container';
 import CssBaseline from '@material-ui/core/CssBaseline';
+import FormControlLabel from '@material-ui/core/FormControlLabel';
+import FormGroup from '@material-ui/core/FormGroup';
 import Grid from '@material-ui/core/Grid';
 import LinearProgress from '@material-ui/core/LinearProgress';
 import PropTypes from 'prop-types';
 import React from 'react';
 import Slider from '@material-ui/lab/Slider';
+import Switch from '@material-ui/core/Switch';
 import TextField from '@material-ui/core/TextField';
 import Typography from '@material-ui/core/Typography';
 import log from 'electron-log';
 import {Connection} from '@solana/web3.js';
-import {withStyles} from '@material-ui/core/styles';
-import {ReactThemes, ReactTerminal} from 'react-terminal-component';
 import {EmulatorState, OutputFactory, Outputs} from 'javascript-terminal';
+import {ReactThemes, ReactTerminal} from 'react-terminal-component';
+import {withStyles} from '@material-ui/core/styles';
+import Store from 'electron-store';
 
 import {url} from './url';
 import {Replicator} from './replicator';
@@ -38,11 +42,11 @@ const styles = theme => ({
     marginTop: theme.spacing(5),
   },
   progressBar: {
-    marginTop: theme.spacing(1),
+    marginTop: theme.spacing(2),
   },
   footer: {
-    marginTop: 'auto',
-    backgroundColor: 'white',
+    marginTop: theme.spacing(1),
+    backgroundColor: 'lightgray',
   },
 });
 
@@ -51,10 +55,19 @@ class App extends React.Component {
     super(props);
     this.terminalHeight = 25;
 
+    const storeSchema = {
+      enabled: {
+        type: 'boolean',
+        default: false,
+      },
+    };
+    this.store = new Store({schema: storeSchema});
+
     this.state = {
       transactionCount: 0,
       totalMined: 0,
       totalSupply: 0,
+      enabled: this.store.get('enabled'),
     };
     this.connection = new Connection(url);
     log.info('connection:', url);
@@ -63,7 +76,11 @@ class App extends React.Component {
     this.addTerminalText(`Cluster entrypoint: ${url}...`);
 
     this.replicator = new Replicator(this.connection, this);
-    this.replicator.start();
+    if (this.state.enabled) {
+      this.replicator.start();
+    } else {
+      this.addTerminalText('Mining disabled');
+    }
   }
 
   componentDidMount() {
@@ -150,6 +167,17 @@ class App extends React.Component {
     }
   }
 
+  onEnabledSwitch = event => {
+    const enabled = event.target.checked;
+    this.store.set('enabled', enabled);
+    this.setState({enabled});
+    if (enabled) {
+      this.replicator.start();
+    } else {
+      this.replicator.stop();
+    }
+  };
+
   render() {
     const {classes} = this.props;
 
@@ -181,6 +209,19 @@ class App extends React.Component {
               </Typography>
             </Grid>
             <Grid item xs={10} sm={5}>
+              <FormGroup row>
+                <FormControlLabel
+                  control={
+                    <Switch
+                      checked={this.state.enabled}
+                      onChange={this.onEnabledSwitch}
+                      color="primary"
+                    />
+                  }
+                  label="Enable"
+                />
+              </FormGroup>
+              <p />
               <Typography variant="subtitle1" gutterBottom>
                 Gigabytes of ledger to store:
               </Typography>
@@ -229,7 +270,11 @@ class App extends React.Component {
               </Grid>
             </Grid>
           </Container>
-          <LinearProgress className={classes.progressBar} />
+          <LinearProgress
+            variant={this.state.enabled ? 'indeterminate' : 'determinate'}
+            value={100}
+            className={classes.progressBar}
+          />
           <ReactTerminal
             theme={{...ReactThemes.default, height: '50'}}
             emulatorState={emulatorState}
diff --git a/src/index.js b/src/index.js
index 6a90e5f..5cc6a24 100644
--- a/src/index.js
+++ b/src/index.js
@@ -24,7 +24,7 @@ app.on('ready', async () => {
   const devModeExtra = isDevMode ? 200 : 0;
   mainWindow = new BrowserWindow({
     width: 1000 + devModeExtra,
-    height: 750,
+    height: 800,
     resizable: isDevMode,
   });
 
diff --git a/src/replicator.js b/src/replicator.js
index 7de4dae..55d2047 100644
--- a/src/replicator.js
+++ b/src/replicator.js
@@ -11,6 +11,8 @@ export class Replicator {
     this.connection = connection;
     this.terminalOutput = terminalOutput;
     this.running = false;
+    this.mainPromise = Promise.resolve();
+    this.cmdCancel = () => undefined;
 
     const userDataPath = electron.remote.app.getPath('userData');
     this.solanaInstallBinDir = path.join(
@@ -30,29 +32,31 @@ export class Replicator {
     this.solanaInstallDataDir = path.join(userDataPath, 'install');
   }
 
-  start() {
+  async start() {
     if (this.running) {
       log.warn('Replicator already running, ignoring start()');
       return;
     }
+    await this.mainPromise;
     this.running = true;
-    this.main();
+    this.mainPromise = this.main();
   }
 
-  stop() {
+  async stop() {
     if (!this.running) {
       return;
     }
-    this.terminalOutput.addTerminalText('^C');
     this.running = false;
-    // TODO: signal main to exit...
+    this.terminalOutput.addTerminalText('^C');
+    this.cmdCancel();
+    await this.mainPromise;
   }
 
-  restart() {
+  async restart() {
     if (!this.running) {
       return;
     }
-    this.stop();
+    await this.stop();
     this.start();
   }
 
@@ -63,6 +67,7 @@ export class Replicator {
     this.terminalOutput.addTerminalCommand(`${command} ${args.join(' ')}`);
     const env = Object.assign({}, {RUST_LOG: 'solana=info'}, process.env);
     const child = spawn(command, args, {env});
+    log.info(`pid ${child.pid}`);
 
     child.stdout.on('data', data =>
       this.terminalOutput.addTerminalText(data.toString()),
@@ -70,7 +75,16 @@ export class Replicator {
     child.stderr.on('data', data =>
       this.terminalOutput.addTerminalText(data.toString()),
     );
-    return child;
+    return Promise.race([
+      child,
+      new Promise((_, reject) => {
+        this.cmdCancel = () => {
+          log.info(`cmd cancelled, killing pid ${child.pid}`);
+          child.kill();
+          reject(new Error('User abort'));
+        };
+      }),
+    ]);
   }
 
   /**
@@ -142,5 +156,12 @@ export class Replicator {
     } catch (err) {
       this.terminalOutput.addTerminalError(err.message);
     }
+
+    if (!this.running) {
+      log.info('main: not running anymore');
+      return Promise.resolve();
+    }
+    log.info('main: still running, restarting');
+    return this.main();
   }
 }
diff --git a/yarn.lock b/yarn.lock
index 76df6c3..2115afc 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -1331,6 +1331,18 @@ babel-core@^6.13.2, babel-core@^6.26.0:
     slash "^1.0.0"
     source-map "^0.5.7"
 
+babel-eslint@10.0.2:
+  version "10.0.2"
+  resolved "https://registry.yarnpkg.com/babel-eslint/-/babel-eslint-10.0.2.tgz#182d5ac204579ff0881684b040560fdcc1558456"
+  integrity sha512-UdsurWPtgiPgpJ06ryUnuaSXC2s0WoSZnQmEpbAH65XZSdwowgN5MvyP7e88nW07FYXv72erVtpBkxyDVKhH1Q==
+  dependencies:
+    "@babel/code-frame" "^7.0.0"
+    "@babel/parser" "^7.0.0"
+    "@babel/traverse" "^7.0.0"
+    "@babel/types" "^7.0.0"
+    eslint-scope "3.7.1"
+    eslint-visitor-keys "^1.0.0"
+
 babel-generator@^6.26.0:
   version "6.26.1"
   resolved "https://registry.yarnpkg.com/babel-generator/-/babel-generator-6.26.1.tgz#1844408d3b8f0d35a404ea7ac180f087a601bd90"
@@ -4449,6 +4461,14 @@ eslint-restricted-globals@^0.1.1:
   resolved "https://registry.yarnpkg.com/eslint-restricted-globals/-/eslint-restricted-globals-0.1.1.tgz#35f0d5cbc64c2e3ed62e93b4b1a7af05ba7ed4d7"
   integrity sha1-NfDVy8ZMLj7WLpO0saevBbp+1Nc=
 
+eslint-scope@3.7.1:
+  version "3.7.1"
+  resolved "https://registry.yarnpkg.com/eslint-scope/-/eslint-scope-3.7.1.tgz#3d63c3edfda02e06e01a452ad88caacc7cdcb6e8"
+  integrity sha1-PWPD7f2gLgbgGkUq2IyqzHzctug=
+  dependencies:
+    esrecurse "^4.1.0"
+    estraverse "^4.1.1"
+
 eslint-scope@^3.7.1:
   version "3.7.3"
   resolved "https://registry.yarnpkg.com/eslint-scope/-/eslint-scope-3.7.3.tgz#bb507200d3d17f60247636160b4826284b108535"