🔧 Read file on Windows

Clicking in the window re-captures the mouse.

.gitignore

@@ -1,4 +1,4 @@
 node_modules
 out
-src/renderer/images
+src/images
 .DS_Store

README.md

@@ -1,11 +1,43 @@
-# Windows95
+# windows95
 
 This is Windows 95, running in an Electron app. Yes, it's the full thing. I'm sorry.
 
+## 💿⏬ [Download it here](https://github.com/felixrieseberg/windows95/releases).
+
+![Screenshot](https://user-images.githubusercontent.com/1426799/44532591-4ceb3680-a6a8-11e8-8c2c-bc29f3bfdef7.png)
+
+## Does it work?
+Yes! Quite well, actually.
+
+## Should this have been a native app?
+Absolutely.
+
+## Does it run Doom (or my other favorite game)?
+You'll likely be better off with an actual virtualization app, but the short answer is yes. [Thanks to
+@DisplacedGamers](https://youtu.be/xDXqmdFxofM) I can recommend that you switch to a resolution of
+640x480 @ 256 colors before starting DOS games - just like in the good ol' days.
+
+## How's the code?
+This only works well by accident and was mostly a joke. The code quality is accordingly.
+
 ## Credits
 
 99.999% of the work was done over at [v86](https://github.com/copy/v86/) by Copy.
 
+## Contributing
+
+Before you can run this from source, you'll need the disk and state images. They're not part of the repo,
+but [you can download them here](https://mega.nz/#!euxygQBT!i03vtE4kYTgrZ1rjZa1gT2F8hvhcwIAgGBsY4ECjs0w).
+
+Unpack the `images` folder into the `src/renderer` folder, creating this layout:
+
+```
+./src/images/default-state.bin
+./src/images/windows95.img
+```
+
+Once you've done so, run `npm install` and `npm start` to run your local build.
+
 ## License
 
 This project is provided for educational purposes only. It is not affiliated with and has

forge.config.js

@@ -3,7 +3,9 @@ const package = require('./package.json');
 
 module.exports = {
   packagerConfig: {
-    asar: true,
+    asar: {
+      unpack: '**/images/*.img'
+    },
     icon: path.resolve(__dirname, 'assets', 'icon'),
     appBundleId: 'com.felixrieseberg.windows95',
     appCategoryType: 'public.app-category.developer-tools',
@@ -20,7 +22,7 @@ module.exports = {
       name: '@electron-forge/maker-squirrel',
       platforms: ['win32'],
       config: {
-        name: 'windows98',
+        name: 'windows95',
         authors: 'Felix Rieseberg',
         exe: 'windows95.exe',
         noMsi: true,

issue_template.md

@@ -0,0 +1,7 @@
+⚠️ Thank you for reporting an issue!
+
+Before we go any further, understand that I probably won't be able to fullfil feature requests.
+Feel free to report what feature you'd love to see, just don't get angry when I don't have
+time to implement it 🙇‍♂️
+
+I will however _gladly_ help you make a pull request if you're willing to play with Javascript!

package-lock.json

@@ -1,6 +1,6 @@
 {
   "name": "windows95",
-  "version": "1.0.0",
+  "version": "1.2.0",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
@@ -1531,6 +1531,11 @@
         }
       }
     },
+    "electron-is-dev": {
+      "version": "0.3.0",
+      "resolved": "https://registry.npmjs.org/electron-is-dev/-/electron-is-dev-0.3.0.tgz",
+      "integrity": "sha1-FOb9pcaOnk7L7/nM8DfL18BcWv4="
+    },
     "electron-osx-sign": {
       "version": "0.4.10",
       "resolved": "https://registry.npmjs.org/electron-osx-sign/-/electron-osx-sign-0.4.10.tgz",
@@ -2545,6 +2550,14 @@
         "assert-plus": "^1.0.0"
       }
     },
+    "github-url-to-object": {
+      "version": "4.0.4",
+      "resolved": "https://registry.npmjs.org/github-url-to-object/-/github-url-to-object-4.0.4.tgz",
+      "integrity": "sha512-1Ri1pR8XTfzLpbtPz5MlW/amGNdNReuExPsbF9rxLsBfO1GH9RtDBamhJikd0knMWq3RTTQDbTtw0GGvvEAJEA==",
+      "requires": {
+        "is-url": "^1.1.0"
+      }
+    },
     "glob": {
       "version": "7.1.2",
       "resolved": "https://registry.npmjs.org/glob/-/glob-7.1.2.tgz",
@@ -2901,6 +2914,11 @@
       "integrity": "sha1-5HnICFjfDBsR3dppQPlgEfzaSpo=",
       "dev": true
     },
+    "is-url": {
+      "version": "1.2.4",
+      "resolved": "https://registry.npmjs.org/is-url/-/is-url-1.2.4.tgz",
+      "integrity": "sha512-ITvGim8FhRiYe4IQ5uHSkj7pVaPDrCTkNd3yq3cV7iZAcJdHTUMPMEHcqSOy9xZ9qFenQCvi+2wjH9a1nXqHww=="
+    },
     "is-utf8": {
       "version": "0.2.1",
       "resolved": "https://registry.npmjs.org/is-utf8/-/is-utf8-0.2.1.tgz",
@@ -4650,6 +4668,24 @@
       "resolved": "https://registry.npmjs.org/universalify/-/universalify-0.1.2.tgz",
       "integrity": "sha512-rBJeI5CXAlmy1pV+617WB9J63U6XcazHHF2f2dbJix4XzpUF0RS3Zbj0FGIOCAva5P/d/GBOYaACQ1w+0azUkg=="
     },
+    "update-electron-app": {
+      "version": "1.3.0",
+      "resolved": "https://registry.npmjs.org/update-electron-app/-/update-electron-app-1.3.0.tgz",
+      "integrity": "sha512-OXfcmeenpjMyzXmadZ6NqxnrpPpiLji0sLUpXkexfX97XM8Gnk4iLovk4TlK4N8dzlETWdm9klgMmo9HpRbK7Q==",
+      "requires": {
+        "electron-is-dev": "^0.3.0",
+        "github-url-to-object": "^4.0.4",
+        "is-url": "^1.2.4",
+        "ms": "^2.1.1"
+      },
+      "dependencies": {
+        "ms": {
+          "version": "2.1.1",
+          "resolved": "https://registry.npmjs.org/ms/-/ms-2.1.1.tgz",
+          "integrity": "sha512-tgp+dl5cGk28utYktBsrFqA7HKgrhgPsg6Z/EfhWI4gl1Hwq8B/GmY/0oXZ6nF8hDVesS/FpnYaD/kOWhYQvyg=="
+        }
+      }
+    },
     "username": {
       "version": "3.0.0",
       "resolved": "https://registry.npmjs.org/username/-/username-3.0.0.tgz",

package.json

@@ -1,7 +1,7 @@
 {
   "name": "windows95",
   "productName": "windows95",
-  "version": "1.1.0",
+  "version": "1.2.0",
   "description": "Windows 95, in an app. I'm sorry.",
   "main": "src/index.js",
   "scripts": {
@@ -19,6 +19,7 @@
   },
   "standard": {
     "globals": [
+      "appState",
       "V86Starter",
       "windows95"
     ],
@@ -29,7 +30,8 @@
   "dependencies": {
     "electron-default-menu": "^1.0.1",
     "electron-squirrel-startup": "^1.0.0",
-    "fs-extra": "^7.0.0"
+    "fs-extra": "^7.0.0",
+    "update-electron-app": "^1.3.0"
   },
   "devDependencies": {
     "@electron-forge/cli": "^6.0.0-beta.22",

src/es6.js

@@ -0,0 +1,29 @@
+const { protocol } = require('electron')
+const fs = require('fs-extra')
+const path = require('path')
+
+const ES6_PATH = path.join(__dirname, 'renderer')
+
+protocol.registerStandardSchemes(['es6'])
+
+async function setupProtocol () {
+  protocol.registerBufferProtocol('es6', async (req, cb) => {
+    console.log(req)
+
+    try {
+      const filePath = path.join(ES6_PATH, req.url.replace('es6://', ''))
+        .replace('.js/', '.js')
+        .replace('.js\\', '.js')
+
+      const fileContent = await fs.readFile(filePath)
+
+      cb({ mimeType: 'text/javascript', data: fileContent }) // eslint-disable-line
+    } catch (error) {
+      console.warn(error)
+    }
+  })
+}
+
+module.exports = {
+  setupProtocol
+}

src/index.js

@@ -3,11 +3,19 @@ const path = require('path')
 
 const { clearCaches } = require('./cache')
 const { createMenu } = require('./menu')
+const { setupProtocol } = require('./es6')
 
 if (require('electron-squirrel-startup')) { // eslint-disable-line global-require
   app.quit()
 }
 
+if (app.isPackaged) {
+  require('update-electron-app')({
+    repo: 'felixrieseberg/windows95',
+    updateInterval: '1 hour'
+  })
+}
+
 let mainWindow
 
 const createWindow = () => {
@@ -16,13 +24,13 @@ const createWindow = () => {
     width: 1280,
     height: 800,
     useContentSize: true,
-    nodeIntegration: false,
     webPreferences: {
+      nodeIntegration: false,
       preload: path.join(__dirname, 'preload.js')
     }
   })
 
-  mainWindow.loadURL(`file://${__dirname}/renderer/index.html?system=win98`)
+  mainWindow.loadURL(`file://${__dirname}/renderer/index.html`)
 
   mainWindow.on('closed', () => {
     mainWindow = null
@@ -30,8 +38,10 @@ const createWindow = () => {
 }
 
 app.on('ready', async () => {
+  await setupProtocol()
   await createMenu()
   await clearCaches()
+
   createWindow()
 })
 

src/menu.js

@@ -1,8 +1,49 @@
-const { app, shell, Menu } = require('electron')
+const { app, shell, Menu, BrowserWindow } = require('electron')
 const defaultMenu = require('electron-default-menu')
 
+function send (cmd) {
+  const windows = BrowserWindow.getAllWindows()
+
+  if (windows[0]) {
+    windows[0].webContents.send(cmd)
+  }
+}
+
 async function createMenu () {
   const menu = defaultMenu(app, shell)
+    .map((item) => {
+      if (item.label === 'View') {
+        item.submenu = item.submenu.filter((subItem) => {
+          return subItem.label !== 'Reload'
+        })
+      }
+
+      return item
+    })
+    .filter((item) => {
+      return item.label !== 'Edit'
+    })
+
+  menu.splice(1, 0, {
+    label: 'Machine',
+    submenu: [
+      {
+        label: 'Send Ctrl+Alt+Del',
+        click: () => send('ctrlaltdel')
+      },
+      {
+        label: 'Restart',
+        click: () => send('restart')
+      },
+      {
+        type: 'separator'
+      },
+      {
+        label: 'Go to Disk Image',
+        click: () => send('disk-image')
+      }
+    ]
+  })
 
   Menu.setApplicationMenu(Menu.buildFromTemplate(menu))
 }

src/preload.js

@@ -1,43 +1,45 @@
-const { remote } = require('electron')
-const fs = require('fs-extra')
+const { remote, shell, ipcRenderer } = require('electron')
+const path = require('path')
 
-const { STATE_PATH, getState, resetState } = require('./state')
+const { STATE_PATH, resetState, restoreState, saveState } = require('./state')
 
 window.windows95 = {
   STATE_PATH,
-
+  restoreState,
   resetState,
+  saveState,
 
-  async saveState () {
-    return new Promise((resolve) => {
-      if (!window.emulator || !window.emulator.save_state) {
-        return resolve()
-      }
+  showDiskImage () {
+    const imagePath = path.join(__dirname, 'images/windows95.img')
+      .replace('app.asar', 'app.asar.unpacked')
 
-      window.emulator.save_state(async (error, newState) => {
-        if (error) {
-          console.log(error)
-          return
-        }
-
-        await fs.outputFile(STATE_PATH, Buffer.from(newState))
-
-        console.log(`Saved state to ${STATE_PATH}`)
-
-        resolve()
-      })
-    })
+    shell.showItemInFolder(imagePath)
   },
 
-  async restoreState () {
-    try {
-      window.emulator.restore_state(getState())
-    } catch (error) {
-      console.log(`Could not read state file. Maybe none exists?`, error)
-    }
-  },
-
-  quit () {
-    remote.app.quit()
-  }
+  quit: () => remote.app.quit()
 }
+
+ipcRenderer.on('ctrlaltdel', () => {
+  if (!window.emulator || !window.emulator.is_running) return
+
+  window.emulator.keyboard_send_scancodes([
+    0x1D, // ctrl
+    0x38, // alt
+    0x53, // delete
+
+    // break codes
+    0x1D | 0x80,
+    0x38 | 0x80,
+    0x53 | 0x80
+  ])
+})
+
+ipcRenderer.on('restart', () => {
+  if (!window.emulator || !window.emulator.is_running) return
+
+  window.emulator.restart()
+})
+
+ipcRenderer.on('disk-image', () => {
+  windows95.showDiskImage()
+})

src/renderer/app-state.js

@@ -0,0 +1,8 @@
+export function setupState () {
+  window.appState = {
+    cursorCaptured: false,
+    floppyFile: null,
+    bootFresh: false,
+    infoInterval: null
+  }
+}

src/renderer/buttons.js

@@ -0,0 +1,44 @@
+const $ = document.querySelector.bind(document)
+
+export function setupButtons (start) {
+  // Start
+  $('.btn-start').addEventListener('click', () => start())
+
+  // Disk Image
+  $('#show-disk-image').addEventListener('click', () => windows95.showDiskImage())
+
+  // Reset
+  $('#reset').addEventListener('click', () => windows95.resetState())
+
+  $('#discard-state').addEventListener('click', () => {
+    window.appState.bootFresh = true
+
+    start('win95')
+  })
+
+  // Floppy
+  $('#floppy').addEventListener('click', () => {
+    $('#file-input').click()
+  })
+
+  // Floppy (Hidden Input)
+  $('#file-input').addEventListener('change', (event) => {
+    window.appState.floppyFile = event.target.files && event.target.files.length > 0
+      ? event.target.files[0]
+      : null
+
+    if (window.appState.floppyFile) {
+      $('#floppy-path').innerHTML = `Inserted Floppy Disk: ${window.appState.floppyFile.path}`
+    }
+  })
+}
+
+export function toggleButtons (forceTo) {
+  const buttonElements = $('#buttons')
+
+  if (buttonElements.style.display !== 'none' || forceTo === false) {
+    buttonElements.style.display = 'none'
+  } else {
+    buttonElements.style.display = undefined
+  }
+}

src/renderer/index.html

@@ -11,6 +11,11 @@
 </head>
 
 <body class="paused">
+  <div id="status">
+    Disk: <span id="disk-status">Idle</span>
+    | CPU Speed: <span id="cpu-status">0</span>
+    | <a onclick="document.querySelector('#status').style.display='none'">Hide</a>
+  </div>
   <div id="buttons">
     <div id="start-buttons">
       <!-- <div class="btn" id="win98">Windows 98</div> -->
@@ -26,14 +31,15 @@
       <div class="btn" id="reset">Reset Machine & Delete State</div>
       <div class="btn" id="floppy">Insert Floppy Disk</div>
       <div class="btn" id="discard-state">Discard State & Boot From Scratch</div>
+      <div class="btn" id="show-disk-image">Show Disk Image</div>
       <input id="file-input" type='file'>
     </div>
     <div id="information">
       <p id="floppy-path"></p>
       <p>You can insert a floppy disk image with the ".img" format.</p>
       <p>
-        Boot the machine from scratch if you've inserted a new floppy disk to
-        make sure that Windows can load it.
+        Boot the machine from scratch if you've inserted a new floppy disk
+        or if you've changed the disk image.
       </p>
     </div>
   </div>
@@ -41,8 +47,8 @@
     <div style="white-space: pre; font: 14px monospace; line-height: 14px"></div>
     <canvas style="display: none"></canvas>
   </div>
-  <script>
-    require('./renderer.js')
+  <script type="module">
+    import("es6://renderer.js")
   </script>
 </body>
 

src/renderer/info.js

@@ -0,0 +1,36 @@
+const $ = document.querySelector.bind(document)
+
+export function setupInfo () {
+  const diskStatus = $('#disk-status')
+  const cpuStatus = $('#cpu-status')
+  let lastCounter = 0
+  let lastTick = 0
+
+  window.emulator.add_listener('ide-read-start', () => {
+    diskStatus.innerHTML = 'Read'
+  })
+
+  window.emulator.add_listener('ide-read-end', () => {
+    diskStatus.innerHTML = 'Idle'
+  })
+
+  window.emulator.add_listener('ide-write-end', () => {
+    diskStatus.innerHTML = 'Idle'
+  })
+
+  window.emulator.add_listener('screen-set-size-graphical', (...args) => {
+    console.log(...args)
+  })
+
+  setInterval(() => {
+    const now = Date.now()
+    const instructionCounter = window.emulator.get_instruction_counter()
+    const ips = instructionCounter - lastCounter
+    const deltaTime = now - lastTick
+
+    lastTick = now
+    lastCounter = instructionCounter
+
+    cpuStatus.innerHTML = Math.round(ips / deltaTime)
+  }, 500)
+}

src/renderer/listeners.js

@@ -0,0 +1,41 @@
+export function setupCloseListener () {
+  window.appState.isQuitting = false
+
+  const handleClose = async () => {
+    await windows95.saveState()
+    window.appState.isQuitting = true
+    windows95.quit()
+  }
+
+  window.onbeforeunload = (event) => {
+    if (window.appState.isQuitting) return
+
+    handleClose()
+    event.preventDefault()
+    event.returnValue = false
+  }
+}
+
+export function setupEscListener () {
+  document.onkeydown = function (evt) {
+    evt = evt || window.event
+    if (evt.keyCode === 27) {
+      if (window.appState.cursorCaptured) {
+        window.appState.cursorCaptured = false
+        document.exitPointerLock()
+      } else {
+        window.appState.cursorCaptured = true
+        window.emulator.lock_mouse()
+      }
+    }
+  }
+}
+
+export function setupClickListener () {
+  document.addEventListener('click', () => {
+    if (!window.appState.cursorCaptured) {
+      window.appState.cursorCaptured = true
+      window.emulator.lock_mouse()
+    }
+  })
+}

src/renderer/renderer.js

@@ -1,24 +1,16 @@
-const $ = document.querySelector.bind(document)
-const $$ = document.querySelectorAll.bind(document)
+import { setupState } from 'es6://app-state.js'
+import { setupClickListener, setupEscListener, setupCloseListener } from 'es6://listeners.js'
+import { toggleButtons, setupButtons } from 'es6://buttons.js'
+import { setupInfo } from 'es6://info.js'
 
-const BUTTONS = $('#buttons')
+setupState()
 
-let cursorCaptured = false
-let floppyFile = null
-let bootFresh = false
-
-const OPTIONS = {
-  win95: {
-    hda: {
-      url: './images/windows95.img',
-      async: true,
-      size: 242049024
-    }
-  }
-}
-
-async function main (id) {
-  const opts = Object.assign({
+/**
+ * The main method executing the VM.
+ */
+async function main () {
+  // New v86 instance
+  window.emulator = new V86Starter({
     memory_size: 64 * 1024 * 1024,
     screen_container: document.getElementById('emulator'),
     bios: {
@@ -27,110 +19,48 @@ async function main (id) {
     vga_bios: {
       url: './bios/vgabios.bin'
     },
+    hda: {
+      url: '../images/windows95.img',
+      async: true,
+      size: 242049024
+    },
     fda: {
-      buffer: floppyFile || undefined
+      buffer: window.appState.floppyFile || undefined
     },
     boot_order: 0x132
-  }, OPTIONS[id])
+  })
 
-  // New v86 instance
-  window.emulator = new V86Starter(opts)
+  // High DPI support
+  if (navigator.userAgent.includes('Windows')) {
+    const scale = window.devicePixelRatio
 
-  // Restore state. We can't do this right away.
+    window.emulator.screen_adapter.set_scale(scale, scale)
+  }
+
+  // Restore state. We can't do this right away
+  // and randomly chose 500ms as the appropriate
+  // wait time (lol)
   setTimeout(async () => {
-    if (!bootFresh) {
-      await windows95.restoreState()
+    if (!window.appState.bootFresh) {
+      windows95.restoreState()
     }
 
-    cursorCaptured = true
+    setupInfo()
+
+    window.appState.cursorCaptured = true
     window.emulator.lock_mouse()
     window.emulator.run()
   }, 500)
 }
 
-function start (id) {
-  BUTTONS.remove()
+function start () {
   document.body.className = ''
-  main(id)
-}
 
-function setupButtons () {
-  // Start
-  $$('.btn-start').forEach((btn) => {
-    btn.addEventListener('click', () => start(btn.id))
-  })
-
-  // Reset
-  $('#reset').addEventListener('click', () => {
-    if (window.emulator.stop) {
-      window.emulator.stop()
-    }
-
-    windows95.resetState()
-
-    if (window.emulator.run) {
-      window.emulator.run()
-    }
-
-    $('#reset').disabled = true
-  })
-
-  $('#discard-state').addEventListener('click', () => {
-    bootFresh = true
-
-    start('win95')
-  })
-
-  // Floppy
-  $('#floppy').addEventListener('click', () => {
-    $('#file-input').click()
-  })
-
-  // Floppy (Hidden Input)
-  $('#file-input').addEventListener('change', (event) => {
-    floppyFile = event.target.files && event.target.files.length > 0
-      ? event.target.files[0]
-      : null
-
-    if (floppyFile) {
-      $('#floppy-path').innerHTML = `Inserted Floppy Disk: ${floppyFile.path}`
-    }
-  })
-}
-
-function setupEscListener () {
-  document.onkeydown = function (evt) {
-    evt = evt || window.event
-    if (evt.keyCode === 27) {
-      if (cursorCaptured) {
-        cursorCaptured = false
-        document.exitPointerLock()
-      } else {
-        cursorCaptured = true
-        window.emulator.lock_mouse()
-      }
-    }
-  }
-}
-
-function setupCloseListener () {
-  let isQuitting = false
-
-  const handleClose = async () => {
-    await windows95.saveState()
-    isQuitting = true
-    windows95.quit()
-  }
-
-  window.onbeforeunload = (event) => {
-    if (isQuitting) return
-
-    handleClose()
-    event.preventDefault()
-    event.returnValue = false
-  }
+  toggleButtons(false)
+  setupClickListener()
+  main()
 }
 
 setupEscListener()
 setupCloseListener()
-setupButtons()
+setupButtons(start)

src/renderer/style/style.css

@@ -16,6 +16,28 @@ body.paused {
   font-family: Courier;
 }
 
+#buttons {
+  user-select: none;
+}
+
+#status {
+  user-select: none;
+  position: absolute;
+  z-index: 100;
+  left: calc(50vw - 110px);
+  background: white;
+  text-align: center;
+  font-family: Courier;
+  font-size: 10px;
+  padding-bottom: 3px;
+  border-bottom-left-radius: 15px;
+  border-bottom-right-radius: 15px;
+  overflow: hidden;
+  padding-left: 10px;
+  padding-right: 10px;
+  max-height: 18px;
+}
+
 #floppy-path {
   background: beige;
   padding: 5px;

src/state.js

@@ -2,9 +2,15 @@ const fs = require('fs-extra')
 const path = require('path')
 const { remote } = require('electron')
 
-const DEFAULT_PATH = path.join(__dirname, 'renderer/images/default-state.bin')
+const DEFAULT_PATH = path.join(__dirname, 'images/default-state.bin')
 const STATE_PATH = path.join(remote.app.getPath('userData'), 'state.bin')
 
+/**
+ * Returns the current machine's state - either what
+ * we have saved or alternatively the default state.
+ *
+ * @returns {ArrayBuffer}
+ */
 function getState () {
   const statePath = fs.existsSync(STATE_PATH)
     ? STATE_PATH
@@ -13,12 +19,58 @@ function getState () {
   return fs.readFileSync(statePath).buffer
 }
 
-function resetState () {
-  fs.removeSync(STATE_PATH)
+/**
+ * Resets a saved state by simply deleting it.
+ *
+ * @returns {Promise<void>}
+ */
+async function resetState () {
+  if (fs.existsSync(STATE_PATH)) {
+    return fs.remove(STATE_PATH)
+  }
+}
+
+/**
+ * Saves the current VM's state.
+ *
+ * @returns {Promise<void>}
+ */
+async function saveState () {
+  return new Promise((resolve) => {
+    if (!window.emulator || !window.emulator.save_state) {
+      return resolve()
+    }
+
+    window.emulator.save_state(async (error, newState) => {
+      if (error) {
+        console.log(error)
+        return
+      }
+
+      await fs.outputFile(STATE_PATH, Buffer.from(newState))
+
+      console.log(`Saved state to ${STATE_PATH}`)
+
+      resolve()
+    })
+  })
+}
+
+/**
+ * Restores the VM's state.
+ */
+function restoreState () {
+  try {
+    window.emulator.restore_state(getState())
+  } catch (error) {
+    console.log(`Could not read state file. Maybe none exists?`, error)
+  }
 }
 
 module.exports = {
   STATE_PATH,
+  saveState,
+  restoreState,
   resetState,
   getState
 }