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Because none of the screen savers that I've tried did just what I wanted. The feature-packed screen savers tend to want plenty of RAM, CPU cycles, and disk space, and they patch a lot of traps in order to work. On the other end, the bare-bones screen savers don't provide the ability to lock your screen with password access. Also, most screen savers of both types are implemented as system extensions, so you have to reboot your machine to run them or to get rid of them. That isn't optimal if you want to install a screen saver on a networked Macintosh which is busy acting as a server. BlackWatch solves these problems. It's small, quick, simple, compatible, and free.
BlackWatch requires a Macintosh (or compatible) computer with Color QuickDraw. This means that it won't work on a Macintosh Plus or SE, but it will run on the SE/30 and later machines. System 7.0 or later is required.
BlackWatch will run in as little as 64K of RAM (a 128K partition is recommended).
BlackWatch is a standard Macintosh application. Just double-click to run it, then leave it running in the background while you work on other things.
You will probably want to put the BlackWatch application (or an alias to it) in the Startup Items folder. This will cause BlackWatch to run automatically whenever you restart your computer. If you want the Finder brought to the front after BlackWatch launches, there's an option in the Preferences dialog to do that.
After 5 minutes of inactivity (or whatever time interval you specify), BlackWatch will fade the screen to black and optionally display a simple clock. The clock is redisplayed at a random location every 5 seconds. Moving the mouse, inserting a disk, or typing any key will restore the screen. If you don't want the screen saver waking up each time your mouse gets bumped slightly, another Preferences dialog option lets you tell BlackWatch to wake up only when the mouse is clicked.
You can fade the screen immediately by moving the mouse into one corner of your main screen, or prevent the screen from fading by placing the mouse in another corner. The Preferences dialog lets you specify which corners to use. This is conventional behavior for most screen savers.
If desired, you can specify a password (up to 15 characters) that will be required to unlock your screen. When a password is set and BlackWatch is activated, the debugger and force-quit entry points are temporarily disabled to prevent unauthorized access. This level of security lets you walk away from your desk knowing that an intruder would need to reboot your machine in order to gain access to your files, and therefore would not be able to view or use applications and services you may currently be logged into, such as file servers, databases, or personal e-mail. BlackWatch does NOT prevent someone from restarting your machine; it simply provides a deterrent to casual snooping while you're away from your desk.
Select the "Preferences..." item in the Edit menu to bring up the Preferences dialog. These are its options:
• Idle interval
Specify the time, in minutes, after which BlackWatch should fade the screen if there has been no user activity.
• Draw clock
If this box is checked, BlackWatch draws a clock (of the style selected in the adjacent pop-up menu) when sleeping. Otherwise, it will simply fade the screen to black. You can choose whether the clock's second hand is displayed, and whether to draw graduations (tick marks) on the clock's dial. Other options are available, depending on the particular clock style that you select.
• Dismiss alerts automatically
If this box is checked, BlackWatch will attempt to dismiss any alerts which come up in the frontmost layer while the screen is being saved. Typical examples are notification alerts which tell you that a file server has shut down, or you've dropped a modem connection. When BlackWatch detects an alert window being updated, it will simulate pressing the Return key to close the alert. Uncheck this box if you would rather not miss any alerts.
• Bring Finder to front at startup
If this box is checked, BlackWatch will put itself into the background and make the Finder the active application when launched. This option helps make BlackWatch a little less obtrusive, while still keeping it readily available from the process menu.
• Sleep immediately at startup
If this box is checked, BlackWatch will immediately go to sleep when it is launched. By selecting this option and requiring a password to wake up, you can lock your Mac's screen by launching BlackWatch.
• Wake up if mouse moves
If this box is checked, BlackWatch will wake up when you move the mouse (or click the mouse, hit a key, or insert a disk.) Unchecking the box causes BlackWatch to ignore mouse movement; all other events will still wake the screen saver. You might want to uncheck this box if you find yourself manually activating BlackWatch and then accidentally waking up the screen saver by jostling the mouse, and that sort of thing bugs you.
• Require password to wake up
If this box is checked and a password has been specified, you will need to type that password to unlock the screen after sleeping. Checking this box will initially have no effect until you set a password. Click the "Set Password..." button to specify your password, or to change the existing password. Your password is remembered if you uncheck the box, so you don't have to re-specify it later. To clear the password entirely, you can simply set a blank password, or throw away the BlackWatch Preferences file (located in the Preferences folder in the System Folder).
• Sleep Now & Never Sleep corners
These options appear as miniature screen icons, with a dark triangle indicating the currently selected corner. To select a different corner, simply click in that corner of the icon. Note that the "Sleep Now" and "Never Sleep" corners can't be the same; if your choice conflicts with the other corner, an adjacent corner is automatically selected. When the mouse is placed in the designated "Sleep Now" corner on your main monitor (and remains there for at least 1 second), BlackWatch will activate and go to sleep. If the mouse is placed in the "Never Sleep" corner, Black Watch will never go to sleep.
Two reasons. First reason: simplicity. Applications are visible in the process menu when they're running, and they have a "Quit" menu item to make them go away cleanly. If this were implemented as a system extension or "background-only" app, the expectation that you would need to reboot your machine to run it or get rid of it is automatically set, even if that isn't technically required. It would require a separate application or control panel to launch or quit the background process and to change preference settings, causing potential confusion: the program could still be running in memory even after quitting its user interface component.
Second reason: compatibility. Background-only processes are not supposed to own windows or do any drawing. It's technically possible to use the Text Services Manager to create a window and get around this restriction, but event handling becomes much more complex, with increased compatibility risks. It's also possible to have the background-only process launch a separate foreground process when it's time to sleep, an approach which seems unnecessarily CPU-intensive and prone to failure in low-memory situations.
Where are the clock pictures stored? I want to display my own picture instead.
Sorry, this version doesn't use pictures or bitmaps. Individual clock components are drawn as needed using QuickDraw primitives, which requires less memory and helps to make things fast. A future version of BlackWatch may include the ability to specify a PICT resource to display, instead of a clock. This is the feature for which I consistently get the most requests; most people want the ability to display a custom picture or a text message of some sort. I'm reluctant to add any feature which increases the screen saver's memory requirements, but I'm open to suggestions.
This software has been tested in daily use on many different machines for over two years. No software is perfect, however. If you encounter a problem with BlackWatch, here are some things to try:
- Increase the memory partition. (This is done by selecting the BlackWatch application icon in the Finder, choosing "Get Info" from the File menu, and changing the values in the "Memory Requirements" box.) The default minimum size works well under almost all conditions; however, it doesn't leave much free space, and certain system calls occasionally require more memory. Try setting the preferred size to 128K (or more). This usually eliminates any problems caused by a shortage of memory.
- Throw away the "BlackWatch Preferences" file, located in the Preferences folder inside the System Folder. Note that this file contains all the settings you specify in the Preferences dialog, including your password. In the unlikely event that this file has become corrupted, removing it will cause BlackWatch to automatically create a new one, and restore all settings to defaults.
If you use the "Scheduled Shutdown" feature of the Energy Saver control panel, you may have noticed that Energy Saver displays an alert when the system is about to shut down. The default button in this alert tells Energy Saver to wait 5 minutes before shutting down. When BlackWatch's automatic alert dismissal feature is active, it presses this button and system shutdown is postponed indefinitely. To avoid this situation, make sure to uncheck the "Dismiss alerts automatically" option in the Preferences dialog if you plan to use Energy Saver to shut down your machine.
Retrospect
If you use Retrospect (by Dantz Development) and want to script an unattended backup operation, there is one important workaround to note when using BlackWatch. You will need to leave the Retrospect application running (it must already be running before BlackWatch goes to sleep.) If your scheduled backup is to occur more than once, you will also need to ensure that Retrospect doesn't quit after running a script. Retrospect's Preferences panel has an option (in "Unattended Options") to "Stay in Retrospect" when a script completes execution. Keeping the application running is necessary because it can't be launched while BlackWatch is sleeping. The Finder will defer launching a foreground application whenever certain kinds of windows (including the one that BlackWatch displays when sleeping) are in the frontmost layer. This problem does not affect Retrospect Remote, since it isn't an application.
- Added a "Sleep immediately at startup" option, after multiple requests for this feature.
- Added a "Bondi blue" option to the "Apple Logo" style, for style-conscious iMac owners.
- BlackWatch will now wake up from sleep if a modifier key (shift, option, command, or control) is pressed.
- Fixed a bug which caused a crash when the Preferences dialog was opened under Mac OS 8.5.
- Fixed a bug which caused a crash if you turned "Draw Clock" off, then clicked "Cancel" in the password dialog when waking up from sleep.
- Fixed a bug where BlackWatch would occasionally go to sleep while the mouse was moving, or during typing.
- Fixed a bug where BlackWatch would always go to sleep if the mouse entered the Sleep Now corner and was not moving 1 second later, regardless of whether it actually remained in the corner for 1 second.
- Fixed a bug where moving the mouse into the "Sleep Now" corner would do nothing if BlackWatch was in front.
- Fixed a bug which caused a 32-byte memory leak every time the password dialog was displayed.
• What was new in 1.2 (2/15/98)
- Added a digital clock option to the QuickTime logo.
- Checkboxes in the Preferences dialog now have more meaningful titles, depending on which clock style is selected.
- Fixed a problem with the idle interval not being properly rendered under the Appearance Manager if the text was greater than a single digit. BlackWatch now forces the line width to be recalculated when opening the Preferences dialog.
• What was new in 1.1 (11/17/97)
- BlackWatch now takes advantage of the Appearance Manager, if it's present (Mac OS 8 and later.)
All dialogs and controls are drawn in the current system-wide appearance.
- Fixed a problem with the way BlackWatch checked the "Sleep Now" corner. When certain CPU-intensive applications were running, it was possible to move the mouse into the "Sleep Now" corner and nothing would happen.
• What was new in 1.1b1 (10/28/97)
- The "Apple Logo" style now has some additional features. If "Display graduated dial" is checked, the Apple logo is drawn in its full six-color glory. If this option is unchecked, a solid-colored Apple is drawn using one of the 6 colors each time. If both "Display second hand" and "Display graduated dial" are unchecked, the Apple logo is always drawn in red, as in previous versions.
- Increased the preferred memory partition to 128K, since a few people were still experiencing problems starting up with lower sizes.
• What's new in 1.0 (8/15/97)
- First version for general release.
• What was new in 1.0b4 (8/13/97)
- Added an option to display the Apple logo.
- Fixed a bug which could allow another application to bring itself to the front while BlackWatch was sleeping.
- Fixed a bug which prevented Energy Saver from executing a scheduled shutdown while BlackWatch was sleeping.
• What was new in 1.0b3 (8/3/97)
- Made waking up on mouse movement optional, after multiple requests for this feature.
- Fixed a bug where BlackWatch wouldn't respond to a 'quit' Apple event while it was sleeping.
- BlackWatch now waits to fade the screen until after it has become the active process. This eliminates a confusing behavior in previous versions where the screen could fade to black, then wake up a few seconds later if the frontmost application was too busy to relinquish control of the machine (or was displaying a modal dialog.)
• What was new in 1.0b2 (7/3/97)
- Fixed a bug which caused a small memory leak each time "Fade Screen" was selected from the File menu. The fix was to unhilite the menu immediately before hiding the menu bar.
- Fixed a problem with the way BlackWatch checks for system activity. This fix should eliminate the possibility of having BlackWatch go to sleep while you are busy typing away in another application.
- Made all the 'ICON' resources nonpurgeable, to avoid having them purged while the Preferences dialog is active.
- BlackWatch now resets the arrow cursor when becoming the front process, in case another application changed it.
• What was new in 1.0b1 (7/2/97)
- BlackWatch is now "fat" with native binary code for PowerPC and 68K.
- Added an option to dismiss alerts automatically when BlackWatch is sleeping. If BlackWatch notices that an update event for a dialog window occurs while it's asleep, it will generate a "fake" Return key press to close the alert.
- Added a delay threshold for the "sleep now" corner. Previously, it was too easy to accidentally hit the corner when moving the mouse up to the menu bar, causing the screen saver to activate immediately. Now the cursor must be in the corner for at least 1 second before activation will occur.
- Made the Preferences dialog moveable.
- Added the Orbitron clock variation.
- BlackWatch is now Display Manager-aware to handle dynamic screen configuration changes.
- Fixed a problem where BlackWatch was not relinquishing the processor as often as it should have when the screen saver was active, causing potentially slower file transfer rates.
- Fixed a bug which caused a small memory leak each time any dialog box was opened and closed.
Apple, the Apple logo, Macintosh, Power Macintosh, and QuickTime are trademarks of Apple Computer, Inc., registered in the U.S. and other countries. PowerPC is a registered trademark of International Business Machines Corporation.
