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Reprinted from Macworld  1/1984, pp. 28-30. Published with permission.
Scans and OCR courtesy of Douglas P. McNutt and Katherine L. Harras from
The MacNauchtan Laboratory.
The Macintosh desktop environment was designed to make working on a personal computer
easier and more productive. And the key to working in that environment is the mouse.
This little, handheld device puts you in control of all the Mac’s unique features.
 |  The Macintosh mouse |
The juxtaposition of a mouse and a computer on a modern office desktop or your cozy
office at home might seem strange indeed. Is it some kind of marriage between high
technology and the rodent population, or an example of the arcane Silicon Valley
sense of humor?
Actually the mouse is not new to computers. It has been around since the early 1960s
when Douglas Engelbart, an associate at the Stanford Research Institute (SRI), created a
small, mouse-shaped device with three protruding control buttons that looked like ears
and a cable connecting the device to the main unit of the computer that looked
like a mouse tail. Engelbart’s objective was to design interactive computer
aids that made using the machine more natural and less alienating.
Basically, the mouse works as a combination cursor-movement and all-purpose function
key that allows you to operate a computer independent of the keyboard. With the
Macintosh mouse, for example, you slide the device over a smooth surface with your
hand, and the graphic pointer on the screen precisely follows its movement. A single
button on top of the mouse allows you to select information or objects and
activate commands. Essentially, the keyboard is a supplement to the mouse in
the Macintosh desktop environment.
The desktop mouse
Most people’s first reaction to the mouse or even the idea of a mouse-driven
menu system is skepticism; they are leery of the mouse and cannot conceive of a
computer without the noble keyboard and the familiar alphabet, numerals, and other symbols
engraved on the keytops. No creature from the lower end of the evolutionary tree
(or a mechanized gimmick) can replace the human intelligence embodied in a typewriterlike
machine.
But after you spend a few minutes moving the mouse around and performing simple
operations on a computer like the Mac, the thought of a standard cursor and the
familiar keyboard seems less appealing. At first you may have problems coordinating
your hand and eyes as you move the mouse and simultaneously watch the pointer
move on the screen. You may end up playing “chicken” with the mouse and
the end of your desk as you try to figure out how to reach the topmost cell
of a worksheet without sliding the mouse off the desk (just pick up the mouse and
try again, and you’ll get your bearings). But after a few hours, you’ll
feel like an expert as you edit a letter or work on your budget with newfound
ease and speed.
Using a mouse draws on an innate human skill: pointing. It’s as natural as
throwing a ball, but more importantly, it increases your productivity and frees
you from the constraints of the keyboard. Because the mouse minimizes use of
the keyboard, you can concentrate on what’s happening on the screen, and you
won’t have to memorize or look up all sorts of keyboard command codes to
do your work. For tasks that don’t require extensive typing, a mouse in the
hand is an efficient device.
Mouse lingo
As with other practical tools, specific terms are used to describe the actions of
a mouse. Initially, you will focus on sliding the mouse on the desktop. However,
once you get accustomed to working with the mouse, your reference point will be the
screen. Rather than concentrating on sliding the mouse, you’ll be thinking in
terms of selecting or dragging objects on the screen; if you press and
hold down the mouse button when the pointer is over an icon, you can drag the icon
to a new location. Clicking (pressing and releasing) the mouse button selects
a location within a document or activates an object.
Double-clicking (pressing and releasing the mouse button twice in rapid
succession) is a shortcut method you’ll quickly master; for example, instead
of selecting an icon and then moving the pointer to the File menu to choose a command,
you can double-click the mouse button in most instances. This action cuts down on the
amount of mouse movement and the number of steps you need to complete certain tasks.
Anatomy of a mouse
 | | A MacPaint portrait of the Macintosh mouse |
The plastic casing of the mouse hides a rather sophisticated piece of technology. If
you look at the bottom of the mouse, you’ll see a small rubber-encased steel tracking
ball surrounded by a circular ring. When you slide the mouse across a desk,
the ball mechanically stimulates two orthogonal shafts that drive signals in two
corresponding channels: an x channel that monitors horizontal movement, and a
y channel that monitors vertical movement.
The movement of the mouse is initially detected by optical sensors on each channel.
There are two light-emitting sources and two light-detecting sensors for each channel.
An optical wheel at the end of each shaft has slots, or apertures, in the optical signal
paths. When the wheel rotates, it breaks and releases the beams of infrared light.
The optical signals are in turn converted to electrical quadrature signals
(x1, x2, y1, y2) by means of the sensors. These electrical pulses generate interrupts
in the computer. Depending on the status of the x and y quadrature
signals, the interrupt handler will either increment or decrement the x and
y locations in memory.
The computer picks up the speed of the mouse by the number of times the infrared beam
is broken or unbroken. The maximum speed that you can move the mouse without losing pulses
(interrupt signals) is ten inches per second. That speed is very quick; however, if
you exceed that limit, the pointer may not perfectly track the movement of the mouse.
 | | The tracking ball is easily removed for cleaning the mouse |
The Mac allows you to modify certain aspects of the mouse’s operation. The
Control Panel option in the Apple menu has two mouse-related control features.
You can choose from among three settings to determine the length of time between
clicks that will effect a double-click.
The other mouse control feature, scaling, involves the relationship between the
speed of mouse movement and the distance covered by the pointer on the screen.
You can set the mouse scaling so that the pointer addresses each dot on the screen,
or you can speed up mouse movement by setting the mouse scaling so that the pointer skips
over every other dot on the screen. However, the scaling feature will not work unless
you move the mouse rather quickly; moving the mouse slowly will address each dot
no matter which option is selected.
Apple’s research showed that the one-button configuration makes it easier and
less confusing for people learning to use the mouse. For more expert usage, the
mouse can be used in conjunction with the keyboard. In MacPaint, for example,
holding down the Option key while you drag a selected part of a drawing will
“stretch” the image.
 | | The bottom of the mouse. The two rollers within the tracking-ball shell rotate when the mouse (tracking ball) moves, sending signals down two channels that monitor mouse movement |
The mouse is a sturdy beast, but don’t let it fall off the table or allow your dog
or cat to chew on it. Having your workspace as free of dust as possible helps to
keep the mouse in good working condition. You should also clean the mouse periodically.
The Macintosh owner’s manual gives detailed instructions for this simple procedure.
It’s in the software
The mouse will come of age in the 1980s because the software developers at Apple have created
a working environment that superbly implements mouse technology. The mouse did not
become a part of the Mac system as an afterthought, but, as in the design for the
Lisa, was part of the overall concept from the beginning. The Mac’s mouse-driven,
uniform working environment allows users to concentrate on their tasks, rather than on
memorizing the keyboard commands and eccentricities of various application programs.
As the community of Mac users multiplies, and as other computer manufacturers adopt
similar mouse-based working environments, the mouse will become a constant companion
of the keyboard, taking over many of its functions. The mouse may not be the ultimate
device for interfacing with computers, but for the time being it’s the
best system yet devised for making computers more compatible with the people who use them.
Daniel Farber
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