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Reprinted from Softalk 9/83, pp. 144-157.
Once upon a time, three blind men were led to an elephant so that they might experience the nature of the
beast. One man held the trunk in his hands and said, “The elephant is like a giant snake.” Another
man stood by one of the elephant’s legs and, wrapping his arms around the leg, said, “Oh no; the
elephant is strong and tall like a tree.” The third man put his hands on the elephant’s side
and said, “No, this beast is like a great wall.”
Although you no doubt see the folly of their observations, we are all intellectually blind to greater and
lesser degrees regarding the many things and subjects to be found in the world. On the nature of simple
objects, like a table or a chair, we can pretty much agree; although those of greater experience, like
a carpenter or cabinetmaker, may have perceptions far more detailed than those of the average person.
The more complex the subject, the more our views of its nature are likely to differ from other
people’s and the more our own personal experience (or lack thereof) is apt to produce a view
unique to ourselves – most likely a view blind to certain aspects of the thing in question.
The Lisa computer, released last June by Apple Computer, definitely qualifies as a complex subject, and therefore
it is unlikely that many people will fully appreciate or even understand all about its nature and
capabilities. This observation has a lot to do with the answer to one of the more often posed questions,
“Is the Lisa worth the price?” After an introduction to the machine, we’ll explore the possible
answers to that question, as well as to the question of how this new computer could impact upon the current
state of computer usage.
The “blind-man effect,” as we’ll call the analysis problem, also means that no one author
is likely to perceive all the aspects of the Lisa, nor can one article answer all the questions that the
readers are likely to have. In this article, we’ll try to present two views of the Lisa, one centering
on the more applications-minded person who is mainly interested in the immediate uses of the machine, and
another that concentrates on hardware and software details of the machine for those interested in the
technical aspects.
The First Date with Lisa
| Figure 1. |
Unpacking a Lisa and the boxes of its various components is a little
like a blind date with someone whom you’ve heard is better than perfect. Expectations can be a
little overdemanding, and nervousness and excitement abound.
With all the media talk of the Lisa being so easy to use, you half expect it to jump out of the boxes
and set itself up. Well, needless to say, it isn’t quite that easy.
Although the Lisa manuals are very good, it’s not always obvious which of the many chapters one should
be reading. Besides, the notion of reading a manual when your brand-new Lisa is inches away is rather like
the thought of taking along an etiquette book on that blind date.
Well, eventually everything is in its place and the Lisa is brought to life. Figure 1 shows how everything
looks when set up (this is how you keep your computer set up, isn’t it?), and figure 2 shows what
the usual office system screen setup looks like with the basic icons present.
| Figure 2. |
The office system is the environment in which the various tools (Lisa’s applications programs) are used. The
tools, stored on the ProFile, are LisaWrite, LisaCalc, LisaDraw, LisaGraph, LisaProject, and LisaList.
The screen depicts an executive desktop where all of our electronic paper-pushing is about to occur. Icons
are the graphic symbols used to represent the various tools, documents, and devices available to you.
A document is any file that you can open up and write information in by using one of the tools.
The mouse is sort of an upside-down track ball that can be rolled around on your own (real) desktop to
control a pointer on Lisa’s (electronic) desktop that selects the icon you wish to manipulate. Besides
just moving things around, clicking the button on the mouse with the pointer on a menu choice selects
that choice. For example, in figure 2, clicking the mouse with the menu bar highlighted as shown
“opens” up most icons so that you can view their contents.
On first exposure, it’s easy to spend some time (certainly more than fifteen minutes, but it
doesn’t seem like it) just experimenting before you run any actual program. It’s fun just to
move the mouse around and poke all the screen icons to see what happens.
Of course, one can never resist the temptation to do things like put the ProFile icon in the
trashcan icon to see what happens. Lisa is very forgiving of such youthful mischief; the ProFile
icon merely scurries back to its original spot on the desktop when you try such antics.
| Figure 3. |
When you choose an icon, the display is dramatic. A box outline pops out of the icon and swiftly expands
from tiny icon size into a large window. Closing the document the window displays does the same thing in
reverse. Figure 3 shows the desktop with three windows opened. These experiments usually draw a
crowd (if there’s anyone around) and each icon’s opening and closing elicits the oohs and aahs
usually associated with a fireworks display. The ultimate cheap thrill is opening as
many icons as possible on the screen and then telling Lisa to close tha all at once. (As you can tell
by now, this article was researched in only the most professional of manners.)
Well, on with the story. You’ll notice that there are four basic icon on the screen desktop. There
is a ProFile, which represents the five megabyte hard disk that comes with the Lisa. There is also
the wastebasket, which is used to dispose of unwanted items. The clipboard is a temporary storage spot
whose primary use is in editing documents and in copying all or part of one document to another. For
example, one could take part of a spreadsheet generated in LisaCalc and copy it to a letter being
written in LisaWrite simply by copying the desired text to the clipboard, moving from
LisaCalc to LisaWrite, and then retrieving the data from the clipboard to put in the letter.
Learning the Ropes
| Figure 4. |
One of the big advantages of the Lisa is that the principles you learn in
one portion of the system usually apply to even other section as well. This means that, once you have
learned how to use one tool, you can learn the others very quickly. These general principles of operation are
even extended to the Workshop, an optional (meaning you buy it separately) developers’ package that
is essentially the programming level of the Lisa. In addition, the manuals for all the tools
share a common format, and the bulk of each manual is a good tutorial on the features of that tool.
You can probably tell already that one of the nicest things about the Lisa is that you can do
almost everything on a very intuitive level. The old Apple directory format of catalogs and file
types does not exist. Instead, files are arranged in treelike structures and, for the user, it’s even
simpler than that sounds.
| Figure 5. |
For example, when the ProFile is opened, you find a number of items stored there. Remember that on the
Lisa opening a file is a very fundamental concept. It’s more like opening up the drawer of a filing
cabinet than it is like opening a computer file. You can choose to look at the contents in a
variety of ways. For example, figure 4 shows the contents of the ProFile arranged by icon.
Figure 5 shows the contents arranged chronologically, with the size of each file, date of origin,
and other information written out in a way that’s a little more like a disk catalog.
If you wanted, for example, to create a chart, the first step would be to find on the ProFile the icon
labeled LisaGraph Paper. This is analogous to finding a tablet of graph paper in your office when you
want to create a chart. When the LisaGraph Paper icon is located, selecting it performs an operation
known as “tearing off a sheet” of LisaGraph paper. This creates the single sheet
of paper (the data file) on which our graph will be made.
| Figure 6. |
Figures 6 and 7 illustrate what the screen might look like after a graph has been created. On the
left portion of the screen is part of a simplified spreadsheet on which the basic data for the graph has been
recorded. On the right in each photo is the graph created from the data. It should be noted that all
scaling, labeling, and even shading is performed automatically by the software, with the user being
responsible only for entering the data correctly.
The different graphs were created by pulling down the chart-type menu at the top of the screen and
selecting either pie chart or bar chart with the mouse pointer. A chart of one type can be regraphed
as another type nearly instantaneously.
Printing the chart is also easily done by selecting the print option from within the file/edit menu. The
Apple Dot Matrix Printer has about average abilities when driven by an Apple II, but with the Lisa
software telling it what to do it can create unusually good reproductions of the document as shown on
the screen using the page layouts (full page, half page, vertical, or horizontal orientation, and so on)
selected by the user. (See figure 8.)
| Figure 7. |
Files can be stored directly back to the ProFile by closing the window of the document (and thus the
document itself) and then using the mouse pointer to pick up the document and move it onto the ProFile
window or directly over the icon for the ProFile.
A better way, though, is to take advantage of another file concept called the folder. This is also
an icon; it’s used to represent a group of documents. You could, for example, create a
folder titled My Charts and put the two charts into the folder. Folders can also be nested. That is,
you could have a folder entitled My Charts, in which are stored three other folders, one titled Test
Charts, in which you keep any number of experimental charts and graphs.
| Figure 8. |
What You Get with Lisa
So, just what do you get when you buy a
Lisa? For the time being, the Lisa cannot be purchased without the software or the ProFile, so the list looks
something like this:
| | | Lisa main unit with one megabyte of RAM, monitor, and two floppy drives (0.8 megabyte each) built in.
|
| | | ProFile hard disk, five-megabyte capacity.
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| | | Keyboard with number pad, detachable.
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| | | Mouse control unit (one button).
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| | | Lisa owner’s manual with LisaGuide tutorial software.
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| | | LisaWrite, a word processor.
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| | | LisaCalc, spreadsheet software.
|
| | | LisaGraph, graphing/plotting software.
|
| | | LisaDraw, freestyle graphics software.
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| | | LisaList, database software for simple lists.
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| | | LisaProject, project management software.
|
| |
| Figure 9. |
The Lisa unit itself has three interface slots in the back, each of which accommodates two devices. These
can be printers, modems, even more ProFiles. There are three built-in ports along the back, two serial
and one parallel. (See figure 9.) The ProFile is usually connected to the built-in parallel port.
There’s even a reset button back there, but its use is recommended only in the most drastic
of circumstances, namely a complete system lock-up, since any files currently open when reset is pressed
would be lost. You can’t use the power button to recover from a lock-up because it isn’t
actually connected to the power line; it’s more accurately thought of as a “power-down-request”
button.
Apple had maintenance in mind when they designed the Lisa. All major parts with exception of
the video tube and related parts can be removed by the user by hand, with no special tools (not even
a screwdriver!) required. Figure 10, for example, shows the front panel removed
and the disk drive unit slid halfway out. Presumably the notion is that you just take the part that
needs to be replaced in to your dealer and get a new one that works.
| Figure 10. |
(..) Figure 11 shows the back panel removed. You can see the three interface slots and some of the
circuitry of the Lisa. The yellow handles at the end of each slot open the slot up like a Venus’s-flytrap
to allow insertion or removal of the interface cards without having to push them in from above. The cards
are very tall (exactly the height of the available space, to be exact), so this approach is
necessary. The self-cleaning effect of taking cards in and out on the Apple II is probably nonexistent
here, but maybe Lisas don’t oxidize either!
The power supply is on the far right of the Lisa in figure 11 and is a separate, removable unit. The
center portion of the Lisa also slides out and holds four circuit boards, one with the cpu, one
with the I/O circuitry, and two with a half megabyte of RAM each for a total of one megabyte.
| Figure 11. |
The keyboard is a nice one, as shown in figure 12. There is a numeric keypad, and special functions
are provided by the option and apple keys in the lower left and right corners of the keyboard. The
keyboard hardware is designed so that the keys are all individually identifiable by software, which
allows for a great deal of flexibility.
The software included is enough to accomplish some of the more obvious functions of an office computer.
Realistically, the bundled programs are probably Apple’s attempt to make sure that the most
important classes of software are immediately available (not to mention providing revenues for
the company).
LisaProject is perhaps the most fascinating of the software packages included with the Lisa,
and some example screen displays are shown in figure 13. This software allows a person to
break down a major project into a network of interdependent events or tasks to be done by various
persons. The user estimates how much time is required to complete each task. LisaProject then adds
the various amounts of time together to determine the earliest and latest possible completion dates and also
highlights the tasks that are most critical timewise to the project’s completion. This process is
usually called critical path analysis, and it’s quite time-consuming without the aid of a computer.
| Figure 12. |
LisaProject also redisplays the project diagram information in bar-chart form, with the
bars representing the time taken for each project by each person in the project (figure 14).
Most of the software is somewhat similar to products available for the Apple II; the big difference lies
in the degree of integration between the packages, the sophistication of the screen displays, and
the general processing power available.
Many of the packages can exchange data among themselves where appropriate. You tell Lisa to transfer data
simply by copying the parts desired to the clipboard and then going to the next tool.
The displays for the Lisa tools all follow a common theme, so going from one tool to another is
quite simple. The screen is a high-resolution display (720-by-364) so text is easy to read
and graphics are sharp. All the programs have error messages that are for the most part clear
in their meaning, and various error messages are accompanied by unique sound patterns (earcons, perhaps?).
| Figure 13. |
The real secret to the Lisa software is the sophistication of the hardware system that runs it. The
amount of computing power in the Lisa is staggering; it amounts to nothing less than having
a mainframe/minicomputer-level computer sitting on your desk. Although the technical section to follow
will go further into the specifics, it can be said that the real excitement in the Lisa lies more
in the software that the future will bring than in any of the software that exists now.
It’s interesting to note, however, that things never change; only the form they take does. For
example, there’s a comparison between some familiar functions of the Apple II and the Lisa in figure 15.
Apple II | Lisa |
Catalog | Open ProFile, disk, or folder (File names can be nested) |
Programs | Tools |
Files | Documents |
Run | Open paper with tool available |
Open | Select with mouse and click twice |
Close | Set aside |
Save | Put away |
Delete | Move object to wastebasket |
Lock, unlock | (No equivalent) |
Volume, slot, and drive | (No equivalent; continuous storage throughout disk) |
Memory map | Transparent use of 16Mb logical memory with 1Mb actually in machine |
PR#, IN# | Select devices graphically |
Menu selections | Mouse and pull-down menus |
Reset | Back of machine, but powers down Lisa |
Figure 15.
| Figure 14. |
We’ve already discussed many of the file-related aspects of the Lisa, but we should also make a
brief mention here of some of the differences in disk and memory storage of data, and how I/O
devices are handled.
You’ll notice that there are no slot, drive, or volume parameters associated with the disk system
on the Lisa. A ProFile or floppy disk is treated as a continuous block of storage media so that all
of the storage devices may be used at any time. The numbers 1 and 2 on the built-in disk drive units are
for the most part arbitrary. Whenever a disk is inserted, it’s captured by the drive (and not given back
until Lisa feels like releasing it!) and a disk icon appears on the desktop. The disk eject buttons on the
drives are similar to the power button; they are actually eject request buttons and don’t immediately release
the disk when pressed. Only after all associated files are automatically put away is the disk ejected.
For the programmer, memory maps are no longer a concern because, even at the program level, virtually (so
to speak) all of memory is automatically managed by internal hardware. That is to say, even though
there is actually one megabyte of RAM in the computer, the memory management unit (MMU) makes
any program in memory (and there can be several at a time) think it’s operating in a sixteen-megabyte
environment (although it can’t store that much data at one time, of course).
This brings us to the inner workings of the Lisa and the technical aspects of its operation. If you’re
the applications sort of person who’s just waiting for the final opinion on Lisa, skip ahead
to the conclusion. Otherwise, hang in here and we’ll get into the bits and bytes of things.
Getting inside the Lisa
Glad to see you’re here! Now it’s time to get really dirty.
Any readers with weak stomachs or uncertain alignments may not survive this odyssey through Dante’s
Inferno. So grab your schematics, logic diagrams, and memory maps and come along!
Speaking of memory maps, let’s jump into what is probably the most difficult aspect of Lisa to
understand (no one said this was going to be easy). Everyone by now knows that the Lisa comes standard
with one megabyte of memory. With the Apple IPs 64K memory map etched in all of our heads, it may
be somewhat unnerving to learn that nothing in Lisa’s memory is where it thinks it is.
What? Well, the Lisa uses a technique called virtual memory, which fools the computer into thinking it
has more memory than it actually does (a college education can have the same effect on people).
The RAM memory in Lisa is actually a collection of windows, called segments, which look into a
much larger apparent address space. When the microprocessor looks at an address that isn’t contained
within one of the segments, the command is halted while the memory management unit loads from disk
the needed block, which is then fooled into thinking it is where it’s supposed to be. Operation
then continues, as if nothing had ever happened.
Did you get that? Let’s try an example. But before we do, there are two terms you should become acquainted
with: logical address and physical address. Logical address is where the program or data block
thinks it is, and physical address is where in the RAM memory it actually is. An example: A
program is running along and off-handedly references a memory location or subroutine or whatnot that’s
not currently in any segment. In such a case, hardware control is given to the memory management unit. The
MMU loads in from disk the block of memory containing the whatnot referenced and places it within a
free segment.
Now here’s the important part: The MMU then fools the microprocessor into thinking the segment
where the block was loaded is its true location when execution continues. All this happens without the
microprocessor having the slightest inkling that it has. This is where logical address and physical
address come into play. The logical address in our example was whatever memory location was referenced,
but its physical address was wherever the MMU placed it in actual memory. To the program and for
all intents and purposes, the logical address is where it actually is, but this is only because the MMU
is pulling a couple of fast ones and causing the addresses to pretend they’re someplace else.
If you’re still here, then you’ve passed through the hardware Inferno’s first ring and are
ready for a bit of refinement. First off, that explanation of virtual memory is sufficient only to get us
through the rest of this article. The actual workings of virtual memory are much more complex, and
deserve an article of their own (for example, when and how does the MMU decide that a segment no
longer needs to reside in memory? What happens when all the segments are full and another is needed?
Ah, well...). It isn’t necessary to understand virtual memory to write a program on the Lisa.
What is important is to realize that, with virtual memory, each program isn’t restricted to addressing a
measly megabyte, but has a workspace of a gigantic sixteen megabytes.
So far, there has been no mention of what microprocessor is in the Lisa. That is because there are
actually five microprocessors working in unison to produce all the dazzling effects and unheard-of
reliability associated with Lisa. Before all you multiprocessor nuts drag out your programming sheets,
note that only one processor is accessible to the assembly language programmer. But what a processor it is!
This microprocessor is the Motorola 68000. The heart of all the tricks seen on the Lisa, this
chip has power. Anyone who’s dabbled in 6502 assembly can appreciate the improvement of the 68000
with its sixteen thirty-two-bit registers and more addressing modes than you could ever use in
one program. It’s interesting to note that, although the 68000 can reference memory addresses up
to thirty-two bits wide (that’s four gigabytes, or sixty-five thousand times as much memory as
the die-hard Apple II), only twenty-four of these bits are brought out of the 68000. The reason for
this is a restriction of the physical construction of the 68000 integrated circuit. If you’ve ever
lifted the lid on your Apple, you know what an IC looks like. Well, the 68000 with sixty-four pins (most
ICs have sixteen or twenty-four) recalls images of huge black monoliths from a Kubrick film. There just
wasn’t enough room on the 68000 package to put eight more pins to bring out those eight other
bits. This is the reason Lisa’s virtual memory can only address sixteen megabytes, which is what
twenty-four bits gives you.
As a small example of the 68000’s power, realize that the Lisa’s screen is always in the graphics
mode, and that all text displayed is generated by software (somewhat like Apple’s hi-res character
generator). This is the key to Lisa’s great flexibility when dealing with the screen, and it
accounts for Lisa’s twelve different type styles (not to mention boldface, italics, underline,
shadow, hollow, super and subscripting...) and addictive interactive nature. Scrolling is likewise done
in software, yet it’s accomplished without the nauseating wavy motion you would expect with hi-res
scrolling. More on the screen later.
Under the 68000’s command are four other processors, each serving a specific function and
each having its own limited memory and operating on the firmware supplied for it.
First there’s the Z8 microprocessor within the ProFile. Although the ProFile is not really
a part of Lisa proper, it is standard with the Lisa and is an integral part of the Lisa system. Without
the ProFile and its intelligent Z8 controller, the Lisa’s virtual memory scheme (so important, yet so
transparent) would be impossible. Instead of having to dedicate its entire attention to such mundane
tasks as disk I/O, Lisa is able to specify what data on the disk to read from or write to, and the
ProFile takes over. On a down note, it is discouraging that the ProFile has only a five-megabyte
capacity, whereas other hard disk systems of comparable price contain as much as twenty megabytes.
The other mass-storage related chip is the 6504, which controls Lisa’s two built-in floppies, or
twiggies, as Apple calls them. The 6504 is a limited 6502, with less addressing space (8K) and fewer
control functions (such as no nonmaskable interrupt). The 6504, teamed with the twiggies’ sophisticated
hardware, increases the drives’ capacity to 860K as well as
improving the reliability.
| Figure 16. |
The stepper motor that moves the disk head over the twiggy disk is capable of microstepping, which translates to
reliability beyond comprehension and sophisticated error recovery. If the 6504 can’t find a track where
it thinks it is, it can move in and out in small fractions of a track until it finds it. Also, the
motor that spins the disk is capable of varying its speed, slowing down on the outer tracks and thus
keeping a constant 10,000 bits per linear inch over the entire disk, giving the outer tracks, which have greater
circumferences, more to store. This advanced system requires a special variety of disk,
shown in figure 16.
As a note, the error rate of a twiggy drive is so low that Apple couldn’t measure it, but they estimate
it at something like one error for every trillion operations, which should get you through this century
without problems. All disk drives revolve, but only twiggies are revolutionary.
Speaking of getting through this century, Lisa for some reason can only keep accurate time and date through
1995. The time and date are controlled by a National Semiconductor COPS microprocessor, one of two
within the Lisa. The second COPS is responsible for decoding the keyboard and transmitting the keycodes to
the other COPS via the keyboard’s twisted cable. Together, the two of them handle all the low
level I/O and functions within the Lisa. The time and date COPS stays active even when Lisa is off.
It updates the time and date while waiting for someone to come along and press the power
button (figure 17). If Lisa is unplugged while in the off state, internal batteries power the
time and date COPS for up to twenty hours.
| Figure 17. |
So much for the Inferno’s second ring. Now things are starting to get a bit easier. On to the fun ones!
The first thing that breaks even the seasoned programmers’ cool facade is Lisa’s graphics.
Even the coolest among them lose their staid dispositions and join the chorus of “oohs”
and “ahhs” when they see Lisa at work. The hardware behind all this is amazingly simple.
A bit-mapped graphics screen very similar to the Apple’s but consisting of 720 pixels by 364 lines provides
the resolution that makes Lisa’s desktop metaphor so believable. Every byte within the 32K of
screen memory is directly mapped to the video display (with the exception of the eight bytes
left over). Back to our virtual memory, the screen memory is located just about anywhere a contiguous
segment of 32K is sitting on a 32K boundary. What this means is that the screen memory is nowhere in
particular, but almost everywhere at one time or another.
Although the current screen is black and white, the screen software supports up to thirty-two bit
planes (which means that up to four trillion colors are possible), and the technical manuals hint left
and right at a color board that should be out soon. A retrace interrupt is provided which can be used
to synchronize screen access with the retrace timing so that flickerless graphics can be attained.
Also, since the screen’s contrast is software controlled, a program can produce any sort of
eye-killing effects. On the more practical side, software-controlled brightness allows Lisa to dim the
screen to a specified level after a specified period of inactivity to save video screen phosphor. Nice.
What is that little thing with such a long tail sitting next to Lisa? Why, that’s a mouse,
one of the most innovative peripherals yet. Mice have been around for some time, but only
now are they making such a noise in the marketplace. It has been estimated that the average mouse will
travel almost twenty miles in a year’s usage, and Apple’s mouse is not one to be caught
without its track shoes. It’s rumored that the plotter used to put Lisa’s mouse through its paces died
before the mouse even began to sweat.
For no apparent reason (except perhaps novelty), Lisa’s mouse comes complete with a software odometer that
is reset to zero on each power-up. Real cute. Essential to successful mousing is the cursor, a 16-by-16-bit image
necessary to translate the mouse’s movement from the physical desktop to the metaphysical one. The feel
of actually moving the cursor on the screen is phenomenal, and it’ll take anyone with an arm no
time at all to accept the mouse as standard. In fact, on Lisa’s desktop, 90
percent of the interaction is done with the mouse. What a joy to use!
The biology of a mouse is such (for those who want the gory details):
A hard rubber ball (which doesn’t bounce too well) rests under the mouse
and just touches whatever surface the mouse is sitting on. As the mouse
is shoved from one location to another (as only mice will tolerate), the
ball within likewise revolves, turning two small flywheels. Each flywheel
is responsible for recognizing its particular axis of motion. As each flywheel
turns, a small Benham-like disk turns also, causing a light beam to
be interrupted and a movement of one unit to be recognized. Motion in
any direction is recorded as a series of these small movements, and internally
they are translated to screen coordinates. Basically, a mouse’s life is
uneventful (with a few exceptions), but what it does, it does well.
What Turns Lisa On?
One of the hardest things to accept for someone
who’s always flipped a toggle switch is that Lisa never really turns off.
When a power-off request is made (by pressing the on/off button),
Lisa calmly closes any open files and powers down with the sophistication
expected from a computer of such background. When “off,” Lisa is
internally in a low-power mode, updating the time and date and patiently
waiting for someone to come along and press her button. When this happens,
the COPS which senses the power-on request energizes a relay that
turns Lisa on. Control is then passed to a very specialized boot ROM
which contains 16K of 68000 diagnostics and power-on sequences.
After the Lisa examines itself for any anomalies and passes all tests, the boot ROM reads a
block of boot code from the predefined default boot device (either ProFile or twiggy) unless
the default is overridden at power-on. The selection of the boot device is made from the
preferences window of the desktop and maintained in low-power RAM. After the boot code
is loaded, it is executed. What happens next depends on the boot code, but in a standard
Lisa configuration (using Lisa’s own operating system), System.OS and a host of
friends (System.LLD, System.LOG, and others) are loaded in and System.OS is executed.
Let’s digress for a moment and explain what System.OS is. Probably the best analogy is to
the Apple IPs own DOS. System.OS is like DOS’s file manager, consisting of hundreds of routines used to
control every aspect of the operating system and its environment. These include calls to the file
system, process handling, memory management, exception and event handling, and system configuration.
Like the file manager, System.OS (to be called “the operating system” from here on) needs
some controlling program to provide the user interface. DOS’s equivalent would be what we
all mistakingly call DOS, but what is really just the command interpreter to supply the necessary
man-machine interface.
| Figure 18. |
Lisa’s operating system, once in memory, loads and executes System.Shell, which is Lisa’s
command interpreter. In the desktop environment that we usually see Lisa displaying, this shell
is the Environments window (see figure 18), which is normally transparent on bootup and is
responsible for bringing up the desktop software. If, however, the default shell to use on power-on is
the Workshop, for example, then Environments will load and execute the Workshop shell. Basically,
System.OS loads and runs System.Shell, which is the interface between user and operating system.
What is the Workshop? The Workshop is a shell that provides a UCSD Pascal-like environment for writing
and debugging programs. Complete with the Workshop are an editor, Pascal and Cobol compilers, a Basic
interpreter, a 68000 assembler and debugger, and an ample supply of support programs. These languages
and utilities make up the Lisa development package, which doesn’t come with Lisa but may be purchased
separately. All the operating system calls can be made from Pascal and assembly. In fact, most of
the operating system was written in Pascal (some 900,000 lines worth!), with only a few speed-critical
routines, such as the graphics software, written in 68000 assembly (only 40,000 lines).
It was this Workshop that Apple developers used to write all of the software for Lisa. Sound like a
chicken and egg situation? Well, the original Pascal compiler from the Apple II language system
was strapped onto a very young Lisa, then used to write the rest of the operating system. By the way,
the Pascal compiler in the Workshop translates source to an intermediate file, which is enhanced p-code
and is good for nothing except the Workshop generator, which produces 68000 machine code. All in
all, anything is possible in the Workshop.
Where were we? Oh yes, Lisa’s power-up sequence... Well, in some sort of roundabout manner, we’ve
just explained it.
Don’t let anyone tell you otherwise: The Lisa is anything but a micro. With multitasking (which
we haven’t discussed, but which essentially means that many processes can run concurrently) and
virtual memory (giving each process sixteen megabytes of program and data space), the Lisa easily
competes against many of the “all-powerful” mainframes. In fact, the only apparent reason
that it’s not considered a mainframe is that it doesn’t fill a specially air-conditioned room and
doesn’t require a flock of smocked technicians to operate. Outside the desktop, Lisa is
still a completely integrated system, with an extremely powerful operating system running very powerful
state-of-the-art hardware. There will certainly be a large quantity of very happy Lisa owners
still around when the real-time clock peaks out in 1995. Apple Computer had better be prepared to supply
a firmware patch for all these people to carry them through the rest of the century.
Conclusion(s)
After all of two weeks with Lisa, what do we think of it? Granted that
the honeymoon’s not over, we still have some general impressions.
When you first see a demonstration of the machine, you’re apt to have a feeling about it
rather like the one you probably had when you got your first Apple. Many of us came to computers knowing
little about them or about what could be done with one, but they seemed intrinsically fascinating.
Even if you now know at least a little more about computers, you’ll probably have much the same feeling
about the Lisa.
Any single word is too weak to accurately describe the sense of the incredible the machine can elicit.
The potential housed in that simple case is truly staggering. The most expert, most veteran Apple
II users have yet to explore even a fraction of the potential of their machines. The internal power and level
of integration of the Lisa seems like going from a bicycle to a starship.
Your reactions to the machine might well vary, though. When you first start using the machine, you’re mainly
aware only of the appearance of the applications software, the tools. Initially very impressed, you might
then begin feeling like the $10,000 price tag is, for the average person, a lot to pay for the
convenience of smooth graphics and easy data transfer between programs. For the stereotypical business
executive, the usability of the Lisa is probably worth the expense, but the cost factor is certainly high.
In all fairness, even with this view, the price difference is not as high as you might think. An Apple
II with all the equivalent hardware and software could still cost more than half the cost of a Lisa. With
that in mind, the convenience factor is not costing as much as you would originally suppose.
If then you learn more about the inner nature of the machine and begin to realize its tremendous
potential, a different picture emerges.
The first conclusion is that cost is a very relative thing. Think for a moment about your reaction to
the possibility of paying $10,000 for a television, a car, or a house.
Ten thousand dollars for a television is certainly expensive. For a car, it is at least within current price
ranges, and for a house it would be a bargain. Expensive then is not an absolute value, but rather a ratio between
actual cost and perceived value. In addition, even large amounts of
money do not present as big a barrier to purchase as many people seem
think. Most likely, many of the people you know own things like houses and cars in spite of their high
cost. In addition, think of the number of people who own motorhomes that cost far in excess of $10,000 and at
that only use them once a year.
Clearly, the real question is not, “Is it expensive?” but rather, “Is it worth the price?”
The ultimate answer will depend on a number of things. For someone in a business environment, the likelihood of
a Lisa being worth it is much greater. Along with doing the research on the Lisa for
the purposes of this article, we’ve put it to use in our office, and there are
already at least a half a dozen people using the Lisa for official functions. Even those who never quite got
around to learning to use the Apple lis seemed to be attracted immediately to using the Lisa.
The graphics and printer output on LisaWrite, LisaDraw and LisaGraph alone give one the equivalent
of an in-house graphics studio. The cost savings in this area alone help justify a major portion
of the machine’s cost. In addition, the graphics capabilities will make possible professional-looking
documents, forms, diagrams, and charts for those projects that wouldn’t ordinarily justify the expense of
a graphics department. For the home user, it’s probably still a matter of waiting a little longer for
more software. You might look at it this way: Would you buy a motorhome before a Lisa?
You can bet that time will very quickly change all the factors in both business and home. It should be clear
by now that the power of the machine is scarcely even hinted at by the existing software. If you
think back for a moment about what has been done in software for the Apple II, considering the comparatively
limited capabilities of the machine, the potential of the Lisa seems almost limitless.
The second conclusion is how the Lisa and computers like it are going to affect us all. There is
more than enough written about how computers are going to change our lifestyles. This will probably
happen, and there are some changes that we should see very soon.
An example at hand is the dot-matrix printer. There’s still a tendency to think that people really
need letter-quality printers to generate business correspondence on their computers. The assumption seems
to be that either dot-matrix print is totally unreadable or that people will be offended to receive any letter
that was done on a computer rather than on a typewriter.
Ignoring for a moment that dot-matrix printers are improving to the point where they are less
and less distinguishable from a daisy-wheel printer (read “typewriter”), the real point is,
dot-matrix printers do the job better than typewriters. For someone to criticize a dot-matrix letter because
it doesn’t look like a typewriter is like criticizing a car because it doesn’t look like a horse.
| Figure 19. |
The Lisa printer graphics are like this. You might look at an invoice form (and I mean the pretty
lines and logos, not the numbers) generated by a Lisa and say, “But it doesn’t look like it
was done by hand.” That is precisely the point. Would you deride a neighbor’s new wallpaper because
it wasn’t hand-painted? Of course not, and neither should anyone get too picky about being able to tell
that a form or a letter was done by a computer.
The point is that a computer is a far more efficient way of accomplishing a given task, and that the
person not using one is to be pitied for not yet having caught on to the revolution already surrounding us.
My prediction? No predictions at all. Look today for the Lisa-generated letters, project charts, financial
reports, and invoice forms. The people generating those are the people who know where the future lies.
by Roger Wagner and Joe Holt
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