|
The Macintosh’s operating system is friendly, but at what price?
Reprinted from Byte, issue 12/1984, pp. A94-A101.
The Finder: in a world of operating systems with names like
MS-DOS, XENIX, and CP/M-86, the name of the Macintosh’s new
operating system sounds both friendly and nontechnical. That’s
what Apple had in mind.
Early in the Macintosh design process, Apple set an objective –
to make its new computer immediately useful to a novice. Apple’s
computer needed an operating system that was easy to learn. To this
end, Apple designed a window and mouse operating system, called the
Finder, using the graphic symbol concepts the corporation had
developed for its more expensive Lisa computer. The Finder is
friendly to the novice. People with little or no computer experience
can sit down before a Macintosh and perform useful work in a short
time. But users are novices only once, and more experienced computer
users who are new to the Macintosh may find conventional
command-oriented operating systems more intelligible.
Internal Organization
The Finder is only the top level of a multilevel Macintosh operating
system. The lowest level consists of various hardware interfaces and
drivers and occupies about a third of the 64K-byte ROM in the
Macintosh. The next level is the user-interface toolbox, which
contains a wide variety of routines for implementing complex
window/mouse-based programs. This code occupies the remaining two-thirds
of ROM. At the highest level of these ROM routines is the Finder
program itself, stored as a disk file. The Finder has an accompanying
file, called the System file, mainly used to store font images, icon
images, and text messages but also some code. The Finder program
manages the Macintosh’s desktop. It is equivalent to the
command-line interpreter part of a more conventional operating system.
The Finder is a rather large program. If it were to stay in memory
all the time, little memory would be left for application programs.
Therefore, the Finder is dumped from memory whenever you start
an application program. This differs from most microcomputer operating
systems, which stay in memory and provide an interface between the
application program and the hardware. Macintosh application programs
do not work through the Finder; they access the Macintosh hardware
by calling the routines in ROM on their own.
When you return to the Finder, the computer essentially performs a
“warm boot” and reloads the Finder from disk.
This makes quitting an application program a relatively time-consuming
task (often taking 15 or 20 seconds).
Finder Concepts
The Finder is built around several key concepts: the desktop
metaphor, data as objects, mouse integration, and the shared
user interface.
Desktop Metaphor: The computer’s screen can be
represented as a desktop. A number of items can be present on
the screen “desk” at one time, just as you can have
a calendar, file folder, and notepad on an actual desktop.
Data as Objects: Data, whether in programs or files,
can be represented as objects on the desktop. You can move
them around. The Finder assigns graphic symbols (called icons) to
such data-objects.
Mouse Integration: The mouse is an integral part of the
Finder; it controls the cursor and is your interface to the
operating system. The Macintosh does not include any cursor-control
keys, and you cannot use the Finder without using the mouse.
Shared User Interface: The Macintosh provides a consistent
user interface for all programs. This ROM (read-only memory)
interface allows different programs to share and exchange data.
To run efficiently, all software must adhere to this common
interface.
The Finder at Work
 |  Figure 1: The Finder’s desktop. The disk icon in the upper-right corner of the desktop represents the disk used to boot the computer. The Trash icon in the lower-right corner is used to dispose of files. |
|
 | | Figure 2: Using the pop-down File menu to open a disk. |
|
 | | Figure 3: The desktop after a window has been opened for the Write disk. The top three icons in the window represent application and utility programs, while the lower two icons represent folders containing files. |
|
 | | Figure 4: The MacWrite word-processor window. The bar on the right side of the window is used to scroll the document being worked on. The box at the bottom of this bar is used to resize the window. The small box in the upper-left corner of the window is used to close the window. |
|
 | | Figure 5: The desktop after quitting the word processor. A new icon representing the letter just written is visible. |
|
 | | Figure 6: Copying a file from one disk to another. The file “Smith 5/19” is dragged over to the backup disk. While in transit, the outline of the document follows the pointer. |
|
Suppose you want to use your Macintosh to write a letter. The
basic steps are start the computer, load and run a word-processing
program, and copy the newly created letter to a separate disk
for backup. (I’ll ignore printing the letter for the purposes of
this example.)
When you first turn on the Macintosh, the screen prompts you
to insert a disk by displaying a disk icon with a question mark.
(You may turn the computer on with the disk already in the computer
if you wish.) After you insert a disk, the desktop is set up,
and an icon representing the disk you inserted is displayed in the
upper right-hand corner of the desktop (figure 1). The name of
the disk (“Write” in this example) is displayed underneath
the icon. Write contains the word-processing program you will be using.
To access the contents of Write, you select the disk by moving
the pointer over the disk icon and pressing the mouse button.
(The pointer is a little arrow on the desktop that you move
around with the mouse.) This causes the icon to darken, indicating
that Write has been selected. Next, you move the pointer up
to the menu bar (the top line of the screen where various menu
categories are displayed) and position it over File. When you
press and hold down the mouse button – an operation called
“dragging” – the menu choices under File pop down from
the menu bar like a window roller shade (figure 2). Since you
want to “open up” the Write disk, you move the pointer
down to the OPEN command and release the mouse button. This opens
a window on the desktop that displays the contents of
Write (figure 3).
One of the files displayed in the window is the word-processing
program you want to use – MacWrite. Starting the word processor
involves the same sequence of steps used to open the disk:
you select the MacWrite icon by clicking on it, then you drag
the File menu down to the OPEN command. This opens a new window
for the word-processing program (figure 4).
After exiting the word processor, the Finder dumps you back to
the desktop. As you can see in figure 5, a new icon is now
visible (labeled “Smith 5/19”); it represents the document
file for the letter you wrote with MacWrite.
To back this file up, you need to copy it to another disk. First
you need to put the backup disk on the desktop. If you have two
disk drives, you simply insert the backup disk in the second
drive. If you have a single-drive Macintosh, you need to eject the
Write disk by selecting the Write disk icon and selecting Eject with
the File menu. You then can insert the backup disk. In either
case, a new disk icon (previously labeled “Backup”)
representing the backup disk appears on the screen.
Copying a file involves dragging its file icon to the desired
destination. In this case, you need to drag the Smith 5/19 file
icon to the Backup disk icon (figure 6). The Finder will
then copy the file. If you have a single-drive Macintosh, you
are in for a few disk swaps. (The Macintosh always ejects a
disk and prompts you for the name of the next disk it
wants during disk swaps.)
Finder Performance
But how well does the Finder perform? I evaluated the Finder
in seven general areas: speed, ease of use, hardware insulation,
flexibility, overhead, interfacing capabilities, and ease of
program development.
Although this is not intended to be a rigid evaluation, with
benchmarks and the like, I used MS-DOS 2.0 (running on a
floppy-disk-based IBM PC) as a general yardstick for comparison.
Speed: The Finder seems very quick and responsive, as long
as disk I/O (input/output) is not involved. Window operations
(resizing, opening/closing, and scrolling) are virtually instantaneous.
Unfortunately, the small Macintosh memory necessitates frequent
trips to the disk drive. In these cases, the Finder seems quite
slow compared to MS-DOS. Opening or quitting an application
program typically takes from 15 to 30 seconds (30 to 60 seconds
for the round trip). MS-DOS can typically load or quit application
programs in a few seconds. Inserting or ejecting a disk takes from
2 to 15 seconds of computer time depending on the configuration of
windows for the disk and how many disk icons are on the
“desktop.” With MS-DOS, disk handling is not under
software control, so no computer time is required. Finally,
the Finder takes from two to fives times longer than MS-DOS to
copy files from disk to disk. This disadvantage is most pronounced
when comparing copy times on single-drive computers.
At times, these delays make the Finder cumbersome. For example,
suppose you wanted to copy one small file to several different disks.
With the Finder, you need to go through an ejection/insertion
step for each disk just to get each disk icon on the screen:
this can easily take 20 or more seconds of computer time per
disk. With MS-DOS, you can perform this task as quickly as
you can get disks in and out of the drive.
If your work keeps you in application programs the majority of the
time, these delays make little or no difference. However, if
you are running several different programs (especially with a
single-drive Macintosh), these delays can become very annoying.
Ease of use: For novice users, the Finder is much easier
to learn than MS-DOS. Most first-time Macintosh users are able
to understand the basics of the Finder within an hour with
little or no reference to the manual. The novice MS-DOS user
had better plan on some serious study of a needlessly complex
manual followed by a few tough initial hours at the computer.
While the first hour with the Finder may be bliss, later hours
may not be as smooth. First, the Finder has a great deal of
hidden behavior, and the non-technical manual glosses over
explanations with an “I’d-only-confuse-you”
sort of style. Second, efficient use of the Finder often requires
careful technique in order to avoid memory and disk-space
limitations (see the sidebar, “Tips for Single-Drive
Users”). These techniques require a fundamental understanding
of the Finder, which goes against its basic principles. Finally,
the Finder gives up nothing to MS-DOS when it comes to cryptic
keystroke/mouse sequences for a few commands (see table 1).
| Operation | Keystroke/Mouse Sequence |
| Internal disk ejection | Command-Shift-1 |
| External disk ejection | Command-Shift-2 |
| Create a MacPaint document of screen | Command-Shift-3 |
| Print active window | Command-Shift-4 |
| Print screen | Caps Lock-Command-Shift-4 |
| Multiple icon selection | Shift-Click, or Drag a box |
| Move window without making window active | Command-Drag Window |
|
| Table 1: Special Finder commands.
Apple touts the Finder as not requiring the memorization of any commands.
As this list shows, the claim is not entirely true. |
Hardware insulation: The Finder does an excellent job of
insulating users from the Macintosh hardware. Finder users can
completely ignore issues like disk formats, serial-port
configuration, file buffers, and device drivers because the
Finder ignores this Macintosh hardware. While MS-DOS lets you
access the serial port directly from the operating system, the
Finder provides no such support; you have to use a separate
application program.
Flexibility: One way to make an operating system easy to
use is to limit the number of things it can do. This is the
Finder’s approach, and it does limit its flexibility. Here
is a partial list of advanced operations supported by MS-DOS
that are absent from the Finder: tree directories, batch
processing, automatic batch-file execution, user-directed disk
repair, user-installable device drivers, RAMdisks, I/O redirection,
sorting, and filters. Of course, the first release of MS-DOS did
not have many of these things, and future releases of the
Finder may incorporate features that will make it more flexible.
But these add-ons are likely to compromise the Finder’s basic simplicity.
The Finder does support a feature that allows files to be placed
in “Folders,” enabling you to organize your
desktop in a hierarchy similar to MS-DOS’s tree directories.
Unfortunately, this structure extends only to the organization
of icons on the desktop and does not allow you to set up separate
directories, each insulated and separate from one another. This
is no great problem for a Macintosh with its 3½-inch disks,
because the number of files on any disk is usually small. A
hard-disk Macintosh, on the other hand, may have thousands of
files, and the lack of separate directories could be a problem.
Overhead: For the Finder, it can be described in a word:
high. Apple has done quite a job of squeezing an incredibly complex
operating system into a small amount of code, but the disk space
and memory requirements tend to push the Macintosh’s limited resources.
| The Finder, version 1.1g (Macintosh) | MS-DOS 2.0 (IBM PC) |
| Disk-Space Requirements (bytes) | Disk-Space Requirements (bytes) |
| System | 132K | IBMBIO/IBMDOS | 23K |
| Finder | 46K | COMMAND.COM | 18K |
| Imagewriter | 17K |
| Clipboard | 1K |
| Notepad | 2K |
| Scrapbook | 1K |
| — | | — |
| Total | 199K | Total | 41K |
|
| Table 2:
Disk-space requirements (in bytes) to store the Finder’s and MS-DOS’s
operating system files. The System file for the Finder will vary depending on how
many character fonts are retained. The size shown assumes that all fonts on the
version 1.1g Write/Paint disk are retained. Approximately 65K bytes of fonts can
potentially be deleted; however, a 10K- to 20K-byte reduction is typical. The
Clipboard and Scrapbook file sizes assume both are empty.
|
Table 2 presents a comparison of the disk-space overhead (the amount
of disk space required to store the operating system) between the
Finder and MS-DOS. Memory overhead (the amount of memory used by
the operating system that is unavailable to application programs)
is roughly similar. The Finder’s memory overhead is about
22K bytes, compared to about 25K bytes for MS-DOS. (This 22K is
only the part of the operating system that stays in memory while
the application is running; the Finder program itself is much
larger.) Of course, 22K bytes tends to cut deeper on the Macintosh
than it does on a typical IBM PC with a lot of RAM; the Macintosh
is limited to 128K bytes of RAM (random-access read/write
memory), and the display takes 21K bytes of this.
Interfacing capabilities: The Finder includes a simple but
powerful system of exchanging text and graphic images between
different application programs. MS-DOS has no comparable system.
The Finder’s system consists of two separate but complementary
storage areas called the Clipboard and the Scrapbook. The Clipboard
stores a single text passage or graphic image and is used as a
temporary storage area for cutting, copying, and pasting
operations. The Scrapbook, which can store many text passages or
images, allows you to set up a library of frequently used items.
Both are designed to be easily accessible from application
programs, provided the programs are designed with the Clipboard and
Scrapbook in mind.
The system works well. Its only drawback is slowness; both the
Clipboard and Scrapbook are stored as disk files and access can be tedious.
Ease of program development: For noncommercial software
developers, the Macintosh has (or will shortly have) a variety
of innovative and easy-to-use interpreters in BASIC, Pascal, and
Logo. If your program does not require the speed of a compiled program
or large amounts of memory, the Macintosh, with its superior
program-development and debugging capabilities, is a great machine.
But MS-DOS is a better choice for large, complex programs that must
run quickly. Don’t expect to see something as powerful as
Lotus 1-2-3 running on a 128K-byte, single-drive Macintosh.
| Item | List Price |
| Macintosh computer | $2495 |
| Imagewriter printer | $495 |
| Lisa 2/5 computer | $4495 |
| 512K-byte memory card for Lisa | $1495 |
| Imagewriter accesory kit for Lisa | $50 |
| Lisa Pascal Workshop | $595 |
| “Inside Macintosh” Manual (draft) | $150 |
| Macintosh software supplement to Lisa Pascal Workshop | $100 |
| — |
| Total | $9875 |
|
| Table 3:
Minimum recommended Macintosh software development system. This system allows
the development of stand-alone Macintosh software that can take control of the
entire desktop. The cost of this system (June 1984) is approximately 50 to 100
percent higher than comparable MS-DOS development systems. (Apple has a
Certified Developer Program that provides for substantial discounts for qualified
commercial software developers. However, delays of several months in
obtaining equipment have been typical.)
|
Commercial software developers, who typically want to develop
high-performance, stand-alone, compiled programs, share a
problem. Macintosh software development requires a significant
investment in terms of time and money. Programming is complex.
Apple has not done a good job of distributing quality technical
documents. Currently, you need a Lisa system to develop stand-alone
application programs (table 3).
Conclusions
The Finder provides an excellent environment for the novice computer
user, and nearly everyone will find it fun to work with. It does
especially well in providing a graphic representation of your
data and programs. And the Finder’s method of exchanging
data between application programs is innovative and powerful.
The Finder’s weaknesses are not as obvious, but just as
real. For one, the system seems... well, ponderous might be the
best word. Simple tasks often seem to occur in slow motion as the
Finder shuttles back and forth to disk for code and data. The
lack of any batch-processing capability means repetitious command sequences
must be clicked or keyed in each time they are needed. But
these drawbacks are largely academic if you stay in application
programs most of the time. The window/mouse concept works
beautifully in programs like MacPaint, MacDraw, and Microsoft
Chart; it just doesn’t seem to come off as well with the Finder.
Specialized application-program support is also a weak area for
the Finder. The Macintosh is not an easy system to develop programs
for, and Apple has compounded the problem by failing to provide
quality technical information and software tools for the small
software developer. The common applications will be well served by
giants like Microsoft, but don’t expect commercial programs for
managing your bowling league any time soon. The Finder is definitely
not the operating system for the hacker.
More than anything, the Finder, like the Macintosh, is an enigma.
It is an extremely elegant operating system that is seriously
flawed because Apple did not provide sufficient memory and disk
storage in the basic Macintosh. (Apple’s decision to limit
the Macintosh to 128K bytes – and to solder the chips
directly to the main digital board – is unfathomable.) Too
often, the Finder simply overwhelms the hardware. With 512K
bytes and double-sided disk drives, the Finder will probably perform
effectively. Until then, it will continue to attract new
people to computers and frustrate users who need to get a
lot of work done quickly.
by Mark S. Jennings
Sidebars:
| 
Home 
