December 95 - Macintosh Q & A
Macintosh Q & A
Q How do I determine whether a Power Macintosh has PCI expansion slots?
A If there's a Name Registry, you can use it to determine whether a PCI bus
exists. To determine whether the Name Registry exists, use the new Gestalt
selector gestaltNameRegistryVersion ('nreg'). If the Name Registry exists, the
value returned is the version number of the Registry; otherwise,
gestaltUndefSelectorErr is returned, and you can assume that the machine
doesn't have PCI slots.
If the Name Registry exists, call RegistryEntrySearch to look for an entry
having a property name of device_type and a propertyValue of pci. If an entry
is found, there is a PCI bus on the machine.
Q Our software doesn't awaken properly on a PowerBook that has come out of
sleep mode. Are there any special handling requirements to recover from sleep
A The changes to the system state when a PowerBook goes to sleep include the
- All AppleTalk connections are lost, because the AppleTalk driver is turned
- The serial ports are entirely shut down to conserve power.
are two Macintosh Technical Notes that relate to your situation: "Little
PowerBook in Slumberland" (HW 24), which provides a brief overview of the sleep
process, and "Sleep Queue Tasks" (HW 31), which presents additional material
regarding the sleep process. The second one includes sample code that
demonstrates a sleep queue task implementation. The sleep queue task enables
your program to save state information that otherwise might be lost. Typically,
this is important for a networked process that needs to reestablish a
connection upon awakening.
Q Can we define our own extensions to QuickTime's ImageDescription structure?
In other words, can we just attach any kind of data to the end of the
ImageDescription structure? Our codec would use this data only on the
A Yes, you can add any extended data you like, with the utility routines
provided for this purpose (described in Inside Macintosh: QuickTime Components,
starting on page 4-65). You have complete control over how your codec
interprets the extensions. Therefore, as long as the default image description
handle remains intact (for the benefit of the various Movie Toolbox calls that
depend on the documented structure being there), you can add whatever
information you like. Note that Apple reserves all extension types consisting
entirely of lowercase letters.
Q We're trying to write a QuickTime codec, but we're having trouble because
Inside Macintosh: QuickTime Components was written before the universal
headers, and the sample codec source doesn't build at all with the latest
headers. Where can we get a QuickTime codec that builds for PowerPC under the
current universal headers?
A Until a PowerPC-native codec example becomes available, you can get the
information you need from the Macintosh Technical Note "Component Manager
version 3.0" (QT 5), which provides details on creating native components. Note
that you have to use Resorcerer or Rez to create the component templates;
ResEdit won't suffice.
Q Our codec needs to provide more options to the user than the normal
image-compression dialog contains. The documentation suggests that it's
possible to provide an extra Options button in the dialog, and I've seen some
applications that do provide an Options button for certain codecs. Is this a
function of the application? How does the application know to do this?
A If your codec component has an exported function named CDRequestSettings, the
standard image-compression dialog will automatically provide the specific
button. In other words, QuickTime checks the codec component, adds the button
(provided it's available), tracks clicks in the button, and calls your
CDRequestSettings routine appropriately. For further details, see the Macintosh
Technical Note "QuickTime 1.6.1 Features" (QT 4) where CDRequestSettings is
Q We have a non-Macintosh device that creates and reads QuickTime movies, and
we need to pass additional information about the images between the
non-Macintosh device and our QuickTime codec. It seems that the logical place
to put this information is in an ImageDescription extension (within the sample
description atom), since this is about all that's accessible to a codec. Is the
format of this extension documented anywhere? We've looked at the extension
created by SetImageDescriptionExtension, and the format seems simple, but it
would be nice to know what the "official" format is.
A Chapter 4 of Inside Macintosh: QuickTime has a listing of the atoms and their
formats. Sample description atoms are described on page 4-35. Note that each
media format has its own sample description tables, which are not directly
The official guideline is to use, if possible, the provided APIs for creating
sample description atoms. If you're working on a platform for which there are
no Toolbox APIs, you'll have to obtain a source-code license agreement to get
real source code showing how the atoms are constructed. (For details regarding
licensing part or all of the QuickTime source code, contact Apple Software
Licensing at AppleLink SW.LICENSE or (512)919-2645.)
Q Our application plays QuickTime movies. Some older movies played well in
System 7.1, but they don't play properly in System 7.5 or 7.5.1. We happened to
find the Apple Multimedia Tuner, and it solves the problem. What is the Apple
Multimedia Tuner, who needs it, how does a customer get it, and can we
A The real solution to your problem is just to preroll the movie before playing
it, which is what the Apple Multimedia Tuner is doing for you. QuickTime 2.1
incorporates all the Tuner improvements, so there's no longer any need to
distribute the Tuner separately.
Q We have a problem when we draw to an offscreen GWorld under low-memory
conditions (when the system heap can't grow) on a Power Macintosh. The GWorld
drawn contains digital noise. The same code works just fine in an 680x0
environment. Any idea what's happening?
A It sounds as if the Code Fragment Manager is unable to load the code from the
PowerPlug library into temporary memory. This will cause QuickTime to issue a
noCodecErr error. You should always try to catch QuickTime-generated errors,
checking, for instance, for playback errors after each MoviesTask call like
anErr = GetMoviesStatus(Movie theMovie, Track *problemTrack);
a possible workaround to your problem: Launch a small application that has the
QuickTimeLib (PowerPlug) library statically linked in, so that it's loaded.
This application should launch the main application and then kill itself. The
second application could try to grow to a predefined size and handle low-memory
conditions in whatever way it wants, but the CFM libraries are already in
memory by then.
The Code Fragment Manager will never load fragments into an application heap,
because there's a global registry of CFM libraries present. If another
application registers to use a CFM library that's in an application heap that
subsequently goes away, this will obviously be a Bad Thing. In the 680x0
environment, the codecs are components, and the Component Manager will always
try to load components into the application heap if the system heap doesn't
have any available space.
Q I need to add print items to a QuickDraw GX dialog box. In attempting to use
the Experiment no.9 sample, I found what appears to be a bug. This example uses
GXGetMessageHandlerResFile when it calls GXSetupDialogPanel, but it should call
A You're right. Applications should call CurResFile. GXGetMessageHandlerResFile
is reserved for extensions and drivers.
For additional code examples that add print items to a QuickDraw GX dialog box,
see the Worldwide Developers Conference 1995 Technology CD (or the Mac OS
Software Developer's Kit). The Extension Shell, UserItems, and Additions
samples provide the basic item adding/handling code that you require.
Q Where can I find some good sample code that demonstrates the techniques
required for a "panel" with QuickDraw GX printing (as an application -- not an
A There are two sample applications ("Experiment no.9" and "Banana Jr.") that
show how to do this. In both of these applications, the panels appear in the
Custom Page Setup dialog. However, the sample code can easily be modified to
add panels to the Page Setup and Print dialogs.
Q How can I draw and print hairlines with QuickDraw GX? We use a picture
comment in the normal print code, but this seems to make QuickDraw GX fail. We
get a -51 error (reference number invalid) when we call GXGetJobError after
calling GXFinishJob, and we sometimes get this error without the picture
We also tried calling GXSetShapePen in our spool procedure. When we set it to a
fractional value, we get a wide line, but when we set it to a wide value, such
as 8, it works properly. What do we need to do to print fractional widths?
A Here are two ways to get QuickDraw GX to draw hairlines when printing:
- Call GXSetShapePen(myShape, 0). This sets your pen width to 0, meaning as
thin as possible on the output device. QuickDraw GX always draws hairlines at
the resolution of the output device -- one pixel wide.
- Call GXSetStylePen(myStyle, 0). This also sets your pen width to 0,
with the same result.
When using GXSetShapePen and GXSetStylePen, don't
specify the pen width as an integer: remember that it's a fixed-point value.
GXSetStylePen(myStyle, 1) sets the pen width to 1/65536; GXSetStylePen(myStyle,
ff(1)) sets it to 1.0.
QuickDraw GX uses a backing store file (an invisible file within the System
Folder) to send QuickDraw GX objects to disk when additional space is needed
within the QuickDraw GX heap. Almost all -51 errors from within QuickDraw GX or
an application using QuickDraw GX are caused by double-disposing of a QuickDraw
GX object (that is, a shape, ink, style, or transform). The -51 error occurs
because the double dispose causes QuickDraw GX to set the shape attributes,
which indicates that it has sent the object to disk. When it needs this object,
it goes to the backing store and tries to get it, but it's not there. We've
found a few cases where QuickDraw GX itself was double-disposing of objects,
and these were fixed in QuickDraw GX version 1.1.
Before calling GXDrawShape, call GXValidateShape on the shape or shapes you're
trying to print. This ensures that a shape is valid before it's drawn or
printed. It slows things down a little, but you'll be able to determine whether
a shape is still available before you attempt to draw it (you might be
disposing of a shape before you draw it). If you have an error handler
installed, you usually receive the "shape_already_disposed" message, but you
may not receive this message if something is wrong with the QuickDraw GX
It's also possible that the hairline drawing problems you're encountering are
related to the translation options you're using. A translator takes your
QuickDraw drawing commands and converts them to QuickDraw GX objects, based on
options you provide. If you use the gxDefaultOptionsTranslation setting, a
QuickDraw line turns into a six-sided filled polygon. When your object is a
polygon, changing the pen width has no effect.
To avoid translation problems, call GXInstallQDTranslator with the
gxSimpleGeometryTranslation or the gxReplaceLineWidthTranslation option.
- gxSimpleGeometryTranslation turns on both the simple-lines and
simple-scaling translation options, and it translates QuickDraw lines into
QuickDraw GX lines with flat endcaps. The QuickDraw GX line shape runs along
the center of the original QuickDraw line, and it covers all the pixels of the
QuickDraw line and more.
- gxReplaceLineWidthTranslation turns a QuickDraw line into a QuickDraw
GX line with a width that is the average of the original pen's width and
height. This option also affects the way the SetLineWidth picture comment is
Once you set the translation option, your calls to
GXSetShapePen or GXSetStylePen should behave as you expect them to, because
they're acting on QuickDraw GX lines, not polygons. When you've installed a
translator, be sure to remove it with GXRemoveQDTranslator. To learn more about
the translation options, see Chapter 1 of Inside Macintosh: QuickDraw GX
Environment and Utilities.
Q I'm trying to send messages from within a QuickDraw GX message override. I
want to send GXWriteData to flush the buffer so that I can send the
GXGetDeviceStatus message. I override the GXHandlePanelEvent message. In my
override, sending messages causes the system to crash. What would cause this to
A The crash is occurring because there's no connection to the printer at the
time you're sending the message. You have to send the GXOpenConnection,
GXWriteData, and GXCloseConnection messages. Note that when you send
GXOpenConnection, QuickDraw GX puts up the default job status dialog for a
short time. If you don't want this dialog to appear, you can override the
GXJobStatus message to prevent it from being shown. See also Dave Hersey's
Print Hints column, "Writing QuickDraw GX Drivers With Custom I/O and
Buffering," in develop Issue 21.
Q I used the sample driver showing how to do custom dialogs as the basis for
the compatibility part of our QuickDraw GX PostScript driver, and I added an
Options dialog to it for our printer-specific features. I have two problems
with it when using applications that aren't QuickDraw GX-aware. First, the
paper-type always defaults to the fifth paper-type listed in the resource file,
so whichever paper-type is the fifth one listed becomes the default paper-type
in the QuickDraw GX compatibility driver. This is, of course, reflected in the
Page Setup dialog. Second, the driver always defaults to having the "Print to
File" checkbox on. What can I do about these problems?
A Both the quirks you describe (improper default paper-type and the "Print to
File" checkbox defaulting to on) can be fixed by modifying the 'PREC' 0
resource in the driver.
When an application using old-style printing calls PrintDefault to request the
default print record from the current printer driver, the driver gives it the
contents of the 'PREC' 0 resource. Then, when the application calls PrJobDialog
or PrStlDialog, it passes in that print record. In its overrides, the QuickDraw
GX printer driver interprets the contents of the old-style print record to set
up the states of the dialog's buttons, checkboxes, and so on.
To determine which paper-type radio button to select in the Page Setup dialog,
QuickDraw GX compares the page rectangle specified in the old-style print
record to the rectangles of all the paper-types in the driver (or paper-type
extensions, such as "3-Hole Punch"), and tries to find the best match. Because
of the way that the old-style print record in the sample is defined, that best
match turns out to be the fifth paper-type in your list. So, to fix this quirk,
all you have to do is change the bounds setting in the 'PREC' 0 resource so
that it matches the bounds of the US Letter paper-type in the driver.
To determine the state of the "Print to File" checkbox, the driver looks at the
UlOffset field of the old-style print record. (You might not think to look
here, but old-style print records are limited to 120 bytes, and there was no
better place to store this information.) Because the 'PREC' 0 resource in this
driver has this field set to 1, the checkbox defaults to on. So, to fix this,
all you have to do is set the field to 0.
Q I want to create an extension for the Page Setup/Format dialog that performs
"flipping" functions. Is it feasible to create an extension for the Page
Setup/Format dialog rather than the Print dialog?
A There's nothing to prevent you from creating an extension that adds a panel
to the Page Setup dialog. Most printing extensions add to the Print dialog
because in most cases this is the proper place to add a panel that affects the
entire output, and because what extensions usually do is best suited for the
Print dialog. Drivers and applications, on the other hand, typically add to the
Format dialog. Note that if you're trying to modify an existing sample
extension so that it adds to the Page Setup dialog, you have a bit of work to
There's a way that you can test your flipping code without writing a new
extension, by the way. Applications can override the GXJobDefaultFormatDialog
or GXFormatDialog message. There are two examples ("Experiment no.9" and
"Banana Jr.") that demonstrate overriding GXFormatDialog. You might try adding
your flipping code to one of these.
Q A car passed me the other day with one of those round white country stickers
that said WAL. Where was it from?
A Sierra Leone.
Q In QuickDraw 3D, when we have the interactive renderer on and we try to turn
off the draw context's clearImageMethod (setting it to kQ3ClearMethodNone), it
still clears. This works properly with the wireframe renderer, but we need this
feature in the interactive renderer, since we're pasting in background pictures
that we want to act as a backdrop to our 3D models. The interactive renderer
always obliterates the background with the clearImageColor. What can we do?
A Unfortunately, this is a renderer-dependent feature that's supported by the
wireframe renderer, but not the interactive renderer. We intend to provide a
"Clear with picture" method in the next major release of QuickDraw 3D (version
Q The interactive renderer doesn't draw flat surfaces that are parallel to the
camera view direction with the orthographic camera, but the wireframe renderer
does. We put in a "floor" of polygons, and when we look along the edge of the
floor with the orthographic camera, it totally disappears. With the wireframe
renderer, we see a line where the floor is, which is as expected. What gives?
A Filled primitives have no thickness, so when you look at them edge-on, they
do not appear. Lines, however, are a mathematical abstraction, so they always
appear to be one pixel thick (when you zoom in on a line, its thickness doesn't
increase). While this may seem somewhat odd, it's the way many libraries work.
To achieve the effect you want, make the floor a thin box, and texture-shade
the top surface. If the depth of the box is nonzero, it appears to be a
slab-like structure, and it won't disappear when viewed edge-on.
Q If we iterate through the vertices in a mesh, will the vertices still be in
the same order as they were when they were added?
A Yes. The ordering of the vertices doesn't change until you duplicate the mesh
or write it out. A duplicated mesh (or one that was written out and read back
in) doesn't necessarily have the vertices in the same order as when they were
Q When I try to render models with different types of lights, the point light
and the directional light work correctly, but the spot light doesn't. Any idea
A The spot light's cone of light needs to touch a number of vertices for any
effect to be seen. If the light is attenuated, it may have insufficient
intensity when it strikes the surface. The cone of light also needs to be wide
enough to cover a significant area of the object being modeled for the renderer
to draw a reasonable effect.
Q What effect does the TQ3ViewObject parameter have in the bounding box
calculating routines (Q3View_StartBoundingBox and Q3View_EndBoundingBox)? The
old geometric-object routine descriptions refer to world space, but if this is
so, there's no need for a view parameter. However, if the view's camera is
used, the bounding box is returned in camera coordinates rather than view
coordinates. Since both are useful, would it be possible to have both sets of
routines available? I can apply a rotation/translation matrix to all of the
items to be drawn to generate camera coordinates from a world coordinate
routine, but I need to find out if I need to do this or if this has already
A The QuickDraw 3D routines return the bounding box or bounding sphere in local
coordinates. Part of the reason that the API was modified to use submit calls,
rather than having separate picking, rendering, and writing calls, is that the
transformations that are applied matter more than the camera. Since these
modifications were made, the submit calls for everything (including
transformations, if they're not stored in the group) can be in one submission
function that's called from inside the picking, rendering, or writing loop. If
you need the bounding box for a single geometry in its own coordinate space,
this is also easy to do -- you can write a simple routine that performs bounds
calculations on a single object. For example:
Does QuickDraw 3D prefer meshes or NURB patches? Which kind of data yields
A Meshes are convenient for editing, but they take quite a bit of memory, so
the tradeoff is time versus space. NURB patches are more convenient for dealing
with surfaces as a whole and for representing surfaces at different
Although meshes exhibit better performance than NURB patches in the first
version of QuickDraw 3D, later versions may have improved patch performance. In
the meantime, consider experimenting with the tessellation factor for your
patches, since overtessellating reduces performance.
Q I'd like to make sure that I'm running under version 1.0.2 of QuickDraw 3D.
When I get the version from Q3GetVersion the major version is 1 and the minor
version is 0, but I can't get the revision (the third number). Is there a
Gestalt selector for this?
A Starting with version 1.0.2, there is a Gestalt selector to get the version
of QuickDraw 3D: gestaltQD3DVersion. The return value has two bytes for the
major version, a byte for the minor version, and a byte for the revision. So
for version 1.0.2 Gestalt will return 0x00010002. Note that this Gestalt
selector works only with QuickDraw 3D 1.0.2 and later.
Q The ColorSync documentation (in the reference section of Inside
Macintosh: Advanced Color Imaging) states that each color component in the
L*a*b* color space is within the range of 0 to 65,280. Shouldn't this be 0 to
65,535, since this is the value for the other spaces and the value in the ICC
Profile Format Specification?
A No. The correct maximum value for this particular color space is 65,280
(0xFF00). Note that the final documentation is now available as Advanced Color
Imaging on the Mac OS, published by Addison-Wesley.
Q What exactly are the internal parameters for the ColorSync quality settings?
That is, how large a lookup table is built for "draft" versus "normal" versus
A The quality flag bits provide a place in the profile for an application to
indicate the desired quality of a color match (potentially at the expense of
speed and memory). In ColorSync 2.0, these bits do not mandate the use of one
algorithm over another, or one lookup table size over another; they're just
recommendations that a particular CMM may choose to ignore.
Let's look at how the default Apple CMM uses the quality recommendations
specified in the flag bits. Other CMMs, of course, will have different
When Apple's CMM builds a color world from two or more profiles, and one or
more of these profiles contain TRC curves or A2Bx tables, the CMM also builds a
private, multidimensional lookup table. The quality flag bits determine the
resolution of this private table. Draft quality is treated the same as Normal
quality, so there are really only two effective settings, Normal/Draft and
Best. In most cases, the quality is only slightly better in Best mode, so the
difference is difficult to see, unless one of the profiles has a high gamma
value. For high gamma values, the extra resolution in the lookup table is
Best mode typically takes twice as long to build a color world (about two
seconds, versus one second in Normal/Draft mode). However, once the color world
is built, the time to use it is the same for either mode (approximately 1.5
MB/second on a Power Macintosh 8100/110).
Best mode also requires significantly more memory than Normal/Draft mode. A
color world typically requires 120K of heap space in Best mode versus 25K in
Normal mode, and the "high-water" memory requirement while a color world is
being built is typically 300K for Best mode versus 90K for Normal mode.
Note again that these guidelines apply only to the default Apple CMM. The
tradeoffs between speed, quality, and resources may be quite different for
Q I want to go directly from an input CMYK space to an output CMYK space
(without going through an intermediate three-component space) to preserve the
original GCR/UCR settings. Can I create a "link" profile for this purpose? If I
do, will I have to write my own CMM to use it?
A You can build a CMYK-to-CMYK device-link profile for this purpose, and you
can use it without writing your own CMM.
Q I'm using the ColorSync call CWCheckBitMap to do gamut checking in a plug-in
for Photoshop. The result bitmap is not what I expected, and seems to be
different every time I try it. Any idea what could be going on?
A CWCheckBitMap sets each pixel in the result bitmap to black if the
corresponding pixel in the source bitmap is out of the gamut. It doesn't,
however, set each pixel in the result bitmap to white if the pixel in the
source bitmap is in the gamut. If you aren't erasing the bitmap before calling
CWCheckBitMap, that would explain what you're seeing. Always erase the result
bitmap to white before calling CWCheckBitMap. (This is also true of
CWCheckPixMap and CWCheckColors.)
Q If I have a physical drive ID, how can I determine whether that drive is a
network volume? I'm not sure where to look, and I need to know whether the
information is dependable and not subject to change.
A Under the current Macintosh file system, there's no completely dependable way
to determine whether a volume originates over a network or is implemented on a
local disk. This is the result of the way external file systems are implemented
-- a third party can build a network file system in a variety of ways.
You can, however, easily determine whether a volume uses the AFP (AppleShare)
file system, which in many cases is adequate. To make this determination,
compare the driver refNum in the drive queue entry to the AppleShare client's
The following code enumerates the drive queue and displays the relevant
QHdrPtr drvQHdr = GetDrvQHdr();
short afpRefNum = 0;
// Get the driver refNum for AFP.
errNo = OpenDriver("\p.AFPTranslator", &afpRefNum);
if (errNo != noErr)
// Scan each drive in the drive table.
dqeP = (DrvQElPtr) drvQHdr->qHead;
// Is it an AFP volume or SCSI device?
if (dqeP->dQRefNum == afpRefNum) printf("AFP");
} while (dqeP =(DrvQElPtr) dqeP->qLink);
other third-party file systems, such as DECNET and NFS, you have to determine
the name of the driver and then compare it to the AppleShare client's refNum.
Q I need to get a list of files in a particular directory. Should I use
PBCatSearch, or should I use indexed PBGetCatInfo or PBGetFInfo requests?
A The "Cat" in PBCatSearch stands for "Catalog" and that's what PBCatSearch
searches: the whole volume catalog. You can specify that matches found by
PBCatSearch be limited to a specific directory by setting the fsSBFlParID bit
in the ioSearchBits field of the parameter block, and then specify the
directory to match on by setting ioFlParID in ioSearchInfo1 and ioSearchInfo2
to the directory ID you're interested in. However, PBCatSearch may not be what
you want to use, for a couple of reasons:
- The matches PBCatSearch finds by matching based on ioFlParID are only in
that one directory, not in any of that directory's subdirectories.
- Because the whole catalog file is searched, this is usually not the
fastest way to look through a specific directory's contents.
If you need
matches in both the directory and its subdirectories and you don't want to
search the whole volume, there's a routine in the MoreFiles sample code named
IndexedSearch that's compatible with PBCatSearch's parameter blocks, except
that IndexedSearch lets you specify what directory you want to search. It uses
indexed PBGetCatInfo calls to search a directory and its subdirectories.
If you need matches from only a single directory (and not from that directory's
subdirectories), you can use the MoreFiles routine named GetDirItems. This
routine uses PBGetCatInfo to index through a directory's entries and returns
FSSpecs to the entries found. In this case, making indexed PBGetCatInfo calls
is much faster than searching the whole catalog with PBCatSearch.
Q I need to nest two CustomGetFile dialogs, but I'm running into trouble. Under
some circumstances after the user dismisses the second dialog (usually via the
Cancel button), I lose all of the custom controls in the first dialog. What's
A The Standard File Package is not reentrant, so there really isn't a way to
nest standard file dialogs that will work right. The real problem is in the
resources that the Standard File Package uses for the dialog items. When the
second, nested dialog closes, it releases resources that the first dialog is
still using; that's why your items are getting messed up.
There's a kludgy workaround, but it will break under future systems. You could,
however, use sequential calls to the Standard File Package instead of nesting
them. This is a bit of a pain, but should accomplish what you want. Here's how:
Put up the first dialog. In your filter routine, when the user clicks the
control that is to bring up the nested dialog, set a flag in your application
signifying "bring up other," and tell the Standard File Package that you're
done with the first dialog by passing item 1 or 2 back. After you put up the
second dialog and process it, bring the original dialog back. This will be a
little messy cosmetically as the dialogs open and close, but it's the only way
to do it in a manner that will remain compatible.
Q What's the best way to remove an attached leech?
A The best way we know of is to rub a freshly cut lemon or lime on it. Most
leeches will detach immediately, and die a writhing, horrible death shortly
afterward. Fire and salt are also said to be effective.
These answers are supplied by the technical gurus in Apple's Developer Support
Have more questions? See the Macintosh Technical Q&As on this issue's CD.
(Older Q&As can be found in the Macintosh Q&A Technical Notes on the