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`Files
`
`I N S I D E M A C I N T O S H
`
`Addison-Wesley Publishing Company
`
`Reading, Massachusetts Menlo Park, California New York
`Don Mills, Ontario Wokingham, England Amsterdam Bonn
`Sydney Singapore Tokyo Madrid San Juan
`Paris Seoul Milan Mexico City Taipei
`
`Petitioner Apple Inc. - Exhibit 1008, p. 1
`
`(cid:240)
`

`

`Apple Computer, Inc.
`© 1992, Apple Computer, Inc.
`All rights reserved.
`No part of this publication may be
`reproduced, stored in a retrieval
`system, or transmitted, in any form or
`by any means, mechanical, electronic,
`photocopying, recording, or otherwise,
`without prior written permission of
`Apple Computer, Inc. Printed in the
`United States of America.
`No licenses, express or implied, are
`granted with respect to any of the
`technology described in this book.
`Apple retains all intellectual property
`rights associated with the technology
`described in this book. This book is
`intended to assist application
`developers to develop applications only
`for Apple Macintosh computers.
`Apple Computer, Inc.
`20525 Mariani Avenue
`Cupertino, CA 95014-6299
`408-996-1010
`Apple, the Apple logo, APDA,
`AppleShare, AppleTalk, A/UX,
`LaserWriter, Macintosh, MPW,
`and ProDOS are trademarks of
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`Apple SuperDrive, Balloon Help, Disk
`First Aid, Finder, ResEdit, and System 7
`are trademarks of Apple Computer, Inc.
`Adobe Illustrator and PostScript are
`trademarks of Adobe Systems
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`trademark of International Typeface
`Corporation.
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`Corporation.
`Simultaneously published in the United
`States and Canada.
`
`LIMITED WARRANTY ON MEDIA AND
`REPLACEMENT
`
`ALL IMPLIED WARRANTIES ON THIS
`MANUAL, INCLUDING IMPLIED
`WARRANTIES OF MERCHANTABILITY
`AND FITNESS FOR A PARTICULAR
`PURPOSE, ARE LIMITED IN DURATION
`TO NINETY (90) DAYS FROM THE DATE
`OF THE ORIGINAL RETAIL PURCHASE
`OF THIS PRODUCT.
`
`Even though Apple has reviewed this
`manual, APPLE MAKES NO WARRANTY
`OR REPRESENTATION, EITHER EXPRESS
`OR IMPLIED, WITH RESPECT TO THIS
`MANUAL, ITS QUALITY, ACCURACY,
`MERCHANTABILITY, OR FITNESS FOR A
`PARTICULAR PURPOSE. AS A RESULT,
`THIS MANUAL IS SOLD “AS IS,” AND
`YOU, THE PURCHASER, ARE ASSUMING
`THE ENTIRE RISK AS TO ITS QUALITY
`AND ACCURACY.
`
`IN NO EVENT WILL APPLE BE LIABLE
`FOR DIRECT, INDIRECT, SPECIAL,
`INCIDENTAL, OR CONSEQUENTIAL
`DAMAGES RESULTING FROM ANY
`DEFECT OR INACCURACY IN THIS
`MANUAL, even if advised of the possibility
`of such damages.
`
`THE WARRANTY AND REMEDIES SET
`FORTH ABOVE ARE EXCLUSIVE AND IN
`LIEU OF ALL OTHERS, ORAL OR
`WRITTEN, EXPRESS OR IMPLIED. No
`Apple dealer, agent, or employee is
`authorized to make any modification,
`extension, or addition to this warranty.
`
`Some states do not allow the exclusion or
`limitation of implied warranties or liability
`for incidental or consequential damages, so
`the above limitation or exclusion may not
`apply to you. This warranty gives you
`specific legal rights, and you may also have
`other rights which vary from state to state.
`
`ISBN 0-201-63244-6
`1 2 3 4 5 6 7 8 9-MU-9695949392
`First Printing, August 1992
`
`Petitioner Apple Inc. - Exhibit 1008, p. 2
`
`

`

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`
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`
`
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`
`
`
`
`P R E F A C E
`
`About This Book
`
`This book,
` describes the parts of the Macintosh
`Inside Macintosh: Files,
`Operating System that allow you to manage files. It shows in detail how your
`application can handle the commands typically found in a File menu. It also
`provides a complete technical reference to the File Manager, the Standard File
`Package, the Alias Manager, and other file-related services provided by the
`system software.
`If you are new to the Macintosh Operating System, you should begin with the
`chapter “Introduction to File Management.” This chapter describes the basic
`structure of Macintosh files and the hierarchical file system (HFS) used with
`Macintosh computers, and it shows how you can use the services provided by
`the Standard File Package, the File Manager, the Finder, and other system
`software components to create, open, update, and close files. Because this
`chapter is designed to be largely self-contained, the reference and summary
`sections in this chapter are subsets of the corresponding sections from the
`other chapters in this book.
`Once you are familiar with basic file management on Macintosh computers,
`you might want to read other chapters in this book. The chapter “File
`Manager” describes how your application can manage shared files; search
`for specific files in a volume; obtain information about files, directories, and
`volumes; and perform other advanced operations. This chapter also describes
`how the File Manager organizes file and directory data on disk and in
`memory. Much of this information is of interest only to designers of very
`specialized applications or file-system utility programs.
`If you want to customize the user interface for naming and identifying files,
`you need to read the chapter “Standard File Package.” It provides complete
`information on how to customize and display the dialog boxes that let the
`user specify the names and locations of files to be saved or opened.
`If your application needs to keep track of particular files, directories, or
`volumes, you might want to use the Alias Manager. It helps you find objects
`in the file system, even if those objects have been moved or renamed. See the
`chapter “Alias Manager” for complete details.
`The chapter “Disk Initialization Manager” shows how you can initialize disks
`and erase the contents of previously initialized disks. The Disk Initialization
`Manager provides a routine that allows you to present the standard user
`interface for initializing and naming disks. Most applications should call that
`routine whenever they receive a disk-inserted event and the inserted disk
`is invalid.
`
`xv
`
`Petitioner Apple Inc. - Exhibit 1008, p. 3
`
`

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`P R E F A C E
`
`Format of a Typical Chapter
`
`0
`
`Almost all chapters in this book follow a standard structure. For example, the
`chapter “Standard File Package” contains these sections:
`
`n
`
`n
`
`n
`
`n
`
`“About the Standard File Package.” This section provides an overview of the
`features provided by the Standard File Package.
`“Using the Standard File Package.” This section describes the tasks you can
`accomplish using the Standard File Package. It describes how to use the
`most common routines, gives related user interface information, provides
`code samples, and supplies additional information.
`“Standard File Package Reference.” This section provides a complete
`reference to the Standard File Package by describing the data structures and
`routines that it uses. Each routine description also follows a standard format,
`which gives the routine declaration and a description of every parameter of
`the routine. Some routine descriptions also give additional descriptive
`information, such as assembly-language information or result codes.
`“Summary of the Standard File Package.” This section provides the
`Standard File Package’s Pascal interface, as well as the C interface, for the
`constants, data structures, routines, and result codes associated with the
`Standard File Package. It also includes relevant assembly-language
`interface information.
`Some chapters contain additional main sections that provide more detailed
`discussions of certain topics. For example, the chapter “File Manager”
`contains the section “Identifying Files, Directories, and Volumes,” which
`describes the many ways to identify objects in the file system. That chapter
`also contains the two advanced sections “Data Organization on Volumes”
`and “Data Organization in Memory.”
`
`Conventions Used in This Book
`
` uses various conventions to present information. Words that
`Inside Macintosh
`require special treatment appear in specific fonts or font styles. Certain
`information, such as parameter blocks, use special formats so that you can
`scan them quickly.
`
`Special Fonts
`
`All code listings, reserved words, and the names of actual data structures,
`constants, fields, parameters, and routines are shown in Courier (
`this
`).
`is Courier
`Words that appear in
` are key terms or concepts and are defined in
`boldface
`the Glossary.
`
`0
`
`0
`
`xvi
`
`Petitioner Apple Inc. - Exhibit 1008, p. 4
`
`

`

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`P R E F A C E
`
`Types of Notes
`
`There are several types of notes used in this book.
`
`Note
`A note like this contains information that is interesting but possibly not
`essential to an understanding of the main text. (An example appears on
`page 1-6.)
`u
`
`IMPORTANT
`A note like this contains information that is essential for an
`understanding of the main text. (An example appears on page 1-6.)
`
`ss
`
`W A R N I N G
`Warnings like this indicate potential problems that you should be aware
`of as you design your application. Failure to heed these warnings could
`result in system crashes or loss of data. (An example appears on
`page 1-46.)
`
`Assembly-Language Information
`
`0
`
`0
`
` provides information about the registers for specific routines
`Inside Macintosh
`like this:
`
`Registers on entry
`A0
`Contents of register A0 on entry
`
`Registers on exit
`D0
`Contents of register D0 on exit
`
`In addition,
` presents information about the fields of a
`Inside Macintosh
`parameter block in this format:
`
`Parameter block
`
`inAndOut
`
`Integer
`
`output1
`
`input1
`
`Ptr
`
`Ptr
`
`Input/output parameter.
`Output parameter.
`Input parameter.
`
`The arrow in the far left column indicates whether the field is an input
`parameter, output parameter, or both. You must supply values for all input
`parameters and input/output parameters. The routine returns values in
`output parameters and input/output parameters.
`The second column shows the field name as defined in the MPW Pascal
`interface files; the third column indicates the Pascal data type of that field.
`The fourth column provides a brief description of the use of the field. For a
`complete description of each field, see the discussion that follows the
`parameter block or the description of the parameter block in the reference
`section of the chapter.
`
`xvii
`
`Petitioner Apple Inc. - Exhibit 1008, p. 5
`
`s
`«
`‹
`fi
`

`

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`
`P R E F A C E
`
`Development Environment
`
`0
`
`The system software routines described in this book are available using
`Pascal, C, or assembly-language interfaces. How you access these routines
`depends on the development environment you are using. This book shows
`system software routines in their Pascal interface using the Macintosh
`Programmer’s Workshop (MPW).
`All code listings in this book are shown in Pascal. They show methods of
`using various routines and illustrate techniques for accomplishing particular
`tasks. All code listings have been compiled and, in most cases, tested.
`However, Apple Computer does not intend that you use these code samples
`in your application.
` as the name of a sample application for
`This book occasionally uses
`SurfDraw
`illustrative purposes; this is not an actual product of Apple Computer, Inc.
`APDA, Apple’s source for developer tools, offers worldwide access to a broad
`range of programming products, resources, and information for anyone
`developing on Apple platforms. You’ll find the most current versions of
`Apple and third-party development tools, debuggers, compilers, languages,
`and technical references for all Apple platforms. To establish an APDA
`account, obtain additional ordering information, or find out about site
`licensing and developer training programs, contact
`APDA
`Apple Computer, Inc.
`20525 Mariani Avenue, M/S 33-G
`Cupertino, CA 95014-6299
`Telephone:
`800-282-2732 (United States)
`800-637-0029 (Canada)
`800-562-3910 (elsewhere in the world)
`408-562-3971
`171-576
`
`Fax:
`Telex:
`
`If you provide commercial products and services, call 408-974-4897 for
`information on the developer support programs available from Apple.
`For information on registering signatures, file types, Apple events, and other
`technical information, contact
`Macintosh Developer Technical Support
`Apple Computer, Inc.
`20525 Mariani Avenue, M/S 75-3T
`Cupertino, CA 95014-6299
`
`xviii
`
`Petitioner Apple Inc. - Exhibit 1008, p. 6
`
`

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`Figures, Tables, and Listings
`
`Preface
`
`About This Book
`
`xv
`
`Chapter 1
`
`Introduction to File Management
`
`1-3
`
`Figure 1-1
`Figure 1-2
`Figure 1-3
`Figure 1-4
`Figure 1-5
`Figure 1-6
`Listing 1-1
`Listing 1-2
`
`Listing 1-3
`Listing 1-4
`Listing 1-5
`Listing 1-6
`Figure 1-7
`Listing 1-7
`Listing 1-8
`Listing 1-9
`Listing 1-10
`Listing 1-11
`Listing 1-12
`Figure 1-8
`Figure 1-9
`Figure 1-10
`Listing 1-13
`Figure 1-11
`Listing 1-14
`Listing 1-15
`Listing 1-16
`Listing 1-17
`Listing 1-18
`Listing 1-19
`
`1-5
`
`1-8
`1-10
`
`1-16
`1-17
`1-19
`
`1-26
`1-27
`
`The two forks of a Macintosh file
`1-7
`Logical blocks and allocation blocks
`Logical end-of-file and physical end-of-file
`The Macintosh hierarchical file system
`The disk switch dialog box
`1-11
`A typical File menu
`1-12
`1-13
`Handling the File menu commands
`Testing for the availability of routines that operate on
`
`FSSpec
`records
`1-14
`1-15
`A sample document record
`Handling the New menu command
`Creating a new document window
`Handling the Open menu command
`The default Open dialog box
`1-19
`Opening a file
`1-20
`1-22
`Reading data from a file
`1-24
`Writing data into a file
`1-25
`Updating a file safely
`Handling the Save menu command
`Handling the Save As menu command
`The default Save dialog box
`1-28
`The new folder dialog box
`1-29
`The name conflict dialog box
`1-29
`Copying a resource from one resource fork to another
`A Revert to Saved dialog box
`1-30
`Handling the Revert to Saved menu command
`Handling the Close menu command
`1-32
`Closing a file
`1-33
`Opening files at application launch time
`Opening a preferences file
`1-36
`Adjusting the File menu
`1-37
`
`1-30
`
`1-31
`
`1-35
`
`Chapter 2
`
`File Manager
`
`2-5
`
`Table 2-1
`Table 2-2
`Table 2-3
`Table 2-4
`Table 2-5
`
`2-7
`Routines for opening file forks
`2-9
`Routines for operating on open file forks
`2-9
`Routines for operating on closed files
`2-10
`Routines for operating on directories
`Routines for manipulating working directories
`
`2-11
`
`xi
`
`Petitioner Apple Inc. - Exhibit 1008, p. 7
`
`

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`Table 2-6
`Table 2-7
`Table 2-8
`Figure 2-1
`Table 2-9
`Figure 2-2
`Figure 2-3
`Listing 2-1
`Table 2-10
`Listing 2-2
`Table 2-12
`
`Table 2-11
`
`Listing 2-3
`Listing 2-4
`Listing 2-5
`Listing 2-6
`Listing 2-7
`Listing 2-8
`Listing 2-9
`Listing 2-10
`Figure 2-4
`Figure 2-5
`Figure 2-6
`Figure 2-7
`Figure 2-8
`Figure 2-9
`Figure 2-10
`Listing 2-11
`
`2-13
`
`2-16
`
`2-19
`
`2-36
`
`2-12
`Routines for operating on volumes
`Routines for manipulating working directories
`Shared environment routines
`2-15
`Access and deny mode synchronization
`Access mode translation
`2-17
`Access privileges information in the
` field
`ioACAccess
`Identifying a file in HFS
`2-30
`Testing for
`PBCatSearch
`2-34
`How
` interprets its parameters
`FSMakeFSSpec
`Deleting a file’s resource fork
`2-38
`Fields in
` and
` used for a
`ioSearchInfo1
`ioSearchInfo2
`directory
`2-40
`Fields in
` and
` used for a
`ioSearchInfo1
`ioSearchInfo2
`file
`2-40
`Searching a volume with
`2-42
`PBCatSearch
`Searching a volume using a recursive, indexed search
`Constructing the full pathname of a file
`2-46
`Determining the amount of free space on a volume
`Determining whether a volume is sharable
`2-49
`Determining whether file sharing is enabled
`2-50
`Determining whether a file can have ranges locked
`Locking a file range to append data to the file
`2-52
`Organization of partitions on a disk
`2-56
`Organization of a volume
`2-57
`The structure of a B*-tree file
`2-64
`The structure of a node
`2-65
`Structure of a B*-tree node record
`A sample B*-tree
`2-68
`2-69
`Header node structure
`Reading a drive queue element’s flag bytes
`
`2-44
`
`2-48
`
`2-51
`
`2-67
`
`2-86
`
`Chapter 3
`
`Standard File Package
`
`3-3
`
`Figure 3-1
`Figure 3-2
`Figure 3-3
`Figure 3-4
`Figure 3-5
`Figure 3-6
`Figure 3-7
`Figure 3-8
`
`Figure 3-9
`Figure 3-10
`
`Figure 3-11
`Listing 3-1
`Listing 3-2
`Listing 3-3
`Listing 3-4
`Listing 3-5
`
`xii
`
`3-5
`The default Open dialog box
`3-6
`The default Save dialog box
`3-6
`The New Folder dialog box
`3-7
`The name conflict dialog box
`The Save dialog box customized with radio buttons
`The Save dialog box customized with a pop-up menu
`The Open dialog box customized with a pop-up menu
`The Open dialog box customized to allow selection of a
`directory
`3-10
`The Open dialog box when no directory is selected
`The Open dialog box with a long directory name
`abbreviated
`3-11
`3-12
`A volume selection dialog box
`3-14
`Handling the Open menu command
`3-15
`Specifying more than four file types
`Presenting a customized Open dialog box
`The definition of the default Open dialog box
`The definition of the default Save dialog box
`
`3-8
`3-9
`3-9
`
`3-11
`
`3-17
`3-18
`3-18
`
`Petitioner Apple Inc. - Exhibit 1008, p. 8
`
`

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`Listing 3-6
`Listing 3-7
`Listing 3-8
`Listing 3-9
`Listing 3-10
`Listing 3-11
`Listing 3-12
`Listing 3-13
`Listing 3-14
`Listing 3-15
`Listing 3-16
`Listing 3-17
`Listing 3-18
`
`Listing 3-19
`Listing 3-20
`Listing 3-21
`
`Listing 3-22
`
`3-18
`3-19
`
`The item list for the default Open dialog box
`The item list for the default Save dialog box
`A sample file filter function
`3-21
`A sample dialog hook function
`3-27
`3-30
`A sample modal-dialog filter function
`3-31
`Determining the current directory
`3-32
`Determining the current volume
`3-32
`Setting the current directory
`3-32
`Setting the current volume
`3-33
`Setting the current directory
`A file filter function that lists only directories
`Setting a button’s title
`3-35
`Handling user selections in the directory selection dialog
`box
`3-35
`3-37
`Presenting the directory selection dialog box
`3-38
`A file filter function that lists only volumes
`Handling user selections in the volume selection dialog
`box
`3-39
`Presenting the volume selection dialog box
`
`3-34
`
`3-40
`
`Chapter 4
`
`Alias Manager
`
`4-3
`
`Figure 4-1
`Listing 4-1
`Listing 4-2
`
`4-6
`Resolving a relative path
`4-9
`Creating an alias record
`Storing an alias record as a resource
`
`4-12
`
`Chapter 5
`
`Disk Initialization Manager
`
`5-3
`
`Figure 5-1
`Figure 5-2
`Figure 5-3
`Figure 5-4
`Figure 5-5
`Listing 5-1
`Listing 5-2
`Listing 5-3
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`Listing 5-4
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`Listing 5-5
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`5-6
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`5-5
`The disk initialization dialog box
`Alternate buttons for the disk initialization dialog box
`The disk initialization warning
`5-6
`The disk naming dialog box
`5-6
`The Finder’s disk erasing dialog box
`Responding to disk-inserted events
`Reinitializing a valid disk
`5-11
`Reinitializing a validly formatted disk without using the standard
`interface
`5-12
`Initializing an uninitialized disk without using the standard
`interface
`5-13
`Changing default volume characteristics
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`5-7
`5-10
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`5-15
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`xiii
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`Petitioner Apple Inc. - Exhibit 1008, p. 9
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`Petitioner Apple Inc. - Exhibit 1008, p. 10
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`Petitioner Apple Inc. - Exhibit 1008, p. 10
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`

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`1
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`Introduction to File Management
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`C H A P T E R 1
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`Introduction to File Management
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`1
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`This chapter is a general introduction to file management on Macintosh computers. It
`explains the basic structure of Macintosh files and the hierarchical file system (HFS) used
`with Macintosh computers, and it shows how you can use the services provided by the
`Standard File Package, the File Manager, the Finder, and other system software
`components to create, open, update, and close files.
`You should read this chapter if your application implements the commands typically
`found in an application’s File menu—except for printing commands and the Quit
`command, which are described elsewhere. This chapter describes how to
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`create a new file
`open an existing file
`close a file
`save a document’s data in a file
`save a document’s data in a file under a new name
`revert to the last saved version of a file
`create and read a preferences file
`Depending on the requirements of your application, you may be able to accomplish all
`your file-related operations by following the instructions given in this chapter. If your
`application has more specialized file management needs, you’ll need to read some or all
`of the remaining chapters in this book.
`This chapter assumes that your application is running in an environment in which the
`routines that accept file system specification records (defined by the
` data type)
`FSSpec
`are available. File system specification records, introduced in system software version 7.0,
`simplify the identification of objects in the file system. Your development environment
`may provide “glue” that allows you to call those routines in earlier system software
`versions. If such glue is not available and you want your application to run in system
`software versions earlier than version 7.0, you need to read the discussion of HFS
`file-manipulation routines in the chapter “File Manager” in this book.
`This chapter begins with a description of files and their organization into directories and
`
`volumes. Then it describes how to test for the presence of the routines that accept
`FSSpec
`records and how to use those routines to perform the file management tasks listed above.
`The chapter ends with descriptions of the data structures and routines used to perform
`these tasks. The “File Management Reference” and “Summary of File Management”
`sections in this chapter are subsets of the corresponding sections of the remaining
`chapters in this book.
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`1-3
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`Petitioner Apple Inc. - Exhibit 1008, p. 11
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`C H A P T E R 1
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`Introduction to File Management
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`About Files
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`1
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`To the user, a file is simply some data stored on a disk. To your application, a
` is a
`file
`named, ordered sequence of bytes stored on a Macintosh volume, divided into two forks
`(as described in the following section, “File Forks”). The information in a file can be used
`for any of a variety of purposes. For example, a file might contain the text of a letter or
`the numerical data in a spreadsheet; these types of files are usually known as documents.
`Typically a
` is a file that a user can create and edit. A document is usually
`document
`associated with a single application, which the user expects to be able to open by
`double-clicking the document’s icon in the Finder.
`A file might also contain an application. In that case, the information in the file consists
`of the executable code of the application itself and any application-specific resources and
`data. Applications typically allow the user to create and manipulate documents. Some
`applications also create special files in which they store user-specific settings; such files
`are known as
`preferences files.
`The Macintosh Operating System also uses files for other purposes. For example, the File
`Manager uses a special file located in a volume to maintain the hierarchical organization
`of files and folders in that volume. This special file is called the volume’s
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`catalog file.
`Similarly, if virtual memory is in operation, the Operating System stores unused pages of
`memory in a disk file called the
`backing-store file.
`No matter what its function, each file shares certain characteristics with every other file.
`This section describes these general characteristics of Macintosh files, including
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`file forks
`file size and access characteristics
`file system organization
`file naming and identification
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`1
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`File Forks
`Many operating systems treat a file simply as a named, ordered sequence of bytes
`(possibly terminated by a byte having a special value that indicates the end-of-file). As
`illustrated in Figure 1-1, however, each Macintosh file has two
` known as the data
`forks,
`fork and the resource fork.
`A file’s
` contains that file’s resources. If the file is an application, the
`resource fork
`resource fork typically contains resources that describe the application’s menus, dialog
`boxes, icons, and even the executable code of the application itself. A particularly
`important resource is the application’s
` resource, which contains information
`'SIZE'
`about the capabilities of the application and its run-time memory requirements. If the file
`is a document, its resource fork typically contains preference settings, window locations,
`and document-specific fonts, icons, and so forth.
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`1-4
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`About Files
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`Petitioner Apple Inc. - Exhibit 1008, p. 12
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`

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`1
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`Introduction to File Management
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`C H A P T E R 1
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`Introduction to File Management
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`Figure 1-1
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`The two forks of a Macintosh file
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`Resource map(cid:13)
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`Data(cid:13)
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`Resources(cid:13)
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`Data fork(cid:13)
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`Resource fork(cid:13)
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`A file’s
` contains the file’s data. It is simply a series of consecutive bytes of data.
`data fork
`In a sense, the data fork of a Macintosh file corresponds to an entire file in operating
`systems that treat a file simply as a sequence of bytes. The bytes stored in a file’s data
`fork do not have to exhibit any internal structure, unlike the bytes stored in the resource
`fork (which consists of a resource map followed by resources). Rather, your application
`is responsible for interpreting the bytes in the data fork in whatever manner is appropri-
`ate. The data fork of a document file might, for example, contain the text of a letter.
`Even though a Macintosh file always contains both a resource fork and a data fork, one
`or both of those forks can be empty. Document files sometimes contain only data (in
`which case the resource fork is empty). More often, document files contain both
`resources and data. Application files generally contain resources only (in which case, the
`data fork is empty). Application files can, however, contain data as well.
`Whether you store specific data in the data fork or in the resource fork of a file depends
`largely on whether that data can usefully be structured as a resource. For example, if you
`want to store a small number of names and telephone numbers, you can easily define a
`resource type that pairs each name with its telephone number. Then you can read names
`and corresponding numbers from the resource file by using Resource Manager routines.
`To retrieve the data stored in a resource, you simply specify the resource type and ID;
`you don’t need to know, for instance, how many bytes of data are stored in that resource.
`In some cases, however, it is not possible or advisable to store your data in resources.
`The data might be too difficult to put into the structure required by the Resource
`Manager. For example, it is easiest to store a document’s text, which is usually of
`variable length, in a file’s data fork. Then you can use File Manager routines to access
`any byte or group of bytes individually.
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`About Files
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`1-5
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`Petitioner Apple Inc. - Exhibit 1008, p. 13
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`C H A P T E R 1
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`Introduction to File Management
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`Even when it is easy to define a resource type for your data, limitations on the Resource
`Manager might compel you to store your data in the data fork instead. A resource fork
`can contain at most about 2700 resources. More importantly, the Resource Manager
`searches linearly through a file’s resource types and resource IDs. If the number of types
`or IDs to be searched is large, accessing the resource data can become slow. As a rule of
`thumb, if you need to manage data that would occupy more than about 500 resources
`total, you should use the data fork instead.
`
`IMPORTANT
`In general, you should store data created by the user in a file’s data fork,
`unless the data is guaranteed to occupy a small number of resources.
`The Resource Manager was not designed to be a general-purpose data
`storage and retrieval system. Also, the Resource Manager does not
`support multiple access to a file’s resource fork. If you want to store data
`that can be accessed by multiple users of a shared volume, use the
`data fork.
`Because the Resource Manager is of limited use in storing large amounts of
`user-generated data, most of the techniques in “Using Files” (beginning on page 1-12)
`illustrate the use of File Manager routines to manage information stored in a file’s data
`fork. See the section “Using a Preferences File” on page 1-36 for an example of the use of
`the Resource Manager to access data stored in a file’s resource fork.
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`File Size
`The size of a file is usually limited only by the size of its volume. A
` is a portion
`volume
`of a storage device that is formatted to contain files. A volume can be an entire disk or
`only a part of a disk. A 3.5-inch floppy disk, for instance, is always formatted as one
`volume. Other memory devices, such as hard disks and file servers, can contain multiple
`volumes.
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`1
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`Note
`Actually, a file on an HFS volume can be as large as 2 GB ($7FFFFFFF
`bytes). Most volumes are not large enough to hold a file of that size. An
`HFS volume currently can be as large as 2 GB.
`u
`The size of a volume varies from one type of device to another. Volumes are formatted
`into chunks known as
` each of which can contain up to 512 bytes. A
`logical blocks,
`double-sided 3.5-inch floppy disk, for instance, usually has 1600 logical blocks, or 800 KB.
`Generally, however, the size of a logical block on a volume is of interest only to the disk
`device driver. This is because the File Manager always allocates space to a file in units
`called allocation blocks. An
` is a group of consecutive logical blocks. The
`allocation block
`File Manager can access a maximum of 65,535 allocation blocks on any volume. For
`small volumes, such as volumes on floppy disks, the File Manager uses an allocation
`block size of one logical block. To support volumes larger than about 32 MB, the File
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`1-6
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`About Files
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`Petitioner Apple Inc. - Exhibit 1008, p. 14
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`1
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`Introduction to File Management
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`C H A P T E R 1
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`Introduction to File Management
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`Manager needs to use an allocation block size that is at least two logical blocks. To
`support volumes larger than about 64 MB, the File Manager needs to use an allocation
`block that is at least three allocation blocks. In this way, by progressively increasing
`the number of logical blocks in an allocation block, the File Manager can handle
`larger and larger volumes. Figure 1-2 illustrates how logical blocks are grouped into
`allocation blocks.
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`Figure 1-2
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`Logical blocks and allocation blocks
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`Macintosh volume(cid:13)
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`File A(cid:13)
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`File B(cid:13)
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`File C(cid:13)
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`Allocation(cid:13)
`Blocks(cid:13)
`0(cid:13)
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`1(cid:13)
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`2(cid:13)
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`Logical(cid:13)
`Blocks(cid:13)
`0(cid:13)
`1(cid:13)
`2(cid:13)
`3(cid:13)
`4(cid:13)
`5(cid:13)
`6(cid:13)
`7(cid:13)
`
`2n(cid:13)
`2n+1(cid:13)
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`3(cid:13)(cid:13)(cid:13)
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`n(cid:13)
`2(cid:13)
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`The size of the allocation blocks on a volume is determined when the volume is
`initialized and depends on the number of logical blocks it contains. In general, the
`Disk Initialization Manager uses the smallest allocation block size that will allow the
`File Manager to address the entire volume. A nonempty file fork always occupies at least
`one allocation block, no matter how many bytes of data that file fork contains. On a
`40 MB volume, for example, a file’s data fork occupies at least 1024 bytes (that is, two
`logical blocks), even if it contains only 11 bytes of actual data.
`To distinguish between the amount of space allocated to a file and the number of bytes of
`actual data in the file, two numbers are used to describe the size of a file. The
`physical
` is the number of bytes currently allocated to the file; it’s 1 greater than the
`end-of-file
`number of the last byte in its last allocation block (since the first byte is byte number 0).
`As a result, the physical end-of-file is always an exact multiple of the allocation block
`size. The
` is the number of those allocated bytes that currently contain
`logical end-of-file
`data; it’s 1 greater than the number of the last byte in the file that contains data. For
`example, on a volume having an allocation block size of two logical blocks (that is,
`1024 bytes), a file with 509 bytes of data has a logical