An archive is similar to a traditional paper archive — it stores important information that must be retained but rarely needs to be opened. Each archive usually contains several files and is almost invariably compressed to save disk space.
A foreign file is any file that’s foreign to a Mac! It could be a PC file, a document for use with e-mail or a file that stores a Mac format file on other types of computer.
Archives
qqqqqq
  The most common archiving applications are Compact Pro and StuffIt. To
compress files you simply launch the application and select the files to be
compressed. The result can be a standard archive or self-extracting archive (SEA).
A standard archive requires the original compression application to extract and decompress individual files or to expand the entire archive. An SEA automatically decompresses itself when it’s opened without using the original application. An SEA is slightly larger than a standard archive and often carries a filename extension of .sea.
  The StuffIt Engine file, supplied with many Aladdin products, belongs in the
Extensions folder inside the System Folder. Several applications, including
Disk Wizard, can use it to retrieve individual files from archives.
Encryption
wwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwww
Many archiving applications can also create an encrypted archive. More specialised applications, such as QuickEncrypt, can also encrypt a single file. Once encrypted a file or archive can’t be restored to its original form without entering the same password as presented prior to encryption.
The level of security varies — unfortunately, the highly secure Data Encryption Standard (DES) can’t be used outside North America. Care should be taken to ensure that encrypted data is in a suitable form for systems such as e-mail that require pure ASCII text.
Foreign Files
qqqqqqqqq
  Most non-Mac computer systems can’t understand all of the data in a Mac file’s
data fork or the resources in its resource fork. And they can’t use any of the
Finder information — such as icons, file dates or file attributes.
To store a Mac file on a non-Mac machine or to transfer it over an alien communication system it must be converted into a foreign file. In this form it isn’t understood by a Mac but is acceptable to any computer, even one that can’t actually use the file.
Binary Files
One of the most common type of file used for transferring data from one computer to another is a binary file, containing 8-bit data covering all values from 0 to 255. Most non-Mac application files and the data fork of many other Mac files are in this form
Some applications can convert the data fork, resource fork and Finder information in a Mac file into a single binary file. The most common method, used by many applications, is MacBinary. A file in MacBinary format can be stored on any computer — and when converted back to a Mac file on a Macintosh machine will behave exactly as before.
ASCII Text Files
Particular forms of computer software, such as e-mail, can only handle an ASCII text file. This type of file only uses 7-bit values from 0 to 127 to represent standard characters such as letters, numbers, punctuation, tab, carriage return, line feed and form feed. It usually only includes those characters you can see on a QWERTY keyboard.
All other values, including most control codes (with the possible exception of Control-G) are ignored, together with any 8-bit values from 128 to 255. If unsuitable software receives unwanted codes it can cause confusion or total failure!
If you need to transfer a binary file via such a system you’ll need to use software that accommodates ASCII files. Alternatively you could use a utility to convert a binary file to ASCII. At the receiving end the ASCII file must be converted back to binary again!
√π See the Computer Data chapter for more about character codes
Foreign File Types
wwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwww
Several file types for archives and foreign files are listed below, with their filename extensions in brackets. Many of these files can be expanded using the StuffIt Deluxe application. The decompression process may include options for carriage return (CR) and line feed (LF) codes to match those used in the destination computer.
Not all foreign file types store the resource fork or attributes found in the source file.
AppleLink (.pkg)
A package file used with AppleLink to convey several Mac files. It contains the resource forks and data forks of the files, together with attributes and Finder information.
Type: HBSF Creator: GEOL
AppleSingle (.as)
A binary file representing the resource fork and data fork of a single Mac file, together with attributes and Finder information.
Type: BINA Creator: PCXT
Arc (.arc)
Contains the data fork of files compressed using the Arc application.
BinHex4 (.hqx)
An ASCII format, popular with Mac users, containing an encoded version of a file’s data fork. It can be un-binhexed using Compact Pro, StuffIt Deluxe or other applications.
Type: TEXT Creator: BNHQ
btoa (.ascii or .MBin.ascii)
An ASCII format containing an encoded version of a file’s data fork. It originates from the btoa (binary to ASCII) function used on UNIX computers.
The filename extension of the resultant file may modified if it contains MacBinary data. It also contains a btoa header that identifies to it a decoding application.
The atob (ASCII to binary) function in StuffIt Deluxe converts such an ASCII file back to its original form. If MacBinary data isn’t present the result has a Type and Creator of ????.
Type: TEXT Creator: ascii
Compact Pro (.cpt)
Contains one or more Mac files compressed with the Compact Pro application. The archive conveys the resource forks and data forks of the files, together with attributes and Finder information. Archives can also be expanded with StuffIt Deluxe.
Type: PACT Creator: CPCT
MacBinary (.bin)
A binary format, also known as BinHex5, representing the resource fork and data fork of a single Mac file. A MacBinary file can’t be used directly on a Mac but can be converted on the Mac using utilities such as mb2mac, StuffIt Deluxe or the MacLinkPlus Interface.
Type: TEXT Creator: MBin
PackIt (.pit)
Contains Mac files that have been compressed, with optional encryption, using PackIt, PackIt II or PackIt III applications. StuffIt Deluxe can only unpack files created by the last two applications. The archive conveys the resource forks and data forks of the files, together with attributes and Finder information.
tar (.tar)
Contains the data forks one or more files compressed using the UNIX tar archiver or a similar application.
UNIX Compressed File (.Z)
Contains the data fork of a file compressed with the Lempel-Ziv process. This format was originally used on UNIX computers.
Type: TEXT Creator: ttxt
Zip (.zip or .gz)
Contains the data fork of files compressed using the Zip application with optional encryption.
UUCode (.uu)
An ASCII format, originally devised for sending material over UNIX networks but now popular with PC users, containing an encoded version of a file’s data fork.
Type: TEXT Creator: ttxt
PC Files on a Mac
qqqqqqqqqqqqq
Any PC file, either from an MS-DOS or Windows machine, is seen by the Mac as just another foreign file. The Mac can’t understand such a file (with the notable exception of a text file) unless it has a suitable application or translator, and it can’t even read PC-formatted disks without additional software such as PC Exchange.
Transferring Files from PC to Mac
wwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwww
  Data can be transferred between two computers in several ways. Before doing so
you must consider whether you need to prepare the files before putting them on
a Mac. You must also think about the medium used to convey the data.
Although the following refers specifically to a PC it’s also applies generally to any transfer between a non-Mac computer and a Macintosh.
˝ Viruses can’t be transferred from a PC to 680x0 Mac, or vice versa. But it is possible
between a PC and PowerPC. Perhaps you ought to check afterwards anyway!
Àù Any Mac file, including applications, can be stored on a PC as a MacBinary file. Such
files can be converted back to their original form using a Mac utility such as mb2mac
or the MacLinkPlus application — part of MacLink Plus (see below).
Preparing Files
Even if a Mac equipped with PC Exchange displays a PC file’s icon that doesn’t mean there’s an application to open it! For example, PC-based file compression, such as Stacker, may not be accommodated by your Mac’s software. Other compression systems, such as Zip, can be dealt with at the Mac ‘end’ if you have suitable software. If in doubt, just save a set of uncompressed files on the PC and transfer these to the Mac instead.
Although a PC’s file type may seem acceptable to your Mac application there’s no guarantee it will work! This is due to odd differences between file created on Macs and PCs — TIFF and EPSF documents are particularly prone to such variations. Some Mac applications can’t open every variant — or you may have to work on a file to make it presentable. If you’re in doubt try a sample document first!
If you can’t find any common word processing file type you can resort to a pure text or ASCII text file — but this will lack font, font style or other formatting information. In some non-Mac applications you can only produce a text file via the print to disk feature.
It may be possible to extract text from a PC application’s standard document by treating it as if it were a text file. Unfortunately you’ll have to wade through a huge amount of meaningless formatting information!
Network Transfer
This is a fast and convenient way of moving files, particularly if you have a PC with an AppleTalk card and a Mac with PC Exchange. You can use Ethernet ports if both Mac and PC are equipped — but you’ll need extra software for them see each others drives.
PC MacLAN (Miramar Systems) provides software for both Ethernet machines — the PC software is for Windows 95. If you only want the PC to see Mac drives you can used COPSTalk (CoOperative Printing Solutions).
Serial Port Transfer
This is the next best thing to a network. It requires a null-modem cable between a serial communications port on the PC and the printer port or modem port on the Mac. The cable needn’t include hardware handshaking if you run the link at 9.6 kbit/s or less.
With AppleTalk in operation you’re almost invariably restricted to a particular Mac port.
If you have difficulties making the connection you could try plugging each computer via a modem into a telephone socket!
You must install suitable communications applications in both machines and set them up to transfer data in a common format — usually as binary files, containing all possible digital values. If either application doesn’t support binary transfer you must convert each original file to into a text file on the PC prior to transmission and then convert each text file back to binary form on the Mac!
MacLinkPlus (see below) includes all the necessary transfer software, together with file translators and a null-modem cable to establish a serial link.
Hard Disk Transfer
This approach avoids the complexities of networks or serial links — and is highly convenient when both machines have a removable cartridge drive.
Before copying any PC files onto a drive you must format it using the PC as follows:-
• A removable cartridge must be partitioned, initialised and erased using software
suppled with the PC SCSI card or drive — don’t use the Fdisk command!
• An external SCSI hard disk drive must be formatted on the PC using the Fdisk
command or with software supplied with the PC SCSI card or with the drive.
You should use the MS-DOS Format command to complete disk formatting.
Now you can copy the DOS files onto the cartridge or drive, move the drive to the Macintosh and then extract the files as required.
Floppy Disk Transfer
This is the worst option — about as fast as carving digital data in stone! Modern Macs accept 720 K and 1.4 M diskettes formatted to DOS standard, but older drives don’t accept any kind of DOS disk.
  Converting data from a DOS or CP/M-80 5.25 inch disk (either 360 K
or High Density 1.2 M) can be tricky, especially if the disk doesn’t use 48
tracks per inch (tpi). Very few computers have both 3.5 and 5.25 inch
floppy disk drives!
On the PC you can simply copy the files from one floppy drive to the other. Under no circumstances should you copy a disk image from one type of floppy disk to another
— disks always have a different sizes and formatting!
The files on the final diskette can be seen on any Mac that’s equipped with PC Exchange.
Using PC Disks
wwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwww
  You must install the PC Exchange control panel to format, read or write data
onto a DOS or Apple II ProDOS disk. PC Exchange mounts each Mac OS, DOS or
ProDOS partition on a SCSI hard disk drive as a separate drive on the Desktop.
If a disk drive contains both Mac and DOS partitions it only recognises the Mac partition. PC Exchange won’t accept volumes larger than 1 G or ProDOS partitions over 32 M. It can only erase individual partitions if they’re all of the same format — special software is necessary to format or resize mixed partitions.
To initially mount a non-Mac drive you must open PC Exchange, click Options, select the device from the list and then restart the Mac. PC Exchange only recognises such a drive if it’s turned on before your Mac is powered.
To eject a non-Mac cartridge you must drag it’s icon to the Trash. Once the disk has spun down you can eject it manually — you can insert it again later, if required.
· If you leave a removable cartridge engaged during startup you may get a Sad Mac!
· Don’t install any Mac driver onto a SCSI device containing a non-Mac partition.
Opening PC Files
wwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwww
Any document you see on a non-Mac disk won’t have a useful Type code until it’s opened and saved in a specific application. Many PC files are of Type TEXT with a Creator of dosa. Other files, such as JPEG graphics, are of Type BINA and Creator mdos.
If you infrequently open PC files you can simply launch a suitable application for the file you want to open — just select Open and the standard dialog appears. Pick the PC file you want and away you go!
However. it would be much more convenient if the application launched automatically when you double-clicked on the file. To do this you must match the application to be launched against the file’s filename extension within PC Exchange’s control panel. The filename extension is the last three letters of the name, after the decimal point. Sadly, filename extensions don’t always relate very well to the file’s actual contents!
The PC Exchange control panel is shown below:-
 
In this example Color It! automatically opens files with a .GIF suffix and SimpleText opens .TXT files. If you press the Add button you’re presented with a dialog in which you can select an application, the Type of files the application supports and the matching filename extension. You can modify or remove any selected entry in the above dialog by using Change or Remove.
Files created in PC versions of Mac applications can often be easily opened. Examples include ClarisWorks, CorelDraw, Excel, FileMaker Pro, Illustrator, PageMaker, PowerPoint, QuarkXpress, WordPerfect and Word. Most generic files, such as text files, also work easily.
Macintosh Easy Open
wwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwww
  Macintosh Easy Open is an optional feature that automatically comes into action
when you double-click on a document whose Creator is uncertain. It presents you
with a list of available applications that can open the selected Type of file.
The MEO control panel, shown below, automatically remembers your selection — the next time you attempt to open another document of the same Type it uses the same application. If you want it to forget your previous selections just press Delete Preferences.
 
If you check Translate ‘TEXT’ documents it attempts to find all the software that can open TEXT files. If you leave this deselected it makes the opening of text files quicker since PC Exchange will normally point a TEXT file directly to SimpleText — assuming PC Exchange is set up as shown in the earlier illustration.
Include applications on servers allows MEO to go searching for suitable applications on a network whilst Auto pick if only 1 choice reduces the dialogs you have to pass through!
MacLinkPlus
  MacLinkPlus (DataViz) provides extra translators that work with MEO and also
with applications that support the Claris XTND system (see below). The
translators reside in the DataViz folder inside the System Folder. The MacLinkPlus
Setup control panel and MacLinkPlus for Easy Open extension must be installed.
To open Mac files on a PC you can use the corresponding Conversions Plus (DataViz).
Claris XTND
  Claris XTND-compatible applications, such as ClarisWorks, File Maker Pro,
MacDraw Pro, MacWrite II and DOCMaker, offer a choice of file types in both Open
and Save dialogs. If MacLinkPlus is installed you’ll see even more!
They require the Claris XTND System file in the Claris folder, which is inside the System Folder. The translators are kept in the Claris Translators folder, also in the Claris folder.
If some file types don’t appear in your Open or Save dialogs you should quit the
application and remove XTND Translator List from the Preferences folder. Then
relaunch the application and check if all the types appear in the dialogs.
Should you have difficulties with MEO you could try an alternative translator via
an XTND-compatible application. Most translators work well but hybrid documents
containing embedded graphics may give problems.
Àù Some file Types may be given a Creator of ANON or Anon by a translator to indicate
that the file, typically a PICT, JPEG, GIFf, can be used by several applications.
PC Files in Detail
qqqqqqqqqqqqq
  MS-DOS files are much simpler than Mac files, containing only one
part, effectively the same as a Mac file’s data fork.
DOS Filenames
wwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwww
The filenames in DOS contain a maximum of 8 uppercase letters or numbers. This is usually be followed by a decimal point and a filename extension.
Filename extensions can contain a maximum of 3 uppercase letters or numbers.
Àù When transferring data from a Mac to a DOS machine remember that the filename
may become seriously truncated by software such as MacLinkPlus — such shortening
is essential for DOS. In some instances you may need to modify filenames by hand.
· These limitations in filenames don’t apply to PCs using Windows ‘95.
Filename Extensions
wwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwww
  DOS identifies each file type purely by its filename extensions — it doesn’t have
the automatic file identification that’s built into the Mac system.
· DOS machines don’t add these extensions and you’re not forced to use them
This use of extensions has caused untold confusion. For example, a .DOC file can be produced from any application you like!
The most common extensions are:-
.BAT Batch command file
.DOC Document
.EXE Executable binary file (application)
.TXT ASCIl Text file
Common Extensions
The following list shows common filename extensions and associated Mac Type codes. Mac applications rarely use extensions, except perhaps as a visual aid for the user, but are essential if PC Exchange is in action. Some computers, including the Mac, use lower-case letters in filenames instead of upper-case characters. Unless shown otherwise, most extensions apply to both Mac and DOS environments.
Type codes may differ from those shown — it depends on the transfer mechanism. Most files transferred to a Mac with PC Exchange are binary files of Type BINA. Such files can use the full range of numerical values to represent almost anything!
Most non-Mac computers can’t use the resource fork that resides in many Mac files.
Extn Type For Usage
.ARC ARC compressed file
.ARJ ARJ compressed file
.AS BINA AppleSingle: Mac file data/resource forks in binary form
.BAR UNIX binary archive (obsolete)
.BAK WordStar (and others) backup file
.BAS * DOS BASIC program
.BAT * DOS batch command
.BIN TEXT MacBinary (BinHex5): Mac file data/resource forks in binary form
.BMP BINA GR Windows bitmap graphic
.CGM GR Harvard Computer Graphics Metafile (CGM)
.COM * DOS executable binary file
.CPT PACT # Compact Pro compressed file
.CSV TEXT DB • Comma Separated Values (CSV)
.DBF F+DB DB dBase II or IIT
.DIF TEXT WP • Document Interchange File (DIF)
.DOC TEXT WP Multimate 1-3, Microsoft Word
.DOC TEXT • ASCII Text
.DOX WP Multimate 4
.DXF GR Data Exchange Format (DXF) used in AutoCad and others
.EPS EPSF GR • Encapsulated PostScript File (EPSF) with TIFF preview
.EXE APPL * DOS Executable binary file (application)
.FM3 Lotus formatting
.GEM GR Ventura Publisher GEM
.GIF GIFf GR Graphic Interchange File Format (GIFF)
.GZ GnuZip compressed file
.HQX TEXT BinHex4: Mac file data fork in ASCII form
.IMG GR Ventura Publisher Image
.JPG JPEG GR • JPEG compressed image
.JPG JFIF GR • JPEG compressed image
.LHA LHarc compressed file
.MAC TEXT # Mac text in a mixed environment
.MEM DOS dBase Memory file
.MIF WP FrameMaker MIF
.MLP MacLinkPlus Print Capture file
.MOV MooV GR QuickTime Movie
.OBJ * DOS compiled object file
.PC TEXT PC text in a mixed environment
.PCC GR PC Paintbrush
.PCX GR PC Paintbrush
.PCT PICT GR # PICT graphic (Mac environment)
.PDF PDF_ Portable Document File (Adobe Acrobat)
.PIC PICT GR • PICT graphic (Lotus and others)
.PIT # PackIt compressed file
.PKG HBSF AppleLink package (no resource fork)
.PMR ALB3 WP PageMaker 3
.PM4 ALB4 WP PageMaker 4
.PRG * DOS dBase program
.PRN TEXT DB Print file, usually Comma Separated Values (CSV)
.PS TEXT GR PostScript file
.PS EPSF GR PostScript file
.PUB DTP PageMaker 2
.RFT TEXT WP • Revisable Form Text (DCA format)
.FFT TEXT WP Final Form Text (DCA format)
.RTF TEXT WP Rich Text File (RTF)
.SAM WP AmiPro
.SEA APPL # Compact Pro or StuffIt self-extracting archive (Mac)
.SIT SITD # StuffIt compressed file (Mac)
.SK TEXT SS • Symbolic Link (SYLK)
.SLK TEXT SS • Symbolic Link (SYLK)
.STY Microsoft Word Style Sheet
.SYL TEXT SS • Symbolic Link (SYLK)
.SYS * DOS system file
.TAR UNIX tar archive (uncompressed)
.TIF TIFF GR • Tagged Image File Format (TIFF)
.TGZ UNIX tar archive (compressed with GnuZip)
.TXT TEXT • ASCIl Text for any OS
.UU TEXT Uuencoded UNIX file
.UUE TEXT Uuencoded UNIX file
.WAV BINA Windows sound
.WKS SS Lotus 1 spreadsheet
.WKI SS Lotus 2 spreadsheet
.WK3 SS Lotus 3 (3D)
.WMF GR Windows Metafile
.WP WP • Office Writer, WordPerfect
.WPF WP WordPerfect text
.WPG GR WordPerfect graphic
.WPS WDBN WP Microsoft Works
.WP6 WP WordPerfect 6
.WRK SS Symphony
.WRl SS Symphony
.WS WP • WordStar
.XLC Excel chart
.XLM Excel macro
.XLS XLS3 SS Excel 3 spreadsheet
.XY WP • XYWrite
.Z TEXT Lempel-Ziv compressed UNIX file
.ZIP PC Zip compressed file
.ZOO Zoo compressed file
Categories for these files are indicated by:-
DB - Database
DTP - Desktop publishing
GR - Graphics
SS - Spreadsheet
WP - Word processing
• Files commonly used by different applications.
* .EXE files and others can’t be launched on a Macintosh nor APPL files on
a MS-DOS machine without suitable emulation software.
