| Whether using
a PC or a Mac, for business or pleasure,
valuable data should be protected from impending
harm caused by viruses, hackers, power surges,
human error, natural disasters and more.
The most important step in keeping data
safe from being deleted, stolen, lost or
damaged is to back-up regularly. By doing
so, if something should happen to threaten
the integrity of the electronic information,
users will still have a recent copy of all
important files, emails, databases, spreadsheets
and more.
File Systems
A file system is a structure that organizes
large numbers of files on some sort of recording
medium (most commonly a disk drive). The
idea is to store the files on the disk so
that they can be accessed randomly and with
minimal time delay. The PC and Mac differ
in the way they store files. These differences
can make it difficult when copying files
between platforms. Not all Mac files will
be useful on a PC and vice versa. Executable
program files compiled for one platform
can not be used on the other, but there
are many that have a separate version for
each platform.
Mac Files
On a Mac each file can have two parts called
forks - a data fork and a resource fork.
These are actually two files linked to one
name in the Mac file system. The resource
fork holds resources (icons, fonts, menus,
sounds, etc.). Since each resource fork
can hold many resources, it has a specific
structure that allows programs to find and
access a particular resource quickly. The
data fork can hold any type of data (text,
images, etc.) and does not have a required
a structure like the resource fork. Mac
resource forks are generally of no use on
the PC, but it is possible for a PC program
to convert specific resources to a PC format.
Our program CrossFont can do this with Mac
fonts which exist in the resource fork.
The contents of the Mac data fork is usually
all that can be used on a PC. Once a Mac
file is copied to the PC, the resource fork,
type and creator information are lost unless
the file is encoded with MacBinary or a
similar format (HQX, SIT, etc.) that saves
the Mac specific data with the file. This
way the file can exist on a single fork
machine (PC, UNIX) or be telecommunicated
and decoded at the other end with all Mac
information intact.
It is useful to have a way to identify
the type of a file as well as which application
created it. The Mac file system has this
information stored with the file name and
other information. They are two four character
fields called the type and creator. Mac
programs can use many different types of
files. The type field tells the program
what type of data is in each file so it
can parse it properly. It also allows a
program to filter files in an open file
dialog box so the user can only open files
of a certain type. The creator field is
unique for each Mac application. When an
application creates a file, it puts a creator
signature in this field which identifies
that this application should be launched
when a user double clicks on the icon of
the file.
DTI has the capabilities to repair hard
drives, but unlike many competitors, they
also have the software experience to work
on the different types of MAC file systems.
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