PC Compatibility
System 7.0 through 7.1 offered a utility called Apple File Exchange, which could access the contents of FAT- and Apple II-formatted floppy disks. System 7 Pro, System 7.5 and up shipped with PC Exchange, previously a separate product, which allowed the system to mount FAT-formatted floppy disks on the desktop in the same manner as regular Macintosh disks.
OS/2 disks were read as PC-DOS disks, due to fact that OS/2 used the FAT file system. At this time, Macs could also read and write UNIX file systems with the help of extra software.
System 7 allowed users to access PC networks and allowed communication via TCP/IP and other compatible networking stacks. Actual PC software compatibility, however, required third party software such as SoftPC, which allowed some MS-DOS and early Microsoft Windows programs to run, or Connectix Virtual PC, which allowed the Mac to run Windows via full PC emulation.
Other PC compatibility solutions took a more native approach by running Windows and MS-DOS by using x86 expansion cards with an x86 chip on the card. Apple offered some systems configured this way, marketed as "DOS Compatible" — a card with dedicated x86 CPU and RAM was used, while the Mac hard drive, sound subsystem, networking and input provided services to the PC. The PC could run simultaneously with the Mac, and the user could switch between the two in a fashion similar to a KVM switch. The earliest of these systems were 680x0 based systems running System 7. System 7 provided the support for accessing the PC volume from the Mac through its own PC Exchange software, and actual control of the PC hardware was accomplished by way of control panels.
Read more about this topic: System 7