, which stands for the '''''S'''ophisticated '''O'''perating '''S'''ystem'', was the computer
Operating System released in
1980 that was used by the ill-fated
Apple III computer. Despite the failure of the Apple III, SOS was a very forward-thinking operating system in many ways and its features influenced the design of
ProDOS that was later released for the
Apple //e and later Apple II computers. The SOS file system also heavily influenced the design of the
Macintosh Hierarchical File System .
The main interaction with SOS was through the Apple /// System Utilities program. The System Utilities program had three main sections: the Device handling commands section, the File handling commands section, and the System Configuration Program (SCP). The additional benefit of SOS over older Apple DOS versions was the ability to use
Device Drivers to support devices such as
Hard Disk Drives and
RAM drives in addition to 5.25-inch
Floppy Disk drives.
In spite of SOS's advantages, it wasn't natively backward compatible with
DOS 3.2 and
DOS 3.3 , which most Apple II software used at the time. Many average computer users also weren't ready in
1980 for an operating system with the capabilities and flexible configuration options that SOS offered, especially with the Apple III's bad reputation due to poor engineering and its high retail price near $4,000 (£2,420). The
IBM PC , released in
1981 at a lower price than the Apple III, sealed the fate of both the computer and its SOS operating system.
