The project was mainly started because Apple didn’t believe its highly successful Apple II line would maintain its popularity.The Apple III was the first Apple computer not designed by Steve Wozniak.A built-in 5.25″ Shugart 143 KB floppy drive was included, making the main system unit larger and bulkier than the Apple II, which did not include an internal floppy disk drive but used external Disk II drives.A serial port was available on an optional expansion card, and a built-in mono speaker was standard.They thought it was impossible for them to fail, no matter what they did.Jerry Manock designed the Apple II and Apple III casings – and later the Macintosh 128K casing.
The Apple III chassis was designed by Manock and Dean Hovey (an industrial designer under contract).
Linzmayer in Steve Jobs, who supervised the project, didn’t help the situation.
He gave the development team dimensions in which components would not fit and demanded the computer not have a cooling fan because they were “too noisy and inelegant”.
The Apple IIIs actual specifications were very impressive and fared very well considering the competition which was getting stronger all the time.
Although SOS had many advantages, it wasn’t backward compatible with DOS 3.2 and 3.3, which is what most Apple II software used; thus the Apple III had hardly any software available for it compared to thousands of titles available for the Apple II.