What is an emulator ?
Technically speaking, it is merely a software which allows a computer to recreate the behaviour of another computer. The hardware aspects are entierely handled by a logicial basis. A virtual computer is then operating into a dedicated operating system (which is here Mac OSX).
This means that under an emulator session, the programs can be used as if they were used under the real thing.
What are image disks ?
They are duplicates of physical disks into files. Image disks are simply documents. Image disks can also be created of any size as long as the operating system can manage them (such as hard drive, CD-Rom, 5 1/4 floppies...).
So under Mac OSX, you can not longer use floppies. However, you can transform your floppy into a file which becomes an image disk. Thus under emulation, you can carry on using your data as you were working on the real support.
What are the ROM ?
Any emulator needs to get access to a piece of software which was inside the original Apple IIgs computer. This part of the memory is called ROM (Read Only Memory). Several versions of the ROM were created (ROM00, ROM01 and ROM03) by Apple for this computer.
Whithout any ROM, the emulator can not work at all. Therefore a file containing this internal software must be put with the emulator. This is why this file need to be put in the same folder than the emulator itself.
How do I get the ROM file ?
We cannot and will not provide the file. It is copyrighted by Apple Computer and we have not right to use it. To use an Apple IIgs ROM, you are supposed to own legally this computer and make an image of the ROM. In the other hand, you may find a copy of this file on some places on the Internet...
What is if the emulator
doesn’t start ?
This simply means that one of the required files is missing or that the Macintosh you are using does not match the system requirements (that is a Macintosh running Mac OS X 10.2 at least). Read the files given with the emulator to see if any of these two options are not correct, because the emulator should work...
What if I want to customise
the emulator ?
The first time you use the emulator, it works with a default configuration. However, you can change options to modify the behaviour of your virtual Apple IIgs as you want, by adding for example more memory, faster speed, full screen or many others tricks for having the best experience.
And if the emulator does not perform as wished, see the part on what if some functions do not work.