After googling and googling and more googling, burning multiple bootable cd-rom's and searching for experts, Marco (our engineer) found a bootable cd-rom especially for one of the iMac's we bought. Despite this good news, we know it is not enough... What we see on the iMac G4 with OS9.2.2 is not what the cd-rom's showed 20 years ago.
Cd-Roms are bound to hardware?
The iMac G4 was released in 2002, and is one of the last official PowerMacs running an OS9 system. There is a 9 year gap between 2002 and the year the “BlindRom v.0.9” was released (in 1993). BlindRom v.0.9 (1993) and Doors of Perception 1 (1994) are the two lucky cd-rom's we played first. However, it's hard to read some of the pictures because of the running speed of the cd-rom. Later, I found that there are two main reasons for this problem. First, the CPU's clockrate is different, as is the optical disk drive's read frequency. Second, cd-rom's made in those years are bound to hardware and are rarely verified by firmware.
Hardware matters
'The capacity of a CPU (Central Processing Unit) is expressed in "Hz", the higher the clock rate (Hz) the faster the computer process. For a cd-rom, the speed of the cd/dvd drive also determines the output of the cd-rom's content. A dvd-drive with 150KB/s rate reads 150KB of database per second. A modern cd/dvd drive can only be faster and faster. An iMac G4 has a 800MHz PowerMac CPU with 32X Combo CD-RW/DVD-ROM Drive, while my MacBookPro bought in 2013 has an Intel 4 cores CPU 2.8GHz clock rate and a HL-DT-ST DVDRW GS31N (model number) dvd drive.
Back to where they're supposed to be
We need to know a 1993 computer's clock rate and optical disk drive speed The best way is to bring back the computer environment exactly the same as it was 20 years ago. It will be much harder to find the right hardware and collect the right knowledge a few years from now. We invited Hack42, one of the biggest hacker group in the Netherlands, to help us collect the materials needed and recreate the original experience!