Have downloaded minirt_900.gz in the faint hope that it will somehow lead me to a way of obtaining Knoppix 9.0. Have run into two issues so far.
[GvR] The original minirt is just a small file (932KB) included in the Knoppix DVD (4.36GB) that is used during the boot of Linux.

1. whereas your post gives the download size of minirt_900.gz as 23.5MB, Windows file manager gives te size as 63.7 MB (66,866,176 bytes)
[GvR] I just downloaded the file from above link http://s94002264.onlinehome.us/grub/k900/minirt_900.gz and have the correct file size of 24'742'814 bytes.

2. I've searched for the meaning of minirt with Duckduckgo, but the only hit is your post above, so I still have no idea what this file contains or is meant to do
[GvR] The minirt is a init ramdisk loaded by the boot loader at the same time as the Linux kernel that contains add-on boot files necessary to bootstrap Linux.
I customized the original minirt from Klaus Knopper Knoppix 9.0 to add some functionality such as booting from an ISO file and from the network. More precisely I updated the boot script and added some missing Kernel modules to support more network cards and hardware typically used in virtualized environment.

3. I don't have a hash or checksum to test the integrity of the file.
[GvR] Please find here the MD5: 9d150bac17e1598391d0c3bfeb9c1123 *minirt_900.gz

PS. I have a (somewhat) working copy of Knoppix 8.6.1 At least, it boots reliably from flash, but has a fatal flaw it shares with the last six or more versions - Synaptic doesn't work, and I haven't found a way to fix or replace its function. So there is no way to install or update any apps, including virus signatures for Clamv.
[GvR] Please see this post: http://knoppix.net/forum/threads/450...l=1#post189973

I've also been unable to use my desktop monitor with any variants of Knoppix 7.xxx or 8.xxx (the display will not size to fit, so no functions are accessible via gui) and am forced to use my laptop's screen. This is why I keep looking for the latest version, in the faint hope that these issues will have been fixed.
[GvR] Did you try the kernel boot Cheatcodes ?