Trying to utilize an old VST Firewire drive with my mini

If the hub is between the drive and the mini, I would disconnect that and cable the drive and mini directly - hubs can create some bizarre problems, and if nothing else cabling directly will remove a possible issue in troubleshooting this.

If if still doesn't appear, go back to the System Profiler and note the 'BSD Name' of the external drive (mine is disk2s10 for example) showing for it under the FireWire entry. Then open terminal (in applications>utilities) and enter the following command:
/usr/sbin/diskutil mount /dev/disk2s10
(replace the disk2s10 in this example with the name showing for your drive) and press enter.

If the drive is mountable, that should do it.

With the drive connected and powered up, open Disk Utility (in applications>utilities). Does the drive appear on the left? If so, then all you need to do is click on the drive in the left panel, then the Erase tab and reformat it using the MacOS Extended (journaled) option.

If it doesn't appear in the left-hand panel, you may have a faulty firewire cable, or the drive may not have a compatible chipset.... though that seems unlikely.

What you should see in Disk Utility is TWO entries for your internal drive. The first will give the drive size and a model number, the second should be indented and have a name that coincides with the name you see for the drive on the desktop.

Thus with the external drive connected, you should have a THIRD entry below the first two. If you see that, that's the external.

The FW cable would be my first suspect, yes, though it is possible that the drive itself, or the enclosure it is in are not compatible. That would be unusual with any recent drive/enclosure, but is possible with an earlier device.

That it mounts on the Cube only tells us for sure that it is compatible with that system - not that it is with the mini. While there weren't any changes to the FW standard between those two systems, it has been known for drives that worked with earlier systems to fail to function with newer ones due to chipset issues. I hasten to add that it isn't a common thing by any means however.

That it shows in the profiler tends to suggest it is correctly recognized by the mini however.

When you have it connected to the cube and look at it in Disk Utility, what does it show as it's format?

On the Cube, with the external connected and mounted, run Disk Utility, and select the first entry for the drive - the one with the size and model. On the right you should then see, in addition to the other buttons, one for Partition. Click that, then click the Options button at the bottom. Select Apple Partition if your mini is a G4 system, or GUID if it is an Intel. Go ahead and partition the full drive, and then format as MacOS Extended (Journaled). That will ensure it is set up correctly to work with the mini.

After that, connect it to the mini, and power it up to see if it then mounts.

A couple of further thoughts......

VST was bought out if I recall - last I heard it was part of SmartDisk, which I think was subsequently bought out too. There are some support pages at http://sdkbase.smartdisk.com/display/2n/index.asp?c=cpc=e72ylkXWR8u0YnrbMviY&cpc =&cid=1&r=0.7641413 however, which may be worth looking at, with particular emphasis on looking for possible driver updates, since it may be that MacOS doesn't have a driver compatible with it. There had been driver issues with VST drives in MacOS 9.

There's a page there as follows:
+Troubleshooting your FireWire hard drive in Mac OS X+

+If your FireWire hard drive is no longer mounting, or you are unable to access the files stored on the drive. Please try the following and test between each step:+

+-Check our drivers section for drivers for Mac OS X, most FireWire drives do not require drivers, but some legacy VST drives do.+
+-Check all FireWire cables. Connect the cable directly to back of the machine, not through a hub or other device.+
+-Check the FireWire ports. Test other FireWire devices on the ports to verify they are working. If you have multiple FireWire ports, try each port.+
+-If your drive requires an AC adapter, please check all cables, and make sure the drive is switched ON in the back. Test different AC power plugs, and bypass any power strips.+
+-Test the drive on another machine.+
+-If you are still unable to get the drive to mount, the partition on the drive may be damaged or corrupted and you may need to repair or reformat the drive.+

+-You can try third party disk utilities such as Disk Warrior, Norton Disk Doctor, or Data Rescue X to recover or repair the drive.+
+-If you are not concerned with the data, you may be able to reformat the drive. You can use Apple Disk Utility (Applications, Utilities, Disk Utility) to erase or repair the drive.+
+-If you need data recovery, you may need to contact a Data Recovery company to retrieve your data.+

Also, it's not clear what version of MacOS your Cube is running, but I assume it's OS X rather than MacOS 9? If it's 10.4.2 as suggested in your profile, then the drive obviously works with OS X, but possibly you installed a driver for it at some point in the past?

Excellent, thanks for letting us know that it's up and running! Hopefully you won't need any more assistance, but if you do, don't hesitate to ask!