Connecting Multiple Disks to One SCSI ID

[Phipli]

Is there any feasible way to create a drive enclosure that supports multiple SCSI drives on a single ID, each disk using its own LUN? I realise this is basically what LUNs are for, but all I ever see online are basically server admin targeted glossary definitions of what a LUN is, and I have no idea how difficult it might be to create a SCSI disk 'hub'. I haven't seen hardware descriptions, existing products or software that mentions this feature.

My guess is...
It should be possible to have several drives on each SCSI ID. Potentially something like 56 drives total if it is 8 per ID?
You would need SCSI manager 4.3 (so an 040 or later for non boot disks, and a 660av, 840av or PPC for booting (if possible).
You might need a 3rd party disk driver.

Does anyone know much about this?

@cheesestraws @GRudolf94 @Bolle @bigmessowires @Melkhior @max1zzz

 

[Phipli]

For interest

 

[Melkhior]

If I remember from complicated SCSI chains back in the day, it's theoretically possible (that's what LUN are for, as you said), but practically too difficult to bother.
First, on the hardware side. Most drives of the era didn't handle LUN very well. Most of them are hardwired to LUN 0, with no option to have them answer to any other LUNs. Some, in particular older ones, might ignore LUN entirely and answer to all LUNs, effectively expecting the software stack to not use LUNs at all.
On the software side, you need everything in the stack to handle LUNs properly. If something is playing fast-and-loose with LUNs, things will fail in some subtle or not-so-subtle way.

Before trying with 'real hardware', I suggest using one (or more) of the SCSI-emulation thingamajig to test - they should be able to be programmed/configured to handle LUN properly, unlike vintage drives whose firmware you have no control about. No idea which one would already have support, or which one would be easiest to add support to.

I remember some SCSI CD-ROM tower using LUNs to connect 6 or 7 CD-ROM drives to a single SCSI ID back in the day. Lots of care had to be taken to make sure they would work, and usually came with a very small list of supported SCSI controllers and systems, I remember that I also saw similar towers using IDs instead and shipping with their own SCSI controller, which made thing a lot easier on everyone...

EDIT: thinking about it, the LUN-based ones were probably early stuff targeting the workstation market (so likely to have onboard SCSI), while the ID-based ones were later implementations and would have targeted PCs that were much less likely to have onboard SCSI