It was JodieC who mentioned that in this post, and in this subsequent post they said:

JodieC wrote on 2016-02-19, 16:50:

The product was a commercial product from a VTL vendor.

I assume VTL means Virtual Tape Library.

I can't find any information about it either.

Have you considered any other SCSI target solutions?

doshea wrote on 2023-04-25, 03:00:

It was JodieC who mentioned that in this post, and in this subsequent post they said: […]
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It was JodieC who mentioned that in this post, and in this subsequent post they said:

JodieC wrote on 2016-02-19, 16:50:

The product was a commercial product from a VTL vendor.

I assume VTL means Virtual Tape Library.

I can't find any information about it either.

Have you considered any other SCSI target solutions?

Thanks, I did not see that.
I saw another thread which requires setting up a FreeBSD 12.0 machine
PSCSI Disk Emulation success!

Are there other SCSI target solutions easier than that?

Other options I can remember:

- "VirDIS" which is commercial and I think requires its own hardware. I haven't tried it.

- Older versions (or perhaps even worse: patches for older versions) of SCST for Linux supported target mode on some parallel SCSI cards. I managed to find the cards but not the time to install a Linux distribution with the right kernel and then compile SCST. I think this is much harder than the FreeBSD option, although I hope maybe it will work better than FreeBSD.

- "8xxtarg" is a DOS program which works with some Symbios/LSI/NCR cards. It is very limited in what it can do but if you can program in C you can probably improve it fairly easily. I can provide some more information about what it can do if you're interested. It's at least fairly easy to run although it'd be easier if someone wrote a little tutorial (which I could probably do at some point).

I didn't find FreeBSD or 8xxtarg to be perfect. I couldn't get a Macintosh to talk to either of them if I recall correctly, and had trouble with Linux, but DOS and Windows were fairly happy talking to them I think. I have a lot of notes somewhere.

doshea wrote on 2023-04-25, 09:47:

- "8xxtarg" is a DOS program which works with some Symbios/LSI/NCR cards. It is very limited in what it can do but if you can program in C you can probably improve it fairly easily. I can provide some more information about what it can do if you're interested. It's at least fairly easy to run although it'd be easier if someone wrote a little tutorial (which I could probably do at some point).

That would be nice.
Do you need to connect 2 SCSI controllers by cable then, to use that ramdisk?

Yes, you need to connect them together with a cable and with termination set up as you would for any other device connections.

On the target (emulated/RAM disk) machine, you need to run that 8xxtarg program, which isn't a TSR or anything, it runs in the foreground, so it ties up the whole machine. Maybe it can run under DESQview or Windows 3.x or some other multitasker which doesn't mind a program directly accessing a PCI device, or maybe it can be run in a virtual machine with PCI passthrough, I don't know.

8xxtarg is pretty ugly, it prompts you for some non-obvious parameters on startup like the SCSI bus clock speed. I'm not sure how much some of the matter though! It will let you save the RAM disk to file but it's a non-standard disk image file format, I think it was something weird like a normal disk image but with a CRLF-terminated line at the start containing some disk parameters, or something weird like that. It could probably be made a lot nicer without too much work. I've been meaning to get in touch with the author of this post to see if they ever improved it. I would really like it to show some information about activity and throughput, allow the settings to be specified on the command-line, use normal raw disk images, and perhaps do I/O directly to a file so the entire image doesn't need to be in RAM (let SMARTDRV or something do some caching for me).

I've used 8xxtarg mostly with a Symbios Logic SYM22801 card (based on the SYM53C876 chip). I think I have a card with a 53c810 on it which I haven't tested 8xxtarg with so much, if anyone is thinking of buying one of those I could double-check that it works.

What kind of use cases are you considering? I might have some advice I can offer about whether I've tried that myself, or might be able to test it for you.

Well, I always had interest in SCSI networking.
In my younger years, I've connected an 810 and an 875 together and used it for CDROM-sharing and a shared HDD on that bus (one computer Win9x, other computer NT4 with hiding the FAT partition). A SyQuest has been used with write protect setting too.

Here some other postings:
BIOS update for 810 & disks > 8 GB: INT13 Extensions to SDMS 3.0 & 4.0 - SCSI by NCR / Symbios Logic / LSI Logic
Adaptec SCSI bridge: Extending a SCSI bus with Adaptec AIC-3860Q (2940U2W and more)
BIOS update for Adaptec 274xW/284x & disks > 8 GB: Showing some love for Adaptec's ugly ducklings: Adding big drive support to EISA and VL controllers

Disruptor wrote on 2023-04-25, 12:13:

Well, I always had interest in SCSI networking.

It used to just be a means to an end for me, but I realised more recently how powerful it is!

In my younger years, I've connected an 810 and an 875 together and used it for CDROM-sharing and a shared HDD on that bus (one computer Win9x, other computer NT4 with hiding the FAT partition). A SyQuest has been used with write protect setting too.

Nice!

Here some other postings:

Thanks, they look interesting, I'll try to read them later.

I remember that my goals are:

- Something I can use to emulate a hard drive for a 68k Macintosh: neither FreeBSD with an Adaptec card, nor 8xxtarg achieve this.

- Have the storage for retro PCs be hosted on a modern machine where I can snapshot the disk image and possibly mount it in an emulator. I think I managed to achieve this with FreeBSD to a limited extent. I'm not a FreeBSD expert so I had something like this if I recall: retro PC --SCSI--> FreeBSD --iSCSI--> Linux. I think I could achieve something similar with 8xxtarg if it could use a file on a network drive, since even if it only supported a raw file, I could use qemu-storage-daemon to mount a qcow2 disk image (which supports snapshots) on a file mountpoint where it will appear as a raw disk image. I was really hoping to get reliable SCSI before I tried this part though.

doshea wrote on 2023-04-25, 12:05:

Yes, you need to connect them together with a cable and with termination set up as you would for any other device connections.
...

Just curious, the SCSI cable used in target mode is a standard SCSI cable, or it has special wiring like cross-over cable?

sangokushi wrote on 2023-04-26, 17:09:

Just curious, the SCSI cable used in target mode is a standard SCSI cable, or it has special wiring like cross-over cable?

Standard cable. Just stupid daisy-chaining with termination ofc.