Yeah but thats just connecting cards together...
I mean other than proving it can be done, which we already know you can put a SCSI device in a chain, it shows nothing...

Can you use it for anything useful?

What software will you use to look at the devices attached to one controller on another other than at the cards firmware level?

I remember when you posted that original post and scratched my head wondering where it would lead.

nice,

That's an odd setup.
is it

first pc
SCSI controller
- cable -
second pc
SCSI controller - SCSI controller
- cable -
third pc
SCSI controller - SCSI controller
- cable -
fourth pc
SCSI controller - SCSI controller
- cable -
fifth pc
SCSI controller - SCSI controller
?

How many meters of cable do you have between the first bridge & device and did you use extra software to allow for communication between the two scsi controllers per pc
Or am I missing something, like both scsi controllers in one pc are also hooked up by cable. If this last scenario is the case i'm less impressed.

edit: ok so you're running this as a one bus setup. not very impressive.

In the other thread I've quoted that it can be useful to share CDROMs using this technique, perhaps even SCSI scanners.
You also may share hard disks, but the main thing is to prevent initiators (controllers) to write while being unable to synchronize Operating system's caches and buffers!
Sharing a SyQuest also should not be a problem.
Next thing to examinate is IP-over-SCSI.

Unfortuneately I just used 3 PCs in that setup.
The disk was at the U320 controller in an extra PC, on the other end I just booted with an extra SCSI controller and ran SpeedSys.
Despite the drop in transfer rate, the additional latency in this chain was below 200 µs.
It were ~ 16 meters of cable in total. However, each of the LVD connections could have had 12.5 metres if I just have had the cables.
And I noticed spikes in the access time when SE buses got close to the 3 meter limit. The maximum limit could have been 77.5 metres.

What I also could examine were problems with sync negotiation. The longer the connection was the more it was declined to try an unimpossible too fast wide & sync negotiation. In the end I had to limit it manually.

I'm still confused about your cabling. Any chance of getting some photos of it ?

edit: I'm just trying to understand if you're running this as one bus, or some software/configuration on the middle pc is involved .

edit: nevermind.

The most impressive part would be to see a single 12.5 meter long SCSI LVD cable. Internal of course, some of the offices have external ones.

IP-over-SCSI or iSCSI as its more widely known is interesting...
How are you going to do that one?

Nah, I don't have a 12 metre internal LVD SCSI cable.
And the external LVD ones I've seen are just VHDCI to HD68. Ah, I have one LVD certified HD68 to HD68 too. But both are far too short.

IP-over-SCSI is not iSCSI
https://ipoverscsi.sourceforge.net

Disruptor wrote on 2023-11-18, 10:22:

Nah, I don't have a 12 metre internal LVD SCSI cable. And the external LVD ones I've seen are just VHDCI to HD68. Ah, I have one […]
Show full quote

Nah, I don't have a 12 metre internal LVD SCSI cable.
And the external LVD ones I've seen are just VHDCI to HD68. Ah, I have one LVD certified HD68 to HD68 too. But both are far too short.

IP-over-SCSI is not iSCSI
https://ipoverscsi.sourceforge.net

Yeah interesting...
https://www.linuxjournal.com/article/2344

What are you thinking of doing with that then, by the looks of the white papers its only in test stages any way.

Well, that are different implementations at different stages.
The one I quoted seems promising with NCR/Symbios/LSI 875 adapters.
The one you quoted is an incomplete attempt on an Adaptec 1520/1522 adapter.

The one I posted is the initial write up on the subject... Thats where it started.

Its much along the same lines as using firewire cards to network two PCs using the TCP/IP, or even USB for that matter.
Its only real interest is how to over come the problems you would get because youre using the protocol rather than the cables.

Only tangentially relevant, as a curiosity, but Ethernet over SCSI was a thing.

The Mac world had the Asante EN/SC-10T .

https://web.archive.org/web/20060420095149/ht … idges/EN_SC.asp

There may have been commercial/industrial applications but the home users who were most into this kind of setup back in the day were Amiga owners, trying to set up PC/Amiga "twin" systems. Peak interest was around 94-98ish I think. The typical idea was to use a larger PC mid tower and have a 486 or Pentium board for the PC side, possibly running 9x, possibly running linux, or dual boot, that could do things like have an up to date modem installed or take the network card that early cable internet providers sent with their cable modems. Then also installed in the same case would be an Amiga 1200 motherboard and probably Viper accelerator with the SCSI option. Then device sharing through SCSI was set up. I had the concept mentally bookmarked but never got into the details at the time. Probably because I never got a SCSI solution for my A1200.

It would be more impressive if they got it to work over IDE for a floppy controller.

Its the one good thing about owning lot of old hardware you dont care about, the weird things you can do with it all.

darry wrote on 2023-11-18, 14:42:

Only tangentially relevant, as a curiosity, but Ethernet over SCSI was a thing.

The Mac world had the Asante EN/SC-10T .

https://web.archive.org/web/20060420095149/ht … idges/EN_SC.asp

The rascsi emulator allows for an ethernet device to be emulated, though software seems to be limited to macintosh & sharp x68000

darry wrote on 2023-11-18, 14:42:

Only tangentially relevant, as a curiosity, but Ethernet over SCSI was a thing.

The Mac world had the Asante EN/SC-10T .

https://web.archive.org/web/20060420095149/ht … idges/EN_SC.asp

Yes, I have one Mini EN/SC (scsi to 10baseT and 10base2) that has been sitting around for a decade or 2, never got a chance to use it.

ElectroSoldier wrote on 2023-11-18, 16:31:

It would be more impressive if they got it to work over IDE

There was a product announced that did that, it showed up at a trade show but afair never materialized commercially, maybe something about patents? I remember posting about it somewhere around 10 years ago, but cant find it now 🙁 It worked by implementing an active bridge connected over ATA100 pretending to be a small HDD to both computers with drivers exchanging messages by writing to designated files/LBAs. 1Gbit speed with lower latency than ordinary 1Gbit ethernet around ~2000, aimed at budget cluster computing, ghetto InfiniBand/Fibre Channel.

IDE is very fast and has been used for hacks before.
IDE EPROM programmer 1:
https://hackaday.com/2011/02/03/stk200-pocket … nge-programmer/ https://web.archive.org/web/20110209065824/ht … a2isp/main.html
by "simply" telling Linux that IDE port is LPT, “modprobe parport_pc io=0x170 irq=none,none,none” is all it takes 😀
IDE EPROM programmer 2:
http://www.loet.de/flasher_en.html
ATA-to-ISA:
http://www.controllersandpcs.de/ataio.htm

rasz_pl wrote on 2023-11-19, 09:47:

There was a product announced that did that, it showed up at a trade show but afair never materialized commercially, maybe somet […]
Show full quote

ElectroSoldier wrote on 2023-11-18, 16:31:

It would be more impressive if they got it to work over IDE

There was a product announced that did that, it showed up at a trade show but afair never materialized commercially, maybe something about patents? I remember posting about it somewhere around 10 years ago, but cant find it now 🙁 It worked by implementing an active bridge connected over ATA100 pretending to be a small HDD to both computers with drivers exchanging messages by writing to designated files/LBAs. 1Gbit speed with lower latency than ordinary 1Gbit ethernet around ~2000, aimed at budget cluster computing, ghetto InfiniBand/Fibre Channel.

IDE is very fast and has been used for hacks before.
IDE EPROM programmer 1:
https://hackaday.com/2011/02/03/stk200-pocket … nge-programmer/ https://web.archive.org/web/20110209065824/ht … a2isp/main.html
by "simply" telling Linux that IDE port is LPT, “modprobe parport_pc io=0x170 irq=none,none,none” is all it takes 😀
IDE EPROM programmer 2:
http://www.loet.de/flasher_en.html
ATA-to-ISA:
http://www.controllersandpcs.de/ataio.htm

What somebody actually tried to market a device that networked two or more machines together using the IDE connectors?

Back in the mid 90's I got my first cd and put it in an external case. It was between two buslogic controllers in two computers. The computers changed as did the devices in between, canon scanners, plextors, pioneer changers and slot dvd and nakamichi changers. It worked fine. devcon I think it was could enable and disable scanning for hard disc on 2000 up, so they were shared too. Worked fine.