Talk:Star coupler

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Star couplers on DEC Alphas?

Is it really true that star couplers were used with Alphas? I thought they were only used with VAX's.

They certainly weren't used on later-generation Alphas as there was no interface (that I'm aware of) that could connect a CI to a PCI bus-based Alpha. (Just imagine the physical difficulties of connecting those four huge cables to PCI-sized I/O bulkhead panels!) And besides, when you were talking 100baseT or even Gigabit Ethernet, why would you use a 70Mb CI? What I can't remember was whether there was an interface that allowed the early Alphas to connect a VAXBI Bus card cage (from the Futurebus or what-have-you); from there, you could have used a BCI to get to the CI.

But even if it could be done, it certainly wasn't commonly done, though. I'm pretty sure all the "modern" systems in the VMS Development lab were using Etherneting (of one form or another) as their cluster interconnect.

Perhaps someone with a better memory about this than I will come along and clarify things for us both? :-)

Atlant 15:52, 10 October 2005 (UTC)[reply]

This was not that uncommon, when access to heritage equipment was required. Under OpenVMS, AlphaServers could use the CIPCA-AA card (max two per system for AS8400s) that used a PCI slot and another EISA slot for power to connect from PCI to CI. 130.76.64.16

I have a couple of DEC7000 systems - laserbus AXP - that came with XMI-bus CI adapters and star couplers. These were apparently used for disk arrays, not networking or clustering. I can't remember the model of the CI-SCSI interface, but it does exist.

66.69.192.118 21:54, 29 January 2006 (UTC) Doc[reply]

Did DEC use that name?

As far as I can recall (warning: my contact with DEC gear ended over 15 years ago), these things were described as star couplers, but always called "CI" cables etc (for "Computer Interconnect"). But then, I'm Australian; maybe this is a language difference? —Chris Chittleborough 12:51, 23 March 2006 (UTC)[reply]

Never mind, I just found out that DEC sold CI cables plus star couplers. —Chris Chittleborough 14:07, 23 March 2006 (UTC)[reply]

I think the DEC part numbers for the various Star Couplers were SC104 (for a four-port), SC108 (eight-port) and SC116 (for a later sixteen-port version). But I no longer have access to the Dick Best List (officially, the Option/Module List) so I can't say for sure.

Atlant 14:46, 23 March 2006 (UTC)[reply]