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Conference adissw::vme

Title:	VME Bridge Support - See note 231 for DWPVC status
Notice:	DEC VME support
Moderator:	MNATUR::LISTON

Created:	Wed Apr 26 1989
Last Modified:	Tue May 27 1997
Last Successful Update:	Fri Jun 06 1997
Number of topics:	295
Total number of notes:	1067

289.0. "Dual Alphas to Single VME Crate?" by AUSSIE::BEVERIDGE (Why use one word when ten will do?) Wed Feb 05 1997 05:46

Is is possible to connect two AlphaServers to a single VME crate using DWPVCs?

Any information on this would be very helpful.

This may be needed for redundancy.

Many thanks

Tim Beveridge
CSS Sydney

T.R	Title	User	Personal Name	Date	Lines
289.1	Yes, but ?????	ADISSW::TENHAVE		`Thu Feb 06 1997 13:41`	9
	Yes, at least under UNIX. What O/S do you want to use? What kind of things do you want to know? Tim
289.2	Dual CPUs in VME Crate	AUSSIE::BEVERIDGE	Why use one word when ten will do?	`Mon Feb 10 1997 20:38`	18
	We are trying to set up a system that has redundancy 'built-in' where there are several X25 lines coming in to the system. These lines have no redundancy, but they are purchaser provided. The spec requests that these lines are 'received' and the output of the FEP is to be dual redundant feeding to other parts of the system. One of the options is that the VME processor card have an ethernet port, and that two of the cards would give the redundancy that it requires. The problem is that if the processor in slot 0 fails, then the VME crate dies. The operating system is DIGITAL UNIX. Any ideas? Tim Beveridge Sydney Australia
289.3	Some possibilities...	ADOV01::MANUEL	Over the Horizon....	`Wed Feb 12 1997 11:16`	19
	Tim, There are a number of possibilities for redundancy, but what are you trying to achieve here - the crate and the power plug now become the single points of failure, is this really achieving redundancy. Surely two crates using an x.25 ethernet based router for your input lines and dual-homed ethernets between the crates and the alphas would be a more "redundant" consideration. I think there are some types of x.25 pads which can be dual homed as well. Do you really need the vme crates, you could achieve the same just going into the alphas with the same config. Perhaps you could give us a few more details of your configuration for more suggestions. Steve.