 Cisco 3845 C3845-VSEC-SRST/K9 with PVDM2-64 Router Single AC 512D/256F CISCO3845 US $995.00 
|
 Sangoma A20002E 4 FXO analog card PCI Express US $371.00
|
 Sangoma A20010E 20 FXO analog card PCI Express US $1,495.00
|
 Sangoma A20010 20 FXO analog card US $1,495.00
|
 Sangoma A20009E 18 FXO analog card PCI Express US $1,396.00
|
 Sangoma A20009DE 18 FXO analog card PCI Express w/ EC H US $1,678.00
|
 Sangoma A20009D 19 FXO analog card w/ EC HW US $1,678.00
|
 Sangoma A20009 18 FXO analog card US $1,396.00
|
 Sangoma A20008E 16 FXO analog card PCI Express US $1,214.00
|
 Sangoma A20008DE 16 FXO analog card PCI Express w/ EC H US $1,496.00
|
 Sangoma A20008D 16 FXO analog card w/ EC HW US $1,496.00
|
 Sangoma A20008 16 FXO analog card US $1,214.00
|
 Sangoma A20007E 14 FXO analog card PCI Express US $1,115.00
|
 Sangoma A20007DE 14 FXO analog card PCI Express w/ EC H US $1,397.00
|
 Sangoma A20007D 14 FXO analog card w/ EC HW US $1,397.00
|
 Sangoma A20007 14 FXO analog card US $1,115.00
|
 Sangoma A20006E 12 FXO analog card PCI Express US $933.00
|
 Sangoma A20006DE 12 FXO analog card PCI Express w/ EC H US $1,215.00
|
 Sangoma A20006D 12 FXO analog card w/ EC HW US $1,215.00
|
 Sangoma A20006 12 FXO analog card US $933.00
|
 Sangoma A20005E 10 FXO analog card PCI Express US $834.00
|
 Sangoma A20005DE 10 FXO analog card PCI Express w/ EC H US $1,116.00
|
 Sangoma A20005D 10 FXO analog card w/ EC HW US $1,116.00
|
 Sangoma A20005 10 FXO analog card US $834.00
|
 Sangoma A20004E 8 FXO analog card PCI Express US $652.00
|
 Sangoma A20004DE 8 FXO analog card PCI Express w/ EC HW US $934.00
|
 Sangoma A20004D 8 FXO analog card w/ EC HW US $934.00
|
 Sangoma A20004 8 FXO analog card US $652.00
|
 Sangoma A20003E 6 FXO analog card PCI Express US $553.00
|
 Sangoma A20003DE 6 FXO analog card PCI Express w/ EC HW US $835.00
|
 Sangoma A20003D 6 FXO analog card w/ EC HW US $835.00
|
 Sangoma A20003 6 FXO analog card US $553.00
|
 Sangoma A20001D 2 FXO analog card w/ EC HW US $554.00
|
which backplane is better for real time systems VME or PCI?
They say that PCI is not so suited for mission critical systems and it has to be VME. The ADA language is also considred to be more suitable for mission critical systems as compared to java / C++/C.
We are assuming you are comparing VME to a "motherboard" type design with a PCI bus. If you are talking cPCI then the mechanical gets a little less important but multi processor moves up the ladder (cPCI cannot do symmetric multi processing without a bunch of hoop jumping)
I have worked with all 3 and been in the "mission critical business" for last 25 years, so here are my comments:
Start Mechanical:
The "basic PCI" bus is finger edge which means that moisture, shock, oxidation, vibration can all degrade the connection between the board and the back plane. Systems fail because of this
VME and cPCI are a pin and socket design - with din rails and screw "lock downs” the connector is press fit - so it is "airtight”. Very immune to vibration etc; systems have been known to run for 15+ years.
If you look at the connector between VME and cPCI; I would want VME; just more "beef", especially if you are going to remove cards - cPCI pins bend over really easy. If you want hot swap (and you have designed the software to take advantage of it) then cPCI has the edge, but the software and OS get really complicated (heartbeats etc)
VME also has a large number of suppliers of extended temp boards - up to -40C to +85C. which is where a lot of mission crit apps are
"Real time"
Architecture of the communications:
VME is a multi processor system: I can have multiple CPU running in parallel and have one "fail" and the others take over. Systems can be built with up to 21 CPU boards on a single back plane. Adding VITA 31.1 gives you a switching matrix to add a redundant communication channel
PCI is not set up to do that, you can build in some redundancy but it takes work [yes there are redundant PCI systems out there but generally speaking VME lends it self better]
cPCI is horrid for multi processing - unless you use Picmg 2.16, which lets you, set up a confederation. then the whole discussion gets hazy (and I don't want to type that much)
Software
About equal: there are many OS's that are real time; the "real" question is do you need preempt able and deterministic or just real fast.
That will decide the real time question; if "x" happens, how long can the system not respond to it? What happens if the system is "busy" and it takes a long time to respond to "x". If bad things happen if "x" is not taken care of "NOW" then you need "hard real time" which is a preempt able kernel. It should also be deterministic: so you know the worse case for response to an "interrupt".
As far as ADA and C++/C -
very few new applications are ADA; and it is harder and harder to find support for this language, even the US GOV who required ada for some applications has backed off and allows C. Not sure about how much C++ is mission critical comes down to compliers and if they are certified or not. software practices fall into this discussion - "real" mission crit will be CMM SEL level 5 or "a high 4".
As far as "mission critical"; that is a very over used term [like mission critical accounting packages (lol)]: mission critical really means that if something fails, people die or really "bad" things happen (like airplane crashes, brakes fail, bomb drops on "good guys" - stuff like that); very few of those type of applications out there, but I KNOW a LOT of them use VME. [power plants, Nasa, Navy, Airforce, Army, etc]
Based on the little information (reading between the lines that you have a mission crit app) I would go with VME, C and one of the real time OS's (LynxOS and VxWorks come to mind but there are others)
You are welcome to email if you have more questions or want more information.
Thanks,
Jewells
Whats On My YouTube Today?
Magma PCI Expansion Boards and Backplane
Here Are A Few Items From Amazon You Might Be Interested In.
 Adaptec 2236600-R Internal Mini-SASX4 SFF-8087 to 4-SATA Fanout Cable (0.5 Meters) List Price: Sale Price: $27.79 You save: $17.20 (38%)  Eligible for free shipping!Availability: Usually ships in 2-3 business days  |
 Intel Server System w/NA. Pwr Cord List Price: Sale Price: $465.00 You save: $281.59 (38%) Eligible for free shipping!Availability: Usually ships in 1-2 business days |
 ICY DOCK Storage MB994SP-4S 4 In 1 SAS/SATA Hot Swap Backplane RAID Cage Black Retail List Price: Sale Price: $71.42 You save: $53.96 (43%) Eligible for free shipping!Availability: Usually ships in 1-2 business days |
Items recently purchased on this site:
Thanks for visiting!
Tags: hardware