i was trying to have a document about CEE,RoCE,iWarp, RDMA etc..
I searched and find CEE is short for Convergence Enhanced Ethernet, and it includes 802.1Qbb, 802.1Qau, 802.1Qaz standards. Can I look RoCE and iWarp as the realizations of CEE standards, or CEE includes RoCE, iWarp? Another question is what the latest starndards or technologies for RDMA?
Really need help for these information. Thanks in advance.
The more common term now Data Center Bridging (DCB) IEEE 802.1. CEE was an proposal(including several standards) by several companies to improve datacenter networking. They are being (or have been) developed respectively by two separate standards bodies:
The IEEE Data Center Bridging Task Group of the IEEE 802.1 Working Group
Internet Engineering Task Force (IETF).
Convergence Enhanced Ethernet or Converged Enhanced Ethernet (CEE) was defined from 2008 through January 2009 by group of including Broadcom, Brocade Communications Systems, Cisco Systems, Emulex, HP, IBM, Juniper Networks, QLogic
Another question is what the latest starndards or technologies for RDMA?
Latest Standard is RoCEv2 and iWarp
Related
I want to compare two RTOS (e.g. -> Keil-RTX ,Ucos-iii and freertos), but I do not know on what parameters I need to compare them for e.g. Memory footprint, certified etc.
On which points do we compare RTOS ?
You need to compare them on the parameters that are important to your application and meeting its requirements. Those may include for example:
Context switch time
Message passing performance
Scalability
RAM footprint
ROM footprint
Heap usage
OS primitives (queues, mutex, event-flags, semaphores, timer etc.)
Scheduling algorithms (priority-preemptive, round-robin, cooperative)
Per developer cost
Per unit royalty cost
Licence type/terms
Source or object code provided
Availability integrated middleware libraries (filesystem, USB, CAN, TCP/IP etc.)
Safety certified
Platform/target support
RTOS aware debugger support
RTOS/scheduling monitor/debug tools availability
Vendor support
Community support
Documentation quality
The possible parameters are many, and only you can determine what is useful and important to your project.
I suggest selecting about five parameters important to your project, and then analysing each option using the Kepner-Tregoe method. For each parameter you assign a weight based on its relative importance, you score each solution against each parameter, and then you sum the score x weight for an over all score. The method takes some of the subjectivity out of selection and perhaps importantly provides evidence of your decision making process when you have to justify it to your boss.
I am trying to use PERL to extract paragraphs from a text. However, the code does not generate the results I expect. I benefit a lot from the answers by Zaid from this post extracting paragraphs from text with perl. Here are the codes I wrote:
#
my $string = <<'TEXT';
Assembly and Manufacturing
The Company's assembly and manufacturing operations include PCB assembly
and the manufacture of subsystems and complete products. Its PCB assembly
activities primarily consist of the placement and attachment of electronic and
mechanical components on printed circuit boards using both SMT and traditional
pin-through-hole ("PTH") technology. The Company also assembles subsystems and
systems incorporating PCBs and complex electromechanical components, and,
increasingly, manufactures and packages final products for shipment directly to
the customer or its distribution channels. The Company employs just-in-time,
ship-to-stock and ship-to-line programs, continuous flow manufacturing, demand
flow processes and statistical process control. The Company has expanded the
number of production lines for finished product assembly, burn-in and test to
meet growing demand and increased customer requirements. In addition, the
Company has invested in FICO, a producer of injection molded plastic for Asia
electronics companies with facilities in Shenzhen, China.
As OEMs seek to provide greater functionality in smaller products, they
increasingly require advanced manufacturing technologies and processes. Most of
the Company's PCB assembly involves the use of SMT, which is the leading
electronics assembly technique for more sophisticated products. SMT is a
computer-automated process which permits attachment of components directly on
both sides of a PCB. As a result, it allows higher integration of electronic
components, offering smaller size, lower cost and higher reliability than
traditional manufacturing processes. By allowing increasingly complex circuits
to be packaged with the components placed in closer proximity to each other, SMT
greatly enhances circuit processing speed, and therefore board and system
performance. The Company also provides traditional PTH electronics assembly
using PCBs and leaded components for lower cost products.;
TEXT
local $/ = "";
open my ($str_fh), '<', \$string;
while ( <$str_fh> ) {
print "New Paragraph: $_\n","*" x 40, "\n" ;
}
close $str_fh;
#
The text is from annual report of this company https://www.sec.gov/Archives/edgar/data/32272/0000950147-97-000151.txt.
I expect the code returns the paragraphs, however, I got the whole text back.
Would anyone help me with this issue? I am quite confused with these errors.
Thanks so much!!!
Best Regards
When I run the code you posted here, it works fine. It prints each paragraph separately.
Most likely, the lines between paragraphs are not completely blank. If there are spaces on the "blank" lines, then they don't count as paragraph separators.
Can tags and readers do some calculations in a RFID system? I found many papers designed security protocols to enhance the security of RFID systems. In those protocols, tags and readers are required to do necessary calculations, such as exclusive OR (XOR), random number generation, and even hash operation and so on.
However, to my understanding, tags and readers do not have the calculation ability, then how to implement these protocols? We need design special tags and readers? Thank you very much!
This heavily depends on the type of RFID system (frequency, communication standard, etc) and the type of tag (passive or active/semi-passive).
For instance, with UHF backscatter systems, passive tags usually contain only a small memory (and logic to process commands).
In the HF range, there is ISO/IEC 14443. For that standard, there exist lots of passive tags (contactless smartcards) that contain a processing unit and can even execute complex program code. ISO/IEC 15693 (same frequency range, different standard) passive tags usually conain only memory and some additional control logic (e.g. password-based locking/unlocking). The same applies to tags in the LF range.
Active tags (regardless of the standard, as long as the standard contains some form of command response protocol if you want to interact with that functionality), however could do pretty much any calculation if they contain an appropriate processing unit.
According to wikipedia (I read the German version) one can build complex microchips into any RFID. It's also possible to add Sensor as for example GPS. RFID chips do not need to be passive, they can have a battery to power the whole RFID chip (active) or just the microprocessor (semi passive).
In Phillip Haller's PhD thesis he mentioned in section (5.1 Future Work) that one of the interesting areas of research would be to extend the framework with ambient references and he cited Van Cutsen's paper.
Excerpt:
The Scala Actors library includes a runtime system that provides basic
support for remote (i.e., inter-VM) actor communication. To provide
support for fault tolerancy (for instance, in mobile ad-hoc networks),
it would be interesting to extend the framework with remote actor
references that support volatile connections, similar to ambient
references [36]. Integrating transactional abstractions for
fault-tolerant distributed programming (e.g., [52, 142]) into Scala
Actors is another interesting area for future work.
And citated paper is:
[36] Tom Van Cutsem, Jessie Dedecker, Stijn Mostinckx, Elisa Gonzalez
Boix, Theo D’Hondt, and Wolfgang De Meuter. Ambient references:
addressing objects in mobile networks. [...] pages 986–997. ACM, October
2006.
Is this what Akka did? If not, do you think it is still relevant to research this area given the fact that Akka exists today?
Yes, this is possible with Akka.
There are 2 ways to achieve this as far as I know:
akka-remote - Provides remote actor ref, but you need to decide where each actor should exsist.
akka-cluster - Provides cluster sharding. Automatically manages actor physical location and ensures that given shard (Actor) is present on at most one node in the cluster.
Assuming I model a complete system correctly, according to the Modelica syntax, are the compilers 'mature' enough to handle it?
I need to model a system with at least 15 connected components, each components is relatively simple, mathematically speaking, only algebric equations. Modelica is very appealing to me but I am a complete beginner and this project is important to me so I'm a little bit afraid to commit to Modelica.
I understand that compilers can't fully simulate all of the standard library examples and models, how can I know what are the exact limitations?
Thanks.
Well, it depends quite a bit on what tool you choose of course. I can tell you from personal experience that over 10 years ago I used Dymola in a project at Ford Motor Company where we modeled an engine (combustion), transmission (mechanisms and hydraulics) and chassis (multi-body representation). The resulting system had 250,000 equations and certainly hundreds if not thousands of components and connections. You can find more information about the project in a paper I wrote.
Of course, it depends on other things besides the size of your models. Most Modelica tools do not really support variable structure (DAEs with variable index) and others have limitations with respect to some of the language constructs that they fully support (which therefore means some libraries are not fully supported).
Unfortunately, at the moment there is not a comprehensive way to qualify the support from different tools but this is something that the Modelica Association recognizes is a problem and they are working on it.
But overall, Modelica is quite mature and is used in many, many industrial projects. You can find the proceedings from the previous 8 Modelica Conferences at http://www.modelica.org/ and you will see that many big name companies (Ford, BMW, GM, Toyota, Airbus, etc) have published material there.