I have some questions regarding IP verification.
Suppose if a particular design/functionality from an IP specification is missed both in the RTL and the verification plan (Coverage points), how would you identify this bug?
Since it hasn't been implemented in RTL(missed from SPEC), we cannot identify from code coverage.
Please throw some light on this.
Thanks
Someone should be comparing the verification plan against the top-level IP specification. For each point in the spec, the question "how do we show we met this requirement?" needs a good answer.
(If the feature in question is not in there, then the top-level spec needs fixing!)
You could create a feature list and write your tests against that.
The design and testplan reviews generally involve the comparison of the IP specification to said designs and testplans. The IP spec writer is usually present, as well, and can identify points in the spec that are not covered.
Related
I'm pretty new to the subject of Supply Chain Security (SCS) and there are two important key-terms that I see being used quite heavily (provenance and attestation), but I'm not sure that I understand the difference between the two.
For reference, I've been reading the docs for two open source projects, SLSA and Sigstore, which use the terms provenance and attestation, but I do not understand what they really mean and neither one of these projects really define what they mean. Do these terms refer to a data format, process, or something else?
If someone can provide a clear definition as to what an attestation is and what provenance is, and can explain how they relate to each other, I would greatly appreciate it. Thanks.
From RFC 1035:
Authoritative Answer - this bit is valid in responses,
and specifies that the responding name server is an
authority for the domain name in question section.
So, what happens if this bit is set in a DNS query (QD=0)? Do most DNS implementations treat the packet as invalid, or would the bit simply be ignored?
The same question applies to other bits that are specific to either queries or responses, such as setting the RD bit in a response.
My guess is that these bits are simply ignored if they aren't applicable to the packet in question, but I don't know for sure or how I would find out.
I'm asking because I'm writing my own DNS packet handler and want to know whether such packets should still be parsed or treated as invalid.
You either apply the Postel's law ("Be conservative in what you do, be liberal in what you accept from others") - which is often touted as one reason/condition of the success of interoperability of so many different things on top of the Internet - or if you strictly apply the RFC you deem it as invalid and you can reply immediately with FORMERR for example.
In the second case, as you will get deviating clients (not necessarily for your specific case, in the DNS world they are a lot of non conforming implementations on various points), you will need to define if you create specific rules (like ACLs) to accept some of them nevertheless because you deem them to be "important".
Note that at this stage your question is not really programming related (no code) so kind of offtopic here. But the answer also depends what kind of "packet handler" you are building. If it is for some kind of IDS/monitoring/etc. you need to parse "as much as possible" of the DNS traffic to report it. If it is to mimick a real world DNS resolver and just make sure it behaves like a resolver then you probably do not need to deal with every strange deviating case.
Also remember that all of this can be changed in transit, so if you receive some erroneous things it is not obviously always an error coming from the sender, it could be because of some intermediary, willingly or not.
To finish, it is impossible to predict everything you will get and in any wide enough experiment you will be surprised by the amount of traffic you can not undersand how it comes to exist. So instead of trying to define everything before starting you should instead iterate over versions, having a clear view of your target (parsing as much as possible for some kind of monitoring system OR being as lean/simple/secure/close to real world features for DNS resolution as possible).
And as for "how I would find out." you can study the source of various existing resolvers (bind, nsd, unbound, etc.) and see how they react. Or just launch them and throw at them some erroneous packets like you envision and see their reply. Some cases probably exist as unit/regression test and some tools like ZoneMaster could probably be extended (if not doing those specific tests already) to cover your cases.
I am working on one VRP(Vehicle routing problem) to make plan of pickup and drop service, As VRP is NP hard problem user edits plan according to their requirement.Now I am planning to consider their modification while preparing plan. where should I start for same?
The easiest way to incorporate expert knowledge into a VRP optimiser would probably be using constraints. Have a look at JSprit documentation of constraint as a starting point, if you are using JSprit. If the available type of constraints are not enough to model the knowledge your expert has, you may need to dig deeper and play with cost function and search strategy.
Inferring the constraints automatically from the improvements the expert made to a previous route is going to be difficult. There may be many reasons for any change in a route - it's difficult to tell why the expert made a change if they don't tell you explicitly. If possible, ask the expert to define the constraints explicitly. For example, instead of just changing a route so a job from address X and a job from address Y are served by vehicle 1, the expert will tell your system "Address X and address Y always have to be served by the same vehicle".
By the way, since this is a rather general algorithmic question, you might try to post it on the Compute Science Stack Exchange.
I am in the process of developing some Use Cases for a mobile mapping/gps app. Users will be able to use this app similar to google maps. I was wondering if anyone had valuable input into some possible use cases.
Here are some I came up with myself:
1) Get Current Location
2) Set Destination Location
3) Create Fastest Route
4) View Alternative Routes
5) Traffic Estimation on Routes
If someone could help me elaborate or comment on my direction that would be helpful!
My first impulse was to flag your question as "too broad", as you basically ask to help you with your requirements analysis. But I give a few hints.
Your 5 use cases don't look bad. But they appear to be just a first rough sketch of the functionality of your app, that needs to be refined. A good model, be it UML or anything else, must be helpful for its reader to gain some insight. Now these 5 use cases could be named by any child who has seen a navigation device once in her life. To be meaningful, questions like the following should be asked and will probably lead to a more detailed use case analysis:
How are destination locations selected? If there is more than one place called Jacksonville, how will the user be informed, and how will she select the right one? Does selecting the location consist of more than one step, say country - city - road - block, to assist the user?
How do map data get into the application?
What kind of alternative routes are considered and how should they be calculated?
How will traffic data get into the application?
Try to put yourself into the developer's position. Which questions will she need to have clarified to build the right application?
Many websites today (including stackoverflow) and games allow people to perform voting, give feedback, enable additional features etc, according to a score: eg. reputation, or MMORPG credits.
As a programmer that will probably need to implement a community based website in the near future, I am interested in knowing about the existence of basic algorithms and decisions to be made so that everything is balanced. For example, the fact that one vote up grants 10 reputations and one down grants -2 was arbitrary or properly weighted ? How to decide the price of a given item and the rewards in a MMORPG, so that everything is balanced? I guess that WoW designers relied on their experience, but I am also sure that this experience can be found somewhere written down. Although this is a social problem, the pricing of a given feature and the reward for a given task are technical/mathematical ones, as you need to give a value to each feature according to some mathematical criteria (although not easy to devise, I guess)
Of course, this question could bring us far in terms of theory of economics, but I am sort of hoping that there are well defined and known simplified patterns and rules for this issue. I just don't know the keywords to query for.
Probably the most important thing to point out here is that this is a social problem not a technical one.
By that I mean that you could use the exact same system as SO on an MMORPG and it would flop or have really undesirable side effects. Whether a system works or not depends on the community you drop it into and the intended purpose. It can also depend on some luck whether people latch onto it or not. You may get early negative behaviour that sets the tone for future negativity and discourages positive involvement. Or it could go completely the other way.
There is no magic formula that made the vote/rep weighting what it is on SO other than long discussions about how to encourage certain behaviour and then some testing and fine-tuning. For example, a downvote costs 1 rep and is -2 rep to the recipient. The guiding principle was that downvotes should cost. After that, it was trial by error.
You might want to read The Value of Downvoting, or, How Hacker News Gets It Wrong and Vote Fraud for some of Jeff's and Joel's thoughts on that subject. Joel's Tech Talk on Stackoverflow at Google is also enlightening.
Voting is actually a very difficult problem. There are so many models of voting, and they all produce different results. For example, choosing your one favorite candidate versus ranking candidates produces a different result. Choosing your LEAST favorite candidate produces a different result. Organizing choices into good/bad produces different results.
Balancing then becomes something that can be done by asking the community. It's very difficult to balance games of that magnitude, simply because even your most exhaustive tests wont cover all of the cases. Having a properly established forum where users can give their opinions as well as having testers who watch out for balancing issues is probably the best way to go.
Oh, and if you want an abstract about the voting problem I mentioned, it's here:
http://www.cs.rochester.edu/~lane/computational-politics.html