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Nena
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7/30/2007 4:23 PM
Hi there, We are currently having a discussion, where we try to decide, what data we should manage. For sure any primary data e.g hand-edited-schematics, or RTL code should be managed. What do you do with generated data, e.g. a verilog netlist or an extraced cellview. That generates dependencies between different views of the same object that one should track.... I am wondering, what the best approach is. Does anyone have a suggestion or best practice advice? Thanks, Nena

Britta
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8/01/2007 7:22 PM
Hi Nena, We had a similar discussion a while back. We decided to manage any Cadence view as a starting point. That way, we don't have to regenerate the view(s). We also do not include any check-in/check-out calls in our customizations. That has the draw back that the user is responsible to obtain write permissions to the cell view before he does something. It took takes some getting used to that, but it working out as far as I know. For any other generated data we let the users decide what they manage and not. Some of our projects do manage some generated netlists, some don't. I would be interested as well to hear what other's are doing. Regards, Britta

Administrator
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9/03/2007 9:09 AM
This post from tklee@cadence.com was inadvertenly deleted: Here're my 2 cents. There's probably no right or wrong answer here. What you choose to DM depends a lot on your flow, and that's a function of how the tools in your flow behave. If your flow insists that netlists be generated every time right before they are used, DM the netlist might actually cause problems (think of AMS's netlists in cellviews and TMPDIR usage). On the other hand, not DM'ing netlists can leave you in a situation where the more recently generated netlists do not match an older version of schematic you just checked out, and if the tools in your flow just check for time stamp, you can very well be working on netlists which don't match your design. DM and archiving are related, but are really different. As our moderators said in their interviews, DM is so! important for multi-site designs. If you look at DM as something that is active and current, versus archiving which is static, you will consider the management of secondary or generated files as important. The fact that you can generate these secondary files does not mean that your flow will always generate them as needed. Best regards, Teng-Kiat Lee Product Engineering, Central Architecture and Technology

chrisg
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9/05/2007 2:42 PM
As disk has gotten less expensive, I have seen the trend to save more generated data. If the DM system in use can help ensure all the source data is aligned with the generated data, this can save a lot of time when unwinding changes to find the last time something worked. Chris Goldstein

rkstanton
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9/14/2007 3:01 PM
I'd certainly agree with all of the above. But I wanted to add one more thought. I believe that when you talk about "the data", you have to consider what that really means. Things move so fast and process are more complex than ever. Where I see people spending effort is not just in getting a configuration of data, but rather in determining how they got to that state. You have to have a way to store both the data and some of the key driving knowledge, such as intent. Otherwise, you may never know why some changes were made, by whom and when. Sure, your circuit designer and layout designer can ping-pong changes back and forth, but it's the additional layer of knowledge that makes that collaboration more valuable. And that gets magnified over time (how long do you need to keep old designs around?) and complexity. Just something to think about. Rick

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