Hi Mark, > I assume you are comfortable with your system outputting > gerber, it's ODB that has to "prove" it can duplicate the > gerber. Thanks for bringing this up. I'm not suggesting that ODB++ needs to prove itself, as its' market share among fab shops tells me that it does the job. Given the choice, I would also opt for ODB++ as it can carry a lot more than just bare board information. The problem I have is in archiving any data object in more than one format for the reasons explained below. > Here's what I have in mind, an experiment. You asked the > question "The problem is how do you insure that both sets > of output data are identical in every way?" Maybe one way > to test that is to test the input and output capabilities > of Genesis/Enterprise. This will test, for one particular data set, the ability of the Valor tool to translate back and forth between Gerber and ODB++ without accumulating error. It really shows that their forward and reverse translators are accurate inverses of each other. It doesn't show that the two data files produce the same board. Even if we made a test to show that these two data files were comparable, not very many designers use Valor tools to make their output files. Instead, we typically use the data file generators built into our CAD systems. If the CAD system doesn't produce ODB++ directly, and most don't, then we use a third party tool (I use CAM350) to translate into ODB++, either from the native CAD file or from Gerbers. Even if the original CAD tool produced both output formats, the problem remains. Producing an output file, either Gerber or ODB++, from a native CAD database is a translation process. It is more difficult, though fundamentally similar to translating Gerber into ODB++. In both cases, some program looks at a series of data objects and translates them into another series of data objects of a different format. That program is written by human beings and therefore it has bugs. I have yet to own a piece of bug-free software. The software that produces ODB++ is not the same as the software that produces Gerber. It most likely has different bugs. My point is that the two output files will not be exactly the same. I know from experience that there are flaws in the Gerber data generators in most CAD programs. The nastier ones are history but some subtle ones remain. Similarly, different Gerber viewers can display the same data file differently. Occasionally, I have to spend a lot of time working with a fab shop because their Gerber viewers and my Gerber viewers show different results from the same data. This is an unfortunate waste of both my time and theirs, but it has to be done. Because we don't use the same brand and version of software, it is unavoidable. What I want to avoid is dealing with problems in ODB++ data in addition to Gerber data. Also, consider that if ODB++ becomes the Gerber replacement, there will be companies other than Valor writing software for it. That means there will be some differences between how a Valor program and someone else's program interprets the same ODB++ data. This may not come up very often, but it will come up, especially when other vendors first start using ODB++. Unless Valor achieves a 100% market share, we will all have to deal with some subtle differences between vendors' software. This problem could be lessened if an independent industry group produced a validation suite that a program would have to pass to call itself ODB++ compliant. I would be happy to support ODB++ as the single output format for any given board. In fact, I would prefer almost any intelligent data format to Gerber, which is truly a rotten old standard. But until my customers' purchasing departments will accept ODB++ only, the only "universal" option today is Gerber. Until ODB++ becomes as universally accepted by fab shops as Gerber, or the fab shops start to give a big enough discount to offset the extra costs of supporting two data formats, IMO most designers will opt to stay with Gerber. If using ODB++ really saves the fab shops money, and I'm sure it does, all they have to do is pass some of those savings on to their customers who use it and it will become the de facto standard before you know it. Regards, Seth Goodman Goodman Associates, LLC tel 608.833.9933 fax 608.833.9966 --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------