On 23 Dec 2013, at 4:40 am, Neeraj Yadav <neer4j.iit.de...@gmail.com> wrote:
> I have made a small cloud based verilog/vhdl simulator which uses GHDL > and Icarus for VHDL and Verilog respectively. > > http://www.tarangeda.com > > I want comments of ghdl developers, anything you want to say. Makes a great argument for binary distribution under the Affero GPLv3. As Tristan noted earlier a binary work comprised of gcc and a ghdl front end the gcc compiler is distributed under the terms of the GPLv3, which allows adhesion to the Affero GPLv3. Clause 13 of both allow distribution under the Affero GPLv3, which could be used to require corresponding source distribution for any remote network interaction (cloud usage). It effectively means you'd be required to build the versions you use for your cloud service as opposed to using a binary distribution with such additional terms adhesion. I'd personally use those clause 13s for a binary distribution of the composite or aggregate work (a gcc version of ghdl). The affect is to remove the ghdl developer from directly being a target for support requests from users of a business such as yours. Additional terms might include limitations on liability and suitability for use. The ghdl mcode version is distributed solely under the the GPLv2. Other than business issues of ratios of free users and the ability to make money with your site one could wonder about "We use and promote open source software" when that promotion is limited to links on icons at the bottom of a page. Further your privacy policy on Protection of your data doesn't appear intended to extend to design files. Your 'cloud' service doesn't seem to have a strong value proposition over using ghdl, icarus and say gtkwave separately. The added value is the web interface. (I'd be personally curious how fast (responsive) your waveform viewer is). It would seem likely as a business cloud EDA services using open source software is ripe for easy competition in particular when one of those open source links poitd to Codiad. Simulation seems a bit narrow a focus for a business model. > Plus I have a few questions also > 1. Do people use ghdl professionally, or is it still far from any > professional use(I heard this on comp.arch.fpga) You've seen two people (so far) comment that they use ghdl professionally. You'll find there are more. Their use would be predicated on knowing the limitations of ghdl and avoiding problems. That isn't to say any user could use it professionally. As far as I can tell, ghdl isn't fully compliant with the VHDL Standard (IEEE Std 1076-1993, -2002 or -2008). Off hand as far as marketable 'product' distinctiveness ghdl has none. While Tristan doesn't share his plans for ghdl (his original release plan is badly dated), my interest is primarily in achieving full -1993 standard compliance. The Brians are driven by insuring platform availability. There are currently 5 active ghdl contributors only tugging slightly in different directions. The effort could use more still. None of those are focused on supporting an effort such as yours, and currently only an admin can set priorities. Disagreements might tend to effectively lessen the contributor resource pool. (The unpopular guy waving the baton and marching down the street needs to look over his shoulder to see if anyone is actually following). Also being involved in several other VHDL tool development efforts, the things that ghdl isn't compliant with the LRM over are a usually a common set of issues that appear to point to weaknesses in how well the IEEE standard conveys requirements. > 2. Is it okay the way I am using ghdl on my site?Are there any license > restriction etc? I'm not aware of any licensing terms for ghdl that are in conflict with your usage (a personal opinion only). That sounds like something for which you might seek legal counsel. As the GPL says, you aren't 'conveying a covered work', unless you are providing download access to elaborated (executable) VHDL models. (The ghdl runtime library is released under the GPLv2, apparently requiring distribution under the terms of the GPL). Again, you might want to seek legal counsel. > I also want to contribute to GHDL, I need someone to give me a clear > idea how far ghdl from say a OEM version of ModelSim? There are obvious limitations on ghdl. It doesn't have the an interactive shell for simulation (run/stop/step, save restore). It doesn't have the ability (currently) to select signals saved to a waveform. This likely has a performance impact (and is something Tristan has indicated support for in the past). It isn't a dual HDL front end system. You're web site can't do mixed HDL models using ghdl. It's not a GUI based tool (and frankly enclosing it with a web interface doesn't make it one). It's utility for co-simulation is limited. (ghdl also doesn't support specification of a resolution limit for type TIME (See 3.1.3.1 Predefined physical types). Any sense of urgency on the part of someone making money off ghdl in conveyng bug reports and feature requests doesn't have the same impact it might have for a proprietary product generating income (for those active developers). Without supplying your own end user support you're use of ghdl doesn't widen the audience of ghdl users appreciably. ghdl's warning and error messages aren't always accurate and in some cases segmentation faults occur instead. Modelsim's verror facility for instance (or comparable for Altera) goes a long way to user friendliness. There's a general shortcoming in the documentation and usage examples. The amount of release or validation testing ghdl undergoes is (currently) limited. ghdl's performance doesn't match commercial offerings on the same platform. Some proprietary performance enhancements may be (still) covered by patents. (And a lot of this points to intended users, a commercial product is intended for and must be responsive to a wider audience.) In general those denigrating ghdl for it's shortcomings are those who would be interested in it's commercial exploitation otherwise. The rest of us like to focus on what ghdl does right. ghdl appears to standard compliantly deal with configuration, likely said of few other tools. That being said, it's an underutilized facility in the face of EDA being dominated by FPGA development. It doesn't compete with proprietary offerings. And if it were comparable in features, support and user friendliness it'd ruin the market for proprietary VHDL simulators offering full features instead of a limited freemium model. _______________________________________________ Ghdl-discuss mailing list Ghdl-discuss@gna.org https://mail.gna.org/listinfo/ghdl-discuss
