Rigol's New DHO800 Oscilloscope unbox & teardown

[ataradov]

No, but other scopes will also not give you the source code, even when GPL software is used. You can complain all you want, but it will not change much.

[Pao3]

Thank you for your reply, Fungus.
I thought I would regret it if the new DHO804 had terminals for a signal generator and logic probe and was the same price, but it seems that was not the case, so I'm relieved.

[norbert.kiszka]

No, but other scopes will also not give you the source code, even when GPL software is used. You can complain all you want, but it will not change much.

Scopes are not forced to give a source code. Manufacturers are.

[Fungus]

Good luck buying an oscilloscope if that's a deal breaker.

Are You suggesting that other scopes doesn't have something that Rigol can do?

I'm suggesting that if you require open source then you'll be waiting a while. They're pretty much all Linux/Android based now.

[gitm]

No, but other scopes will also not give you the source code, even when GPL software is used. You can complain all you want, but it will not change much.

Scopes are not forced to give a source code. Manufacturers are.

There seems to be some confusion around the GPL/LGPL.  The GPL and LGPL require source distribution for those programs DERIVED, in whole or part, from GPL/LGPL licensed source code.  Rigol clearly displays these licenses on their scopes, for example on the MSO5000 in the “Content” menu.  However, this source distribution applies only to the GPL/LGPL derived software, it does not apply to original software that operate with other GPL/LGPL software, even in the same hardware environment, including linking.

As such, Rigol’s “scope” is an application running on Linux/Android.  Rigol and other manufacturers are not required to release the source to these applications if they are original works, which appears to be the case.  And many software packages were offered to developers under dual GPL/LGPL or proprietary licensing models, such as QT.  But even with GPL/LGPL licensing, the derived programs (e.g. base OS with modifications) being required to be freely source distributable, the proprietary drivers running in the OS are not.  This was a not insignificant motivation for Debian and the elimination of proprietary binary drivers, such as NVDIA’s display drivers.

And some of you may recall the considerable “discussion” around the infectious nature of the GPL which led to the LGPL from the likes of Stallman, Raymond, Torvalds, et al.

[norbert.kiszka]

No, but other scopes will also not give you the source code, even when GPL software is used. You can complain all you want, but it will not change much.

Scopes are not forced to give a source code. Manufacturers are.

There seems to be some confusion around the GPL/LGPL.  The GPL and LGPL require source distribution for those programs DERIVED, in whole or part, from GPL/LGPL licensed source code.  Rigol clearly displays these licenses on their scopes, for example on the MSO5000 in the “Content” menu.  However, this source distribution applies only to the GPL/LGPL derived software, it does not apply to original software that operate with other GPL/LGPL software, even in the same hardware environment, including linking.

As such, Rigol’s “scope” is an application running on Linux/Android.  Rigol and other manufacturers are not required to release the source to these applications if they are original works, which appears to be the case.  And many software packages were offered to developers under dual GPL/LGPL or proprietary licensing models, such as QT.  But even with GPL/LGPL licensing, the derived programs (e.g. base OS with modifications) being required to be freely source distributable, the proprietary drivers running in the OS are not.  This was a not insignificant motivation for Debian and the elimination of proprietary binary drivers, such as NVDIA’s display drivers.

And some of you may recall the considerable “discussion” around the infectious nature of the GPL which led to the LGPL from the likes of Stallman, Raymond, Torvalds, et al.

Linux kernel and Rigol modules are GPL v2 licensed. So they are forced to give a source code with all modifications as it is compiled to a given binary. They didn't even make any reply, after my many attempts. I didn't ask them for application source code - only kernel with all modules which was delivered in a binary form and with GPL v2 license.

[ebastler]

Linux kernel and Rigol modules are GPL v2 licensed. So they are forced to give a source code with all modifications as it is compiled to a given binary.

In my understanding, that would be correct if Rigol took an existing module which is licensed under GPL v2 and made modifications to it. If they wrote their own modules, or took a non-GPL'd module as their starting point, I do not see why an obligation to provide source code would arise.

The fact that the kernel itself is under GPL does not "infect" the modules to my knowledge, since modules are loadable/unloadable rather than compiled and linked "into" the kernel?

[Fungus]

It's Android kernel.

The 'scope application is completely separate.

(it's an installable/removable Android application)

[norbert.kiszka]

Linux kernel and Rigol modules are GPL v2 licensed. So they are forced to give a source code with all modifications as it is compiled to a given binary.

In my understanding, that would be correct if Rigol took an existing module which is licensed under GPL v2 and made modifications to it. If they wrote their own modules, or took a non-GPL'd module as their starting point, I do not see why an obligation to provide source code would arise.

The fact that the kernel itself is under GPL does not "infect" the modules to my knowledge, since modules are loadable/unloadable rather than compiled and linked "into" the kernel?

Wrong again. All modules in this scope are GPL v2 licensed - each one. Linux kernel in module.c checks license information in a module. If it's something different than GPL, then module is not loaded.

You can check module informations, including license, with insmod and modprobe commands - even on a completely different system (but You need to make a copy of module).

[ebastler]

Wrong again. All modules in this scope are GPL v2 licensed - each one. Linux kernel in module.c checks license information in a module. If it's something different than GPL, then module is not loaded.

You can check module informations, including license, with insmod and modprobe commands - even on a completely different system (but You need to make a copy of module).

Why "again"? I had not chimed in on this matter before.

Could you provide a link which documents the "all modules must be under GPL" requirement? Does it apply to every Linux version? The documentation I find suggests that all kinds of license models are possible for kernel modules -- is it outdated?
https://docs.kernel.org/process/license-rules.html#id1

Also, do you know (or assume) that Rigol to have modified specific kernel modules? Which ones?

[ataradov]

Non GPL modules "taint" the kernel, and I believe Android kernel disables support for the tainted kernel operation.

At the same time, a typical workaround for this is what Nvidia is/was doing for its drivers - a simple GPL dummy module that just loads a proprietary binary blob. This way your module code is available, but completely useless. This also annoys kernel developers, since they do not accept bug reports from the tainted kernels, and this Nvidia workaround messes with that.

In case of Rigol, they just mark the module as GPL because they really don't care.

[norbert.kiszka]

Wrong again. All modules in this scope are GPL v2 licensed - each one. Linux kernel in module.c checks license information in a module. If it's something different than GPL, then module is not loaded.

You can check module informations, including license, with insmod and modprobe commands - even on a completely different system (but You need to make a copy of module).

Why "again"? I had not chimed in on this matter before.

Could you provide a link which documents the "all modules must be under GPL" requirement? Does it apply to every Linux version? The documentation I find suggests that all kinds of license models are possible for kernel modules -- is it outdated?
https://docs.kernel.org/process/license-rules.html#id1

Also, do you know (or assume) that Rigol to have modified specific kernel modules? Which ones?

I suggest to look into module.c of a Linux kernel 4.4.126. Same version number as used in a DHO800 and DHO900 series.

[gitm]

Linux kernel and Rigol modules are GPL v2 licensed. So they are forced to give a source code with all modifications as it is compiled to a given binary.

In my understanding, that would be correct if Rigol took an existing module which is licensed under GPL v2 and made modifications to it. If they wrote their own modules, or took a non-GPL'd module as their starting point, I do not see why an obligation to provide source code would arise.

The fact that the kernel itself is under GPL does not "infect" the modules to my knowledge, since modules are loadable/unloadable rather than compiled and linked "into" the kernel?

A small distinction here; it is true that if Rigol were compliant with the GPL (any version) for a GPL derived work, then they would be making source available for derived work.  However, even if they were violating the GPL and not distributing source, they could not be forced to release the source code.  With respect to the Rigol “scope application” running on a linux/android OS, it may very well be proprietry and non-GPL infringing.

Eben Moglen — at the time being General Counsel for FSF and charged with enforcing the GPL — explains infringing the GPL cannot cause proprietary code to be “forced open”.  Relevant link http://www.groklaw.net/article.php?story=20031214210634851 with a good overview of the legal landscape, especially the distinction between a contract, license, and possible remedies.

"Because the GPL does not require any promises in return from licensees, it does not need contract enforcement in order to work. A GPL licensor doesn't say in the event of trouble "But, judge, the licensee promised me he wouldn't do what he's doing now." The licensor plaintiff says 'Judge, the defendant is redistributing my copyrighted work without permission.' The defendant can then either agree that he has no permission, in which case he loses, or assert that his permission is the GPL, in which case he must show that he is obeying its terms. A defendant cannot simultaneously assert that the GPL is valid permission for his distribution and also assert that it is not a valid copyright license, which is why defendants do not 'challenge' the GPL.

"The claim that a GPL violation could lead to the forcing open of proprietary code that has wrongfully included GPL'd components is simply wrong. There is no provision in the Copyright Act to require distribution of infringing work on altered terms. What copyright plaintiffs are entitled to, under the Act, are damages, injunctions to prevent infringing distribution, and--where appropriate--attorneys' fees. A defendant found to have wrongfully included GPL'd code in its own proprietary work can be mulcted in damages for the distribution that has already occurred, and prevented from distributing its product further. That's a sufficient disincentive to make wrongful use of GPL'd program code. And it is all that the Copyright Act permits.”

[norbert.kiszka]

A small distinction here; it is true that if Rigol were compliant with the GPL (any version) for a GPL derived work, then they would be making source available for derived work.  However, even if they were violating the GPL and not distributing source, they could not be forced to release the source code.  With respect to the Rigol “scope application” running on a linux/android OS, it may very well be proprietry and non-GPL infringing.

If they modified anything in a GPL licensed code and delivered it in a binary (compiled) form, then they are obligated to deliver a source code for anybody who asks. No matter how much top secret staff they are hiding in it.

Same thing, when they delivered a binary with a GPL license made with their own code.

https://www.gnu.org/licenses/gpl-faq.html

[ebastler]

If they modified anything in a GPL licensed code and delivered it in a binary (compiled) form, then they are obligated to deliver a source code for anybody who asks. No matter how much top secret staff they are hiding in it.

I think nobody is disputing that. Gitm's point was that if they violate that obligation, you cannot get a court order to force them to publish the code -- you can only sue them for damages and/or require them to stop using the code.

[NE666]

you cannot get a court order to force them to publish the code -- you can only sue them for damages and/or require them to stop using the code.

Exactly. And here "you" means either the licensor whose work has been infringed, or their designated representative. Not just any self-appointed third party with an interest and/or grievance.

Of course, the bottom line to all of this is that we all know from the outset who we are dealing with. Those who have, have purchased Rigol TE for reasons other than first-class customer support and impeccable corporate ethics. Sadly, those cost extra.

[norbert.kiszka]

If they modified anything in a GPL licensed code and delivered it in a binary (compiled) form, then they are obligated to deliver a source code for anybody who asks. No matter how much top secret staff they are hiding in it.

I think nobody is disputing that. Gitm's point was that if they violate that obligation, you cannot get a court order to force them to publish the code -- you can only sue them for damages and/or require them to stop using the code.

IMHO software creator (Linus Torvalds and Google) can sue them because of violation of license. But only in a China...

I don't know how it's related to their "promise" in the document available in a scope app menu. Anyway, they lied to us.

[carl0s]

Got my DHO804.

It's super cute. I like it :-)

Not much more to say about it. I like that it runs from a power bank. I love the definition of the screen. I will not buy a >10" Siglent 12bit scope until one comes out with higher resolution LCD display than their current ones. If one comes out like that, I will buy it to replace my SDS2104X Plus. I would spend £2 - £3k maybe. Come on Siglent, take my money.

Shame you can't dim down the LEDs on the panel.. seems like somebody screwed that up - it doesn't light up the symbols, but just shines a bright light through.

[Ohmy]

I know the review is for the DHO800, but I was wondering about the DHO900. Can the logic analyzer port be used with a bunch of jumper wires or is the logic analyzer probe required? I'm thinking of rigging something up as the price of the LA probe is a little spicy.

[ebastler]

I know the review is for the DHO800, but I was wondering about the DHO900. Can the logic analyzer port be used with a bunch of jumper wires or is the logic analyzer probe required? I'm thinking of rigging something up as the price of the LA probe is a little spicy.

It's not that simple. There are active comparators in the probe, with differential low-voltage outputs as expected by the scope. The comparators also have a threshold voltage that is settable from the scope. Don't feed 3.3V or 5V logic levels directly to the scope -- you may damage the FPGA, i.e. the core component of the scope!

There are a few DIY solutions, e.g here: https://www.eevblog.com/forum/testgear/low-cost-compatible-rigol-pla2216-logic-probe-for-dho900-(and-hacked-dho800)/msg5211147/#msg5211147. Even the DIY solutions are not really cheap since the fast comparator chips are expensive.

If you don't need the settable thresholds and can get by with fixed 5V and 3.3V logic levels you can also buy a cheap solution on ebay. Look for "PLA2216 clone" or similar. They are also advertised as probes for the MSO5000, which uses the same logic probe as the DHO900.

[Fungus]

I know the review is for the DHO800, but I was wondering about the DHO900. Can the logic analyzer port be used with a bunch of jumper wires or is the logic analyzer probe required? I'm thinking of rigging something up as the price of the LA probe is a little spicy.

You could do that, but it's very risky. You probably need voltage dividers for most jobs and any mistake with input voltage could kill the 'scope, dead.

The probe has high-speed comparators to buffer the signals. It also has programmable threshold voltage to let it accept a wide variety of inputs.

[Ohmy]

Alright. Scratch that idea. I handled one of these probes and thought the circuitry was inside the scope. I'll check out the eBay LA probe clone though, thanks.

[kirill_maker]

So, new toy from late 70s with our scope… looks nice

[Fungus]

Warning: Do NOT switch the 'scope off in XY mode if you've installed firmware 1.03.

It won't boot again if you do.

(I recommend downgrading to 1.02 until they fix it)

[kirill_maker]

I'm running on 1.02.02 (I guess), and they're reverted 1.03 as far as I know. But thanks for the warning.