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Topic: IMB with Raspberry PI

Pietro Clarici
Expert Film Handler

Posts: 136
From: Foligno (PG) Italy
Registered: Sep 2008

posted 08-06-2017 06:11 AM

quote: Marcel Birgelen
There's no way to get any form of commitment if the Pi3B will still be available in even a few months time. It could've been replaced with a Pi3C or Pi4, with totally different specs and connector layout for example.

I could be wrong, but I think they can stockpile on standard or lightly modified Pi3s for less than a custom on-board integration. At this point, anything D-Cinema related is going to be very small volume, probably doesn't justify high upfront costs.

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Marco Giustini
Film God

Posts: 2713
From: Reading, UK
Registered: Nov 2007

posted 08-06-2017 06:37 AM

quote: Mark Gulbrandsen
Which Broadcom and for what purpose? Broadcom makes a lot of different processors...

The one installed on the Pi3?

DTS went for standard off the shelf parts in the past. Their DTS6 and DTS6D were just i386/i486 computers with a few proprietary boards. How many versions of motherboard and SCSI boards and CDROM's have we seen in the past? How many customers had to pay an arm and a leg to swap a bad CDROM drive because they also had to replace the SCSI controller which went EOL in the meantime?

Nothing against the Broadcom chip, but I'd like to see a GDC board with the chip on it - not a Pi3.

That said, isn't the Pi3 an open source project? Maybe GDC simply took it, modified and used it for their server. In that case, it's a GDC board they manufacture and which has full GDC support.

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Carsten Kurz
Film God

Posts: 4340
From: Cologne, NRW, Germany
Registered: Aug 2009

posted 08-06-2017 06:50 AM

The PI already has a nice footprint of being held compatible between previous and successor models as much as possible. So I wouldn't be too concerned about that issue. Whoever uses a PI in a commercial product, is able to benefit from all community efforts targeted at the PIs hard- and software development. It's big and healthy enough a project to rely on it for a product like an IMB I'd say.
You only need to make sure the board will not become a performance bottleneck.

- Carsten

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 08-06-2017 10:33 AM

quote: Marco Giustini
DTS went for standard off the shelf parts in the past. Their DTS6 and DTS6D were just i386/i486 computers with a few proprietary boards.

Well, DTS-6 & 6D motherboards were very reliable and there was no foreseen need to have to upgrade the computing power in them... they were what they were so to say. However, a good example is when DTS went through some serious issues with the XD-10 and it's first verson motherboards all failed because they got caught in the capacitor scam some years back. All of the first generation XD-10's motherboards eventually failed. DTS could rebuild the player, but the cost was 1200 USD to do it. It required a new motherboard which of course was quite a bit different than the original. This entailed replacing some parts of the chassis and metal work to accommodate the new board. The rest of the boards more or less stayed the same, although the D to A board had to be modified to work with the new power supply. And of course.... the original motherboard could just be re-capped in about an hour and was the subject of a post I did on here some years ago. Eventually, I recapped several dozen of the first Gen DTS motherboards rather than submit to the 1200 USD repair by DTS.
So assume this is Doremi or Dolby having these capacitor issues on the motherboard in their server... Dolby did in fact have this issue with some of their CP-650 power supplies. Thank god those supplies were not part of the main board!

Mark

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Marco Giustini
Film God

Posts: 2713
From: Reading, UK
Registered: Nov 2007

posted 08-06-2017 03:30 PM

I don't want to go OT, Mark, but I clearly remember that DTS also had issues with CDROM's - which weren't lasting forever anyway - and the original 2x SCSI required a different controller than the later 4x SCSI and they then went for a SCSI to IDE bridge for the latest models.

We can argue as much as you want on this, the bottom line is that if you rely on a off the shelf part, you cannot control its availability.

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David Buckley
Jedi Master Film Handler

Posts: 525
From: Oxford, N. Canterbury, New Zealand
Registered: Aug 2004

posted 08-06-2017 04:01 PM

That absolutely is a Pi 3, if you blow the images up you can see the component annotations are the same.

However, this is nothing unusual, the Pi is used in truckloads of applications exactly like this. In exactly the same way that many boxes one buys have the standard PC socketry on the back, because under the covers, there is a standard PC motherboard in the box.

Why reinvent wheels?

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Carsten Kurz
Film God

Posts: 4340
From: Cologne, NRW, Germany
Registered: Aug 2009

posted 08-06-2017 04:08 PM

Marco - isn't nearly every part an off-the-shelf part? [Wink]

Sometimes this is a benefit in itself - relying on a standard part that can be expected to be available for a longer period of time, because you can consider it an industry standard. Like a USB interface. Yes, sometimes your estimate goes wrong and something is gone sooner than you expected. But then, maybe DTS did not rely on a CD-ROM drive, but a SCSI interface, and because SCSI was so popular so long, they could later even source off-the-shelf SCSI-ATAPI bridges. Given the enormous speed of development and thus volativity of computer hardware during the nineties, not such bad track record. We can still source SCSI CD-ROM drives today. Yes, not for new products, but you still benefit from their huge previous market penetration.

Maybe, on this IMB, they do not rely on a PI 3B, but an embedded board with a Linux based OS and Ethernet connectivity. If there will be no PIs in three years ( highly unlikely), they can easily source another system with this minimal feature set.

- Carsten

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Marco Giustini
Film God

Posts: 2713
From: Reading, UK
Registered: Nov 2007

posted 08-06-2017 05:08 PM

indeed they could manufacture their own Broadcomm board and then declare it EOL when the Broadcomm chip is not available anymore. But I think the Pi is another story. Pi4 will be out at some point and what happens to the GDC's? Maybe they'll just adapt the Pi4. Or maybe they'll ask you to install an adaptor and a different board at 2x the price.

Indeed DTS was able to keep the 6 and 6D alive for a long time relying on SCSI technology. However, lots of customers had to pay fortunes to replace the whole chain CDROMS -> SCSI boards when the technology changed.

If you design your own board, you can issue a rev2 with a different chip when the older chip is not available anymore.

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Marcel Birgelen
Film God

Posts: 3357
From: Maastricht, Limburg, Netherlands
Registered: Feb 2012

posted 08-06-2017 07:04 PM

I'd say, if you simply put some kind of Atom reference design on your IMB, you can go all directions you want to go. It's something that can be done almost out of the box. A modern Atom will also handle gigabit speeds with ease for most applications. And, as a bonus, interfacing with the mediablock, should be easier. You can put the heavy lifting stuff right on the PCIe for example.

I still don't get what this RPI3 will be doing there. Will it be the "controller part" of the IMB? Will it run the User Interface and control APIs? How will it communicate to the rest of the IMB? Via Ethernet? It all sounds pretty bloated to me. Or will it just fulfill some auxiliary functions which we're forgetting about?

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 08-09-2017 11:18 AM

quote: Marcel Birgelen
I still don't get what this RPI3 will be doing there. Will it be the "controller part" of the IMB? Will it run the User Interface and control APIs?

Yes, it will be the main system controller, just like the Atom board is that is used on the SX-3000 now. I believe the Quad Core on the current Raspberry Pi is actually quite a bit more powerful than the Atom is, although I need to confirm which Atom is being used next time I go into the bios.

In the case of the current AR GDC Media Block, It acts as a media block/motherboard. Adding extra components gets you an SX-3000 and one of the larger added components is the Atom processor board that's under the black heat sink. It is field replaceable and the RAM Drive is right below it on the bottom side.

So, if the RP-3.0 is as powerful or better, then why not use it instead? Its inexpensive and very reliable. I have one here that I made a nifty NTP time server out of.

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Tom Bert
Expert Film Handler

Posts: 134
From: Belgium
Registered: Apr 2010

posted 08-10-2017 06:14 AM

quote: Marcel Birgelen
Or will it just fulfill some auxiliary functions which we're forgetting about?

quote: Tom Bert
I believe that specific part of the module is onboard (flash) storage: combined with the external NAS/DAS it creates a hybrid system: (some) integrated + (mainly) remote storage

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Marcel Birgelen
Film God

Posts: 3357
From: Maastricht, Limburg, Netherlands
Registered: Feb 2012

posted 08-10-2017 06:26 AM

That's specifically were I see the potential pitfalls of using a RaspberryPI 3(B), because the thing has only a Fast Ethernet connection. Also, the USB interfaces are only USB 2.0.

While USB 2.0 can theoretically achieve 53 MB/s, Fast Ethernet is stuck at a theoretical 12 MB/s. By all means, the Pi3 doesn't sound like the best solution for such a function.

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Leslie Hartmier
Expert Film Handler

Posts: 100
From: Edmonton, Alberta, Canada
Registered: Jul 2012

posted 08-10-2017 01:59 PM

For those people who mentioned the longevity of access to Pi3B, remember that the schematics for making your own are available.

It is easy to buy Pi3Bs. It is fun to make Pi3Bs.

Just saying.

Leslie

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 08-10-2017 07:15 PM

quote: Marcel Birgelen
because the thing has only a Fast Ethernet connection.

Actually, it does have other interfaces besides ethernet, usually it's through other boards that plug on to the Pi.

Mark

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Marcel Birgelen
Film God

Posts: 3357
From: Maastricht, Limburg, Netherlands
Registered: Feb 2012

posted 08-10-2017 07:42 PM

It does, it has plenty of GPIOs, it has HDMI, it has a "camera" port and a "display" port.

The GPIOs obviously don't outperform Ethernet and USB and the other interfaces aren't really the most suitable ports for interfacing with a "motherboard" or daughter card.

The thing misses a generic high-speed bus like PCI-e, which the Atom actually does offer.

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