[poll; updated] eMMC vs. uSD; modular eMMC

[vcoleiro1]

Looks like nano SSD is not viable , maybe an option in a few years time when speed(assuming you do need 4 channels for the speed) /price/power consumption  comes more into our range.

If you really must have uSD as well as the eMMC + 5 removeable and upgradeable storage options ie 2 x SD, + 3 x USB 2, + 1 x USB 3 that are planned (USB Flash drives by the way use very little power , down to .07W active).    Why not lobby for the uSD/SIM solution?. Whats happening with that?

 

[hns]

Well, another option could be this: http://www.ti.com/lit/ds/symlink/txs02612.pdf

So we could switch between a uSD/SIM and let's say the left big SD slot.

I have no idea if Linux can support that. And it limits the bandwidth (since only one card can be active).

 

[vcoleiro1]

@gta04,

Switching gears for a second,   what eMMC do you have in mind for the Pyra?, like what size , what category 4.5 or 5.0, and what speeds?

 

[Natsu]

No, not both at the same time. Unless you want to sacrifice one of the fullSD slots. That's why I think it makes sense to have a µSSD (using the SATA interface which would otherwise not be used at all) and a µSD slot for optional extra internal storage.

I see.

I don't think µSSD + eMMC makes sense, no point in having two different kinds of non-upgradeable internal storage.

Well, of course. I agree.

If you really must have uSD as well as the eMMC + 5 removeable

I really don't see many people counting flash drives as part of the argument because I see most peoplejust using SD cards and don't want things hanging off the device.

I don't even remember the last time I used a flash drive.

 

[Neelix]

Well, another option could be this: http://www.ti.com/lit/ds/symlink/txs02612.pdf

So we could switch between a uSD/SIM and let's say the left big SD slot.

I have no idea if Linux can support that. And it limits the bandwidth (since only one card can be active).

I could see a case for using that to switch between an on board eMMC and a uSD slot, but not for swapping one of the main SD slots for a uSD.

- Neelix

EDIT: (in that case you could toggle selection based on whether a uSD was inserted, and the kernel itself need never know or care about it)

 

[vcoleiro1]

@Natsu,  Of course flash drives are part of the argument, are we to discount the fact they are there and can be used. For no reason but your say so , as  all your arguments against them have been discredited.   

 

[Exophase]

The OMAP5 has 4 SD/SDIO/MMC ports. We want to use one for eMMC, two for the standard SD slots and one for SDIO for the WiFi. So there is nothing left over. Connecting WiFi over USB is a potential option - but there are no easily available BT/WiFi combo chips with USB for the WiFi side. They almost always use SDIO. So by solving one end we have just moved the problem to the other

Also, even if there's a good wifi/BT chip over USB (technically possible to present as two USB devices, we've all used wifi and BT USB dongles) I don't think it'd be good for power consumption. That 5V it'd be powered over will be stepped back down in the USB device, and possibly not in an efficient manner.

If you really must have uSD as well as the eMMC + 5 removeable and upgradeable storage options ie 2 x SD, + 3 x USB 2, + 1 x USB 3 (USB Flash drives by the way use very little power , less than .07W active). that are planned. Why not lobby for the uSD/SIM solution?. Whats happening with that?

I don't think any modern USB flash drive with decent capacity and performance would use so little as 70mW. Maybe if you look back at some 1GB drives with ~10MB/s read..

 

[vcoleiro1]

^ I said they go down to that much, in general they are a low power storage option , they vary greatly by manufacturer in regards to power consumption. The suggestion before was that they drain huge amounts of power, which is completely false.  They are not that dissimiliar in power draw to similiar sized&speed alternatives like SD cards. 

 

[Natsu]

@Natsu, Of course flash drives are part of the argument, are we to discount the fact they are there and can be used. For no reason but your say so , as all your arguments against them have been discredited.

Because arguments such as don't want things hanging of their device should be discredited?
You are disregarding whole a lot of people who said they don't want the Pyra much bigger and want it to remain

pocket-able. As well as not wanting to carry extra devices. Flash drives sticking out of the device goes against that.

 

[vcoleiro1]

@Natsu, You made the comment that a USB drive would stick way out of the device, I showed you that USB drives are tiny and would only stick out 3mm.  That was backed up by others who made the same comment, someone even posted a picture.   You then went on to say they were slow, that was also discredited. Then you said , ohh, ahhh, no to big again.  Do you see why people would get frustrated with you.  Apologise if I lost my cool with you .  

 

[Natsu]

@Natsu, You made the comment that a USB drive would stick way out of the device, I showed you that USB drives are tiny and would only stick out 3mm.  That was backed up by others who made the same comment, someone even posted a picture.   You then went on to say they were slow, that was also discredited. Then you said , ohh, ahhh, no to big again.  Do you see why people would get frustrated with you.  Apologise if I lost my cool with you .

Being tiny still doesn't go against my argument, it's still sticking out of the device (as you said) when people can just use SDcards that won't make the device any bigger. I seen the pic btw.

 

[vcoleiro1]

^ I never said they wouldn't use SD, I said USB flash shouldn't be discounted as an option as you said.  If you don't want to use them because they stick out 3mm, others would.  

 

[Natsu]

^ I never said they wouldn't use SD, I said USB flash shouldn't be discounted as an option as you said.  If you don't want to use them because they stick out 3mm, others would.

I'm saying it should be discounted as it compare to SD and eMMC. We are talking about storage options for inside the device.
In any case, let's just let people themselves see if that is a compelling reason. Otherwise we'll be going in circles.

 

[vcoleiro1]

So your definition now is that it has to be 100% within the device and not 90%.  Ok, I see.

You're right, we will have to agree to disagree.

 

[Saber]

Wait, we can't do eMMC+uSD?

We want to use one for eMMC, two for the standard SD slots and one for SDIO for the WiFi. So there is nothing left over. Connecting WiFi over USB is a potential option...

First part sounds good.

 

[comradekingu]

>Good

>Usb sticking out only 3 mm

Pick one.

 

[vcoleiro1]

^ You mean like this which reads at 79.1 MB/s  .  Of course there's many options and speeds to choose from. Some even faster, particularly in the write speed.

 

[comradekingu]

Yes, sticks out only 3 mm, _not_ good

http://www.techpowerup.com/reviews/PQI/i-mini_usb_3_32gb/3.html  10MB/s writes  Thats twice as fast as a 52x CD-rom write, speed goggles not included

The 4k performance benchmarks look like they have been written by the brothers grim

http://www.filarakia.net/wp/2013/02/21/pqi-i-mini-usb-3-0-benchmark

Albeit on usb 2.0, but still, and if you go by adapter to the usb.3.0 port its not 3mm anymore.

 

[vcoleiro1]

There are also reasonably fast and small USB 2.0 drives , do I really need to start pulling them out.  Remember how fast  uSD cards are at low cost. They are not blisteringly fast either. That's not saying bigger USB drives are not faster, they are,. It's just that it's missleading to say you cant get reasonable speed small USB drives - you can. 

 

[comradekingu]

Remember how only some uSD cards are feasible even at moderate cost, and mostly a recent event. Small usb drives are bad without fail. I did the research around the time when sandisk extreme 3.0 was new, not only did nothing come close to touching it, most other solutions, especially the smaller ones, were orders and orders of magnitude worse.

With how much the sata solutions costs, that tradeoff for cost is better made towards more ram on top of uSD. Wish the ram was cheaper though, that would have been great.