SD vs MMC, 2 simple questions - General Topics

I read the XDA supports SD and MMC cards.
:?: 1st: What are the differences, advantages, and disadvantages of SD vs MMC ?
:?: 2nd, I found a lot of SD Reader on various stores' sites. Are all "Readers" also "Writers" ?
Bernard

droletbe said:
:?: 1st: What are the differences, advantages, and disadvantages of SD vs MMC ?
Click to expand...
Click to collapse
The maximum transfer rate of the SD card is 4 times that of the MMC.
The SD card has a write-protect switch (similar to that in a floppy disk).
You can copy-protect an SD card to prevent piracy. This is why it's called Secure Digital. However, the security feature takes up a few 100 KB of space. This means that the SD card has less available space than an MMC of the same storage capacity.
The MMC is usually cheaper. But in some stores, the price of MMC and SD cards are the same.
droletbe said:
:?: 2nd, I found a lot of SD Reader on various stores' sites. Are all "Readers" also "Writers" ?
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Click to collapse
Yes.

Related

4MB SD memory card

My Qtek 9000 cannot recognize 4GB SD card (DANE-ELETC)
Your help much appreciated.
Rom 2.05.00
Rom Date 04/09/07
Radio V. 1.15.00
Protocol 42.51.P8
I guess you mean 4Gb SD Card.
Is it SDHC?
If so, then it would be worth looking in the Universal accessories board at what people have to say, which is 'no' for the sdhc cards.
I bought a 4 Gb card but it is a non-sdhc type so that it would work.
Cheers
Fish
I can't seem to find the manufacturer's website. Can you post the the spec sheet of the model you have got?
fishtastic said:
I guess you mean 4Gb SD Card.
Is it SDHC?
If so, then it would be worth looking in the Universal accessories board at what people have to say, which is 'no' for the sdhc cards.
I bought a 4 Gb card but it is a non-sdhc type so that it would work.
Cheers
Fish
Click to expand...
Click to collapse
Yes is a SDHC, So the qtek 9000 need a non=sdhc type 4Gb Card.
Thank you
jose
josedias said:
Yes is a SDHC, So the qtek 9000 need a non=sdhc type 4Gb Card.
Click to expand...
Click to collapse
Exactly...I'm using a 4Gb transcend non-HC and it's works find ...!! I heard about problems concerning the SDHC for the universal... Maybe you should change your SD
Transcend 4GB 'SD' card getting corrupted repeatedly
I have one annoying problem,It is the third time that my Transcend 4GB SD card got corrupted without any reason ( as far as I know ).
It goes like this --I just moved one .jpg image ( clicked with my Universal ) from main memory to card -- a my document--my pictures folder,then I checked it ,the entire my document folder is empty..around 150 MB.No data recovery tool can retrieve it.
The default file explorer and Resco explore read the card differently --950 Mb and 1100 MB respectively.The data is gone,the space 150 MB is gone.On previous two occasions,there was not any transfer of any data from device to card yet it happened .I had the card replaced,but it is very annoying to live in this impending possibility of losing the data.
What is the cause of this problem?WM6?Universal?ROM?4GB?Transcend?
I never had this problem with 1 GB cards.What is the solution?Please suggest something,anything.
There are a couple of WM6 roms which can corrupt your SD card.
But it shouldn't make a difference if you have a 512 mb card or 4 gb.
Did you upgrade to WM6 and then got the 4gb card?
You could try to flash back to the original wm5 rom from your manufacturer, good change the problem's gone then.
ROM change?
No Sir,
I did have this problem with WM5 and to get rid of it I shifted to WM6,but the problem persists.Other people with WM5/6 with 'NCP' 4GB are doing fine,I am also going to try it.Like I said I never had any problems with 1GB.
I like the HTML mail support in WM6 and I need it for the attachments so I'd rather keep WM6.
One more thing, the file explorer SOMETIMES shows two separate folders viz. storage card 1 & storage card 2, and in storage card 1 there are only files called mail attachments.At the same time all the today shortcuts and programmes on the card are 'uninstalled',Then I have to hard reset and install the back-up file and everything comes to normal.What does it mean?Please clarify.
kalya said:
One more thing, the file explorer SOMETIMES shows two separate folders viz. storage card 1 & storage card 2, and in storage card 1 there are only files called mail attachments.At the same time all the today shortcuts and programmes on the card are 'uninstalled',Then I have to hard reset and install the back-up file and everything comes to normal.What does it mean?Please clarify.
Click to expand...
Click to collapse
This is a known issue. Sometimes the system forgets about the exixstence of SD card. You can brows here for such cases. People claim that it happens while the battery goes low or for some other reason.
However, if this happens, and some of your apps are set up for using Storage Card for saving it's data, then the system creates a folder named "Storage Card" in the main memory. Then if you softreset or recharge your device, the system finds again your SD card and tries to give it a name "Storadge Card", but this already exists, so it names it as "Storadge Card1", and so on.
Solution:
Ither delete the "Storage Card" folder from main memory or rename it as you wish, and then rename your card as "Storage Card" and softreset your device. It should help.
okay
Tadeusz said:
This is a known issue. Sometimes the system forgets about the exixstence of SD card. You can brows here for such cases. People claim that it happens while the battery goes low or for some other reason.
However, if this happens, and some of your apps are set up for using Storage Card for saving it's data, then the system creates a folder named "Storage Card" in the main memory. Then if you softreset or recharge your device, the system finds again your SD card and tries to give it a name "Storadge Card", but this already exists, so it names it as "Storadge Card1", and so on.
Solution:
Ither delete the "Storage Card" folder from main memory or rename it as you wish, and then rename your card as "Storage Card" and softreset your device. It should help.
Click to expand...
Click to collapse
Okay,
Thanks for explaining and the simple solution.
But a soft reset doesn't solve it,reinstalling the backup(I use SPB)does.
But what about the card getting corrupted,losing data and vanishing folders?Is there any cause and solution for it? Or should I go for another card manufacturer as decided?
i have tested 1 gig sdhc
i have tested 1 gig sdhc toshiba class4 and it worked on universal
onlineemails said:
i have tested 1 gig sdhc toshiba class4 and it worked on universal
Click to expand...
Click to collapse
SDHC start at 2gb, you have a normal SD.
Native universal SD driver does not support SDHC, the driver ignores CMD8 that is required for SDHC to work. I've purchased 8Gb card and can tell that after patching - Uni started to recognize it. But testing is required before publishing a patch.
mamaich said:
SDHC start at 2gb, you have a normal SD.
Native universal SD driver does not support SDHC, the driver ignores CMD8 that is required for SDHC to work. I've purchased 8Gb card and can tell that after patching - Uni started to recognize it. But testing is required before publishing a patch.
Click to expand...
Click to collapse
mamaich, you are wonderful.
mamaich said:
SDHC start at 2gb, you have a normal SD.
Native universal SD driver does not support SDHC, the driver ignores CMD8 that is required for SDHC to work. I've purchased 8Gb card and can tell that after patching - Uni started to recognize it. But testing is required before publishing a patch.
Click to expand...
Click to collapse
Does this patch involve physically deforming the SD Card such that its lifetime warranty (lifetime warranty is applicable to some SD cards only) becomes void?
Does this patch involve physically deforming the SD Card such that its lifetime warranty (lifetime warranty is applicable to some SD cards only) becomes void?
Click to expand...
Click to collapse
LOL
_____
RE
Quote
"Native universal SD driver does not support SDHC, the driver ignores CMD8 that is required for SDHC to work. I've purchased 8Gb card and can tell that after patching - Uni started to recognize it. But testing is required before publishing a patch"
Can it work with the Universal running WM5?
Thanks
FOSA said:
Can it work with the Universal running WM5?
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Click to collapse
Very curious to hear the answer to this as well!!
FOSA said:
Can it work with the Universal running WM5?
Thanks
Click to expand...
Click to collapse
no. WM6 aku 0.2 and later are required.
mamaich said:
LOL
_____
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Click to collapse
I always wished a scenario would come up where I could ask such a question and make it seem valid at the same time
How about 4GB SDHC?
If 8GB SDHC can be used then how about using a 4GB SDHC card?
And please make it possible,soon,Mamaich.Thanks.

[Q] Widgets to show true SD card capacity?

Are there any widgets or anyway to show the true "removable" SD card card capacity? I use mini widget but it only shows the SD card as the internal and all the other widgets I tried are the same.
You should try using StorageEther. It gives free space values for internal and all removable storage as well.
AcIdC0R3 said:
You should try using StorageEther. It gives free space values for internal and all removable storage as well.
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Click to collapse
Got it thanks, works as advertised!
I have Sandisk Memory Zone and it's a nice little tool.
It's still in beta, and only supports internal and the MicroSD so far, at least it isn't showing the SDHC card I have in the dock.
It can also show dropbox and other cloud service usage.

Apps installed on SD

Many people want to move their apps to SD because of the space issue.
I am a minimal app user
What I concerned is performance or speed.
Will the performance increases if I move an app to the internal SD card?
Some say that the phone will run faster because less phone space is used.
Another question is the internal SD card really an SD card?
hotisopropyl said:
Many people want to move their apps to SD because of the space issue.
I am a minimal app user
What I concerned is performance or speed.
Will the performance increases if I move an app to the internal SD card?
Some say that the phone will run faster because less phone space is used.
Another question is the internal SD card really an SD card?
Click to expand...
Click to collapse
No... I don't think there will be any change... Just saves a little space...
And internal sd card is not an sd card like external sd card i.e. memory card... It is like a memory card placed on phones motherboard... Maybe It includes system partition and other partitions... You can't remove it or change it yourself...
Sent from my Galaxy Nexus using xda premium

Samsung 64GB SD Card - SO SLOW

So I ordered a Samsung 64GB Class 10 micro SD card, and it seems VERY slow.
While I gone so much mind the slowness, as I dont play a lot of games and would use it more for pictures and music I was wondering if I could get a few questions answered before I send it back or just give it to someone else.
1: Does the S4 have problems with 64GB cards?
- I am running Sacs KitKat V2
2: should I format with a format (NSFT/exFat) and is it better done on a Mac or PC?
3: what should the Unit Size be?
4: I just copied my old sd card on to this one, and some of the big games I do have stopped showing up. but when I put my old card back in, they are there again.
Why would this happen?
Thanks for the help everyone!
You have to format the card using the phone itself. Go into settings then storage and the option should be there. Try that, then re-copy your stuff to the card. If you still have problem then it is probably a dud card.
Sent from my SAMSUNG-SGH-I717 using xda app-developers app
You shouldn't re-format it at all from stock, but if you do you should try the official SD Formatter: https://www.sdcard.org/downloads/formatter_4/
I have a samsung 64GB microsd in my S4 and it's ridiculously fast according to SD Tools (http://i.imgur.com/EXUVIP7.png), probably a caching causing that; but anyways, it's great in normal use copying roms over/etc.
Oishikatta said:
...probably a caching causing that
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Click to collapse
LOL, you don't say! Divide those numbers by 10 and you have a more realistic speed indication :good:
Pfeffernuss said:
LOL, you don't say! Divide those numbers by 10 and you have a more realistic speed indication :good:
Click to expand...
Click to collapse
No, samsung does claim the card gets 70MB/s read and 20MB/s write - and the reviews on amazon match that even for the lower priced card:
http://www.amazon.com/Samsung-64GB-PLUS-Micro-Adapter/dp/B00I4ZMNY4/
Obviously the SD Tools benchmark isn't testing the actual card performance, but what matters is that in actual use the samsung cards are great.
Windows/crystaldiskmark can also easily be used to do a real test.
Here's in a usb 2.0 card reader:
Sequential Read : 23.455 MB/s
Sequential Write : 17.352 MB/s
Random Read 512KB : 22.898 MB/s
Random Write 512KB : 16.407 MB/s
Test : 100 MB [D: 32.1% (18.8/58.5 GB)] (x5)
Date : 2014/03/26 11:16:15
OS : Windows 8.1 [6.3 Build 9600] (x64)
If @chaos67731 isn't getting at minimum 10-20MB/s after formatting the card then there's probably something wrong with it.
chaos67731 said:
1: Does the S4 have problems with 64GB cards?
- I am running Sacs KitKat V2
2: should I format with a format (NSFT/exFat) and is it better done on a Mac or PC?
3: what should the Unit Size be?
4: I just copied my old sd card on to this one, and some of the big games I do have stopped showing up. but when I put my old card back in, they are there again.
Click to expand...
Click to collapse
1: A good amount of users (including me) had problems with their SD cards on S4s. The problems are between:
occasional unmount/remount (the system does this for no apparent reason). S4 cant read cards after a sudden unmount, and cards usually get killed. most of the cards reported are 16,32 and 64 GB micro SD kingstone. SandDisk has problems too but I'm not sure about Samsung's.
2: Just use the official SD formatter mentioned by @Oishikatta above.
3: if you used the official SD formatter you wont have to deal with Unit Size. (personally, I dont know what's that)
4: Do you use a card reader when you copy your memory card? or do you just connect the phone using a cable? try using a card reader when copying your SDs. Some hidden files may not appear if you used the cable.
I hope I helped and excuse my English, its not my native language.
Well if you have a SanDisk they want you to format exfat. http://kb.sandisk.com/app/answers/d...sion/L3RpbWUvMTM5NTg5ODI5OS9zaWQvRDdTTFVmUWw=
Oishikatta said:
No, samsung does claim the card gets 70MB/s read and 20MB/s write.
Click to expand...
Click to collapse
Sure, on a PC with an appropiate very fast SD-card reader. Using a phone you won't get those advertized speeds.
This is the result with a more proper SD-benchmarking app (although internal and external SD are shown in reverse):
These values will be more realistic. SD-Tools results (cached) don't mean jack, unfortunately.

I am extremely disgusted by the internal SD card. Why?

Hello all,
It seems that nowadays all vendors decide to go with the approach to have a virtual SD card that uses an emulated filesystem to make us feel happy in case we do not have a real SD card. I honestly do not understand the reasoning behind this so I am reaching out to you to let me know what you think the reason is.
For now I can see the following pros and cons of this approach:
Pros:
Have SD card support in case you do not have a real one and you have an app that requires it.
Cons:
You no longer can move applications to external SD card on most devices (all that I have tried).
The application data (obb) that is essentially the largest thing an app can offer goes directly to the internal SD card and you can not move it to the external SD card.
You are now even restricted by what you can write on the external SD card because if not there is a security issue. That's also a thing that I do not understand that is conveniently not explained and just implemented.
Your CPU cycles are used to process the data yet once more just so that you can have the luxury of an emulated file system.
The fuse filesystem in most devices lacks some basic features like links.
Essentially the internal SD card seems like a Huge hack to me. Why is that? Even just the name gives it all away. "Internal SD card". That is not an SD card. It's not even a separate flash chip. Not even a separate partition on most devices. There is times where this is just a folder in your userdata partition made to look like an SD card by the magic of fuse.
The only reason I could find for this monstrosity is that there is some kind of compatibility issue with some apps in case you do not have an SD card and so that's why they came up with this.
So please let me know what the big idea that I seem to be missing here is as to why this humongous hack is needed. Thanks in advance!
Cheers,
Sakis

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