Writing to SD card in WP8

Hi,
is there really no way to programmatically write to a SD card in Windows Phone 8? Maybe in the future?
Thx,
Ph

Am I correct to assume that WP 8.1 is lifting this restriction and allowing apps to write to the SD card ?? The page below seems to suggest it will, but can anyone confirm this ?
http://msdn.microsoft.com/en-us/library/windows/apps/xaml/dn611857.aspx
If so, the only problem is that WP 8.1 is not available yet on my Nokia 520 phone which I test WP8 app with... I found an article online saying that WP 8.1 is due for release in June 2014... So I guess I will have to wait. ( See http://www.theepochtimes.com/n3/650092-windows-phone-8-1-update-release-date-not-until-june-exec-says/
Storing files to phone memory or an SD card which can be accessed from a PC has been available on Android and iPhone for ages...
Anthony.

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Urgent ! writing a java card applet -APDU problem

hi
i'm fairly new to the java programming language. i'm trying to write an RSA java card applet to run on a java card simulator.
I am not sure at all what code i need to write for the CLA byte in the command APDU and what code i need to write for the INS byte in the command APDU, and where exactly to put it in my program.
if anybody knows please could you help me out.
So far i have written the code below.
thanx
louise
import javacard.framework.*;
import java.math.*;
import java.util.*;
/*the public key is the public part of the key. Anyone
can have it. It can only encrypt data, not decrypt.*/
public class publickey extends Applet{
//code of the CLA byte in the command APDU header
final static byte publickey_CLA = (byte)0x00;
//max number of characters for text message is 60
final static char MAX_TXT_MSG = 0x3c;
//MAX number of tries (3) before PIN is blocked
final static byte PIN_TRY_LIMIT = (byte)0x03;
//size of PIN must be 4 digits long
final static byte PIN_SIZE = (byte)0x04;
//below status word(SW) values are returned by applet
//in certain circumstances:
//signal that the PIN verification failed
final static short SW_PIN_VERIFICATION_FAIL = 0x6300;
//signal that PIN validation required for txt msging
final static short SW_PIN_VERIFICATION_REQUIRED = 0x630;
//instance variables declaration
OwnerPIN pin; //variable for holding owners pin
BigInteger n,e;
String owner;//variable for holding owners name
/*make a public key. Do not do it yourself, but
make a public key from a private key.*/
publickey(String iowner,BigInteger in,BigInteger ie){
owner=iowner;
n=in;
e=ie;
public void process (APDU apdu) {
byte[] buffer = apdu.getBuffer();
//check Select APDU command
if((buffer[ISO7816.OFFSET_CLA] ==0) &&
(buffer[ISO7816.OFFSET_INS] ==(byte) (0xA4)) )
return;
if(buffer[ISO7816.OFFSET_CLA] !=publickey_CLA)
ISOException.throwIt
(ISO7816.SW_CLA_NOT_SUPPORTED);
/*read the key back from a string.*/
publickey(String from){
StringTokenizer st=new StringTokenizer(from," ");
owner=st.nextToken();
n=readBI(st.nextToken());
e=readBI(st.nextToken());
/*use the key to encrypt a 'message' m. m should be a
number from 1 to n (n not included).
use makemessage to convert your message to a BigInteger.
BigInteger encrypt(BigInteger m){
return m.modPow(e,n);
/*make a string from this key.*/
public String toString(){
return owner+" "+printBI(n)+" "+printBI(e);
/*help methods for reading and writing:*/
final static int radix=36;
static String printBI(BigInteger b){
return b.toString(radix);
static BigInteger readBI(String s){
return new BigInteger(s,radix);
/* these methods convert an arbitrary message,
in the form of an array of bytes, to a message
suitable for encryption. To do this random bits
are added (this is needed to make cracking of the
system harder), and it is converted to a BigInteger.*/
BigInteger makemessage(byte[] input){
/*to understand this part of the program,
read the description of the BigInteger constructor
(in the standard java help). */
if(input.length>128 ||
input.length*8+24>=n.bitLength())
return new BigInteger("0"); //error! message to long.
byte[] paddedinput=new byte[n.bitLength()/8-1];
for(int i=0;i<input.length;i++)
paddedinput[i+1]=input;
paddedinput[0]=(byte)input.length;
for(int i=input.length+1;i<paddedinput.length;i++)
paddedinput[i]=(byte)(Math.random()*256);
return new BigInteger(paddedinput);
/*the inverse of makemessage.*/
static byte[] getmessage(BigInteger b){
byte[] paddedoutput=b.toByteArray();
byte[] output=new byte[paddedoutput[0]];
for(int i=0;i<output.length;i++)
output[i]=paddedoutput[i+1];
return output;
class privatekey{
/*the data of a key*/
BigInteger n,e,d;
String owner;
int bits;
Random ran;
/*unimportant things, needed for calculations:*/
static int certainty=32;
static BigInteger one=new BigInteger("1"),
three=new BigInteger("3"),
seventeen=new BigInteger("17"),
k65=new BigInteger("65537");
/*make a new key. supply the name of the owner of the
key, and the number of bits.
owner: all spaces will be replaced with underscores.
bits: the more bits the better the security. Every
value above 500 is 'safe'. If you are a really paranoid
person, you should use 2000.*/
privatekey(String iowner,int ibits){
BigInteger p,q;
bits=ibits;
owner=iowner.replace(' ','_');//remove spaces from owner name.
ran=new Random();
p=new BigInteger(bits/2,certainty,ran);
q=new BigInteger((bits+1)/2,certainty,ran);
n=p.multiply(q);
BigInteger fi_n=fi(p,q);
e=chooseprimeto(fi_n);
d=e.modInverse(fi_n);
/*read the key back from a string*/
privatekey(String from){
StringTokenizer st=new StringTokenizer(from," ");
st.nextToken();
n=readBI(st.nextToken());
e=readBI(st.nextToken());
d=readBI(st.nextToken());
/*some help methods:*/
static BigInteger fi(BigInteger prime1,BigInteger prime2){
return prime1.subtract(one).multiply(prime2.subtract(one));
static BigInteger BI(String s)
{return new BigInteger(s);}
BigInteger chooseprimeto(BigInteger f){
/*returns a number relatively prime to f.
this number is not chosen at random, it first
tries a few primes with few 1's in it. This
doesn't matter for security, but speeds up computations.*/
if(f.gcd(three).equals(one))
return three;
if(f.gcd(seventeen).equals(one))
return seventeen;
if(f.gcd(k65).equals(one))
return k65;
BigInteger num;
do{
num=new BigInteger(16,ran);
}while(!f.gcd(num).equals(one));
return num;
final static int radix=36;
static String printBI(BigInteger b){
return b.toString(radix);
static BigInteger readBI(String s){
return new BigInteger(s,radix);
/*returns the public key of this private key.*/
publickey getpublickey(){
return new publickey(owner,n,e);
/*the same encryption that the public key does.*/
BigInteger encrypt(BigInteger m){
return m.modPow(e,n);
/*decryption is the opposite of encryption: it
brings the original message back.*/
BigInteger decrypt(BigInteger m){
return m.modPow(d,n);
public String toString(){
return owner+" "+printBI(n)+" "+printBI(e)+" "+printBI(d);
/*this main demonstrates the use of this program.*/
public static void main(String[] ps){
say("************ make key:");
privatekey priv=new privatekey("sieuwert",92);
publickey pub=priv.getpublickey();
say("the public key:"+priv);
say("************ encrypt message:");
byte[] P="RUOK?".getBytes();
BigInteger Pc=pub.makemessage(P);
say("converted:\t"+printBI(Pc));
BigInteger C=pub.encrypt(Pc);
say("coded message: "+printBI(C));
say("************ decrypt message:");
BigInteger Pc2=priv.decrypt(C);
say("decoded:\t"+printBI(Pc2));
byte[] P2=publickey.getmessage(Pc2);
say("deconverted: "+new String(P2));
static void say(String s){
System.out.println(s);

Command APDU is not written in your source code, rather it is sent from PC or programmed Card Acceptance Device/ Card Reader/ Terminal.
The code installed in the Java Card should be able to handle the Command APDU received and process it accordingly, and finally your code should be able to send out response APDU.
You may think your code as a decoder, to retrieve each byte (CLA, INS, P1, P2, DATA, LC) using the Java Card API, you should be able to do it.
Also, I notice in your code that you want to work out with strings, but Java Card does not support strings, chars, long, float, double ...
to send out reponse APDU, there are certain steps that you can use, not just simply print like ordinary J2SE may use.
hope this will help u

Problem writing to SD card in Ricoh card reader

I have a Gateway 4540GZ laptop with a Ricoh card reader. Whenever I plug in an SD card, it recognizes it as usual. But it won't let me write data in dd, gnome-disks, gparted, caja, et cetera. So I remove it and flip the lock switch to lock, plug it in, and I can't write any files, but I can write data in dd, gnome-disks, and gparted. Thinking it was because I was using an 8GB SDHC card, I swap it for a 2GB SD card and I get the same results. What am I doing wrong?
Last edited by Bolt473 (2013-11-15 04:19:52)

Hello!
I have the same type of problem so I post there.
I' try to write on a file on the SD card, and if I don't open and close the file on the loop, there's only one line writed.
Unfortunately, on my application, I have to read the measure and write them on a file quickly than 10 ms and if I open and close the file each time, writing part take too long.
Is there a tip to resolve this?
Regards,
Cédric

HP Pavillion dv6-1245dx problems writing to MicroSDHC card - errors

I've purcahsed two different brands of MicroSDHC 32GB cards. They will allow me to write 1-2GB of info before giving me an error code: 0x80070052. I was using Windows 7 and read that this was an issue that was going to be resolved in Windows 8, so I installed Windows 8 on my laptop (It's legitimate through Microsoft's MSDN program).
I went looking for product specifications for my laptop on the HP site and it just gives this vague answer: 5-in-1 integrated Digital Media Reader for Secure Digital cards, MultiMedia cards, Memory Stick, Memory Stick Pro, or xD Picture cards.
It doesn't specify SD, MicroSD, MicroSDHC or any variation. I am inclined to believe that the laptop doesn't support cards as large as 32GB. The largest card I've ever tried before this was an standard size 8GB SDHC, so at least I know it will handle the SDHC part. However, I have had issues with 32GB USB drives as well, where the drive gets half full and then starts having problems writing (no error codes though).
I'd like to know if MicroSDHC cards as large as 32GB are or aren't supported before I commit to purchasing a third card. I've tried multiple adapters as well, so I know it's not 1) Me trying to stick a tiny card in a large hole, 2) poor contact between the adapter and the laptop, or 3) poor contact between the card and the adapter.
Thank you.

card readers are prone to problems with the internal contacts, particularly multi-card readers. If you get a card inserted a little bit wrong it can cause it to go out. HP should warrant the problem but if you can't get relief, the expresscard multi-readers are cheap and work well. My laptop has no built in card reader so that is what I use.

Canon 30d tethered not writing to CF card

When I use my canon 30d for tethered shooting with LR 3.2 or 3.3, the photos are only stored on the computer not on the cf-card in the camera.
I am on an Imac with 10.6.5 and a little bit helpless now, anyone with the same problem?
B.M.

Hi Pete,
Thanks for your quick response. But the 30d has only a setting to shoot with or without card, either setting are with the same result only writing the files to the computer.
B.M.

Generating a tri state waveform pattern and writing into DAQ card

Hi,
I am using LV8.0 and NI-6259 DAQ card.
I want to generate a waveform pattern which initially goes to +5v and goes to 0v and then again goes to -5v
and finally goes to 0v.
I have used the waveform pattern generator and have generated 4 kinds of waveform with some particular samples
and I will be appending all the 4 waveform patterns(+5, 0, -5, 0) and the appended waveform will be written into DAQ card.
The problem is:
When I probe CRO at the Analog output pin of the DAQ card, the pin level will be always at +5v and sometimes
it goes to 0 and back to +5v. But I am expecting a waveform with 3 voltage levels i.e.., +5( some 100 samples), 0v(for some 1000 samples.
-5v(same as +5v) and 0v( 2000 samples).
How to get this kind of waveforms in NI-6259 DAQ(M Series) card.
Please find the attached VI which I have created.
Letme know the loophole in the VI and correct way of generating a tristate waveform.
Thanx in advance,
Yogesh
Attachments:
PWM_sample.vi ‏43 KB

Hello YogeshaYS,
Thanks for your post!
I see that you are wanting to output a waveform that goes from 5 to 0 to -5 and then back to 0. It looks like from your code that you want to do this in a continuous fashion? If this is so you will need a while loop to output the waveform. Take a look at one of our shipping examples that shows how to do analog output waveform. Go to Help >> Find Examples. When here go to Hardware Input and Output >> DAQmx >> Voltage >> Cont Gen Voltage Wfm-Int Clk.vi. Your VI works great but it only does the output once so that may be why you see some interesting results on your output. Let me know if any of this information helps you with your program. I was able to run it in a continuous mode and see the voltage levels go from 5 to 0 to -5 just like you were wanting. Have a great day YogeshaYS and please reply if you have any other questions on this.
Cheers!
Corby_B
http://www.ni.com/support

Leopard does not support reading/writing to SD card via network?

I have a Pixma MX700. I can read and write to SD cards using the card reader built into this machine ... IF I use Windows XP. Leopard will mount the card and allow me to view it contents but the minute I try to import a file to my iMac, I get error code 1401.
I've been told by Canon support that the new MP Navigator EX driver for Leopard disables reading from the memory card over a network. They claim Leopard does not support this function and reading the posts from others having the same issue using different multi-function printers, this would appear to be a Leopard issue, not a Canon issue.
Can anyone confirm this and/or offer a fix?
Thanks!

Hi,
Could you check for SAP Note 1952701 - DBSL supports new HANA version number
Regards,
Gaurav

Apps Writing To SD Cards

I realize this is a Google "problem" and not a Sony "problem" but i'm hoping to find some help here ...
Is it possible for apps to get access to the SD Card without rooting the phone ?
A few apps like QuickPic & File Manager seem to work. But apps like Player Pro (for my music) and Vignette (for my camera) don't.
Please Help !!!

No,there are few apps that allow this,generally for pics and maybe some GPS.Without rooting,there is not much you can do.As to say,you are limited.
All we have to decide is what to do with the time that is given to us - J.R.R. Tolkien

Question on "Writing a Java Card applet" by Ed Ort

Hi,
in the wallet apple i defined the variable
short balance
that is the wallet in the Sim, but i don't understand where the value of this variable is initialized the first time.
Could someone help me?
Thank you
Luigi

It's initialized to 0(zero) per the Java/JavaCard specification(either by the VM or at compile time).
For myself, I prefer to explicitly initialize values.
It terms of the application, it would be "initialized" with an initial deposit as mentioned by DurangoVA.
Steve

Lumia 625 does not detect MicroSD cards, please he...

My Lumia 625 does not detect MicroSD cards when inserted.
I have tried powering off/on.
I have tried formating them in my PC.
I have updated my phone to 3050.0000.1334.0007
I have tried a Kingston 64GB SDXC Class10
I have tried a Sandisk Ultra 64GB SDXC Class10
I have tried formatting the cards in various ways including exFAT / FAT32 / FAT64 etc.
The only progress i made was when i tried formatting in NTSC and after inserting the card i recieved a message saying "incomattable formatted card inserted, do you whish to format the card in a compattable format?" After choosing yes, the phone formatted the card and then the card was undetected...
This was confirmed by checking the card in my PC, which confirmed that the card had been formatted using exFAT, which i believe is the correct format for the phone/card.
Clearly the phone is somehow detecting and writing to the card and the card is functioning properly, except that the phone does not detect that the card exists as expanded memory and will not allow me to use it.
Any help with this would be really appreciated!
Becoming quite frustrated now...

Hi Pepperami33,
Have you tried to perform a reset? It will delete all your data so backup is required. See this link: http://www.windowsphone.com/en-us/how-to/wp8/basics/back-up-my-stuff for the steps on how to backup your files. After creating a backup, go to Settings > About > Reset your phone.
If the reset will not work, it is best to have your phone checked by our care point. Visit www.nokia.com/support for more info about the repair process.

Need suggestion regarding simulation of Java Card using a floppy

Hi All,
I am working on a project wherein I have to simulate a Java Card application using a floppy. I am writing my own Card Terminal and CardTerminalFactory. Thats what I have started working on. Will that serve the purpose or do I have to think about some other approach like just overriding the cardInserted method of CTListener class? I want to achieve communication between the host application and the floppy(which is my java card) Please advise.
I would like to thank DurangoVa and Nilesh for helping me out sorting out the error in running the converter.
Thanks in advance

Are you referring to a Floppy diskette drive ?

What does it take to build smart card applications?

Just out of interest I was wondering what does it take to build smart card applications:
- Can I do it at home with my PC or do I have to have access to expensive hardware?
- How difficult is it to master given that I do it on my own with no help. Does it involve a lot of hardware issues?
- If hardware is required (a smart card and a cable connection), where do I get it and how much does it cost?

Let me rephrase my question.
I understand that the deployment process may not be so easy. That does not disturb me.
I just want to know whether I'll experience hardware probelms. If reading/writing to the card involves putting it inside and taking it outside from the device just like a floppy disk without any complications, then I don't have any worries.
By the way, does the reader device is used for both reading AND writing?

Nokia Lumia 1520 video recording on Microsd card i...

First off, I have a Nokia Lumia 1520 for about one month now. I love the screen size and everything. My picture/video recording to phone memory works fine. I have recently purchased a Class 10 Sandisk Pixtor 64GB microsd card from Best buy for video/pictures storage due to this device having only 16GB of memory.
http://www.bestbuy.com/site/sandisk-pixtor-64gb-microsdhc-class-10-memory-card/1299201.p?id=12190475...
Picture taking is fine writing to this card. However, I noticed that on all video recording mode (720p to 1080p), the video would sometimes skip and lose a few frames here and there. For example, when i try to record a video of a kid running, the video playback will show the kid run across but would jerk or freeze a bit during his run (almost like the phone is too busy doing other tasks during recording). Playing the same videos on a computer show the same result which means the video taken were bad to begin with. My temporary fix is to switch video/picture recording to the phone storage itself but that defeats buying the sd card in the first place.
Anybody else having this issue? I couldn't find another microsd card to test but i wonder if the phone itself is having a performance issue with sd cards in general. Should i engage with tech support from Nokia?

It is quite well known that Class10 card are overkill on a mobile phone and in many cases have been proven to actually have worse performance when compared to even Class4 cards.
Class10 cards really only make sense in (high end) DSLR ca,eras where itis a requirement the shots can be written to the card fast. In practical use the class only indicates the card cab sustain a transferrate of X MB/s and with that in mind a Class4 card even will be plenty fast for your mobiel phone.
Due to the fact a Class10 card is basically overspec for the hardware it may even cause timing issues.
Click on the blue Star Icon below if my advice has helped you or press the 'Accept As Solution' link if I solved your problem..

Memory card quality

I would like to ask the members of the Forum if there is any photo quality difference between different brands of memory cards? I am using Sandisc in both my 7530 Kodak and my Canon 20d. I just want to make sure that my photos are as good as possible, especially with my new 20d. Thanks

Bill,
You may like to have a look at this site where it compares a few cards - http://www.robgalbraith.com/bins/multi_page.asp?cid=6007-7303
Like all things like this, you may get a good one or be unlucky to get a bad one which fails quickly.
I feel the speed is important and I would go for the fastest I can afford (certainly not below 20x) - Although some of the cameras are not that fast when writing to the card, I think that you will find that on the 20D, if you shoot in burst mode, the buffer will clear quicker. Another reason is that when downloading via a card reader, the faster cards are much quicker.
Personally, I go for Fuji, mainly because I had a Sandisk one which was very slow and that seems to stick in my mind. There were problems with Lexar CF cards a little while back but I think they are reliable now.
Brian

Smart Card and Java Card (URGENT)

Dear everyone.
I have purchased a card reader (which is supposed to be java card compatible).
I have 2 problems.
1. I just wonder if i can use a Smart Card generally available. Do i need to have a special card for Java Card??
2. Can i use card kit to interface to the reader/writer? How do i install my applets??
Please reply soon.
Thank you very much.

I tried to execute the OCF samples.
this code
OpenCard.services = com.ibm.opencard.factory.MFCCardServiceFactory
did not give any trouble
this code
OpenCard.terminals = com.ibm.opencard.terminal.pcsc10.Pcsc10CardTerminalFactory
gave some troubles. May be because iam not using ibm terminal(card).
And also, i think the OCF samples will not work anyhow, because the Reflex reader is not OCF complaint.
So the following may not work
OpenCard.services = com.slb.opencard.Cyberflex
I have most imp. questions to ask you now.
1. What card should i purchase and from whom (along with some software if necessary)?
2. What is the procedure for reading/writing to that card using the Reflex reader.
Please help.
Thanks
Goldy.

Writing to SD card in WP8

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