Category Archives: tech

counterfeit SanDisk micro SD?

Not sure at the moment.

I have just bought an Android phone (HTC Desire), and immediately bought a 32 GB SanDisk Micro SD card on eBay to expand the available memory. I then realised that stories abound about people selling counterfeit flash memory, particularly on eBay.

The product description states:
– SanDisk® microSDHC™  mobile memory card 32 GB Class 6
– File system Format : Fat 32
– write speed 3-4 MB/S
– read speed 7-8 MB/S
– High Quality microSDHC card backed by 5 year limited warranty

I do like the 5 year limited warranty, although I wonder how the warranty is limited.

I have decided to verify/not verify the memory card. The reason I started doing this is that I thought that it didn’t connect/copy particularly fast when I first put it in.

This is what I have done so far.
1. Check the size in Windows: 30.4 GB. (Nb. This is the same as what Android says it is). Fair enough – there are obviously formatting overheads here, but 1.6 GB is certainly a fair shake of the sauce bottle. As expected, it is formatted as FAT32.
2. On the advice of Mr. Google, I have then sought to test it, using the H2testw 1.4 test:

The actual test is downloaded from here. Sometimes I really wish I could speak German — they are so good at doing things. If I could meet these programmers I would say ‘Guten morgen’ to them, because that is all I can say in German.

3. This is the result of my first test, where I only tested 200 MB for the sake of brevity.
Warning: Only 200 of 31186 MByte tested.
The media is likely to be defective.
0 KByte OK (0 sectors)
200 MByte DATA LOST (409600 sectors)
Details:0 KByte overwritten (0 sectors)
0 KByte slightly changed (< 8 bit/sector, 0 sectors)
200 MByte corrupted (409600 sectors)
0 KByte aliased memory (0 sectors)
First error at offset: 0x0000000000000008
Expected: 0x0000000000000011
Found: 0x0000000000000000
H2testw version 1.3
Writing speed: 3.37 MByte/s
Reading speed: 3.13 MByte/s

4.  Well, that is a little problematic, isn’t it? I think that we need to test the whole thing — although, the fact that it says it has lost the whole lot is a bit disturbing, and makes me wonder about the veracity of the test. While the writing speed is within range, the reading speed is well outside of range.

5. I have now reformatted the whole thing, and completely wiped it, and have run the write + verify over the whole thing. It is going to take some time before I get results, so I will update in 3 and a bit hours time.

Update:

Am well along the path of H2testw, and it looks much better this time — it has written over more than half of my drive so far, which means that it is at least capable of working with more than 16GB. Writing speeds look fairly slow, but this may be attributable to the fact that I am using my phone as a card reader. Am not sure about this or not. Would like to give this a go with a proper MicroSD card reader.

Update 2:

Things are not looking good at the moment. It took an interminable 4 hours and 42 minutes to ‘write’ 31189 MB to the card. I thought that sounded good, as it meant it could fit that much stuff on there. It is now in the process of verifying the contents of that write and says that:

The media is likely to be defective.
1.8 GByte OK (3823988 sectors)
2.0 GByte DATA LOST (4202124 sectors)
2.0 GByte corrupted (4202124 sectors).

Am going to run this out, but things are not looking really good at the moment.

Update 3:

Test is still going. In the meantime, I have seen that eBay itself contains a recommendation of the H2testw test.

Update 4:

Not real happy about this, although I think I can quite reasonably request a refund:

The media is likely to be defective.
1.8 GByte OK (3914208 sectors)
28.5 GByte DATA LOST (59960864 sectors)
Details:760 KByte overwritten (1520 sectors)
0 KByte slightly changed (< 8 bit/sector, 0 sectors)
28.5 GByte corrupted (59959344 sectors)
760 KByte aliased memory (1520 sectors)
First error at offset: 0x0000000074b2e800
Expected: 0x0000000074b2e800
Found: 0xffffffffffffffff
H2testw version 1.3
Writing speed: 1.84 MByte/s
Reading speed: 3.58 MByte/s
H2testw v1.4

Nifty little test, though!

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