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I tested the micro SD card of my phone with testdisk, and it says somethings about heads/cylinder mismatch. What is that? SD card should not have heads...

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Germano Massullo
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  • What exactly is your question? It looks like you may have up to three questions here: (1) why does TestDisk mention CHS for a memory-card? (2) why does TestDisk report an inconsistency in the card’s structure? (3) How can you fix some file-access problems or something similar? – Synetech Apr 11 '14 at 02:20
  • You told me that your card had no problems, but then accepted harry's answer on the assumption that the card is bad. So what happened? Was the card bad or not? Did you fix the problem? If so, how? – Synetech Apr 20 '14 at 22:54

2 Answers2

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The SD card is formatted in a way that mismatches the standard number of heads-per-sectors that is built-into in TestDisk for FAT32.

This is just a warning and one can usually try and go ahead with TestDisk (with no guarantee of success, of course).

However, TestDisk is primarily designed to help recover lost partitions, so might not be the tool you want if you wish to save files.

SD cards are usually very fragile, and when they go that's it. To be in good health the card should first show up in Windows Explorer as a drive with the files visible.

Here is one free Android test app : SD Card Tester, and a PC test program : H2testw 1.4.

If any problem is found, reformat the card using slow format, and if problems reoccur then junk it.

harrymc
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  • The card I am testing is a microSD 32Gb I use in my Android phone. I am experiencing a trouble with OsmAnd maps and I suspect this could be related to a possible SD card corruption. Another synthom is that when I poweron the phone, I obtain the process android-media-process go to about 100% CPU for a few minutes. So I need to test the microSD card integrity. – Germano Massullo Apr 10 '14 at 07:59
  • SD cards are usually very fragile, and when they go that's it. To be in good health the card should first show up in Windows Explorer as a drive with the files visible. There is one free Android test app : [SD Card Tester](https://play.google.com/store/apps/details?id=air.com.anotherflexdev.sdcardtester.SDCardTester). Also a PC test program : [H2testw 1.4](http://www.softpedia.com/get/System/System-Miscellaneous/H2testw.shtml). If any problem is found, reformat the card using slow format, and if problems reoccur then junk it. – harrymc Apr 10 '14 at 08:38
  • You can add infos of your last comment in the answer – Germano Massullo Apr 10 '14 at 12:03
  • Did as requested. – harrymc Apr 10 '14 at 13:42
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I tested the micro SD card of my phone with testdisk, and it says somethings about heads/cylinder mismatch. What is that? SD card should not have heads...

No, not physically, however they do, or at least can have them logically. You can convert large-block addresses to cylinder/head/sector addresses and vice-versa, so technically you can use either format to address any sort of sotrage medium regardless of its physical attributes.

In addition, flash media is usually formatted in such a way as to create “blocks” which are written to wholesale. Depending on their internal makeup, they can vary in what block configuration is optimal, and will usually come pre-formatted in a way to maximize speed and reduce wear. That is why formatting a memory-card is usually advised against, and why there are special formatters to restore them to their factory settings.

Testdisk on SD card heads/cylinder mismatch

It looks like there is a difference in the card layout to what Testdisk is calculating. There are a few distinct possibilities that could be causing this:

  • The card-reader is bad/cheap/incompatible. What kind of card reader are you using? Cheap card-readers like the kind of cheap Chinese ones on eBay tend to be buggy and can cause full-on corruption due to buggy programming in their card-structure handling.

  • The card has been formatted incorrectly or in a non-standard format with the phone. It is possible that a phone may have formatted the card in a way that is not standard, so the computer which is expecting a standard format is seeing it as unusual.

  • The card is mounted incorrectly. If it is an external reader, make sure that the cord is plugged in correctly and that the pins on the cable and USB port are clean because a poor connection can lead to read errors, which may be causing it to mount as a hard-drive instead of a memory-card.

  • It could be a formatting issue. The card is showing as 32GB, but it looks like it was formatted with FAT which does not support that size. For a 32GB card, you would need to use FAT32 (or exFAT), so something (the phone?) may have formatted it incorrectly.

There’s a few things to try:

  • Test with a different card, preferably an identical one.

  • Test with a different card-reader, preferably a high-quality one, like the kind that are often built-in.

  • If possible, try formatting it with the computer (make sure to use a format that is compatible with the phone like FAT32).

Synetech
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  • The card reader is the best usb 3.0 San disk card reader I found on Sandisk website – Germano Massullo Apr 10 '14 at 18:01
  • Then it’s one of the other causes. Have you tried other cards in your phone? Do they come up wonky? If not, then it is the card itself. That it seems to be formatted as FAT seems highly suspicious; where did you get the card and who formatted it? Is it full? How much of its space have you actually used? – Synetech Apr 10 '14 at 19:05
  • the card never caused special problems, and I bought that Sandisk SDcard and I used it without formatting it – Germano Massullo Apr 10 '14 at 21:10
  • Your phone may have “initialized” it. If it it empty, try formatting it with the computer. If it is not, try transferring the data to the computer, then formatting it with the computer (especially using the SD Format utility I linked to). Moreover, is there an actual *problem* you were asking about or were you simply curious about the disparity reported by Testdisk? That is, does the card work in your phone? You mentioned having trouble with an app, but that would only relate to the structural disparity if you are unable to access all of the files. – Synetech Apr 11 '14 at 02:19