this is why i don't like solid state memory

Discussion in 'EP121 Slate' started by kwg06516, Aug 21, 2011.

  1. kwg06516

    kwg06516 Pen Pal - Newbie

    Messages:
    27
    Likes Received:
    0
    Trophy Points:
    5
    using sd cards to supplement the minimal ssd has its advantages and disadvantages. advantages like it doesn't stick out on the side the way a thumbdrive does. disadvantages like the data corruption in evidence.

    memory in an sd card isn't stored in a physically addressed space like with magnetic drives and tapes. it's stored in logic gates on a printed circuit and is moved around to suit processes like wear leveling.

    i bought transcend 32gb sdhc cards that were recommended here by other users and they worked fine until i tried writing a file that was over 4gb. that's when i discovered they came formatted in fat32. so i reformatted them.

    the problems started when i put more than a few gb on one of them. files turned into garbage like the screen grabbed example attached to this post. i also lost some work when i didn't realize that a backup overwrote uncorrupted copies on an external magnetic hdd.

    i fully reformatted back to fat32, but the problem persists. i also tried an sd card formatter by hp. i am basically stuck with a pair of $50 guitar picks.
     

    Attached Files:

  2. coldpenguin

    coldpenguin Scribbler - Standard Member

    Messages:
    279
    Likes Received:
    0
    Trophy Points:
    31
    Did you buy it somewhere reputable? SD cards are not that bad usually with corruption, but, there are a lot of fakes around which are basically smaller cards that are re-badged. I always write at least 50% to the card, then run a speed benchmark which checks what was written = what is read.
    Two cards I purchased recently, both 32g, one claimed to be class 10, but corrupted at 8g, and was really class 2.
    The second was class 4, but writes/reads at class 6, and doesn't corrupt.
     
  3. excalibur1814

    excalibur1814 Scribbler - Standard Member Senior Member

    Messages:
    2,331
    Likes Received:
    307
    Trophy Points:
    101
    All my SD cards be they SDHC, SD or SDXC have zero issues with NTFS. Suppose I'm lucky
     
  4. CF77

    CF77 Love Tablet. Senior Member

    Messages:
    2,303
    Likes Received:
    8
    Trophy Points:
    56
  5. excalibur1814

    excalibur1814 Scribbler - Standard Member Senior Member

    Messages:
    2,331
    Likes Received:
    307
    Trophy Points:
    101
    "don't use the Win7 format for sd."

    But... that's all I've ever used :/
     
  6. Steve S

    Steve S Pen Pro - Senior Member Super Moderator

    Messages:
    7,605
    Likes Received:
    3,111
    Trophy Points:
    331
    <<...i bought transcend 32gb sdhc cards that were recommended here by other users...>>

    ...Well, you sure didn't get that recommendation from me. I have always advised buyers to approach Transcend memory products with caution. Note that solid-state memory is just like any other product; you always need to look beyond low price and consider other factors like reliability and durability. Based on what I've seen, Transcend is a little light on both...
     
  7. kwg06516

    kwg06516 Pen Pal - Newbie

    Messages:
    27
    Likes Received:
    0
    Trophy Points:
    5
    coldpenguin's reply is giving me chills. the performance of the 32gb cards felt below that of some class 4 4gb cards from best buy. I bought the 32gigs from amazon, which i thought to be reputable but they've turned the marketplace over to the rabble, as it turns out the actual seller is just some guy behind an email address. caveat emptor.

    cold, what software do you use to test these cards?
     
  8. spamnco

    spamnco Pen Pal - Newbie

    Messages:
    27
    Likes Received:
    0
    Trophy Points:
    5
    A simple way to test your card is to copy a movie of 4 gigs or more several times (8 times for a 32 GB) and then try to read the movie clips from your SD card.
    If your SD card is a fraud then you won't be able to read the last files you copied although they appear on your card !

    I bought two 32 Gb SD cards over the last months and both were actually fakes!
     
  9. coldpenguin

    coldpenguin Scribbler - Standard Member

    Messages:
    279
    Likes Received:
    0
    Trophy Points:
    31
    I use some software called iozone (www.iozone.org).
    I would run a test for 2g at the start of the partition. I would then fill the disk at least half full, like the above suggestion, and re-run iozone again. Then fill to almost full, and run iozone again. Then a checkdisk should return no errors. Delete all files, and checkdisk again should return no errors.
    Note, iozone is intended to be a benchmarking tool, but, it happens to also check that what it reads is what was written, which is why I trust it over other benchmark tools.
    Linux checking a volume would be much easier (no filesystem required)
    The type of command I would use would would be like:
    iozone -a -g 2g -n 2g
    to force a 2 gig test file, multiple records, or change the -a to -r 4096k for a fixed 4meg record size.


    On the fakes, I will write fake to the disk contents. Probably won't be seen though.
     
  10. LanMan85

    LanMan85 Pen Pal - Newbie

    Messages:
    12
    Likes Received:
    0
    Trophy Points:
    5

Share This Page