[IAEP] [Testing] Dextrose Install Snags

Caryl Bigenho cbigenho at hotmail.com
Mon Sep 13 00:21:59 EDT 2010

Date: Sun, 12 Sep 2010 17:21:20 -1000
From: wmb at laptop.org
To: cbigenho at hotmail.com
CC: testing at lists.laptop.org; iaep at lists.sugarlabs.org; support-gang at laptop.org
Subject: Re: [Testing] Dextrose Install Snags




    On 9/12/2010 5:09 PM, Caryl Bigenho wrote:


      Date: Sun, 12 Sep 2010 16:41:34 -1000

      From: wmb at laptop.org

      To: cbigenho at hotmail.com

      CC: testing at lists.laptop.org; iaep at lists.sugarlabs.org;
      support-gang at laptop.org

      Subject: Re: [Testing] Dextrose Install Snags




      On 9/12/2010 4:12 PM, Caryl Bigenho wrote:

        I was trying to
            install Dextrose on an XO-1.5 today.  I was following the
            instructions on:   http://wiki.sugarlabs.org/go/Dextrose
        There was only
            one file listed to download for the XO-1.5 : os373pyg.zd.  I
            followed the directions on the page and got an error message
            that the file was all in "one chunk"

      at which step in the directions did the error message appear?

      The message
            appears after entering " fs-update
                u:\os373py.zd  at the "ok" prompt.

    Is the message like "WARNING: The file specified N chunks but wrote
    only M chunks"?


    "The file was all in one chunk" is not a particularly close
    approximation ...


    The warning message shown above typically indicates that the .zd
    file is truncated, missing parts at the end.
__________________________________________________OK.  I put the saved file back on the usb stick and tried again. This is what I got...
When I typed 
"fs-update u:\os373.zd" it returned: 
Can't open file
So, I thought I might be reading the instructions incorrectly and put in 
"fs-update u:(space)\os373.zd"  It returned 
WARNING: The file specified 0 chunks but wrote only 1 chunks00:00:00\os373.zd ?ok
I do not believe the machine is secured in any way.  I asked Adam if I needed a Developer Key for it, but I haven't had an answer.



      The machine is unsecured. All of the
                XO-1s I have have Developer Keys.  Am I correct that a
                Developer Key is not needed for the XO-1.5?

    Whether or not a developer key is needed does not depend on XO-1 vs
    XO-1.5, but rather how the individual machine is configured at the
    factory. XO-1 and  XO-1.5 systems can both have security either
    enabled or disabled.





          So I am trying
              to do it for an XO-1 instead.  However, I notice that
              while there are two files for the XO-1, the .img file and
              the .crc file, there is only one for the XO-1.5, the .zd

          When I
              installed 852 on both types of machines, there were 2
              files for each.  Is there a file missing on the Dextrose
              page listed above?  Can I just use the fs.zip file from

          While I am
              asking, is there a reason why the files for the XO-1 for
              852 are .img and fs.zip while those for Dextrose are .img
              and .crc?  I am not a whiz on file types so I haven't a
              clue why these would be different.

        fs.zip is a security bundle, needed only for updating a system
        with security enabled.  fs.zip does not contain any actual
        filesystem data; instead, it contains a much-shorter list of
        hash values that represent the actual data, and a signature that
        authenticates that hash list.


        fs.img is for XO-1 only.  It contains raw data that goes
        verbatim into the internal NAND FLASH inside the XO-1.


        fs.crc, for XO-1 only, contains a list of check values that
        represent the data in fs.img.  Its purpose is to catch corrupted
        fs.img files, which sometimes happen due to download problems or
        USB stick errors.  The checksum algorithm in fs.crc (CRC-32) is
        much weaker than the hash algorithm used in fs.zip.  CRC-32 is
        good enough to catch accidental file corruption, but not strong
        enough to prevent a determined attack.


        fs.zd is a new format that was introduced for XO-1.5.  It
        combines checking (via the strong hash code) and the actual
        filesystem image data in one file, with explicit compression to
        shrink the file to a manageable size.  It was necessary to come
        up with a new format because XO-1 and XO-1.5 have very different
        internal storage.  XO-1 uses raw NAND FLASH that is formatted
        with the JFFS2 filesystem layout, while XO-1.5 uses a micro-SD
        card that emulates a hard disk, formatted with the same
        ext2/ext4 filesystem layout.  JFFS2 filesystem data is already
        internally compressed, so there is no need for explicit
        compression.  That is not the case for ext2 filesystem data, so
        the compression had to be explicit in the .zd file format.


        The fs.zip files for XO-1 and XO-1.5 are similar, but not
        identical.  For XO-1, fs.zip contains hash values suitable for
        checking fs.img.  For XO-1.5, fs.zip contains hash values too,
        but their format is different, being suitable for checking



          I need to get
              this done in time for a "show and tell" at Montana State
              University on Thursday morning.


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