[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:
Hi...
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.
Caryl_________________________________________________
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.
Caryl
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
file.
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
852?
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
fs.zd.
I need to get
this done in time for a "show and tell" at Montana State
University on Thursday morning.
Thanks,
Caryl
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