Nandblasting not working in one xo
wad at laptop.org
Mon Jul 9 23:48:05 EDT 2012
NANDBlaster uses a fixed transmit speed (modulation).
If the signal budget for a laptop isn't sufficient to support
that speed, it will fail to receive many packets.
When using normal WiFi, the transmit speed (modulation)
is decreased until reliable communication can be obtained ---
therefore a laptop with decreased signal budget (e.g. bad antenna)
may still work, although with degraded performance.
On Jul 9, 2012, at 11:10 PM, James Cameron wrote:
> That the antenna change did not work shows the problem is in the
> wireless card.
> You asked why not use the same mechanism as Sugar?
> Consider the transmitter performance.
> Your network used by Sugar probably has an access point with higher
> transmit power and better antenna than the laptop being used as
> NANDblaster sender.
> So it is perhaps the combination of small damage to one laptop and
> large damage to another laptop, that causes NANDblaster to fail. But
> the combination of good access point and large damage causes Sugar
> networking to be successful.
> See http://wiki.laptop.org/go/Antenna_testing#Link_Budget for a
> calculation of wireless success, to see what variables are important.
> Does Sugar in ad-hoc wireless mode work between the two laptops? Or
> Sugar in mesh wireless mode with no other laptops nearby?
> If so, that's very interesting.
> Open Firmware and Linux use different commands sent to the wireless card.
> I've checked, and we are using the same wireless firmware 5.110.22.p23
> in both Open Firmware and Linux (build 883).
> Daniel, do you know of any commands that the Linux kernel may have
> sent to the card that may improve signal, even by accident?
> On Mon, Jul 09, 2012 at 04:06:16PM +0545, Roshan Karki wrote:
>> I tried with antenna change but as you told, didn't work. So I think this is
>> the dead end. Thank you for your help. But one question I wonder is in Sugar I
>> can use very poor network very well. Why not use the same mechanism in OFW as
>> On Fri, Jul 6, 2012 at 10:41 AM, James Cameron <quozl at laptop.org> wrote:
>> Thanks for the photographs. There's nothing wrong that I can see
>> Repair may attempt antenna change, but it is unlikely to be fixed with
>> only antenna change.
>> Perhaps the radio module has been damaged. On XO-1 the module is
>> soldered down and is impractical to replace. In later models (XO-1.5,
>> XO-1.75) the module is in a socket.
>> James Cameron
> James Cameron
> Devel mailing list
> Devel at lists.laptop.org
More information about the Devel