| L'explication
de TRG sur le probléme de DRAM 8mo:
Q: What
is the problem?
A: A faulty memory chip used in production of TRGpro computers will
cause random fatal errors and data corruption. TRG’s upgrade to Palm
OS 3.5.1 addresses the issue, and users are encouraged to upgrade. The upgrade
can be downloaded from http://www.trgpro.com/support/update.html.
Q: What are the symptoms?
A: The most common symptom is a “Fatal Exception” error
after the unit has been powered off for a period of time. Other symptoms
include corrupted data in the unit.
Q: If I buy a TRGpro today, will it have this problem?
A: TRGpro computers purchased directly from TRG Products will not
have this problem. It is possible that a user could purchase a unit through
a distributor that contains the faulty chip. If this happens, the user will
need to upgrade to OS 3.5.1. If the unit has OS 3.3, the user is encouraged
to upgrade to OS 3.5.1.
Q: How do I determine what OS version my unit has?
A: From the launcher, press the menu icon, and select "System Info..."
Q: What
if I don’t see any problem with my unit?
A: TRG still recommends that the user upgrade their operating system.
The problem could occur in the future.
Q: Can
I swap my unit?
A: The new operating system will completely solve the problem, and
there is no need to exchange units.
Q: What
if I don’t want to upgrade to OS 3.5.1?
A: TRG recommends that the user upgrade to OS 3.5.1, but a patch for
OS 3.3 will be available shortly for those users who do not want to upgrade.
Q: How
do I upgrade my unit?
A: Go to TRG’s web site at http://www.trgpro.com/support/update.html.
Instructions there will guide you through the process.
Q: What
happens to a TRGpro device with an affected DRAM chip?
A: There are three possible outcomes:
(1) Random data could be written to an unused portion of memory, which
has no effect on the user.
(2) Random data could be written to a portion of memory storing users'
data. This could cause the user's data to be overwritten.
(3) Random data could be written to a portion of memory storing
operational code. This could causes the device to fail to wakeup, or even
to experience an error requiring a complete reset of the device.
Q: Is
this a Palm OS problem?
A: No. This is related to an 8 MB DRAM component supplied to TRG.
Q: How
is TRG Products going to resolve this issue for its customers?
A: The latest Palm OS 3.5.1 fixes the problem and can be quickly and
easily downloaded from the web site.
Q: Should
I stop using my TRGpro?
A: No but you should upgrade your Palm OS to Palm OS 3.5.1
Q: What
if my applications fail on Palm OS 3.5.1?
A: Please make sure that the applications are compliant with Palm
OS 3.5. If they are not please contact the developer about an upgrade. Staying
on Palm OS 3.3 is not a good option. TRG Products and Palm will work with
developers to encourage them to upgrade to Palm OS 3.5.
Q: Will
the I loose access to certain parts of memory with the fix?
A: The fix simply avoids the use of DRAM self-refresh mode (see bleow).
The amount of available memory will not be affected.
Technical
Description of the Problem
Q: What causes the DRAM problem?
A: The exiting of self-refresh mode on a certain vendor's DRAM was not
implemented correctly. This can cause a portion of memory to become corrupted.
Details: The Palm OS goes to sleep and wakes up once every minute
to perform some housekeeping functions. This, in turn, causes the DRAM to
enter and exit self-refresh mode once per minute. Since self-refresh mode
is flawed in certain vendor's DRAMs, there is a chance for data corruption
to occur every time self-refresh mode is exited on units which use that vendor's
DRAMs.
Q: What
is DRAM self-refresh mode?
A: When your unit is on, the processor is responsible for maintaining
the contents of DRAM. When the unit is "off", the processor is shut down
and the DRAM is commanded to assume responsibility for its own refresh. This
mode is called DRAM self-refresh.
Q: How
likely is the failure to occur?
A: If your unit contains the faulty DRAM, it is a statistical certainty
given infinite time.
Details: Through testing, TRG has observed that there is about a 1/8000 chance
of a row of data (2K) being corrupted every time self-refresh is exited.
In a 24 hour period, the TRGpro will wake up 1440 times. In 5.5 days, the
unit will experience 8000 wake / sleep cycles. If a corruption occurs in
an area of memory that is in use, you will experience the problem. Since
the location of the failure in memory is random, your odds of detecting the
failure will increase with the amount of memory you use.
Q: How
can software fix this problem?
A: TRG developed a work-around which does not put the DRAM into
self-refresh mode. If self-refresh mode is not used, the problem will not
occur.
Details: TRG refreshes the DRAM using a technique called "burst CBR
refresh". This avoids the need to enter/exit self-refresh mode.
Q: How
did TRG discover this problem?
A: TRG was testing a change to Palm OS3.5 that required the unit to
wake up once every 5 seconds instead once per minute. This increased the
chances of the failure occurring by 12x. With the help of TRG's beta testers,
the problem was then detected and isolated to a particular vendor's DRAM.
TRG then reported the problem to the DRAM manufacturer and developed the
fix. |
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