DiskOnChip life span calculator

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Has anyone tried the DiskOnChip life span calculator, or is it just
a marketing gimmick?  I need to upgrade a system to P4 and am trying
to decide if I should go with DOC or CompactFlash; we've had problems
with hard drives due to environmental issues.  Unfortunately, customer
insists on using Windows NT or Win2k and I'm not sure either one will
work with DOC or CompactFlash.

Re: DiskOnChip life span calculator
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If you use a CF to IDE adaptor then both NT and 2K should work.



Re: DiskOnChip life span calculator

The number I have heard tossed arround is "several days";
significantly less than a week,

That was for WinXP.  I can't imagine any 'non WinCE' variants being
significantly different.

SH7

wrote:

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Re: DiskOnChip life span calculator
Top-posting fixed.


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[...re: using CF on a Win[2k|XP|NT] system ...]
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[...]
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A basic feature of any OS of this type would let you configure a RAM
disk and locate the swapfile and any temporary directories there.  I
know it can be done (i.e., have done it) for various flavors of UN*X.
I can imagine that WinWhatever might not have such a feature, but
would be somewhat surprised if that were the case.

Regards,

                               -=Dave
--
Change is inevitable, progress is not.

Re: DiskOnChip life span calculator
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Maybe you could put some often accesed files on a ram disk, but a swap
file is not one that would be useful.  A swap file is used to hold data
that has overflowed ram.  Putting that in ram would just make the
problem worse.  Better using no swap file at all.  

--

Rick "rickman" Collins

snipped-for-privacy@XYarius.com
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Re: DiskOnChip life span calculator

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during

I know it doesn't make sense, but some systems work better swap files even
if they're on a ram drive. I know in the past Windows really hated not
having swap space even with a significant amount of ram.

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Re: DiskOnChip life span calculator
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I don't know about windows, but Linux can certainly run without a swap
file. One thing that can reduce CF lifetime drastically in Linux is the
fact that the filesystem wants to keep the file's *access* times up to
date, i.e. even if you only read a file (e.g. when executing a binary)
this causes a physical write access to the device. Fortuntely, this can
be disabled by using the -noatime option when mounting the filesystem.

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True.


Rob

--
Robert Kaiser                     email: rkaiser AT sysgo DOT de
SYSGO AG                          http://www.elinos.com
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Re: DiskOnChip life span calculator

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No. This is WRONG. A swap file in RAM will NOT  improve  performance.
It will be much more efficient to use NO swap at all.


Wolfgang Denk

--
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88   Web: www.denx.de
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I cannot speak for Windoze, but creating swap space on  a  RAM  based
filesystem  is  NOT  useful under Linux. As mentioned before, it just
makes things worse.

Wolfgang Denk

--
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88   Web: www.denx.de
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Re: DiskOnChip life span calculator
I have run windows without swap on a box that had like 700-something megs a
loooong time ago. I though, what could go wrong, it has 700mb ram! I was
wrong.

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Re: DiskOnChip life span calculator
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This brings up another interesting topic:  Compressed ram-based swapfile

A custom swapfile manager could lzh-compress the pages on swapout, and
thus tradeoff between speed for often-used pages and small footprint
for less-often-used pages.

Of course this will be dead slow when the memory system is at its limits,
similar to a Windows system with 8MB and literally minutes of continous
HD access.

However, it would provide an elegant and automatic solution to the problem
of never-again-used-pages that you brought up!

Marc

Re: DiskOnChip life span calculator

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Hello,

You need to use WinXp Embedded which has features to minimise the footprint
and the writes to flash disc.
If your customer insists on NT or 2K then as far as I am aware there is no
MS support for prolonging the life of flash disc.

There is a free evaluation kit for XP embedded which allows you to build a
system with a 100 day lifetime.

(All this from MS seminars -  I have not actually done it !!)


Michael Kellett
www.mkesc.co.uk





Re: DiskOnChip life span calculator
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Perhaps I am missing something, but I thought there was a special file
system for Flash which included a wear leveling mechanism to prevent
constant writes to a single file from wearing out the flash drive.  Is
this not included in standard OS, only embedded OS?  

I worked on a system that ran VxWorks and ran for ages using PCMCIA
flash cards.  We could poll each sector and see how much usage it had
received.  In testing we ran a utility to report the worst case usage
and it indicated the drive would last for several years of continuous
usage.  

--

Rick "rickman" Collins

snipped-for-privacy@XYarius.com
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Re: DiskOnChip life span calculator

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...and on the number of power-cycles. It seems some CF cards  perform
wear-levelling only upon power-up.


Wolfgang Denk

--
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88   Web: www.denx.de
We've slightly trimmed the long signature. Click to see the full one.
Re: DiskOnChip life span calculator



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Hello,

Embedded XP can have a large footprint, and push the RAM, and CPU requirements
up.  If there is no need for USB, or hot swap of PCMCIA, Embedded NT might be
viable.  It includes support for DiskOnChip, and one can disable the swap, IIRC.

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M$ does not seem to market the NT product any more, even though it is sold under
the Microsoft label.  It can be obtained from Venturcom, or Avnet, though.
http://www.vci.com /

- Pat



Re: DiskOnChip life span calculator

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OK, nobody else said it, so I will: this looks like you're in serious
need of an upgrade to Customer XP --- the all-new "know what they're
talking about" edition.

:-)
--
Hans-Bernhard Broeker ( snipped-for-privacy@physik.rwth-aachen.de)
Even if all the snow were burnt, ashes would remain.

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