DaveCary: blog-like object

Most recent edit on 2009-10-30 10:34:49 by DaveCary [revert to 2009-06-23 22:34:33]

Additions:
So I searched and searched.

Deletions:
So I searched and searched essay∞.

Edited on 2009-09-22 12:10:40 by EmmaBrennan

Additions:
So I searched and searched essay∞.

Deletions:
So I searched and searched.

Edited on 2009-06-23 22:34:33 by DaveCary [more thoughts on a standard power plug]

Additions:

2009-06-23

My small laptop computer kept giving me the "battery low" message a few days ago.
Eventually it wouldn't even turn on, even with the power adapter plugged in.
So I've been lugging around my big, heavy, backup laptop computer.
Hoping that maybe the small laptop merely needed to charge up a bit longer and then maybe it would work.
Fearing that it is broken.
Today I took a closer look, and I see that the output DC voltage rating on the power adapter is much lower than the input DC voltage rating on the laptop computer.
Apparently some random power adapter had been accidentally swapped with the power adapter that came with the little laptop.
So I searched and searched.
Eventually I found the right power adapter, with the right output DC voltage and current rating, and now the "battery charging" light on the little laptop is on.
What could have been better:
I wish there was some kind of standardized set of power plugs, such that the 12 V power plug obviously would not fit in an incompatible socket. Then I would have immediately figured out what was wrong.
See http://opencircuits.com/Ideas#open_power_connector∞ for more thoughts on a standard power plug.
What could have been much worse:
I could have really destroyed something if I had accidentally used a *higher* voltage power adapter.
If the device did not have a properly labeled voltage and current, I might never have figured out the problem.
Alas, I've seen a few devices that don't bother labeling the device with its voltage and current.

Edited on 2009-05-22 00:29:39 by ElalcSitra [notrocv]

Additions:
http://www.textcaoudron.com∞

Edited on 2009-01-11 17:57:15 by DaveCary [test computer]

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2009-01-11

Setting up a test computer.
Fedora 10 for now, although I'm tempted to use Solaris so I can use ZFS.
And today Paul asked me to look at Btrfs.
I'll test some ideas I have for a fault-tolerant file server, aka robust web server, aka high-availability server, aka distributed wiki, aka FaultTolerantWiki.
Also a few other apps (such as gEDA, MediaWiki, OddMuse, git, etc.) that require Linux, or at least seem to work best with Linux.

Edited on 2008-09-05 06:47:05 by DaveCary [revert]

Deletions:
liorraclidar

Edited on 2008-07-11 01:27:33 by AltrzElelc [sitdronze]

Additions:
liorraclidar

Oldest known version of this page was edited on 2008-02-16 23:47:33 by DronlIchir ["FaultTolerantWiki", etc.]

Page view:

blog-like object

2007-02-21

I am considering starting a business, selling the service of helping people set up their computer systems
in a way that vastly reduces the chance of dataloss.
And perhaps the service of periodic testing to make sure it hasn't slipped into a fault-vulnerable state.
Also replacing failed hard drives, periodically replacing expected-to-fail-soon hard drives, etc.
The guarantee would would clearly reflect the benefits of using data store with better fault tolerance.
(Perhaps the guarantee would read something like this, for a data loss incident: for a multiple-fault-tolerant distributed data store, we would refund all the money they've given us for the past 2 years. For a single-fault-tolerant twin storage, we would refund 3/4 that money ... for a RAID system, we would refund half that money ... and for a single-hard-drive system, nothing.)
This can be seen as form of "data loss insurance".
Perhaps real "data loss insurance" (paying out far more than what was payed in, in the occasional case of a data loss event) would also be a good idea.
The prices and payouts (of the guarantee/insurance) should clearly reflect
the benefits of using data store with better fault tolerance.
(Also, we should clearly distinguish between "data irretrievably lost", which is clearly much worse than "server offline, data inaccessable for a day, but now the server is back online and you can see the data is now accessable")
How would we confirm valid claims on the guarantee / insurance?

I am encouraged that HansWobbe wants to help me build a fault-tolerant wiki / fault-tolerant data store.
I am still astonished that this hasn't already been implemented, and everyone isn't already using it.
http://communitywiki.org/odd/SoftwareBazaar/2007-02-19∞

We want to spread the disk space and bandwidth load over as many people as possible, right?
Is releasing the source code under some Open Source license the best way to get the distributed wiki installed on as many machines as possible?

2007-02-21

OK, that tears it. Too much comment spam.
I'm going to change ACLs so that only people who have a name or a pseudonym can post comments.

2006-12-27

Merry Christmas everyone. And a happy 2007.

I gave my brothers "magnetic white boards", and I helped give my sister a nice camera. I got some very nice things.
I helped set up http://communitywiki.org/odd/TulsaMovieMaker/HomePage∞ .

I want a SVG-friendly wiki engine for the VisualWiki, so I can collaborate with a "virtual white board".
I don't know if that will come first, or the FaultTolerantWiki.

2006-11-26

Finally figured out VNC over SSH.
Let's see if I can write it all down before I forget.
(Should I move this to the Ubuntu wiki http://wiki.ubuntu.com/∞ ?)

I have

a Ubuntu 6.10 ("Edgy Eft") machine hidden behind a firewall
a Windows XP laptop

I want

to remotely access the Ubuntu machine from my laptop, and view graphical CAD programs like gEDA that only run under Linux.

Initial setup at the Ubuntu machine:

set up the firewall to "forward" SSH traffic (port 22) to the Ubuntu machine.
make sure "SSH" is installed ("System > Administration > Synaptic Package Manager", then search for "SSH" and look for "openssh-client" and "openssh-server".
Choose "System > Administration > Users and groups" and make sure the people you want to VNC in have an account username and password.
Choose "System > Preferences > Remote Desktop". Set up the appropriate "security" and "sharing" check boxes, and "the VNC password". (this password is the *same* for every user, so -- since each user has a different password -- "the VNC password" is different from the user password).

That should be it for the Ubuntu end.

Initial setup on the Windows XP laptop:

install PuTTY (free from Simon Tatham).
start PuTTY.exe
Go to the "Connection > SSH > Tunnels" panel
- make sure the "Local" and "Auto" radio buttons at the bottom are set.
- set "Source Port" to "5901"
- set "destination" to "localhost:5900" (to see exactly what shows up on the monitor connected to the Ubuntu box. You can also do something like "localhost:5963" if you want to use gEDA without disturbing anyone else using the Ubuntu box.)
- click "Add". "The details of your port forwarding should appear in the list box."
Go to the "Session" panel.
- fill in the host name or IP address of the Ubuntu box.
- make sure "SSH" is selected.
- Click "Save".

Normal use on the Windows XP laptop:

start PuTTY.exe
Choose the Ubuntu box from the Session list and click "load".
Hit the "open" button to start the PuTTY session, and log in with your username and your password.
Minimize Putty and leave it running in the background.
Start a VNC viewer program.
Instead of doing the normal remotehost:0 for the VNC server,

enter (literally) "localhost:1", and hit "Connect".

You should get prompted for "the VNC password". (This is *different* from your user password). Type it in and hit "enter".
You should see the Ubuntu desktop appear on the Windows XP laptop screen. You might want to make it "full screen".
Optional: If the connection seems to be running slow, you might want to reduce the colors to something less than "full colors", and change the Ubuntu desktop background to a simple solid color ("System > Preferences > Desktop background").

References:

The most useful web page I found from a search on "VNC over SSH" was
http://www.realvnc.com/pipermail/vnc-list/2003-January/036707.html∞

http://trekweb.com/~jasonb/articles/vnc_ssh.shtml∞
describes how to do VNC over SSH
from a Windows laptop running Cygwin.
(but also mentions PuTTY).

http://www.reenigne.org/computer/vnc_ssh.html∞
describes how to do VNC over SSH from one Windows laptop running TTSH
and a VNC viewer
to another Windows laptop running a VNC server (and also running TTSSH)
through a Unix firewall (also running some sort of SSL).

(Some web pages claim I need to "edit the Windows registry", but I never did.).

2006-06-13

I'm still not sure exactly what I want to do with this wiki.
AboutThisWiki

I'm considering bulk-moving "my" text from various other wiki, especially the ones on a "temporary" server such as
* http://visual.wiki.taoriver.net/∞
* http://gfxalgo.wiki.taoriver.net/∞
* http://communitywiki.org/odd/ComputerComponent/HomePage∞
* http://communitywiki.org/odd/MadScientist/HomePage∞
* http://communitywiki.org/odd/SoftwareBazaar/HomePage∞

But if I did that, it would be frustrating if this wiki were to go offline.
On the other hand, if I left the text there, I would feel just as annoyed the next time that wiki goes offline.

I really want to build a
"FaultTolerantWiki"
(also known as a
FailSafeWiki http://wikifeatures.wiki.taoriver.net/moin.cgi/FailSafeWiki∞ ) --
"A wiki where users don't even notice when any one machine is unplugged."
( http://en.wikipedia.org/wiki/Fault-tolerant∞ )

It would be easy to build such a FaultTolerantWiki on top of a full-featured fault-tolerant DataStore.
However, much of the difficulty in building a fault-tolerant DataStore is preventing "non-authorized users" from reading or editing files they don't have "permission" to access, concepts that are irrelevant to Wiki -- it's not part of http://c2.com/cgi/wiki?WhyWikiWorks∞ .
So I think a FaultTolerantWiki could be easier to build and simpler to debug than a full-featured fault-tolerant DataStore.
Perhaps it would be interesting to build a full-featured DataStore on top of a FaultTolerantWiki.
Perhaps it would even work better that way -- in the same way that the "dumb network" (the "World of Ends" http://WorldOfEnds.com/∞ , "When it's dumb to be stupid" http://www.telepocalypse.net/archives/000424.html∞ ) and end-to-end encryption works better than "smart networks" or decrypting and re-encrypting at every hop.

2006-06-03

Josh helped me buy the "http://DaveCary.com/∞" domain name ( http://DavidCary.com/∞ was already taken ),
and helped me set up this wiki.

WikiMailBox

leave public messages for David here.
http://communitywiki.org/TransparentEmail∞

DaveCary : DaveCary

2009-06-23

2009-01-11

blog-like object

2007-02-21

2007-02-21

2006-12-27

2006-11-26

2006-06-13

2006-06-03

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