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1  Linux Stuff / Android for SheevaPlug is Available! / Re: Install Android On SheevaPlug on: December 26, 2010, 07:14:12 PM
Is this Guruplug specific, or will this work with initial Shiva Plugs of last year?

I went thru the whole source forge site on this, but could not get any short or long summary of this project.  The whole site on this very inactive, it would be nice to know what this does Smiley  I have a google phone, and long time I wanted to develop some apps for it for fun.  It is android 1.6, and I did not quite have success using the development kit under Winxp a year ago.  So I am eager to read a summary of this project, before expanding all this tar, I am running off of small compact flash, so dont want to max it out even before knowing what this is all about.  So if anybody can point to a summary of what this does it would be helpful.  I do not have a Guruplug.  Thanks.
2  Hardware and U-Boot firmware / Hardware / Re: SheevaPlug USB Power Supply problems. Can it Drive a USB Ext Disk? on: December 11, 2010, 08:59:38 AM
The better solution for an external pwr supply is to use small 5v switcher type wall wart.  These days even the usb types for many of the newer phones have rating of about 1 to 2 amp.  Many of these supplies seems to last for ever, compared to the ad hoc designs some companies do specifically for the Plug etc.  You need to buy one designed by a pwr supply specialist.

To handle the peak load fluctuations mentioned in a couple of posts below, one simple way is to put 4 AA NiMh rechargeable cells right across the power supply output.  The newer ones have 2500mAHr capacity,  so they would provide 5+ A for short durations, and also will serve as a good short term power backup for upto 30 minutes plus easily.  BTW, 98+ % of power outages last less than 5 minutes in most places in the USA.  At the typicall <5.5v DC, 4 cells will never be over charged.  You can buy 4 for <$6 these days.
3  Hardware and U-Boot firmware / Hardware / Re: Another dead one? on: December 10, 2010, 11:22:07 AM
Yes, I have a spare 5V 3A power brick sitting on the shelf, just in case.  It's really a very handy thing to have for a number of reasons.

As far as WiFi, I'm sure there are some USB devices that could be made to work, but also consider the GuruPlug line, which comes with built-in WiFi hardware.

As for wireless, there are actually two functionality.  One is for the plug to connect wirelessly to the net (instead of using the normal current wire connection).  Implementing this using addon off the shelf wireless adapters designed specificially for the windows stack may be very difficult task.

There is also another wireless use.  I would be interested in using a standard wireless adapter just to communicate with the plug, or for using a wireless data logging link to the plug.  At this point, switching completly over to the guruplug looks like a bit too high a task, not to mention throwing away a good working plug.  Has anybody got any success with a wireless data link like that?  You mentioned some models may be more successful, any specifics?

I have got all my needed apps up and running and I have switched into production mode.  After a few days of use, it seems everything is working well.

Normally I do not use the console port.  Is it possible to use the console port for reading data such as that come from solar electric panels (with appropriate interface)?  Or the console port is very specific to console use?

On the standard plug, is there any bits of io available for say monitoring power failure (with a small battery backup for orderly shutdown) or to control some devices?  If there is any reference how to on these available, kindly direct me that way.  Thank you.
4  Hardware and U-Boot firmware / Hardware / Re: SheevaPlug memory lifetime in production environment on: December 10, 2010, 10:57:19 AM
Since I am remounting to get the relatime effect, and since it was already mounted atime, do I need to do noatime as well, as in

mount -o remount,noatime,relatime /

How does this diratime play into the previous discussion?  Should we, is there any down side, add nodiratime too?
5  Hardware and U-Boot firmware / Hardware / Re: SheevaPlug memory lifetime in production environment on: December 08, 2010, 09:48:20 PM
'noatime' simply inhibits the update of the inode's timestamp on access for ext* file systems.  It thus cuts down on the number of writes to the filesystem.  However, it does create some problems.  A common one is the inability to discern whether or not you have new mail.  (It tends to always look like you do.)  I use 'relatime', which allows an inode update if the current access time on a file is older than the current modification time.  This solves most of the timestamp problems, while still cutting down on file system writes, sometimes significantly.

Thanks for that pointer.  I had just come across 'realtime', but have not really stopped fully understand it.  Also thought that realtime may not be avialble on the ext2 fs on our ShPlug ...

So let me see if I understand relatime correctly:  It does allow an access time update the first time a file is accessed after it has been modified, is that correct?  If so, in my server application, where most files are not modified, it is almost equivalent to noatime, but without the disadvantages you pointed out.  Great.

Since I now mount all the logs on tmps, I will lose the the logs on reboot, unless  do a save of the needed critical ones from a shutdown init.d/script. ...
6  Hardware and U-Boot firmware / Hardware / Re: SheevaPlug memory lifetime in production environment on: December 08, 2010, 05:23:04 PM
I am running from an external SDCard, in the SDCard slot.  I have done the following:
Almost all logs, cache, and tmp diretories are mounted on tmpfs.  For my server application, there is plenty of memory still left, so the majority of new files and writes being on the memory files, will reduce the hits on the flash.

Modern flashes have improved reliabillity, I read, that the life time issues are not as serious a problem as they used to be even a couple of years ago.

Since I run from the external SDCard, in the event the card shows signs of failing, I can easily replace the 4GB card, which is now selling for about $7 online.

I am considering one other final step. Even with very little writes or modifications to the flash (SDCard) files, the way the sytem is normally configured, there are atime and diratime access writes to the directories every time a file is just read, theses could be actual writes to the flash.

I am thinking of miounting the root /  as noatime,nodiratime.  I do not know for sure if this will cause any type of problems with normal operation, such as if some updates or housekeeping is based on the access time of files.

If anybody knows more about the noatime, for our ubuntu on the ShivaPlug, please post.
 
7  General Category / Application ideas and development Q/A / Re: Anybody here successfully running apache2/php5 on ShPlg? on: December 08, 2010, 05:00:27 PM
I simply installed apache2/php5/mysql from repos and it was as easy as on any ubuntu. Apache seems memory-consuming, but it partially is just cache. I am planning to do some php5 execution time comparisons with a typical hosting (an account on a big server) and see if it's a large gap or a canyon Wink
You might want to avoid using gzip and jpeg functions in php as it does floating point math which is not the favourite activity for the Plug.

Newsletter Software

I just want to report, that after my enquiry here a couple of months ago, I have been able to port an apache2/php5 server application successfully.  It runs well and quite fast.  My server, while fairly extensive, still does not need all the 0.5GB of memory, so most things stay in cache.  I was previously running this on another micro server, with a memory of 32 MB Smiley
8  Hardware and U-Boot firmware / Hardware / Re: Another dead one? on: October 29, 2010, 02:40:58 PM
Hi CqCn,
Sorry for the late reply.  I've been out of town myself this past week.

I'm still running on my original unmodified power supply.  I only have one Plug, and it's in service, so I've been hesitant to open it up and experiment.  A friend's PS did bite the dust recently and I have that defective PS board in my possession.  Unfortunately, he tried to fix it first, and I don't have all the caps he removed, so I can't give you a definitive list.  Perhaps someone else on this forum can help.

From what I've read (and my friend's personal experience), it is fairly easy to convert the Plug to an external PS.  You just need a well filtered 5V DC 2A brick.  There is a single connector between the PS board and the processor board, and you can feed the power to the processor from this connector.  A side benefit of using an external supply is that the Plug then runs quite cool.  Apparently most of the heat generated comes from the internal PS.

I have one other thing I'm curious about:  Has anyone ever opened up their Plug and examined the PS after it has been running for a while, but before the PS fails?  I notice a lot of folks think the gunk the find spread all over everything after the PS fails is due to one or more capacitors leaking electrolyte over the board.  But people I've shown the defective PS to who know all about capacitor plague tell me what is on the failed board looks nothing like any capacitor leakage they've seen.  It's a hard, dry substance, not wet electrolyte, and it doesn't appear to emanate from any capacitor.  I personally wonder if what we are seeing is dried glue put on as part of the manufacturing process, perhaps darkened by the heat over time as the PS has run.  If someone can shed some more light on this, I'd be interested.

Welcome back, CqCn.  Let us know when you get your Plug up and running.
Nice to hear back from you.

External switcher supplies of 5v 2A (I think the plug really needs <1W, w/o hard drives) can be found on line for $5 these days.  I like it running much cooler too, perhaps that will quadruple the life of the rest of the plug Smiley

Well, I have completed my dns setup, exactly as I wanted.  Now working on php porting.  The big problem here is the directory and file configs from my last linux box is quite different, but the versions of the needed modules are very close so it should work for my previous functionality.

What is happening with the plug development area? Very little activity here?  Where have people move on to ?

Is there a way to add a wireless module (one of those inexpesive thumb like plugins) the usb port and make the Plug connect to the net wireless?  Has anybody shown how to achive this?

BTW, recently I have been playing with the NXP micro modules, some of them are tiny with huge functionality --- but not a real time full linux like on the Plug.
9  Hardware and U-Boot firmware / Hardware / Re: Another dead one? on: October 23, 2010, 08:58:29 AM
I'm beginning to conclude that although 240V/50Hz operation seems to expedite the breakdown process, it is only a matter of time before the SheevaPlug's PS bites the dust due to capacitor failure.  So, I'm seriously considering replacing all the electrolytics on the PS board on speculation.  I believe there are about 5 of them.

Does anyone have a complete listing of these components (capacity, voltage, temp, etc)?  I'd rather acquire the parts before I take the device out of service and open up the case to do the swap.  (I recently lost another 5V wallwart to a bad capacitor.  Was able to reincarnate it, but jeez, it seems like just about every electronic problem I have at the moment somehow revolves around bad electrolytics.)

Hi restamp,
I am back after being away for about a year.  Just got running  two of 3 critical programs I need to use this as my stable server to replace my 6 year+ running Slug.  Then, noticing very little activity in the forum, I searched for recent posts from you, and came across this one. 

Have you got a spec of all the caps already? Please publish.  There are very long lasting capacitor types now available to replace the older shorter life caps, but they are a lot more expensive.  However, for an individual unit where one has alredy sunk the purchase cost, this type of upgrde might be worth it.

I forgot....  Does the plug allow for an external supply (without mods) ?  If so I would consider switching to external for mine before disastrous burn out happens.  External supplies are quite inexpensive these days, especially if you look for them on line.
10  General Category / Application ideas and development Q/A / Re: Anybody here successfully running apache2/php5 on ShPlg? on: October 19, 2010, 10:49:25 AM
Sorry for the delay, I just forgot to take a look.

Well, there's nothing to suggest instead of JPEG. I just said JPEG is loads of floating-point calculation and the plug has no FPU, so it's slow. Uploading and storing is ok, but decoding and saving jpeg images will take a lot more time. There's nothing you can do.

... or try PNG if php supports it. The images are bigger, but less CPU intensive in decoding and encoding.


naugtur, Your timing is interesting!  After having been away for a long time from using the plug, I am just back and was going to check on the status of apache+php versions on the plug.  I have just finished installing and testing another critical application of mine on the plug in the last couple of days, and apache2+php is the next critical one.

I may have to live with the slower pace of jpg.  For my users, many having very little internet bandwidth from the far corners of the world, image bandwidth reduction is more important for their browsing experience.

Anybody know how current is the Apapche+php on the plug?  Any known issues?
11  General Category / Application ideas and development Q/A / Re: Successful quick backup and update to a second SDCard with rsync on: October 18, 2009, 06:02:33 PM
billybob,

The method I mentioned is very easy to do. It has the advantage of doing a bacup without having to touch your ShPg, even from a remote terminal. While you are logged into your system snd using it normally, you simply execute one command, and full backup will be done within a minute (only the delta of changed/new files are updated/copied).

Sorry, in my last msg I meant fdisk...

Let us say you are running from the SDCardin the sdcard slot.  Have your backup SDCard (or usb stick), formatted just as you formatted your orignal sdcard.  If it is a sdcard, you need an sdcard/usb adapter so that your backup sdcard can be plugged into the usb slot.

BTW, you can format and do all the initialization of any sdcard or usbstick (right after you buy one or an older used one) right in the usb slot.

You setup to access the backup card in the normal way to access thru linux from the usb port.  Now you simply use rsync (which has to be downloaded/installed just like any new utiity, if you do not already have it on your system), and a single command will copy the image of the sdcard over to your new card.  You can stop the computer, and then use the backed up card in the sdcard slot and boot from there.

With other methods described in some of the threads here, you can even avoid having to physically change the cards in the slot.  You can boot the system from the sdcard slot or the usbslot, and then change the procedure to backup from the usb slot (now booted from there) to the sdcard slot, which becomes the backup now.

I do the switching to the new card (booting from there) every so often;  this assures me that the copy  made is functional, without having to wait until trouble strikes.  I usually have 2 or more backup cards (rotated through), which insures that there as at least one good backup all the time. (Suppose you have damaged you working os card somehow, and then made s backup copy.  Now you have two bad cards Smiley  It is in this situation that 3rd copy becomes handy!

If you are not familiar with the necessary linux commands to do all the above (rsync has a lot of options too) steps,  I can write a detailed Wiki how to at sometime soon.  I just got back just now after being away from home for almost a month.
12  Linux Stuff / General Linux questions / Re: Directly connecting the plug with a network cable to a notebook on: September 22, 2009, 10:26:04 AM
no need for crossover since marvell phy being used in the plug autodetects speed, duplux etc...

Rabeeh, thanks, I did not know that.  My netbook does no have gigabit, I think...   But since ShPlg has it, and only one side needs to auto confgiure, will it not work with even non gigbit ones without cross over then?... I am on the road Smiley
13  Linux Stuff / General Linux questions / Re: Directly connecting the plug with a network cable to a notebook on: September 20, 2009, 08:16:03 AM
When directly connecting, how/where should the startup network settings be modified, so that instead of looking for a dhcp server thr Plug will find the notebook?
14  Linux Stuff / General Linux questions / Directly connecting the plug with a network cable to a notebook on: September 19, 2009, 03:48:51 AM
I am interested in just taking my plug and laptop on a trip.  I have a Lenovo netbook.  Can I connect the eithernet with a regular cable (the supplied one of ShPlug) to the notebook and and get connectivity between them?  Or do I need a special cross wired ethernet cable?  Currently I can boot off of the SDCard or USB (both alpah-6 kernel and file system in the external SDCard).

All I am interested is in the how to of directly connecting, avoiding any network.  I am about to go on a long cruise; I do not have much time to experiment; at least I need to have the right cable taken along.  (Currently I boot to a fixed ip in the local 192.168. subnet, to my regular router at home) and ssh from my laptop.  I do have working VMWare and Ubuntu on my netbook.

Any specific guideline will be appreciated.  Any reference/tutorial to this type of direct setup I want here?  I will have only at best spotty (but very very expensive) slow internet access on the boat and I am leaving in a day Smiley
15  Hardware and U-Boot firmware / U-Boot stuff / Re: Where does u-boot store the env variables such as bootargs? on: September 19, 2009, 03:43:11 AM
I've only had my Plug a week, so my set up is rapidly evolving. But currently, it's like this:

I have a linux x86, full desktop / development system, which holds various kernels and root filesystems for the Sheeva. These are ultimately organized under one (grand-)parent directory, and exported over both NFS and TFTP. So switching between kernels or filesystems means changing only one u-boot parameter.

For the record, this development system is actually a VirtualBox virtual machine, hosted on my MacBook Pro, and it has two (virtual) network cards: one is connected (via NAT) to the MacBook's AirPort, for internet connectivity; the other is bridged to the laptop's gigabit ethernet card, which is cabled directly to the Sheeva.

The gigabit interface on the Mac, the gigabit interface on the VirtualBox, and the gigabit interface on the Plug are all configured  on the the 172.16.*.* subnet, and the linux system forwards packets from one interface to the other, so that the Plug can use the VBox's 172.16 address as a gateway.

End result: I can carry all gear with me in my bag, then carry out the following steps when I'm ready to play:
1) Wake laptop from sleep and restore VirtualBox from its latest snapshot (30-45 seconds)
2) Cable Sheeva to laptop and boot. (another 30 seconds or so to SSH prompt)
Any internet access the laptop has is shared among all systems, and there's no need to use the serial cable.*

*except to switch boot settings, which is one more reason why we need this thread resolved!

-Ann

Ann, a while back you wrote the above in a different context to a question of mine.  But now I am interested in just taking my plug and laptop on a trip.  I have a Lenovo netbook.  Can I connect the eithernet with a regular cable (the supplied one of ShPlug) to the notebook and and get connectivity between them?  Or do I need a special cross wired ethernet cable.  Currently I can boot off of the SDCard or USB (both alpah-6 kernel and file system in the external SDCard).

All I am interested in is connecting directly, avoiding any network.  I am about to go on a long cruise; I do not have much time to experiment; at least I need to have the right cable taken along.  (Currently I boot to a fixed ip in the local 192.168. subnet, to my regular router at home) and ssh from my laptop.  I do have working VMWare and Ubuntu on my netbook.

Any specific guideline will be appreciated.  Any reference/tutorial to the type of direct setup I want here?  I will have only at best spotty (but very very expensive) slow speed internet access on the boat and I am leaving in a day Smiley
 
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