Home Server Projects
I've always been interested in installing servers for home use. The ability to customize Linux based servers to the degree that surpasses what is economically available from any other source makes Linux the obvious choice. Linux also offers the home user more latitude in that it will support practically any other desktop operating system with basic services.
Monday 11 February 2008, 4:09 AM
Debbie, the Data Recorder
Looks like I'm going to write some C for the data recorder functions that I'm putting on Debbie.
The idea is to "ping" the radio transceivers I'll be designing into the data gadgets I wrote about earlier. First ping wakes up the remote radio and the MSP430 8 bit micro attached to it. A second ping will command the gadget to send the readings it has and then it will go back to sleep. Debbie goes on to ping the next radio equipped gadget and the cycle continues. Probably only have to run the cycle once a minute or so.
Turns out the TI MSP430 family is extremely well integrated with the TI radios I was looking at earlier. These TI radios are one chip transceivers operating in the 2.4 personal communications band. The transmit power will be in the 10 to 20 milliwatt range so the gadgets will operate on extremely low current. There is also considerably much more support for the MSP430 family than for the Zilog family of 8 bit micros.
The program to operate the pinger will be fairly simple and will likely spend most of its time just counting seconds to the next bunch of pings. Data will be stored in a flat text file. Date and time stamps will be added to the data readings. Converting the data to ASCII will allow me to do the data analysis with Star/Open Office Calc spreadsheets.
Next trick will be to run a second program to read the file and display the data on a web page served up by Debbie's Apache2 server. This would allow me to look in now and then during the day when I'm running experiments on my alt-power projects or just read the weather at home. Its not unusual to have the sky at work be cloud free and the house to be under a major storm cell, or vice versa. Weather info will also be stored into the data file since wind and solar radiation are the means of generating the power I'm interested in collecting.
I have an extreme adversion to opening up home systems to the Internet and serving up web pages or other Internet services. Although I've been operating in and around the Internet from its beginning I don't claim to be an net security expert or an expert system cracker. When it comes to network security, I believe a bit of paranoia is appropriate! I'll be using DDNS for Debbie's web pages only when I'm running my experiments and leave her closed off from the Internet otherwise.
Monday 14 January 2008, 12:23 AM
A Non-obvious Use for Debbie (a Debian 4.0 Home Server)
12/28/2007
One of the things I'd like to replicate here at home is a tool we have at work. Its a 32 channel, 12 bit resolution, analog to digital data acquisition recorder that allows ftp downloads and serves the data up as web pages. (It has an NEC CPU of some unknown type.) I use it to record voltage, current and temperature data when I'm punishing evaluation computers for possible use as parts of future products for the company. It was worth every penny we paid for it 6 years ago. The built-in generic pages it has are programmable and I've used that feature extensively. It also has the ability to serve pages with custom programmed backgrounds with the data tagged for display in specific locations or “windows” on the page. I never bothered with that feature previously but it would be a very attractive feature to use as a sort-of-HMI page that could be viewed by any of the family members and understood without much training. My family doesn't have the budget for that instrument but with Debbie and embedded Linux and some other bits of technology I can make an excellent substitute.
One of the long-term home based projects I'm working on is a grid-free electrical power system using wind and solar thermal energy sources. Assuming I keep it, I'll be at my day-job most of the daylight hours and won't be able to manage or directly collect the data from the system prototypes I've built. A data recorder is the obvious answer to avoid clone duplication and adding one more mouth to the family to feed! An attractive web page is to encourage enthusiasm from the family for the “projects” I'm going to be spending some weekend time on.
Data acquisition will be done by a group of tiny micros feeding their data over a RS485-like Master-Slave radio network to a salvaged P3 single board computer (SBC). It will be dumping the data collected from the micros with date-time stamps into a cvs file onto a compact flash drive. The micros will be little eZ8's from Zilog. Putting the tiny 8 bit micros right at the measurement point avoids long sensor leads and preserves the accuracy of the measurements. I hope to measure voltage, current, termperature, light levels, RPM rates, ambient temperature and whatever else pops up as a needed measurement.
Power to run the micros will be from batteries charged by solar cells located somewhere near the micro. To enhance power efficiency, most of the time the micros will be in sleep mode and a timer will wake the micro up to make its measurements and transmit the results and then go back to sleep.
Later the same micro family will be used as “smart instruments” for system sensing and/or control points of the production system(s). These eZ8 microprocessors are fairly well integrated with built-in a/d convertors, counters and comparator circuits that can be programmed either in C or assembly code with small chunks of code in flash ROM. They also have IO pins that can be used to turn relays or switching transistors on or off or sense switch positions as inputs. The micros have a very easy to use SPI interface and software package to program and debug them. These integrated processors keep the parts count low and the power requirements minimal.
(Before all the Microchip PIC fans go nuts, I know more about the Zilog eZ8 and eZ80 families. Its easier to work with what you know. This is supposed to be fun not work!)
Using little single-chip radios,CC2500 from TI. will allow me to put my experiments where I need to in the backyard without having to run cables all over the place.
One other sub-system I'll need to add is a micro-based “weather station”. This weather station will collect wind speed, direction, temperature and light levels. It might be necessary to be able to sense whether or not its raining, I don't know at this point. I hope to be able to use the same micro for the weather station that I use in all of the other “smart sensors” I install.
The junker P3 computer running a Debian 4.0 image can be located inside the house to stay cool(!) and so it can deliver its web pages and data files to Debbie by either Cat5 or an 802.11b connection and still maintain radio connections with the low power micros. An inexpensive web cam will be installed on the P3 computer. Grabbing stills to stuff into the data stream being fed to Debbie will allow some correlation of the environmental conditions at the time of the data collection. Webcam pictures will also be served up as the background fill for the data display web pages on Debbie. This system will begin by running a small Debian 4.0 OS image stripped down to the essentials needed to for the data collection function. Later I'll put an embedded Linux image on the system to run everything from a Compact Flash drive.
So far Debbie has worked in all of the relatively simple roles I've put her to. AVI, MOV and JPG files all work well on either the Linux or Windows clients when served by Debbie. PDFs work in either Linux or Windows. They even work when accessed by browser plug-ins, either FireFox 2 or IE6 or 7. Copying files to and from Debbie by the kids has been easy to implement. Discovered that an episode of Battlestar Galactica I recorded on a DVD recorder (running Linux on a ARM9, natch!) would NOT playback directly from the DVD on either Windows or Linux. Probably something I did wrong on the DVD recorder. It plays fine on the DVD recorder and other DVD players. Hmmm. Haven't tried playing a commercial DVD I've bought on either OS yet. Trying to record broadcast video straight to the DHS hasn't happened yet. I'll have to seize control of the remotes for the TV, the satellite box and the DVD simultaneously. A feat of monumental ingenuity when confronted with a teenager, a pre-teen and a spouse that considers the TV her property. Even then I might get the Jack Valenti stormtroopers in here to stop me violating some digital rights of the copyright owners.
However, I did find an issue that I need to investigate further.
12/31/2007
Ole Nick was kind and brought me a simple Nikon 6 megapixel still camera with video and audio capability. To me it was: Way Cool! Small enough to stick in my pocket and pull out to capture all kinds of things. Perfect to embarrass my kids in the future! I can yank it out take a still or record a home movie and unless the flash goes off, there will be no one the wiser. So I started putting the Christmas pictures onto Debbie's hard drive through a Samba share from a Windows XP box. No problem.
I started playing them back on the same Windows XP system by downloading them from Debbie. I use XP as a desktop when I have to and as part of my testing. I got distracted more than once in the last 2 weeks and found out that Windows XP will time-out an inactive network share connection even with a media player connected to a file with the file open on the Samba share. Inactive seems to be defined as a connection that hasn't pulled any data down from the server in about 20 minutes. I knew about this Windows desktop “security feature” but it hadn't registered on me that it would be an issue on local intranet connections, just Internet connections through IE, whoops. This can cause issues with files on mapped drives on Samba servers that have been paused using different Windows file viewers. The problem is that the Samba share doesn't seem to time out or at least not at the same time. This is going to require some investigation and likely some XP registry hacking editing.
The effect is that the XP logon to the share is forced to be re-established by the XP desktop regardless of what the connection state on the Samba server and that requires the password to be known by the client. A pain in the posterior when you are trying to make the system seamless and look as if the share is just a folder on the local drive. This was a “security feature” added with SP2. Until I find a hack to “fix” the feature, I'll have to drop scripts and shortcuts on the desktops of the kid's Windows computers.
1/8/2008
Started laying out the schematic for the eZ8 microprocessor I plan on using for the data acquisition and control of my little prototypes. It's going to be a really tiny system. Less than 2 square inches or about 129 square centimeters without solar cells or batteries. All surface mount parts, all real tiny. Cool.
1/12/2008
Still haven't had time to figure out the time-out issue. I have a hard time leaving a computer alone for 20 minutes or more when its on and sitting in front of me.
Without even thinking about, I plugged my USB 2.0 SanDisk flash drive reader-writer into Debbie's USB socket. It immediately mounted the plugged in 1GB SD flash from the Nikon without a hiccup. Debbie let me browse around and copy my impromptu movies and stills onto the Samba shares for immediate sharing with all the other network clients. You long-time Linux hands think: “So what?” Now try it on a Windows 9X or NT or 2K box without the upgrades or installing drivers. What I really hate about XP especially SP2 is that it takes sometimes 90 seconds to 2 minutes to get XP to let go of the USB connected “removable” flash drives. Windows MediaPlayer informed me that I shouldn't look at my little movie I'd made on my Nikon due to potential “security” problems and this is with the local network set as safe. Yeah buddy! I'm going to virus infect my own movies!
Saturday 29 December 2007, 4:59 PM
SAMBA, Microsoft and the real Issue
What most Microsofties vs the Open Source adherents seem to have missed in all the drek passed back and forth is that Microsoft was taken to court in the US and the EU on its monopolist practices. The EU forced Microsoft to comply with the disclosure of source it required for "inter-operability" between Microsoft's OS and the rest of the OS world. That was something the DoJ flying monkeys in Washington DC couldn't seem to understand and that it was the important legal precedent needed to allow ALL operating systems to be able to communicate with each other.
SAMBA compatibility for Microsoft's OS seems to finally gotten through to the idiots' brains in MS's legal department as something that might actually be good for Microsoft. What it means is that the last 10% of computers in the world that won't be running Microsoft software will now hopefully be able to talk to Microsoft OS images on the other 90% of the world's computers. DUH! That is what is truly significant here.
What Microsoft has to understand is that cooperating with organized open source programmers is good for them. They can learn from a programmer culture that is NOT Redmond-centered and can learn something new and perhaps even better than what the droids in Redmond can do.
Programs like Linux, Apache and SAMBA go through a fairly stringent peer-review process that may or may not be going on in Microsoft. The peer review process used in Microsoft though is likely so heavily influenced by the marketing department that its not complete or through enough to mean anything.
If you want proof of that statement, look at Vista, look at XP etc. Vista betas sucked yet they went ahead and released a product they knew was flawed. Talk about Vista SP1 began almost immediately after the release. Microsoft claims better security and so forth. They also claim lower piracy rates. Could it be that lower piracy rates equates to better security? The majority of corporate users using Windows are using XP and Win2K still. Having Vista around will not change that significantly for 5 to 7 years. It took XP nearly 7 years to reach 50% of the installed base of corporate users.
Opening up to large open source projects enough to allow Microsoft's protocols to be understood will allow the "interoperability" that the marketing flacks tout. Gee! Maybe they can sell more servers if people know they will work with other OS systems in the same server room? Ya think?
What's really funny is that if Microsoft published their source code under a copyright, had it printed up, distributed and sold as a book it would qualify as a bestseller immediately. Microsoft could then use peer review both inside and outside Redmond to make their operating system cracker-proof. It also would be covered for more years than a patent. Take all of the other add-ons like DirectX, Multimedia viewers etc out and then they could be sold as add-ons. If you don't play games or watch movies, why have those chunks of code in the OS? I don't think many users would scan all that printed source code into their computer, correct all the errors the optical scanner made, compile the OS and then try to run it when they could go buy a copy of the compiled OS for say, $90?
I know that it could be done. Microsoft is half-way there, they just haven't published the source. Its called Windows XP Embedded.
Sunday 23 December 2007, 4:03 AM
SAMBA.org Buys a Windows license? Has the moon fallen from the sky?
Sam Ranji of Microsoft has admitted that he can work with somebody without Windows in his bloodstream. (See: http://talkback.zdnet.com/5208-12558-0.html?forumID=1&threadID=
42516&messageID=784926&start=0
What's a little unusual is that all revelation of the relevant protocols will be handled through a third party arrangement. I hope that this is a sign that the 800 lb Gorilla will change its ways and start acting graciously to all of the other players on the Internet. That they will become more open and not so willing to bully the standards committees and other people like its customers!
http://www.news.com/8301-13580_3-9836784-39.html?part=rss&subj=
news&tag=2547-1001_3-0-5
(the URLS need to be pasted together at the =breakpoint on both of them)
I'm going to take a "wait-and-see" pose on this and see what happens.
Nothing tells me that Debbie is going to be replaced by a Windows box any time soon!
Thursday 6 December 2007, 3:59 AM
Un-Active Server, In-Active Server, oh drat, roll the Dead Parrot sketch!
I had an interesting experience this morning. I had clicked on a link in an email and my default web browser dragged itself up into the RAM and starting running. I got an error page, that's not entirely unexpected. FireFox 2.0.0.11 is my default browser. I checked my restrictions and a bunch of the add-on extensions were reporting the site wasn't pushing 3rd party pics or any other foreign stuff. I turned on pictures and I looked at the page.
There were animated things and some other ads that were running flash-like items. They were all operating just fine but the central frame was reporting an error. So I looked at the URL and it had a little clue...aspx stuck on as a file extension. Oh crap! An Active Server page. Well that happens a lot and a lot more lately. Its getting really annoying. But this one wasn't really doing much in the page's center frame. Everything around on the edges was running just fine. It was just dead in the center frame. Usually if something craps out, the entire page doesn't get rendered by the browser and you'll get some Apache or IIS error page. Usually the server just can't send you the entire page.
This one has an error message that was supported by two small banner ads! That in itself was funny. Think of a TV test pattern brought to you by “the makers of Crapa-Cola! It leaves a slick fuzzy feeling on your teeth.” Wonder if their advertising contract has a “no-error message” limiting clause in it?
So I copied the link, pasted it into Internet Explorer 7.0.5730.11 and guess what? It did the EXACT same thing. WOW! Well this needed a little more investigation. The only other browser I had was FireFox 3.0 Beta 1. Same thing. I didn't have Opera or any other browsers to try on the site. So that was it.
Now the website was a programmer's site. In fact 80 percent of the staff were web programmers. And the owner of the site was a Microsoft MVP. I don't need to embarrass them any more than the error message was doing. How interesting.
Because the server that was the "front-end" was rendering an error message WITH the other stuff around meant to me at least that the Active Server was running at the very least on a VM or another instance of IIS on another cpu. The programmer was actually relatively smart, he did have an alternative programmed, it just looked like a error page with some moving bits on it. The deceased parrot, although gone to its final reward, chirping in the eternal aerial choir, was still potentially collecting mouse clicks!
It used to be that it was considered a courtesy to have text strings that were attached to a picture to describe what the image was displaying on web pages. That was for the poor guys on the Dial-up Internet that couldn't get better than 1200 baud service. That doesn't happen as much any more. I know that since I run my browser with cross-site pictures turned off on sites I don't know well. I have been to this site a few times but not often enough to loosen the browser restrictions.
Not so far back in the Internet Stone Age, there also was an effort to come up with a web page for browsers other than the ones that were not clearly identifiable or at the very least one page for IE and another html-only page for everybody else, usually Netscape. (Remember them?)
Now it seems as if Microsoft or at the very least the programmers that use its software aren't interested in programming for the instances when the Active Server isn't active! Should a programmer write an event or error handler in those cases when the Active Server functions or the server used to render them is down? Its sort of the same issue first brought up by ActiveX. This time the issue is the same for ALL web browsers. What do you do as a programmer to handle the times when the Active Server goes belly up? or gets maxed out? or gets hit with a DDOS or some other attack vector?
All the more reason to stick to the W3 standards and not get so wrapped up in cool looking stuff that might break or only works part time, no matter what the reason, for server or client.
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