Technology, Innovation & Telecomm

Perhaps I’ve got this blog listed under the wrong categories at the various registration sites. I see that there’s a fair amount of traffic to my site, but I wonder who’s actually reading and what you’re hoping to find here.

Ostensibly, this site is technical in nature, but it’s clear from my posts that we’re not limited to “tech”. That said, I’m curious as to who’s reading and what captures your attention. As an example, my previous post topic is embedded Linux. I believe that I listed the blog as a tech site that includes issues of software development, technology, telecommunications, music and recording, etc. , but so far no one has bitten on my questions. It’s my belief that Linux-lovers would by dying to help me out. But so far, I’ve gotten no response. That leads me to believe that I’m not getting a lot of Linux folk here.

How did you end up here? Are you using a service such as BlogExplosion? If so, what criteria did you put in place for the sites that would interest you?

I’d like to make this site as interesting and informative (and even occasionally entertaining) as possible. Let me know what dropped you on my doorstep and if you’d consider coming back. Think of this post as an informal survey of who reads this and what you want to read about when you arrive.

As my friend Sean well knows, I would really like to get my hands around a project where I can make use of Linux in an embedded system.

I’ve come close in the past; really I have. But every time I think there’s an opportunity, it seems that some situation arises that squashes it. However, a glimmer of light has started to creep into my peripheral vision…I think.

In the past when an opportunity has been there to make use of Linux, the real-time aspect has not been too heavy. That’s made the choice fairly simple, since I had a sufficient level of confidence that it would more than keep up. However, in this new possibility, it may be that a standard Linux distro may not do the trick where raw speed is concerned. To give a general scope, I need to be able to deal with Gigabit Ethernet speeds. We’ll have some hardware assistance, but I need the application to really scream.

I’m aware of a number of changes in the 2.6x kernel that makes it somewhat more amenable to semi real-time applications, but it still seems to me that it is limited enough to consider one of the real-time variants that exist. So, a number of questions come to mind with respect to the hard real-time needs of a high speed application:

1. With any particular variant (standard distro’s or something with real-time extensions), is there a way to put into place very high-speed, deterministic processes that can then communicate with lower-priority, more traditional Linux processes? It occurs to me that I’ve seen products that essentially place an RTOS above the hardware, which in turn runs Linux as a task. My concerns there run to points such as what happens to memory protection in that case? How do real-time processes communicate vs. Linux tasks? How do real-time tasks communicate with Linux tasks? Can the RTOS run in non-protected mode while Linux operates using memory management? And so on…

2. How complicated does the whole thing get with respect to the fact that this application will be hosted on non-Intel hardware that uses FLASH as it’s primary storage instead of a hard disk? If we assume that we’ll be using some variant that has an RTOS at the bottom, how can one partition FLASH up so that both Linux and the RTOS can gain access safely?

3. Can you (here I assume that you can, but I’ll ask anyhow) install interrupt handlers that run independently of the Linux kernel? What are the implications of direct hardware access? That is, I presume that the RTOS portion (again assuming something structured that way) gives you that ability to drive devices in some efficient manner.

4. Just how real-time can I get? (big, broad question)

I’m quite sure these are all easily answered and there are guaranteed to be many more-significant questions to be asked. These stem from my general ignorance of using Linux in such an application and are what pops into my head initially for some reason.

So, if anyone has experiences that they’d like to pass along, I’ll be more than grateful to hear them. Lord knows if I’ll actually get to use Linux this time, but I’m gonna try.

All info greatly appreciated!

Another area that I’m a bit concerned about is the whole issue of GNU and what our final responsibilities would be there. I know the general rules, but I’d love to hear from folks who’ve been through the process.

I wanted to have some kind of GPS navigation on our recent trip to Nashville. Having used the “NeverLost” feature of Hertz Rental cars, I’ve come to truly love what it does for me. I can read a map but I’m not the fastest at it, and so I’ve frequently passed by some turn that I needed by the time I figured out that I did.

I first took a look at the dedicated GPS navigation systems from folks like Garmin, Magellan, etc. They offer a lot of really nice features including voice prompting, 3D maps, tons of waypoints, downloadable maps, etc. But geez, these things are stinkin’ expensive! To get that kind of system, you’re gonna pay anywhere from $500 and up. I wasn’t prepared to spend that kind of moolah, so I began to think…

DeLorme sells their StreetAtlas (tm) product, along with a small USB-powered GPS unit. Looking at the features on the box, I noted that they seemed to support pretty much everything that the dedicated units do, at a way lower cost. Of course, the implication here is that you have some kind of laptop or maybe a PocketPC. It so happens that I have a laptop that is fairly nice and so I thought that perhaps I should consider using that and StreetAtlas for our little trip. But then the thought occurred to me that I couldn’t use the laptop for the entire trip without needing to recharge the batteries a bunch of times. “Aha”, says me to me, “I should get ahold of an invertor and run the laptop from that”. Since I was at BestBuy at the time, I took a little stroll over to the computer section from the software aisle that I was in and asked if they had such a beast. Indeed they did.

So, $100.00 for the DeLorme software and $55.00 for the invertor and I’ve got myself a nice little in-car navigation system. The results? Pretty good overall.

The package lets you load both the software and the entire map database onto your machine if you have the space, which I did. That makes it nice in that you don’t have to keep the CD in the drive while it gets bounced all about your vehicle. Once it’s loaded, you have to download a small update from the Internet and once installed, you’re ready to travel. You do need to set a few preferences up regarding voice prompts, GPS details, map representation, etc. but those are really minor matters that can be decided later (of course, if you expect voice prompts, it’s probably best to configure that early on…)

It’s fairly easy to input a route by entering your start addres and your destination address or just the city. It computes a path and you’re on your way. Once it gets a fix on your current location from the GPS, it will begin voice prompting you about what your next turn will be and how far away it is. The map updates to show your progress and you can see more or less detail by choosing a zoom level. The prompts are a great thing, but I was puzzled by the fact that it will frequently begin to say something but will stop short. That happened a bunch of times. It took a little digging, but I found that you can press the F5 key to get it to repeat its current prompt at any time. You need to do that fairly often anyhow (if you’re me) because the details sometimes escape me when I’m driving.

I need to point out that my wife Lisa was good enough to bear the computer on her lap for the entire trip, so I wasn’t manipulating this thing while I drove. ‘Just wanted to get that out of the way in case you wondered…

Overall, the package worked great. I don’t think I’ll travel anywhere that I haven’t yet been without it. Here’s a summary of my experience:

Pro’s

1. Great overall application. The voice prompts are very helpful and the map details were quite good. When we stumbled off-course, it was able to re-route us using some of the most podunk little side-streets that you can imagine.

2. Fairly straightforward interface. I have to put this as both a PRO and a CON, because while it was ok to use, I think it could be better.

3. Reverse-Route planning is a nice touch. It lets you simply say that you want to return from whence you came, and the package computes that route for you.

4. “Route from current location” is nice too. It lets you start a new route from your present location, rather than having to enter a starting point directly.

5. Pretty excellent maps. Like I said, it was able to route us using some really out of the way paths.

6. It has a pretty nice “points of interest radar” that allows it to announce to you things that might be handy to know, such as gas stations, restaraunts, etc. You can configure what types of things you’re interested in and it can be made to let you know periodically. I didn’t try to do queries for things like “Italian Food”, or “Wendy’s”, etc. I’ll have to snoop around some more.

7. It has a speech-recognition feature that lets you drive the application. The vocabulary is fairly extensive and so you can do lot with it. See the “Cons” section for the downsides of this feature.

Con’s

1. The voice prompts kept terminating early. Not sure why but I imagine others can tell me.

2. The thing got confused a few times about where we were. Not sure why exactly although I’ve heard that urban areas can be particularly challenging for GPS. The net result is that there were a few occasions where we needed to drive around for a bit until it got un-confused. It always did, so once we figured out that it would recover it was less stressful to have it lost itself…

3. The user interface is a little bit clunky. Primarily you interact with it via a row of tabs at the bottom of the screen, below the map. It’s often not obvious which tab you should be looking at. Then, there are sometimes multiple buttons on a given tab that makes deciding your next move a little confusing.

4. It wasn’t clear how to get the software to plan a route from our current position. Finally, I was scrolling through a list box that displayed all of my previous starting addresses and noticed that at the very top of the list is an element that says to use the GPS position.

5. There’s very little documentation accompanying the package. You pretty much have to figure it out yourself and/or use the help system.

6. While the speech-recognition is a nice feature, it does suffer from the fact that noise in a car pretty much swamps out its value. It kept saying that the volume was too high, even when the mic volume was lowered. Plus, you still have to hit a function key before it begins recognition. That’s good in the sense that it knows when to begin listening, but it means that you have to fuss a bit with a key while you’re driving if you don’t have someone like my lovely wife to manipulate the thing.

Like I said, I like it a lot and I’ll be using it for future trips. For my ~=$160.00, I think it was a bargain when you consider the price of a dedicated unit. The thing that would have made it even better would have been to run it on some kind of handheld in order to make the physical aspect a little easier to deal with. If you want some kind of navigation system and can live with a laptop in the car and a wire running up to your dashboard, I’d say the investment would be well worth it.

Truth is, I don’t really like it. I’m more of a jazz guy at heart. That said, my wife and I just returned from a nice little trip to the home of country music: Nashville, TN. It was worth the trip, I assure you.

We went because neither of us has ever been there and Lord knows there’s been a lot of famous folk pass through that town. Also, if you’ve read much of this blog, you know that I’m kinda into recording and music and other media production, so that was another good reason for us to go.

First off, we stayed at the Opryland Hotel. If you read the travel guides, they all recommend at least visiting there as part of your itinerary, with good reason. The place is huge and utterly amazing! As I recall, it’s the largest hotel in the world that doesn’t have a casino as part of it. It has three enourmous atria under glass. Each is populated by lush vegetation, waterfalls, fountains, restaurants, walkways, etc. One of the sections called the “Delta” actually has a stream on which you can take a riverboat ride. There’s also an attached conference center that would suit just about any kind of convention or similary gathering that you can imagine. All in Southern style…

Suffice it to say that the hotel was one of the highlights.

We also got a chance to visit the Country Music Hall of Fame, the Ryman Auditorium (former home of the Grand Ole’ Opry), RCA Studio B (where a ton of hits from artists from many different genres were recorded) and of course the Grand Ole’ Opry of today. The Ryman has a lot of interesting history attached to it. It was also nearly the victim of the wrecking ball. Fortunately a number of intelligent people decided that preserving that piece of history was worth the money, time and effort.

I took a bunch of photos, some of which are up on my online album. Please take a look to get a feel for the beauty and history of this big little city.

Hint: One of my favorites was the RCA Studio B tour!

So, if you’re up for a nice 2-4 day trip and you enjoy Southern hospitality, history, and the music business, I highly recommend Nashville. You don’t even have to like country music to truly enjoy yourself! Again, please visit my album for a look at more of the trip!

(p.s. - Before anyone points out that the photo album is listed as “Studio A”, I know. I managed to goof it up!)

My wife and I are going on a brief, but much-needed vacation. It’s informal and we’ll be back the last part of the week or at the latest, Saturday. My brother-in-law will be house-sitting, but he’s not into blogging so don’t count on anything from him whilst we rest… Look at this as a way to post comments on the topics that have been burning in your inner-most being.

So fear not, posting will resume next week. Stay tuned for another exciting episode. Same Bat-time. Same Bat-channel.

In 1978, I remember desperately wanting to get an Apple II. Truth told, I wanted just about any of the home computers that were big at the time. Do you remember the Sol I? How about the RCA Elf-COSMAC (VIP?)? Now there was an interesting architecture. Registers, registers, registers… There were a ton of totally cool machines, and boy I was totally lusting after each of ‘em.

My first computer was a KIM-1. It had 1K of RAM (if I recall). I managed to up that to 3K by adding a 2K static RAM to it (via wire-wrap wire, perf board and metal stand-offs). I also kludged an RS-232 port onto it so I wouldn’t need to use either the calculator keyboard and 7-segment displays, or the current-loop interface for teletypes… Had great fun modding that thing but oddly, I did’t write a lot of code on it. At the time, I was actually a bit averse to assembler/machine code. Next, I got ahold of a Sinclair ZX81. It was a computer made in England that eventually became the Timex-Sinclair 1000. It’s predecessor was the ZX80. Both were based on the Zilog Z-80 and were doggone cheap for the time. I ordered mine from the UK. Took a long time to get and sadly, it also wasn’t the best vehicle for my computer discovery. I was silly enough to purchase the 16K RAM pack and some software for it. Geez, that stupid RAM module was touchy since it was parked at the back of the already-small computer and stuck up above it. Any movement of the machine (and that was a dead-bang certainty given its size) and you risked losing everything in memory. While I didn’t make much progress on that machine at the time, hindsight has given me a certain respect for it, since Sir Clive Sinclair did a bloody good job of cramming a pretty significant amount of stuff into 4 IC’s.

The first truly useful machine that I got was a Commodore VIC-20. I think it had 3K of RAM but was blessed with a full-sized keyboard. For some reason that machine just clicked with me. I managed to build all manner of hardware interfaces for that thing, including motor controls, speech synthesizers, analog I/O, DTMF decoders, etc. It’s BASIC was pretty powerful and you could get to the heart of the thing pretty easily. It was based on the 6502 and had a 40-column display. I loved it and moved on to the Commodore 64. Since the two machines were so similar in principal (I know, the ‘64 had way better sound capabilities, more RAM, better graphics, etc.), it was a natural for me to move over to it. Somewhere in there, I got ahold of a Rockwell International AIM 65. That was also a 6502 machine with a full-sized keyboard and a decent little LED display. It pre-dated the Commodore hardware, but I got it later on. It was also a lot of fun to develop hardware for. That was my last non-PC hardware until I purchased a Macintosh many, many years later.

The point of this little diatribe is that I somehow managed to gain a lot of valuable experience from those little pieces of hardware. It was a loving exercise in electronics, computers, & software. And…I worry that that kind of experience is harder and harder to come by. While I wasn’t directly involved in the revolution, being a kid around the time that personal computing was being born was quite a priviledge. How does one go about getting the same opportunities? Having electronics as a hobby is pretty hard for a kid these days, since so much of the silicon out there is highly integrated and oftentimes surface mount. One has to be pretty deft to do that kind of fine soldering, etc. to make the kinds of things that would be interesting these days. You can get hand-held game machines that have thousands of times the computing power and resources that we had when I started out, so what I see these days is a kind of “so what” attitude towards tinkering. Not sure what the effect of that will be in the long run. I do know that those experiences were invaluable as I entered the professional work-force.

I suppose I’m getting old and this is the kind of diddy that you’d expect from a geezer (hey, I’m an early-40’s dude. Not *that* old…). I always said I wouldn’t do it. You know, pine for the good old days. But the truth is that I think it’s pretty hard to come back to that kind of experience. And I guess time has moved on to other areas of focus for younger, tech-inclined folks. Let’s hope that their version of what I was able to experience is as much of a blast as I found it!

Anyone who knows me will pretty much tell you that home-repair isn’t my strong suit. (take a look at “Defying the Laws of Physics” for some background.)

It isn’t so much that I can’t do it. Rather, it’s a matter of how long it takes me to get it done before it becomes more cost-effective to have someone else do the work…in something less than geological time scales.

So it came to pass that I was working on one of the closets in a bedroom of our house, repairing plaster. Our house is tiny…I mean it….tiny. Imagine then, what the size of a closet would be in a house so diminuitive and you get a decent mental picture of me working in it (a slight clue: I’m 6′.2″ and about 230 lbs.). Anyhow, I was using a spackling material to correct some minor chasms created by the gradual settling of that part of the structure over time. That stuff smells, let me tell you. In fact, I’m pretty sure it’s at least somewhat intoxicating. I know this because I found myself making the outlines of Mickey Mouse and other Disney characters in the stuff with my fingers and wondering just where my scraper was… The slight buzzing in my noggin’ should have been a clue, but I suppose that by the time the thought made its way forward in my consciousness, it was too late.

Eventually I did have enough sense to back out of the space and let my head clear. Coming back to it a day or so later, I was amused to find various cartoon characters’ images imprinted in the material that was supposed to have *fixed* the closet. I also noticed that I hadn’t even completely covered the spots that I meant to repair, meaning that the drywall mesh I was using was only partially covered in spackle, and there were some spots that weren’t even in need of repair with compound covering ‘em. Go figure.

Lesson learned: limit the time you spend with your head immersed in the vapors of a material that’s really intended to be used in spaces where air is actually flowing… I made my next passes at this in much shorter time periods and last I checked, the areas meant for repair were actually covered.

Now, if I could find that scraper…