Taking the time to isolate the problem and repair the crystal on a 30-year-old computer, when you could as easily have used an emulator or picked up another one on eBay, just because it's more fun to fix it yourself - that's pretty much the definition of a hacker, right there.
Its funny seeing an article on the 99/4A here on HN :)
I'm too young to have had any experience with the home computer generation. A friend of mine, however, cut his teeth on the 99/4A, and he still has a soft spot for it. So much so that his first big project he ever did with an FPGA was to recreate and expand upon the TMS9918A video chip. He finished it a year or so ago and if anyone is interested in reading about it he documented the whole thing on his site http://codehackcreate.com/archives/30
The CPU in the 99/4A was interesting. It didn't have registers. It had a "workspace pointer" that pointed to a space in RAM where your "register" slots were. So you could have multiple "workspaces" (sets of registers) and switch among them by simply setting the workspace pointer. Instant new context. Much slower than real registers of course but also quite flexible.
I have a TI-99/4A somewhere (perhaps in my in-law's basement) and I'm really tempted to dig it out. My first computer was a heavily modified ZX-81, but my first computer with a real keyboard was the TI. Both were amazing platforms for learning, and really the only downside was the use of a cassette recorder for storage. Anyway ... thanks for bringing back some great memories.
As an aside, the inductor isn't so much used to "tune" the frequency of the crystal as it is to make sure the crystal's impedance is matched properly. You can "pull" a crystal's frequency slightly, but you'll also notice the amplitude of the waveform drops significantly as you move away from it's natural resonance.
You could get a floppy disk as an add-on (a whopping 90K .. single density 5.25").
I had one back when I was a kid. Learned BASIC of course, and assembly language. There was a little plug-in cartridge called the "Mini Memory" that provided an extra 4K of RAM and an assembler.
The keyboard was small so a lot of the punctuation was accessed with the "FN" modifier key, unfortunately FN-= was an immediate hard reset which was all too easy to hit accidentally. More than once lost a lot of code that way. Taught me to save frequently.
I seem to recall there was some hack (POKE a value into a specific address?) that would disable that....
I picked up my 99/4A very late (mid-00's, I think), and the battery on MINIMEM gave out and the line-by-line assembler wouldn't load.
Still, I had a lot of fun making speech with it.
Great system, but a lot of strange ideas. The FN-key stuff, the double-interpreted BASIC, requiring the peripheral expansion box to do assembly work (mini memory and the line-by-line assembler came later).
Wow this brings back some memories! My first computer was also a TI 99/4A. I got mine brand new in 1982 through a friend that worked at TI. For a while I suffered through the slowness of using a tape recorder for storage but eventually I bought the expansion box for it which added memory and a 160K, single-sided, 5.25" floppy disk. Compared to the tape drive it was a speed demon!
Ahhhh .. the "good old days" of buying a computer magazine with programs listed in Basic and typing them all in. Sometimes having to figure out how to convert them because the version of Basic wasn't the same one. I don't have the 99/4A anymore but I do still have a book that I bought back then to experiment with called, "Projects in Machine Intelligence for Your Home Computer".
>The error is always "error opening database connection". You should not open any database connection to send back a static block of HTML.
What? The message indicates an error connecting to MySQL. WordPress (a CMS) uses MySQL to store its content. If it cannot fetch that content from the DB, you see an error. What were you expecting?
I was expecting the page to be cached in RAM. Assembling a page from a database for every request is wasteful of limited computing resources. And doesn't work, as the error message mentions.
This isn't a limitation of WordPress. It's a limitation in the stack.
The average WordPress (or any other CMS for that matter) stack doesn't serve pages from RAM.
And even if it did, it could expire, it could be updated, it could become corrupt, the caching server could go down, or have a number of other things go wrong. There would be a call to the DB, the DB could fail and there would STILL be a static html page returned providing information on the error.
My website uses PHP and a persistent MySQL connection, one for each parallel request. This held up perfectly when a post of mine came on the HN homepage (server is an Asus EEE PC with a low-end Intel Atom). This makes me think the problem is not in connecting to a database, it's in Wordpress somehow. A static page with comments would probably not work any better for high traffic websites, sooner or later there'll be an access violation: cache update while someone was loading the page.
As frustrating as I find Wordpress, I doubt this is a Wordpress performance problem unless the author is hosting on his own crappy hardware. Judging from traceroute the site is in a cave in Germany, or possibly in Bratislava where they're still waiting for the train to come.
I was in a demo the other day where the presenter mentioned "making Mr. Bojangles dance". Immediately I knew exactly where he got it. I asked anyway, he said, "well my first computer was a TI-99/4A". I was ecstatic! So was mine.
We had one of those at my high school with the floppy (huge friggin box) and the voice synthesizer. I programmed the thing to say Dakota Sioux (different than Lakota) words[1]. It was quite the toy. Got replaced with a lab of Apple IIe's, but no more speech.
1) trivia: Dakota also has different pronunciation / words depending if a male or female is speaking
This reminds me of a time when the 6.5536mhz crystal was perennially out of stock at radio shack because because of an easy tone dialer hack to make a redbox.
Crystals undergo slow gradual change of frequency with time, known as aging. There are many mechanisms involved. The mounting and contacts may undergo relief of the built-in stresses. Molecules of contamination either from the residual atmosphere, outgassed from the crystal, electrodes or packaging materials, or introduced during sealing the housing can be adsorbed on the crystal surface, changing its mass; this effect is exploited in quartz crystal microbalances. The composition of the crystal can be gradually altered by outgassing, diffusion of atoms of impurities or migrating from the electrodes, or the lattice can be damaged by radiation. Slow chemical reactions may occur on or in the crystal, or on the inner surfaces of the enclosure. Electrode material, e.g. chromium or aluminium, can react with the crystal, creating layers of metal oxide and silicon; these interface layers can undergo changes in time. The pressure in the enclosure can change due to varying atmospheric pressure, temperature, leaks, or outgassing of the materials inside. Factors outside of the crystal itself are e.g. aging of the oscillator circuitry (and e.g. change of capacitances), and drift of parameters of the crystal oven. External atmosphere composition can also influence the aging; hydrogen can diffuse through nickel housing. Helium can cause similar issues when it diffuses through glass enclosures of rubidium standards.
TI finally launched a color version of the TI-84. It's called the TI-84 Plus C Silver Edition; it comes out in Spring 2013[1].
EDIT: This does seem to be off topic. I posted before I read the article (a cardinal sin, I admit) because I could not connect to the site. A second attempt to load the page took about 5 full minutes.
The article is down, and TI used a model number in the same series as their massively-popular handheld calculator line. People are probably thinking the article is complaining about the primitive screens that the calculators have.
Major TI-99/4A fan here too. Parsec was the awesomest shootemup of its time by leaps and bounds. Pixel perfect movement and collision detection. I got good enough to roll over the scoreboard. http://dos486.com/misc/parsec.jpg
The manual claims the sequence of level colors recycles after 16, but that's incorrect. Every level from about 13 to as far as I've reached somewhere beyond 20 is bright yellow. The manual also claims the game keeps getting harder indefinitely, but that's not true either, nothing really changes past level 4. The only difference is that the asteriod belt continues to lengthen each level, but that's generally a good thing as it's worth so many points.
(Yeah, asteriod belt. Parsec misspells it. Blew me away that I played the game for ten-plus years before I ever noticed.)
Awesomely, Texas Instruments released a number of TI-99 cartridge images as freeware. They're included with several emulator distributions. So you can legally and easily play Parsec and TI Invaders and a couple dozen other TI games. http://www.harmlesslion.com/cgi-bin/showprog.cgi?search=Clas...
One day in a distant future, a weakly godlike posthuman entity may want to call a feature of its own stellar system The Asteriod Belt. Other posthuman entities will, immediately recognize a fellow TI-99/4A enthusiast and start to play games together.
I enjoyed the game as well. I remember the thrill of achievement when I figured out it was possible to go backwards through two of the refuelling tunnels.
Also, there's a bug in the bounds checker. When going backwards, hold the joystick up. This lets you go off the left side of the screen and over to the right side, behind the ships attacking you.
Yes. This game invented the whole 3D maze with overhead tactical RPG combat thing, which didn't become popular until SSI's Pool of Radiance, 6 years later.
It was a neat idea to put the game engine on the ROM cartridge, then allow game content to be loaded off cassette or disk. It's just a shame TI only ever released two game modules for it before pulling the plug on their games division.
I heard someone created some Tunnels of Doom tools and that they're floating around on the internet somewhere, along with some modules fans have made with it.
Aging old men used to repair and beautify the cars of their youth. Guess what we do now. Interestingly enough, most of the vintage 8-bits have ethernet and TCP/IP now as well.
What do you think what kind of mindset brought such things as your computer (or the software it runs) to life in the first place ? Oh, the site is called Hacker News, by the way :D
