Henry Baker wrote
Re Crippleware:
A significant source of crippleware is marketing brain damage, but there are also plausible explanations for crippleware:
1. I heard of a truck company in Indiana that "detuned" any engine that exceeded the advertised horsepower. They claimed that the increased horsepower put an unplanned stress on the transmission so that it would fail earlier than expected.
2. The southern NASCAR-type mechanics during the Vietnam war would sometimes "hotrod" the battle tanks, making their MTBF less than 100 miles. With these and other problems, a good fraction of the tanks spent their time either towing other tanks, or being towed themselves.
3. The wear in some mechanical devices goes up dramatically (more than linearly) with increased speed, so that the lifetime is severely compromised.
4. If you are careful, you can utilize low-octane gas in an older car which was designed for high-octane gas. However, it requires a relatively skillful driver to avoid damaging the engine.
5. The IBM 1403 chain printer had its character set sequence cleverly designed so that the probability of a large subset of hammers being fired simultaneously was essentially zero. However, if you studied the chain and then ordered the printer to print a certain sequence of characters, you could easily break the chain, which would wreak havoc on surrounding portions of the printer. If this happened too often, IBM would have been forced to include software to disallow those dangerous character sequences. I guess if IBM had copyrighted those sequences, then such software would have been the first "DRM" software? ("DRM" = Digital Rights Management, used to prevent the copying of copyrighted materials.)
There were even programs to play recognizable tunes in these printers. (Anchors Aweigh? Sailor's Hornpipe?) Their very existence was remarkable due to incredible cost of cpu time--hunreds of 1960s dollars/hr. To save precious seconds, the printer had a very fast form feed controlled by a loop of perforated tape. Depending on which bit position you chose in your format statement, the printer could skip to the next sixth, quarter, third, half, or whole page. (How did it skip 1/4 if there were 66 lines?) There were also unpunched bit positions accessible with a computed, e.g. accidentally overwritten, format string, whose semantics was "skip to new box of paper". These machines were rugged, withstanding besides the hammering chain, the kicking of low paid operators screaming imprecations. --rwg The MITAI Lab got a later model with a spinning drum embossed with the entire character set repeated 120 (132?) times. The row of hammers struck the paper from behind, knocking it into the ribbon and drum at the appropriate millisecond. The rear access doors were featureless rounded rectangles, flush with the back of the printer, and held shut by magnets. It was an IQ test to get them open. Pushing on one around its edges revealed a "soft spot", a deliberate gap in the jamb rabbet opposite the otherwise indistinguishable hinged edge. Punching the soft spots popped open the doors. A good sized magnet might also have worked. Also perhaps the huge double suction cups used for lifting the raised floor panels under which ran all the power and data cables (and refrigerated air). And perhaps not, as I think the surface of those doors was somewhat textured, bearing also the helpful (but non-OEM) legend: "To open, see instructions inside."
5. The Xerox Alto "personal" computers were built from "standard" 74xx-type chips. However, they hadn't used the best "timing" tools, so some of the paths were too tight for reliable operation. As a result, some microprogramming operations worked only on a subset of the Altos. Due to the requirements for synching with things like the display, one couldn't simply slow down the clock. In the design of many chips today, "timing closure" is one of the last tasks to be done after verifying that the data paths work logically. "Timing closure" then tells you how fast you can run the chip without violating various setup time requirements. Circuits that are too close to the edge timingwise may fail when the temperature goes up a little.
6. The whole "digital revolution" is the recognition that standardizing signal definitions and timings mean that when predicting the future digital behavior of a circuit, the details of the digital mapping to the analog circuitry can be safely ignored. From time to time, you can "improve" a circuit in some dimension by "hacking" it (by taking advantage of the details of a particular circuit), but some of these improvements probably won't survive the next series of job layoffs or the next product cycle.
At 09:58 AM 1/1/2009, Eugene Salamin wrote: rwg wrote
The lucky gnurds queueing up for time on the RLE-PDP1 were indebted to the unlucky tools who chose instead to hang out at the Civil Engineering Dept IBM1401, which, a tool told me, had a 407 E8 that cost $tens of thousands less because it was only 2/3 the speed of a regular 407. By virtue of a plugboard with an extra relay circuit to discard every third cycle! Yank the relays and be fully upgraded. Except during scheduled visits by the IBM field service representative.
It amazes me that IBM was able to maintain its hypnotic sway over market opinion while pulling stunts like that.
Perhaps someone at the Computer History Museum can propose an earlier example such a deliberate disfeature. Perhaps even provide a name for the practice. (Failing which: disfeaturement.)
geb trats --rwg
EDGAR T IRONS DENIGRATORS _______________________________________________ This practice is very much alive in current business, whether a pure software product, or software embedded in some device. The name given to such practice is "crippleware".
Gene