Last fall, I attended a 6:00 pm Friday meeting at a busy (24 x 7) company. In the break room, a janitor with a huge plastic container was emptying the (dozen) refrigerators where employees kept food. He turned the reefers off to defrost. Another followed behind him spraying the innards with something and wiping down the walls, shelves and doors.
I was working in a Sun shop... a buddy asked me to sit and type some commands... worked ok. He showed me it was a pc. (Blush) I asked him how in the world he got Solaris working on a pc.
Snake: Use thermodynamics: If we compress air adiabatically into a car-sized tank to 5000 psi, how much do we raise the temperature of the air? How much energy to compress? When heat leaks away and the temperature returns to normal, how much energy has leaked away. What is the efficiency of air motors? How much energy is available at the rear wheels?
"Indeed, Lincoln's own staff was minimal - compare Nicolay and Hay to the modern Executive Office of the President. That Congress did not appropriate funds for White House staff until 1857 underscores the difference. It was only well after Lincoln's death that the size of the White House staff reached six!"
Whazzis? An airplane that flies IN SPITE of its flapping wings? We already know how to make airplanes that develop thrust from engines and lift from wings. I thought the big deal was to duplicate the birds' trick of lift AND thrust (and, oh BTW, control) from a flapping wing.
How does the flapping wing in this story help anything?
Some people are more price-sensitive (PS) than others. Retailers want as much of the business as they can get. One way to attract the PS is to offer a discount. To maximize profit, a retailer doesn't want to offer the discount unless necessary. So coupons and rebates have a certain, extra effort required to get the discount. In this way, the PS select themselves. The non-PS can't be bothered. So they don't get the discount.
No need to imagine conspiracies, rip-offs or playing with the float... just ingenious retailing.
The verification question here is the barest tip of the iceberg. Every forensic instrument that has any software, including programmable gate arrays and rom controllers, is subject to the objections that the code might not work, that the prosecuting agencies are, in any case ignorant of it, and that consequently no one can swear that a defendant committed a crime.
Once the source code can be examined the problem can perhaps be moved back to the compiler. This is actually three problem areas - not just one. First is the syntactical analyzer and error generator which is what we all think of when a compiler is mentioned. Second, there is the library. Many microcontrollers have extremely limited instruction sets. Some don't even have a multiply instruction. Third, there is code generator.
So even if the C code is correct and is correctly analyzed by the compiler, complete verification would have to include the library and the code generator. Finally, how many computers have been formally verified?
As things stand right now, I don't see how any law-enforcement agency, instrument manufacturer, software supplier and hardware manufacturer even in combination could swear that a defendant has committed a crime when a software based instrument provides a crucial measurement.
At age 8, I began to believe the sq root of 2 was irrational - a teacher told me this and I tried for an hour to find a rational root. By age 16 I could prove it was irrational.
In high school, a teacher told me pi was transcendental so I began to believe it. I'm 71 and I still believe it even tho I can't prove it. (I've made a little progress. A coupla years ago I read a proof that pi is irrational.)
I think an awful lot of life including a buncha hi tech depends on things people "know" but can't prove or even document.
I once had a job trying to routinize software production (don't laugh yet). Every workflow tool we tried !required! that we do things the way the tool wanted them done. Even tho the suppliers claimed that the tool could be customized, when all was said and done, the tool could not be made flexible enough.
We ended up writing our own tool. (Laugh now) None of the managers were interested; none of the programmers were interested even tho the project promised to handle a lot of routine paperwork automatically.
This was ten years ago. Are contemporary workflow tools any better?
Slashdot Mirror
The history of humans releasing even natural organisms into new environments is not very encouraging.
Last fall, I attended a 6:00 pm Friday meeting at a busy (24 x 7) company. In the break room, a janitor with a huge plastic container was emptying the (dozen) refrigerators where employees kept food. He turned the reefers off to defrost. Another followed behind him spraying the innards with something and wiping down the walls, shelves and doors.
Bet they had some bad experience like this.
Bill Drissel
For this software guy, my two biggest were the Intel 8251 and the first Western Digital winchester drive controller.
They ended the roll-your-own-but-do-it-wrong era.
Regards,
Bill Drissel
I was working in a Sun shop ... a buddy asked me to sit and type some commands ... worked ok. He showed me it was a pc. (Blush) I asked him how in the world he got Solaris working on a pc.
Regards,
Bill
Theorems are discovered; proofs are invented.
Snake:
Use thermodynamics: If we compress air adiabatically into a car-sized tank to 5000 psi, how much do we raise the temperature of the air? How much energy to compress? When heat leaks away and the temperature returns to normal, how much energy has leaked away. What is the efficiency of air motors? How much energy is available at the rear wheels?
Curious
Bill Drissel
-Charles Farber
Schaum's Outlines ... Murray Spiegel for President ... of the world
Bill Drissel
Whazzis? An airplane that flies IN SPITE of its flapping wings? We already know how to make airplanes that develop thrust from engines and lift from wings. I thought the big deal was to duplicate the birds' trick of lift AND thrust (and, oh BTW, control) from a flapping wing.
How does the flapping wing in this story help anything?
Curious minds want to know.
Some people are more price-sensitive (PS) than others. Retailers want as much of the business as they can get. One way to attract the PS is to offer a discount. To maximize profit, a retailer doesn't want to offer the discount unless necessary. So coupons and rebates have a certain, extra effort required to get the discount. In this way, the PS select themselves. The non-PS can't be bothered. So they don't get the discount.
... just ingenious retailing.
No need to imagine conspiracies, rip-offs or playing with the float
The verification question here is the barest tip of the iceberg. Every forensic instrument that has any software, including programmable gate arrays and rom controllers, is subject to the objections that the code might not work, that the prosecuting agencies are, in any case ignorant of it, and that consequently no one can swear that a defendant committed a crime.
Once the source code can be examined the problem can perhaps be moved back to the compiler. This is actually three problem areas - not just one. First is the syntactical analyzer and error generator which is what we all think of when a compiler is mentioned. Second, there is the library. Many microcontrollers have extremely limited instruction sets. Some don't even have a multiply instruction. Third, there is code generator.
So even if the C code is correct and is correctly analyzed by the compiler, complete verification would have to include the library and the code generator. Finally, how many computers have been formally verified?
As things stand right now, I don't see how any law-enforcement agency, instrument manufacturer, software supplier and hardware manufacturer even in combination could swear that a defendant has committed a crime when a software based instrument provides a crucial measurement.
Regards,
Bill Drissel
At age 8, I began to believe the sq root of 2 was irrational - a teacher told me this and I tried for an hour to find a rational root. By age 16 I could prove it was irrational.
In high school, a teacher told me pi was transcendental so I began to believe it. I'm 71 and I still believe it even tho I can't prove it. (I've made a little progress. A coupla years ago I read a proof that pi is irrational.)
I think an awful lot of life including a buncha hi tech depends on things people "know" but can't prove or even document.
I once had a job trying to routinize software production (don't laugh yet). Every workflow tool we tried !required! that we do things the way the tool wanted them done. Even tho the suppliers claimed that the tool could be customized, when all was said and done, the tool could not be made flexible enough.
We ended up writing our own tool. (Laugh now) None of the managers were interested; none of the programmers were interested even tho the project promised to handle a lot of routine paperwork automatically.
This was ten years ago. Are contemporary workflow tools any better?
Regards,
Bill