Re: Mersenne: Why 2K?
Punched cards didn't have to be readable Hollerith; the maximum storage per card was 80 12-bit columns, or 960 bits when binary punched. The average card is about .006" or so thick by 3 by 8". (About 6700 bits per cubic inch of card; compare that to a CD in its case at 440,000,000 bits/cubic inch.) We still use the cards in our machine shop; they're quite handy for temporary shims, keeping metal parts from marring each other, etc. Ken At 08:41 PM 2000/01/12 -0500, George Woltman [EMAIL PROTECTED] wrote: At 03:48 PM 1/12/00 EST, Ernst wrote: From a programming perspective, my own top "why 2K" question is this this: even given that the person(s) who first used a mere 2 characters to store the year had good reason (e.g. severely limited computer memory) to do so, why didn't they use those 2 precious bytes as a 2-byte integer? I think its due to punched cards. Reading and writing 2 digit dates on the punched card makes using PIC 99 COMPUTATIONAL inappropriate. Regards George P.S. Yes I'm old enough to have used punch cards. _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Mersenne: Why 2K?
Jud McCranie wrote: This is getting off topic, but: The criteria for something to be patentable is that the average practitioner in the field wouldn't think of it. So it boils down to whether the average programmer would think of windowing, given the problem. Well, that's the major criterion (non-obviousness) if no one has explicitly demonstrated or patented a similar thing previously... " Dickens applied for the patent in October 1996 " I was using windowing in 1987, so his patent is invalid (prior invention). ...in that case windowing is considered "prior art," and the patent is invalid on its face. Jud, assuming you have reasonable supporting documentation for your use of windowing prior to 1996, you should consider sending it to the U.S. patent and trademark office, http://www.uspto.gov (even if you have no desire to attempt to patent it - clearly, showing that you merely thought of it before 1996 in order to invalidate Joe Schmoe's patent is much easier than proving that you thought of it before anyone else did and seeking a patent yourself). Note that prior art is most easily established via publication, public use or sale - if you only wrote a windowing script for your own use, it may be more difficult to prove. From a programming perspective, my own top "why 2K" question is this this: even given that the person(s) who first used a mere 2 characters to store the year had good reason (e.g. severely limited computer memory) to do so, why didn't they use those 2 precious bytes as a 2-byte integer? Had they done so, we'd be talking instead about the "Y32K" or "Y64K" bug, and even Microsoft might have had sufficient time to fix their software by then. :) -Ernst _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: Why 2K?
On 12 Jan 00, at 15:48, [EMAIL PROTECTED] wrote: ...in that case windowing is considered "prior art," and the patent is invalid on its face. Jud, assuming you have reasonable supporting documentation for your use of windowing prior to 1996, you should consider sending it to the U.S. patent and trademark office, http://www.uspto.gov (even if you have no desire to attempt to patent it - clearly, showing that you merely thought of it before 1996 in order to invalidate Joe Schmoe's patent is much easier than proving that you thought of it before anyone else did and seeking a patent yourself). Note that prior art is most easily established via publication, public use or sale - if you only wrote a windowing script for your own use, it may be more difficult to prove. What about all the dialects of various languages which allow one to declared windowed arrays? (e.g. Microsoft QBASIC released circa 1988 allows e.g. DIM PROFITS (1984 TO 2018)) Or, sliding variable-size windowing has been in the TCP definition for at least twice as long as that. I think the reason no-one bothered to patent or copyright the idea of windowing is it is that it's so obvious ... From a programming perspective, my own top "why 2K" question is this this: even given that the person(s) who first used a mere 2 characters to store the year had good reason (e.g. severely limited computer memory) to do so, why didn't they use those 2 precious bytes as a 2-byte integer? COBOL programmers probably declared the year variable as PIC(99) - and a COBOL programmer has no direct means of knowing how that's stored in memory. (Note that PIC 99 USAGE COMPUTATIONAL (binary) would still require 7 bits whereas PIC 999 USAGE COMPUTATIONAL would require 10 bits. PIC 9(4) USAGE COMPUTATIONAL is as near as you can get to a 16-bit integer using COBOL but still only stores values - . Anyway, back in the '60s, lots of systems had word lengths based on multiples of 6 rather than of 8, so manipulating an explicit 16-bit integer would not neccessarily have been efficient! Note that, on an 8 bit machine, COBOL compilers would group together variables defined as PIC 99 and align them on byte boundaries, this actually gives quite reasonable packing makes arithmetic easy provided you have BCD arithmetic instructions. In fact, this is why modern processors retain BCD arithmetic - the instructions are hardly ever used, except by programs written in COBOL! Regards Brian Beesley _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: Why 2K?
At 03:48 PM 1/12/00 EST, Ernst wrote: Jud McCranie wrote: This is getting off topic, but: The criteria for something to be patentable is that the average practitioner in the field wouldn't think of it. So it boils down to whether the average programmer would think of windowing, given the problem. Well, that's the major criterion (non-obviousness) if no one has explicitly demonstrated or patented a similar thing previously... " Dickens applied for the patent in October 1996 " I was using windowing in 1987, so his patent is invalid (prior invention). ...in that case windowing is considered "prior art," and the patent is invalid on its face. Jud, assuming you have reasonable supporting documentation for your use of windowing prior to 1996, you should consider sending it to the U.S. patent and trademark office, http://www.uspto.gov (even if you have no desire to attempt to patent it - clearly, showing that you merely thought of it before 1996 in order to invalidate Joe Schmoe's patent is much easier than proving that you thought of it before anyone else did and seeking a patent yourself). Note that prior art is most easily established via publication, public use or sale - if you only wrote a windowing script for your own use, it may be more difficult to prove. From a programming perspective, my own top "why 2K" question is this this: even given that the person(s) who first used a mere 2 characters to store the year had good reason (e.g. severely limited computer memory) to do so, why didn't they use those 2 precious bytes as a 2-byte integer? Had they done so, we'd be talking instead about the "Y32K" or "Y64K" bug, and even Microsoft might have had sufficient time to fix their software by then. :) -Ernst It wasn't so much the computer memory, Ernst, as it was the disk storage space. An insurance application record would have perhaps 6 dates within 100 bytes: date of applicant's birth, date application for insurance was taken, date of proposed enrollment, date the first premium was due, date the premium was received/recorded in the system, date of expiration if the payments stopped, and probably more. Saving the "century" field 6 times was 12 bytes saved in COBOL PIC 99 mode. Clever was the use of COBOL PIC XX as a COMPUTATIONAL field to store a date in 16 bits (which was the length of PIX XX). 7 bits for year since 2^7 = 128 so a year value up to 99 was stored there; 5 bits for day since 2^5 = 32 so a day value was stored there and 4 bits for month as 2^4 = 16 so a month value was stored there. Two bytes for a YEAR-MONTH-DAY value was great. Adding century was a bummer to this idea. The programmer had to have a REDEFINED PIC 99 COMP-4 of the PIC XX and then use a routine to extract three fields. As some may recall, the packed-digits format (COMP-3) was also used to store disk space on the file's record. IBM created/used this format to allow space savings. But the bottom line was that in the 1960's and 1970's, disk store space was expensive and saving it was worth the effort spent in more programming (people were cheaper that computers, in a way). Yes, memory was expensive and limited, but it was not the cause of the Y2K issue. No one in the late 1980's EVER believed that the PC would be as powerful as it is now, that disk storage would be as cheap, and that all these improvement would be in the home !! Only the 1.44 MB diskette of ten years ago remains the same. And I am delighted that MERSENNE.ORG lets me hunt for giant primes even if I never find one. _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: Why 2K?
At 03:48 PM 1/12/00 EST, Ernst wrote: From a programming perspective, my own top "why 2K" question is this this: even given that the person(s) who first used a mere 2 characters to store the year had good reason (e.g. severely limited computer memory) to do so, why didn't they use those 2 precious bytes as a 2-byte integer? I think its due to punched cards. Reading and writing 2 digit dates on the punched card makes using PIC 99 COMPUTATIONAL inappropriate. Regards George P.S. Yes I'm old enough to have used punch cards. _ Unsubscribe list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
