Re: [U2] Prime number file modulos
But, for backwards compatibility, it's still the default in UniVerse Pick flavor accounts. So make sure you always specify separation! - Original Message - From: Dan Fitzgerald [EMAIL PROTECTED] To: u2-users@listserver.u2ug.org Subject: Re: [U2] Prime number file modulos Date: Mon, 05 Sep 2005 07:09:31 + Usually not on purpose... I thought 500-byte frames were a thing of the past. Is anyone still using them? Stewart -- Stewart Leicester | JenSoft Technologies, LLC Per Ardua Ad Astra | mailto:[EMAIL PROTECTED] --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/ --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/ --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/
Re: [U2] Prime number file modulos
Re: 500 byte frames: Just my Microdata clients. Mark Johnson - Original Message - From: Stewart Leicester [EMAIL PROTECTED] To: u2-users@listserver.u2ug.org Sent: Sunday, September 04, 2005 8:36 PM Subject: Re: [U2] Prime number file modulos From: Dan Fitzgerald [EMAIL PROTECTED] Tuning file sizes is vitally important. If you have an average item size of, say, 1700 bytes, and a sep of 1, then even if you pick a very good modulus, it will take 4 disk reads to retrieve the data. If you have a bad modulus on top of that, like 101 when you need 10007, it will take around 400 disk reads to retrieve each item. You and your users will notice this. Additionally, as mentioned earlier, this exposes you to a greater risk of file corruption. If you have 1000 links to overflow in a file, you are 1000 times as likely to get a bad link than someone who has 1 link. And that's before you start thinking about how you're affecting MTBF by artificially hammering your disks that way. I thought 500-byte frames were a thing of the past. Is anyone still using them? Stewart -- Stewart Leicester | JenSoft Technologies, LLC Per Ardua Ad Astra | mailto:[EMAIL PROTECTED] --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/ --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/
Re: [U2] Prime number file modulos
From: Ray Wurlod [EMAIL PROTECTED] But, for backwards compatibility, it's still the default in UniVerse Pick flavor accounts. So make sure you always specify separation! From: Dan Fitzgerald [EMAIL PROTECTED] Usually not on purpose... I thought 500-byte frames were a thing of the past. Is anyone still using them? Stewart I'm confused: what default are you speaking of in UV Pick-flavor accounts? That separation is used, or it has 500-byte frames? So UV and UD both use the same frame/modulo/separation model for static, hashed files, right? If so, surely UV couldn't use 500 byte frames in a Pick-flavor account... Does that mean files in a system could have different frame sizes depending under which flavor it was created? Stewart -- Stewart Leicester | JenSoft Technologies, LLC Per Ardua Ad Astra | mailto:[EMAIL PROTECTED] --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/
Re: [U2] Prime number file modulos
From: Dan Fitzgerald [EMAIL PROTECTED] Tuning file sizes is vitally important. If you have an average item size of, say, 1700 bytes, and a sep of 1, then even if you pick a very good modulus, it will take 4 disk reads to retrieve the data. If you have a bad modulus on top of that, like 101 when you need 10007, it will take around 400 disk reads to retrieve each item. You and your users will notice this. Additionally, as mentioned earlier, this exposes you to a greater risk of file corruption. If you have 1000 links to overflow in a file, you are 1000 times as likely to get a bad link than someone who has 1 link. And that's before you start thinking about how you're affecting MTBF by artificially hammering your disks that way. I thought 500-byte frames were a thing of the past. Is anyone still using them? Stewart -- Stewart Leicester | JenSoft Technologies, LLC Per Ardua Ad Astra | mailto:[EMAIL PROTECTED] --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/
RE: [U2] Prime number file modulos
You can speed it up a little bit thusly: PRINT 'Enter number: ': ; INPUT TARGET NUMBER = (2 * INT(TARGET / 2)) + 1 IF NUMBER NE TARGET THEN PRINT Even numbers can't be prime. PRIME = 0 LOOP UNTIL PRIME DO PRINT NUMBER:' ': PRIME = 1 FOR I = 3 TO INT(SQRT(NUMBER)) + 1 STEP 2 IF NUMBER/I = INT(NUMBER/I) THEN PRIME = 0 J = I EXIT END NEXT I IF NOT(PRIME) THEN PRINT '= ':J:' * ':NUMBER / J NUMBER += 2 END REPEAT PRINT 'is a prime number.' END Larry Hiscock Western Computer Services -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Allen E. Elwood Sent: Friday, September 02, 2005 3:04 PM To: u2-users@listserver.u2ug.org Subject: RE: [U2] Prime number file modulos Here, try this old code I just dusted off (really old, had a LOTTA dust) : Amazingly fast for a brute force algorithm... *FIND.PRIME written by aee 080888 PRINT 'Enter Number ':;INPUT TARGET ORIGINAL.TARGET = TARGET PRIME = 1 LOOP FOR I = 2 TO TARGET-1 ABC = INT(TARGET / I) XYZ = ABC * I IF XYZ = TARGET THEN PRIME = 0 I = TARGET END NEXT I WHILE NOT(PRIME) DO TARGET += 1 PRIME = 1 REPEAT IF TARGET = ORIGINAL.TARGET THEN PRINT TARGET:' is prime' END ELSE PRINT 'Next higher prime was : ':TARGET END STOP Enjoy! Allen www.tortillafc.com -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Mark Johnson Sent: Friday, September 02, 2005 14:41 To: u2-users@listserver.u2ug.org Subject: Re: [U2] Prime number file modulos I found the resize program and all it did was place the new mod in 013 of the DL/ID. Its only proof was that it was numeric and not 'even'. Pretty pathetic. Thanks Mark Johnson - Original Message - From: Allen E. Elwood [EMAIL PROTECTED] To: u2-users@listserver.u2ug.org Sent: Friday, September 02, 2005 4:20 PM Subject: RE: [U2] Prime number file modulos P.S. Could SLOW stand for System Loves Overflow Workspace? Since someone lacked the ability to calculate a prime number, maybe its Serious Lack Of Writhmatic which fails the English test as well ;) -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Mark Johnson Sent: Friday, September 02, 2005 05:53 To: u2-users@listserver.u2ug.org Subject: Re: [U2] Prime number file modulos I just got a copy of the stat report and found over 100 files who's mods are either obviously not prime, ie 1000 or someone's stupid assumption that 1001 is prime. Plus many of these files are 200%-500% under mod'd (is that a word?). Plus it's the second slowest client of mine (my microdatas are currently the slowest, but sized properly). I'm checking to see if there's an erroneous resize program or an erroneous resize programmer. Not truly understood back in the day (circa 1978), but prime numbers were stringently insisted when learning MV101. Thanks. Mark Johnson P.S. Could SLOW stand for System Loves Overflow Workspace? - Original Message - From: [EMAIL PROTECTED] To: u2-users@listserver.u2ug.org Sent: Tuesday, August 30, 2005 5:05 PM Subject: Re: [U2] Prime number file modulos The funniest or most gruesome file tuning that I've seen was a few years ago, at a site that I won't name, who had a master file with a modulo of exactly 100 and where 99% of the ids were numbers ending in 00. Definitely not tuned by FAST - - maybe they'd used SLOW? Answering Mark's question, did it really matter to be prime? . . . No, but if your group distribution is extremely lumpy or spiky, then, as Henry Eggers once said, your file is walking around with a sign taped to the back of its shirt, saying, Hit Me!. -- CONFIDENTIALITY: The information transmitted is intended only for the person or entity to which it is addressed and may contain material that is confidential, privileged and exempt from disclosure under applicable law. Any review, re-transmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited. If you received this in error, please contact the sender and delete the material in a secure receptacle or by shredding the document (s). -- -Mark Johnson wrote: - To: u2-users@listserver.u2ug.org From: Mark Johnson [EMAIL PROTECTED] Sent by: [EMAIL PROTECTED] Date: 08/30/2005 09:16AM Subject: [U2] Prime number file modulos A little non-U2 but I'm sure still answerable by many experienced MV persons. One client (AP-Pro, Native) reported to me a bunch of GFE's. Upon further investigation, all of the involved data files had non-prime modulos. This begs
Re: [U2] Prime number file modulos
You can shorten your prime search routine's execution by limiting the search for factors to the square root of the number being tested for primality. If a number is composite(not prime) it has to have a factor smaller than its square root. --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/
RE: [U2] Prime number file modulos
Hi Larry, The system I originally wrote this on didn't work with EXIT. It would exit *ALL* loops. Weird. But I like the even number filter! I was a math major before I started programming. Took crazy stuff like Euclidian geometry, planer analytical math, quantum math, etc. So this was just a fun little thing I just wanted to do...heh The mentally hardest thing I ever had to program was for not breaking ship packs on sales phantoms. We would sell towel bars to the builder industry and they wanted the bars in their own boxes, the brackets in their own boxes, the hidden brackets in their own boxes, because the finish items were installed by the finish guy, but the hidden brackets were installed by the dry wall guys. The problem was that the hidden brackets came in boxes of 12, the visible brackets in boxes of 10 and the bars in boxes of 8. Used to be if they ordered 300 we would just break open some of the boxes and fill the order that way. But when we started working with the 'big' builders they didn't want any broken boxes because 'shrinkage' would occur. Shrinkage being industry standard verbiage for theft. So I had to figure out a mathematical way of deducing a quantity that, if they ordered 300, I could tell them how many we could ship them, and also work availability into that equation. Because of the different number of items in each box, it was not just as easy as just dividing removing the remainder and multiplying. We had to sell them so that after install there would be exactly the correct number of items so there were no missing pieces, or left over pieces. And it had to be flexible to work with any number of components because we sold all kinds of stuff like this, not just towel bars. Took 4 hours to come up with the idea, and another 2 to program it. Now figure that one out! grin Allen -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Larry Hiscock Sent: Friday, September 02, 2005 23:26 To: u2-users@listserver.u2ug.org Subject: RE: [U2] Prime number file modulos You can speed it up a little bit thusly: PRINT 'Enter number: ': ; INPUT TARGET NUMBER = (2 * INT(TARGET / 2)) + 1 IF NUMBER NE TARGET THEN PRINT Even numbers can't be prime. PRIME = 0 LOOP UNTIL PRIME DO PRINT NUMBER:' ': PRIME = 1 FOR I = 3 TO INT(SQRT(NUMBER)) + 1 STEP 2 IF NUMBER/I = INT(NUMBER/I) THEN PRIME = 0 J = I EXIT END NEXT I IF NOT(PRIME) THEN PRINT '= ':J:' * ':NUMBER / J NUMBER += 2 END REPEAT PRINT 'is a prime number.' END Larry Hiscock Western Computer Services -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Allen E. Elwood Sent: Friday, September 02, 2005 3:04 PM To: u2-users@listserver.u2ug.org Subject: RE: [U2] Prime number file modulos Here, try this old code I just dusted off (really old, had a LOTTA dust) : Amazingly fast for a brute force algorithm... *FIND.PRIME written by aee 080888 PRINT 'Enter Number ':;INPUT TARGET ORIGINAL.TARGET = TARGET PRIME = 1 LOOP FOR I = 2 TO TARGET-1 ABC = INT(TARGET / I) XYZ = ABC * I IF XYZ = TARGET THEN PRIME = 0 I = TARGET END NEXT I WHILE NOT(PRIME) DO TARGET += 1 PRIME = 1 REPEAT IF TARGET = ORIGINAL.TARGET THEN PRINT TARGET:' is prime' END ELSE PRINT 'Next higher prime was : ':TARGET END STOP Enjoy! Allen www.tortillafc.com -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Mark Johnson Sent: Friday, September 02, 2005 14:41 To: u2-users@listserver.u2ug.org Subject: Re: [U2] Prime number file modulos I found the resize program and all it did was place the new mod in 013 of the DL/ID. Its only proof was that it was numeric and not 'even'. Pretty pathetic. Thanks Mark Johnson - Original Message - From: Allen E. Elwood [EMAIL PROTECTED] To: u2-users@listserver.u2ug.org Sent: Friday, September 02, 2005 4:20 PM Subject: RE: [U2] Prime number file modulos P.S. Could SLOW stand for System Loves Overflow Workspace? Since someone lacked the ability to calculate a prime number, maybe its Serious Lack Of Writhmatic which fails the English test as well ;) -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Mark Johnson Sent: Friday, September 02, 2005 05:53 To: u2-users@listserver.u2ug.org Subject: Re: [U2] Prime number file modulos I just got a copy of the stat report and found over 100 files who's mods are either obviously not prime, ie 1000 or someone's stupid assumption that 1001 is prime. Plus many of these files are 200%-500% under mod'd (is that a word?). Plus it's the second slowest client of mine (my microdatas are currently the slowest, but sized properly). I'm
Re: [U2] Prime number file modulos
You don't need to check any other even divisor than 2. Therefore more efficient is to check 2 then FOR I=3 TO MAX STEP 2. An even more efficient mechanism is to limit the divisors to known prime numbers, but let's not get into there. Maximally efficient, of course, is not to reinvent the wheel at all, and use the PRIME verb. - Original Message - From: Mark Johnson [EMAIL PROTECTED] To: u2-users@listserver.u2ug.org Subject: Re: [U2] Prime number file modulos Date: Fri, 2 Sep 2005 23:43:41 -0400 Here's one better if you don't want to EXECUTE PRIME 123 CAPTURING REC INPUT ANS MAX=INT(SQRT(ANS))+1 PRIME=TRUE FOR I=2 TO MAX UNTIL NOT PRIME IF MOD(ANS,I)=0 THEN PRIME=FALSE NEXT I Add your own frosting on this very simple prime calculation. The max number of divisors to test is the SQRT of the object plus 1 to accommodate the fraction. I learned this method in a 1974 Fortran class in college. My 1 cent Mark Johnson Happy Labor Day --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/
Re: [U2] Prime number file modulos
So let's ask the heavy hitters on this forum. How does the TCL verb PRIME do its magic. Thanks in advance. - Original Message - From: Ron Hutchings [EMAIL PROTECTED] To: u2-users@listserver.u2ug.org Sent: Saturday, September 03, 2005 12:41 PM Subject: Re: [U2] Prime number file modulos You can shorten your prime search routine's execution by limiting the search for factors to the square root of the number being tested for primality. If a number is composite(not prime) it has to have a factor smaller than its square root. --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/ --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/
Re: [U2] Prime number file modulos
I just got a copy of the stat report and found over 100 files who's mods are either obviously not prime, ie 1000 or someone's stupid assumption that 1001 is prime. Plus many of these files are 200%-500% under mod'd (is that a word?). Plus it's the second slowest client of mine (my microdatas are currently the slowest, but sized properly). I'm checking to see if there's an erroneous resize program or an erroneous resize programmer. Not truly understood back in the day (circa 1978), but prime numbers were stringently insisted when learning MV101. Thanks. Mark Johnson P.S. Could SLOW stand for System Loves Overflow Workspace? - Original Message - From: [EMAIL PROTECTED] To: u2-users@listserver.u2ug.org Sent: Tuesday, August 30, 2005 5:05 PM Subject: Re: [U2] Prime number file modulos The funniest or most gruesome file tuning that I've seen was a few years ago, at a site that I won't name, who had a master file with a modulo of exactly 100 and where 99% of the ids were numbers ending in 00. Definitely not tuned by FAST - - maybe they'd used SLOW? Answering Mark's question, did it really matter to be prime? . . . No, but if your group distribution is extremely lumpy or spiky, then, as Henry Eggers once said, your file is walking around with a sign taped to the back of its shirt, saying, Hit Me!. -- CONFIDENTIALITY: The information transmitted is intended only for the person or entity to which it is addressed and may contain material that is confidential, privileged and exempt from disclosure under applicable law. Any review, re-transmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited. If you received this in error, please contact the sender and delete the material in a secure receptacle or by shredding the document (s). -- -Mark Johnson wrote: - To: u2-users@listserver.u2ug.org From: Mark Johnson [EMAIL PROTECTED] Sent by: [EMAIL PROTECTED] Date: 08/30/2005 09:16AM Subject: [U2] Prime number file modulos A little non-U2 but I'm sure still answerable by many experienced MV persons. One client (AP-Pro, Native) reported to me a bunch of GFE's. Upon further investigation, all of the involved data files had non-prime modulos. This begs the question. Did it really matter to be prime. I understand the concept of prime numbers and the many forms of hashing so let's not deviate into a hashing thread debate. I'm just interested to learn first-hand observations on native systems with non-prime file modulos. Thanks in advance. Mark Johnson --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/ --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/ --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/
RE: [U2] Prime number file modulos
P.S. Could SLOW stand for System Loves Overflow Workspace? Since someone lacked the ability to calculate a prime number, maybe its Serious Lack Of Writhmatic which fails the English test as well ;) -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Mark Johnson Sent: Friday, September 02, 2005 05:53 To: u2-users@listserver.u2ug.org Subject: Re: [U2] Prime number file modulos I just got a copy of the stat report and found over 100 files who's mods are either obviously not prime, ie 1000 or someone's stupid assumption that 1001 is prime. Plus many of these files are 200%-500% under mod'd (is that a word?). Plus it's the second slowest client of mine (my microdatas are currently the slowest, but sized properly). I'm checking to see if there's an erroneous resize program or an erroneous resize programmer. Not truly understood back in the day (circa 1978), but prime numbers were stringently insisted when learning MV101. Thanks. Mark Johnson P.S. Could SLOW stand for System Loves Overflow Workspace? - Original Message - From: [EMAIL PROTECTED] To: u2-users@listserver.u2ug.org Sent: Tuesday, August 30, 2005 5:05 PM Subject: Re: [U2] Prime number file modulos The funniest or most gruesome file tuning that I've seen was a few years ago, at a site that I won't name, who had a master file with a modulo of exactly 100 and where 99% of the ids were numbers ending in 00. Definitely not tuned by FAST - - maybe they'd used SLOW? Answering Mark's question, did it really matter to be prime? . . . No, but if your group distribution is extremely lumpy or spiky, then, as Henry Eggers once said, your file is walking around with a sign taped to the back of its shirt, saying, Hit Me!. -- CONFIDENTIALITY: The information transmitted is intended only for the person or entity to which it is addressed and may contain material that is confidential, privileged and exempt from disclosure under applicable law. Any review, re-transmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited. If you received this in error, please contact the sender and delete the material in a secure receptacle or by shredding the document (s). -- -Mark Johnson wrote: - To: u2-users@listserver.u2ug.org From: Mark Johnson [EMAIL PROTECTED] Sent by: [EMAIL PROTECTED] Date: 08/30/2005 09:16AM Subject: [U2] Prime number file modulos A little non-U2 but I'm sure still answerable by many experienced MV persons. One client (AP-Pro, Native) reported to me a bunch of GFE's. Upon further investigation, all of the involved data files had non-prime modulos. This begs the question. Did it really matter to be prime. I understand the concept of prime numbers and the many forms of hashing so let's not deviate into a hashing thread debate. I'm just interested to learn first-hand observations on native systems with non-prime file modulos. Thanks in advance. Mark Johnson --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/ --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/ --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/ --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/
Re: [U2] Prime number file modulos
Yeah... the problem with non-prime is that lumpy hashing thing. The wrong prime or file type will do this, too; it's why we call tuning iterative; sometimes it takes a few guesses to get lucky. File corruption doesn't occur just because you picked a bad modulus, type, or sep, but it does increase your risk. Bad flinks and bad blinks don't occur where there aren't any. The more data you can fit into primary space, the less vulnerable you are when something else goes wrong. The Henry Eggers quote captures it. Re-stated, don't tempt Mr. Murphy. Our greatest duty in this life is to help others. And please, if you can't help them, could you at least not hurt them? - H.H. the Dalai Lama When buying selling are controlled by legislation, the first thing to be bought sold are the legislators - P.J. O'Rourke Dan Fitzgerald From: Mark Johnson [EMAIL PROTECTED] Reply-To: u2-users@listserver.u2ug.org To: u2-users@listserver.u2ug.org Subject: Re: [U2] Prime number file modulos Date: Fri, 2 Sep 2005 08:53:01 -0400 I just got a copy of the stat report and found over 100 files who's mods are either obviously not prime, ie 1000 or someone's stupid assumption that 1001 is prime. Plus many of these files are 200%-500% under mod'd (is that a word?). Plus it's the second slowest client of mine (my microdatas are currently the slowest, but sized properly). I'm checking to see if there's an erroneous resize program or an erroneous resize programmer. Not truly understood back in the day (circa 1978), but prime numbers were stringently insisted when learning MV101. Thanks. Mark Johnson P.S. Could SLOW stand for System Loves Overflow Workspace? - Original Message - From: [EMAIL PROTECTED] To: u2-users@listserver.u2ug.org Sent: Tuesday, August 30, 2005 5:05 PM Subject: Re: [U2] Prime number file modulos The funniest or most gruesome file tuning that I've seen was a few years ago, at a site that I won't name, who had a master file with a modulo of exactly 100 and where 99% of the ids were numbers ending in 00. Definitely not tuned by FAST - - maybe they'd used SLOW? Answering Mark's question, did it really matter to be prime? . . . No, but if your group distribution is extremely lumpy or spiky, then, as Henry Eggers once said, your file is walking around with a sign taped to the back of its shirt, saying, Hit Me!. -- CONFIDENTIALITY: The information transmitted is intended only for the person or entity to which it is addressed and may contain material that is confidential, privileged and exempt from disclosure under applicable law. Any review, re-transmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited. If you received this in error, please contact the sender and delete the material in a secure receptacle or by shredding the document (s). -- -Mark Johnson wrote: - To: u2-users@listserver.u2ug.org From: Mark Johnson [EMAIL PROTECTED] Sent by: [EMAIL PROTECTED] Date: 08/30/2005 09:16AM Subject: [U2] Prime number file modulos A little non-U2 but I'm sure still answerable by many experienced MV persons. One client (AP-Pro, Native) reported to me a bunch of GFE's. Upon further investigation, all of the involved data files had non-prime modulos. This begs the question. Did it really matter to be prime. I understand the concept of prime numbers and the many forms of hashing so let's not deviate into a hashing thread debate. I'm just interested to learn first-hand observations on native systems with non-prime file modulos. Thanks in advance. Mark Johnson --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/ --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/ --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/ --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/
Re: [U2] Prime number file modulos
I found the resize program and all it did was place the new mod in 013 of the DL/ID. Its only proof was that it was numeric and not 'even'. Pretty pathetic. Thanks Mark Johnson - Original Message - From: Allen E. Elwood [EMAIL PROTECTED] To: u2-users@listserver.u2ug.org Sent: Friday, September 02, 2005 4:20 PM Subject: RE: [U2] Prime number file modulos P.S. Could SLOW stand for System Loves Overflow Workspace? Since someone lacked the ability to calculate a prime number, maybe its Serious Lack Of Writhmatic which fails the English test as well ;) -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Mark Johnson Sent: Friday, September 02, 2005 05:53 To: u2-users@listserver.u2ug.org Subject: Re: [U2] Prime number file modulos I just got a copy of the stat report and found over 100 files who's mods are either obviously not prime, ie 1000 or someone's stupid assumption that 1001 is prime. Plus many of these files are 200%-500% under mod'd (is that a word?). Plus it's the second slowest client of mine (my microdatas are currently the slowest, but sized properly). I'm checking to see if there's an erroneous resize program or an erroneous resize programmer. Not truly understood back in the day (circa 1978), but prime numbers were stringently insisted when learning MV101. Thanks. Mark Johnson P.S. Could SLOW stand for System Loves Overflow Workspace? - Original Message - From: [EMAIL PROTECTED] To: u2-users@listserver.u2ug.org Sent: Tuesday, August 30, 2005 5:05 PM Subject: Re: [U2] Prime number file modulos The funniest or most gruesome file tuning that I've seen was a few years ago, at a site that I won't name, who had a master file with a modulo of exactly 100 and where 99% of the ids were numbers ending in 00. Definitely not tuned by FAST - - maybe they'd used SLOW? Answering Mark's question, did it really matter to be prime? . . . No, but if your group distribution is extremely lumpy or spiky, then, as Henry Eggers once said, your file is walking around with a sign taped to the back of its shirt, saying, Hit Me!. -- CONFIDENTIALITY: The information transmitted is intended only for the person or entity to which it is addressed and may contain material that is confidential, privileged and exempt from disclosure under applicable law. Any review, re-transmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited. If you received this in error, please contact the sender and delete the material in a secure receptacle or by shredding the document (s). -- -Mark Johnson wrote: - To: u2-users@listserver.u2ug.org From: Mark Johnson [EMAIL PROTECTED] Sent by: [EMAIL PROTECTED] Date: 08/30/2005 09:16AM Subject: [U2] Prime number file modulos A little non-U2 but I'm sure still answerable by many experienced MV persons. One client (AP-Pro, Native) reported to me a bunch of GFE's. Upon further investigation, all of the involved data files had non-prime modulos. This begs the question. Did it really matter to be prime. I understand the concept of prime numbers and the many forms of hashing so let's not deviate into a hashing thread debate. I'm just interested to learn first-hand observations on native systems with non-prime file modulos. Thanks in advance. Mark Johnson --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/ --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/ --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/ --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/ --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/
RE: [U2] Prime number file modulos
Here, try this old code I just dusted off (really old, had a LOTTA dust) : Amazingly fast for a brute force algorithm... *FIND.PRIME written by aee 080888 PRINT 'Enter Number ':;INPUT TARGET ORIGINAL.TARGET = TARGET PRIME = 1 LOOP FOR I = 2 TO TARGET-1 ABC = INT(TARGET / I) XYZ = ABC * I IF XYZ = TARGET THEN PRIME = 0 I = TARGET END NEXT I WHILE NOT(PRIME) DO TARGET += 1 PRIME = 1 REPEAT IF TARGET = ORIGINAL.TARGET THEN PRINT TARGET:' is prime' END ELSE PRINT 'Next higher prime was : ':TARGET END STOP Enjoy! Allen www.tortillafc.com -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Mark Johnson Sent: Friday, September 02, 2005 14:41 To: u2-users@listserver.u2ug.org Subject: Re: [U2] Prime number file modulos I found the resize program and all it did was place the new mod in 013 of the DL/ID. Its only proof was that it was numeric and not 'even'. Pretty pathetic. Thanks Mark Johnson - Original Message - From: Allen E. Elwood [EMAIL PROTECTED] To: u2-users@listserver.u2ug.org Sent: Friday, September 02, 2005 4:20 PM Subject: RE: [U2] Prime number file modulos P.S. Could SLOW stand for System Loves Overflow Workspace? Since someone lacked the ability to calculate a prime number, maybe its Serious Lack Of Writhmatic which fails the English test as well ;) -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Mark Johnson Sent: Friday, September 02, 2005 05:53 To: u2-users@listserver.u2ug.org Subject: Re: [U2] Prime number file modulos I just got a copy of the stat report and found over 100 files who's mods are either obviously not prime, ie 1000 or someone's stupid assumption that 1001 is prime. Plus many of these files are 200%-500% under mod'd (is that a word?). Plus it's the second slowest client of mine (my microdatas are currently the slowest, but sized properly). I'm checking to see if there's an erroneous resize program or an erroneous resize programmer. Not truly understood back in the day (circa 1978), but prime numbers were stringently insisted when learning MV101. Thanks. Mark Johnson P.S. Could SLOW stand for System Loves Overflow Workspace? - Original Message - From: [EMAIL PROTECTED] To: u2-users@listserver.u2ug.org Sent: Tuesday, August 30, 2005 5:05 PM Subject: Re: [U2] Prime number file modulos The funniest or most gruesome file tuning that I've seen was a few years ago, at a site that I won't name, who had a master file with a modulo of exactly 100 and where 99% of the ids were numbers ending in 00. Definitely not tuned by FAST - - maybe they'd used SLOW? Answering Mark's question, did it really matter to be prime? . . . No, but if your group distribution is extremely lumpy or spiky, then, as Henry Eggers once said, your file is walking around with a sign taped to the back of its shirt, saying, Hit Me!. -- CONFIDENTIALITY: The information transmitted is intended only for the person or entity to which it is addressed and may contain material that is confidential, privileged and exempt from disclosure under applicable law. Any review, re-transmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited. If you received this in error, please contact the sender and delete the material in a secure receptacle or by shredding the document (s). -- -Mark Johnson wrote: - To: u2-users@listserver.u2ug.org From: Mark Johnson [EMAIL PROTECTED] Sent by: [EMAIL PROTECTED] Date: 08/30/2005 09:16AM Subject: [U2] Prime number file modulos A little non-U2 but I'm sure still answerable by many experienced MV persons. One client (AP-Pro, Native) reported to me a bunch of GFE's. Upon further investigation, all of the involved data files had non-prime modulos. This begs the question. Did it really matter to be prime. I understand the concept of prime numbers and the many forms of hashing so let's not deviate into a hashing thread debate. I'm just interested to learn first-hand observations on native systems with non-prime file modulos. Thanks in advance. Mark Johnson --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/ --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/ --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/ --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/ --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/ --- u2-users
Re: [U2] Prime number file modulos
If modulus is GT #items, you do have empty frames, yes, and increasing the mod past that point (unless anticipating growth) is pointless. I've seen a lot of this; folks resize a file with 20 items to have a modulus of 10007, and still have 20 items in 200% overflow. A general rule of thumb on BP files is to make them either a type 1 or type 19 (19 allows for longer names), for which mod sep aren't considerations. This makes each program a file in a BP directory. Tuning file sizes is vitally important. If you have an average item size of, say, 1700 bytes, and a sep of 1, then even if you pick a very good modulus, it will take 4 disk reads to retrieve the data. If you have a bad modulus on top of that, like 101 when you need 10007, it will take around 400 disk reads to retrieve each item. You and your users will notice this. Additionally, as mentioned earlier, this exposes you to a greater risk of file corruption. If you have 1000 links to overflow in a file, you are 1000 times as likely to get a bad link than someone who has 1 link. And that's before you start thinking about how you're affecting MTBF by artificially hammering your disks that way. Our greatest duty in this life is to help others. And please, if you can't help them, could you at least not hurt them? - H.H. the Dalai Lama When buying selling are controlled by legislation, the first thing to be bought sold are the legislators - P.J. O'Rourke Dan Fitzgerald From: Mark Johnson [EMAIL PROTECTED] Reply-To: u2-users@listserver.u2ug.org To: u2-users@listserver.u2ug.org Subject: Re: [U2] Prime number file modulos Date: Fri, 2 Sep 2005 17:50:07 -0400 One final Old-school question on MODs. (example mods aren't primed for simplicity) If you have a data file of 460 average byte size, and you have 10,000 records on a 2K system, that would want a prime number near 4600. If you have a BP file with 37 records averaging 15,000 bytes, this math would indicate near 277 frames. Given that BP's are more static than data files, plus their records tend to be bigger, should the separation be considered or is that pretty much a lost art. If this file were 277 frames to begin with, you could never have 37 items hash into all of them. I've heard arguments that the MOD should be the number of BP items in this case. Or even 37,7 with a non-one separation. That doesn't guarantee that they will hash evenly as well. You could still have unoccupied base frames. Is all of this guilding the lily and except for non-prime or extreme under-sizing, the differences aren't worth policing? Thanks in advance. Mark Johnson - Original Message - From: Dan Fitzgerald [EMAIL PROTECTED] To: u2-users@listserver.u2ug.org Sent: Friday, September 02, 2005 4:39 PM Subject: Re: [U2] Prime number file modulos Yeah... the problem with non-prime is that lumpy hashing thing. The wrong prime or file type will do this, too; it's why we call tuning iterative; sometimes it takes a few guesses to get lucky. File corruption doesn't occur just because you picked a bad modulus, type, or sep, but it does increase your risk. Bad flinks and bad blinks don't occur where there aren't any. The more data you can fit into primary space, the less vulnerable you are when something else goes wrong. The Henry Eggers quote captures it. Re-stated, don't tempt Mr. Murphy. Our greatest duty in this life is to help others. And please, if you can't help them, could you at least not hurt them? - H.H. the Dalai Lama When buying selling are controlled by legislation, the first thing to be bought sold are the legislators - P.J. O'Rourke Dan Fitzgerald From: Mark Johnson [EMAIL PROTECTED] Reply-To: u2-users@listserver.u2ug.org To: u2-users@listserver.u2ug.org Subject: Re: [U2] Prime number file modulos Date: Fri, 2 Sep 2005 08:53:01 -0400 I just got a copy of the stat report and found over 100 files who's mods are either obviously not prime, ie 1000 or someone's stupid assumption that 1001 is prime. Plus many of these files are 200%-500% under mod'd (is that a word?). Plus it's the second slowest client of mine (my microdatas are currently the slowest, but sized properly). I'm checking to see if there's an erroneous resize program or an erroneous resize programmer. Not truly understood back in the day (circa 1978), but prime numbers were stringently insisted when learning MV101. Thanks. Mark Johnson P.S. Could SLOW stand for System Loves Overflow Workspace? - Original Message - From: [EMAIL PROTECTED] To: u2-users@listserver.u2ug.org Sent: Tuesday, August 30, 2005 5:05 PM Subject: Re: [U2] Prime number file modulos The funniest or most gruesome file tuning that I've seen was a few years ago, at a site that I won't name, who had a master file with a modulo of exactly 100 and where 99% of the ids were numbers ending in 00. Definitely not tuned by FAST - - maybe they'd used SLOW
Re: [U2] Prime number file modulos
Oops. Went back read; this was not a u2 system. Pick did some pretty horrific things at various times around file sizing; used to be you had to do a restore from tape to resize, after editing that field 13. There was even a brief period where it would write a period into each byte in every unused frame (After starting the frame with something like Advanced Pick), which would take up most of the next day or longer to complete. In this case... still no value in making the modulus larger than the number of items. Plenty of value in converting to u2, though... ;) Our greatest duty in this life is to help others. And please, if you can't help them, could you at least not hurt them? - H.H. the Dalai Lama When buying selling are controlled by legislation, the first thing to be bought sold are the legislators - P.J. O'Rourke Dan Fitzgerald From: Mark Johnson [EMAIL PROTECTED] Reply-To: u2-users@listserver.u2ug.org To: u2-users@listserver.u2ug.org Subject: Re: [U2] Prime number file modulos Date: Fri, 2 Sep 2005 17:40:48 -0400 I found the resize program and all it did was place the new mod in 013 of the DL/ID. Its only proof was that it was numeric and not 'even'. Pretty pathetic. Thanks Mark Johnson - Original Message - From: Allen E. Elwood [EMAIL PROTECTED] To: u2-users@listserver.u2ug.org Sent: Friday, September 02, 2005 4:20 PM Subject: RE: [U2] Prime number file modulos P.S. Could SLOW stand for System Loves Overflow Workspace? Since someone lacked the ability to calculate a prime number, maybe its Serious Lack Of Writhmatic which fails the English test as well ;) -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Mark Johnson Sent: Friday, September 02, 2005 05:53 To: u2-users@listserver.u2ug.org Subject: Re: [U2] Prime number file modulos I just got a copy of the stat report and found over 100 files who's mods are either obviously not prime, ie 1000 or someone's stupid assumption that 1001 is prime. Plus many of these files are 200%-500% under mod'd (is that a word?). Plus it's the second slowest client of mine (my microdatas are currently the slowest, but sized properly). I'm checking to see if there's an erroneous resize program or an erroneous resize programmer. Not truly understood back in the day (circa 1978), but prime numbers were stringently insisted when learning MV101. Thanks. Mark Johnson P.S. Could SLOW stand for System Loves Overflow Workspace? - Original Message - From: [EMAIL PROTECTED] To: u2-users@listserver.u2ug.org Sent: Tuesday, August 30, 2005 5:05 PM Subject: Re: [U2] Prime number file modulos The funniest or most gruesome file tuning that I've seen was a few years ago, at a site that I won't name, who had a master file with a modulo of exactly 100 and where 99% of the ids were numbers ending in 00. Definitely not tuned by FAST - - maybe they'd used SLOW? Answering Mark's question, did it really matter to be prime? . . . No, but if your group distribution is extremely lumpy or spiky, then, as Henry Eggers once said, your file is walking around with a sign taped to the back of its shirt, saying, Hit Me!. -- CONFIDENTIALITY: The information transmitted is intended only for the person or entity to which it is addressed and may contain material that is confidential, privileged and exempt from disclosure under applicable law. Any review, re-transmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited. If you received this in error, please contact the sender and delete the material in a secure receptacle or by shredding the document (s). -- -Mark Johnson wrote: - To: u2-users@listserver.u2ug.org From: Mark Johnson [EMAIL PROTECTED] Sent by: [EMAIL PROTECTED] Date: 08/30/2005 09:16AM Subject: [U2] Prime number file modulos A little non-U2 but I'm sure still answerable by many experienced MV persons. One client (AP-Pro, Native) reported to me a bunch of GFE's. Upon further investigation, all of the involved data files had non-prime modulos. This begs the question. Did it really matter to be prime. I understand the concept of prime numbers and the many forms of hashing so let's not deviate into a hashing thread debate. I'm just interested to learn first-hand observations on native systems with non-prime file modulos. Thanks in advance. Mark Johnson --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/ --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/ --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/ --- u2-users mailing list u2-users
Re: [U2] Prime number file modulos
Here's one better if you don't want to EXECUTE PRIME 123 CAPTURING REC INPUT ANS MAX=INT(SQRT(ANS))+1 PRIME=TRUE FOR I=2 TO MAX UNTIL NOT PRIME IF MOD(ANS,I)=0 THEN PRIME=FALSE NEXT I Add your own frosting on this very simple prime calculation. The max number of divisors to test is the SQRT of the object plus 1 to accommodate the fraction. I learned this method in a 1974 Fortran class in college. My 1 cent Mark Johnson Happy Labor Day - Original Message - From: Allen E. Elwood [EMAIL PROTECTED] To: u2-users@listserver.u2ug.org Sent: Friday, September 02, 2005 6:03 PM Subject: RE: [U2] Prime number file modulos Here, try this old code I just dusted off (really old, had a LOTTA dust) : Amazingly fast for a brute force algorithm... *FIND.PRIME written by aee 080888 PRINT 'Enter Number ':;INPUT TARGET ORIGINAL.TARGET = TARGET PRIME = 1 LOOP FOR I = 2 TO TARGET-1 ABC = INT(TARGET / I) XYZ = ABC * I IF XYZ = TARGET THEN PRIME = 0 I = TARGET END NEXT I WHILE NOT(PRIME) DO TARGET += 1 PRIME = 1 REPEAT IF TARGET = ORIGINAL.TARGET THEN PRINT TARGET:' is prime' END ELSE PRINT 'Next higher prime was : ':TARGET END STOP Enjoy! Allen www.tortillafc.com -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Mark Johnson Sent: Friday, September 02, 2005 14:41 To: u2-users@listserver.u2ug.org Subject: Re: [U2] Prime number file modulos I found the resize program and all it did was place the new mod in 013 of the DL/ID. Its only proof was that it was numeric and not 'even'. Pretty pathetic. Thanks Mark Johnson - Original Message - From: Allen E. Elwood [EMAIL PROTECTED] To: u2-users@listserver.u2ug.org Sent: Friday, September 02, 2005 4:20 PM Subject: RE: [U2] Prime number file modulos P.S. Could SLOW stand for System Loves Overflow Workspace? Since someone lacked the ability to calculate a prime number, maybe its Serious Lack Of Writhmatic which fails the English test as well ;) -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Mark Johnson Sent: Friday, September 02, 2005 05:53 To: u2-users@listserver.u2ug.org Subject: Re: [U2] Prime number file modulos I just got a copy of the stat report and found over 100 files who's mods are either obviously not prime, ie 1000 or someone's stupid assumption that 1001 is prime. Plus many of these files are 200%-500% under mod'd (is that a word?). Plus it's the second slowest client of mine (my microdatas are currently the slowest, but sized properly). I'm checking to see if there's an erroneous resize program or an erroneous resize programmer. Not truly understood back in the day (circa 1978), but prime numbers were stringently insisted when learning MV101. Thanks. Mark Johnson P.S. Could SLOW stand for System Loves Overflow Workspace? - Original Message - From: [EMAIL PROTECTED] To: u2-users@listserver.u2ug.org Sent: Tuesday, August 30, 2005 5:05 PM Subject: Re: [U2] Prime number file modulos The funniest or most gruesome file tuning that I've seen was a few years ago, at a site that I won't name, who had a master file with a modulo of exactly 100 and where 99% of the ids were numbers ending in 00. Definitely not tuned by FAST - - maybe they'd used SLOW? Answering Mark's question, did it really matter to be prime? . . . No, but if your group distribution is extremely lumpy or spiky, then, as Henry Eggers once said, your file is walking around with a sign taped to the back of its shirt, saying, Hit Me!. -- CONFIDENTIALITY: The information transmitted is intended only for the person or entity to which it is addressed and may contain material that is confidential, privileged and exempt from disclosure under applicable law. Any review, re-transmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited. If you received this in error, please contact the sender and delete the material in a secure receptacle or by shredding the document (s). -- -Mark Johnson wrote: - To: u2-users@listserver.u2ug.org From: Mark Johnson [EMAIL PROTECTED] Sent by: [EMAIL PROTECTED] Date: 08/30/2005 09:16AM Subject: [U2] Prime number file modulos A little non-U2 but I'm sure still answerable by many experienced MV persons. One client (AP-Pro, Native) reported to me a bunch of GFE's. Upon further investigation, all of the involved data files had non-prime modulos. This begs the question. Did it really matter to be prime. I understand the concept of prime numbers and the many forms of hashing so let's not deviate into a hashing thread
Re: [U2] Prime number file modulos
I never heard of populating blank frames with periods. I believe that it's the DUMP command displaying non-printable (control or char(0)) characters as periods. Since disc space is always full of something even if empty, then the periods could be just a visible thing. I've done beaucoups of restores in my day as well as fresh formatting for the first install and never waited past the load-in for these periods. My 1 cent. Mark Johnson - Original Message - From: Dan Fitzgerald [EMAIL PROTECTED] To: u2-users@listserver.u2ug.org Sent: Friday, September 02, 2005 9:01 PM Subject: Re: [U2] Prime number file modulos Oops. Went back read; this was not a u2 system. Pick did some pretty horrific things at various times around file sizing; used to be you had to do a restore from tape to resize, after editing that field 13. There was even a brief period where it would write a period into each byte in every unused frame (After starting the frame with something like Advanced Pick), which would take up most of the next day or longer to complete. In this case... still no value in making the modulus larger than the number of items. Plenty of value in converting to u2, though... ;) Our greatest duty in this life is to help others. And please, if you can't help them, could you at least not hurt them? - H.H. the Dalai Lama When buying selling are controlled by legislation, the first thing to be bought sold are the legislators - P.J. O'Rourke Dan Fitzgerald From: Mark Johnson [EMAIL PROTECTED] Reply-To: u2-users@listserver.u2ug.org To: u2-users@listserver.u2ug.org Subject: Re: [U2] Prime number file modulos Date: Fri, 2 Sep 2005 17:40:48 -0400 I found the resize program and all it did was place the new mod in 013 of the DL/ID. Its only proof was that it was numeric and not 'even'. Pretty pathetic. Thanks Mark Johnson - Original Message - From: Allen E. Elwood [EMAIL PROTECTED] To: u2-users@listserver.u2ug.org Sent: Friday, September 02, 2005 4:20 PM Subject: RE: [U2] Prime number file modulos P.S. Could SLOW stand for System Loves Overflow Workspace? Since someone lacked the ability to calculate a prime number, maybe its Serious Lack Of Writhmatic which fails the English test as well ;) -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Mark Johnson Sent: Friday, September 02, 2005 05:53 To: u2-users@listserver.u2ug.org Subject: Re: [U2] Prime number file modulos I just got a copy of the stat report and found over 100 files who's mods are either obviously not prime, ie 1000 or someone's stupid assumption that 1001 is prime. Plus many of these files are 200%-500% under mod'd (is that a word?). Plus it's the second slowest client of mine (my microdatas are currently the slowest, but sized properly). I'm checking to see if there's an erroneous resize program or an erroneous resize programmer. Not truly understood back in the day (circa 1978), but prime numbers were stringently insisted when learning MV101. Thanks. Mark Johnson P.S. Could SLOW stand for System Loves Overflow Workspace? - Original Message - From: [EMAIL PROTECTED] To: u2-users@listserver.u2ug.org Sent: Tuesday, August 30, 2005 5:05 PM Subject: Re: [U2] Prime number file modulos The funniest or most gruesome file tuning that I've seen was a few years ago, at a site that I won't name, who had a master file with a modulo of exactly 100 and where 99% of the ids were numbers ending in 00. Definitely not tuned by FAST - - maybe they'd used SLOW? Answering Mark's question, did it really matter to be prime? . . . No, but if your group distribution is extremely lumpy or spiky, then, as Henry Eggers once said, your file is walking around with a sign taped to the back of its shirt, saying, Hit Me!. -- CONFIDENTIALITY: The information transmitted is intended only for the person or entity to which it is addressed and may contain material that is confidential, privileged and exempt from disclosure under applicable law. Any review, re-transmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited. If you received this in error, please contact the sender and delete the material in a secure receptacle or by shredding the document (s). -- -Mark Johnson wrote: - To: u2-users@listserver.u2ug.org From: Mark Johnson [EMAIL PROTECTED] Sent by: [EMAIL PROTECTED] Date: 08/30/2005 09:16AM Subject: [U2] Prime number file modulos A little non-U2 but I'm sure still answerable by many experienced MV persons. One client (AP-Pro, Native) reported to me a bunch of GFE's. Upon further
[U2] Prime number file modulos
A little non-U2 but I'm sure still answerable by many experienced MV persons. One client (AP-Pro, Native) reported to me a bunch of GFE's. Upon further investigation, all of the involved data files had non-prime modulos. This begs the question. Did it really matter to be prime. I understand the concept of prime numbers and the many forms of hashing so let's not deviate into a hashing thread debate. I'm just interested to learn first-hand observations on native systems with non-prime file modulos. Thanks in advance. Mark Johnson --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/
Re: [U2] Prime number file modulos
This begs the question. Did it really matter to be prime. I understand the concept of prime numbers and the many forms of hashing so let's not deviate into a hashing thread debate. I'm just interested to learn first-hand observations on native systems with non-prime file modulos. Non-prime number modulo values are likely to lead to clustering of records and hence more overflow. Although GFEs should never happen, the probability of damage to links in chains of overflow blocks at system failures, etc is roughly proportional to the length of the chain. No overflow, no GFEs (in theory!). Martin Phillips Ladybridge Systems 17b Coldstream Lane, Hardingstone, Northampton NN4 6DB +44-(0)1604-709200 --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/
Re: [U2] Prime number file modulos
The funniest or most gruesome file tuning that I've seen was a few years ago, at a site that I won't name, who had a master file with a modulo of exactly 100 and where 99% of the ids were numbers ending in 00. Definitely not tuned by FAST - - maybe they'd used SLOW? Answering Mark's question, did it really matter to be prime? . . . No, but if your group distribution is extremely lumpy or spiky, then, as Henry Eggers once said, your file is walking around with a sign taped to the back of its shirt, saying, Hit Me!. -- CONFIDENTIALITY: The information transmitted is intended only for the person or entity to which it is addressed and may contain material that is confidential, privileged and exempt from disclosure under applicable law. Any review, re-transmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited. If you received this in error, please contact the sender and delete the material in a secure receptacle or by shredding the document (s). -- -Mark Johnson wrote: - To: u2-users@listserver.u2ug.org From: Mark Johnson [EMAIL PROTECTED] Sent by: [EMAIL PROTECTED] Date: 08/30/2005 09:16AM Subject: [U2] Prime number file modulos A little non-U2 but I'm sure still answerable by many experienced MV persons. One client (AP-Pro, Native) reported to me a bunch of GFE's. Upon further investigation, all of the involved data files had non-prime modulos. This begs the question. Did it really matter to be prime. I understand the concept of prime numbers and the many forms of hashing so let's not deviate into a hashing thread debate. I'm just interested to learn first-hand observations on native systems with non-prime file modulos. Thanks in advance. Mark Johnson --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/ --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/
Re: [U2] Prime number file modulos
I've definitely seen some non-prime modulos make a mess of things on platforms that allow them. UniData forces everything to a prime number, but UniVerse and some PICKs don't. If I remember rightly, Sequoia forced it to a number ending in 1, 3, 7, or 9. I remember an argument years ago - supported by Dick Pick, I believe - that said any number that is not divisible by 2 or 5 would be OK with a mod-10 hashing algorithm. I've never played with the math of it, but it sounds valid on the surface. I've seen lots of files with a modulus of 301 - apparently people think it looks kinda prime-ish - that worked as well as the actual prime of 307. But change it to 300 and it's a different story. Tim Snyder Consulting I/T Specialist , U2 Professional Services North American Lab Services DB2 Information Management, IBM Software Group --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/
