John W. Colby
jwcolby at colbyconsulting.com
Wed May 18 14:29:13 CDT 2005
That's true, however... If I am working in assembler and I want to add 21 +1 it takes a single instruction. ONE MACHINE LEVEL INSTRUCTION. In a compiled language like 'C', if you were to look at the resulting machine code it would be large. Yes, a compiler does produce machine code but it does NOT produce anything close to the equivalent of assembler. In INTERPRETED VB it will require calls to functions to even discover what the PCODE is, that process runs once for every time the code runs. That Pcode interpreted calls predefined functions that will EVENTUALLY perform the same machine level instruction. So yes, EVENTUALLY VB will execute the same machine instruction, but the surrounding processes are MANY orders of magnitude slower / more complex. Access (VBA) BTW does NOT compile anything, so the PCODE is always interpreted on demand and that interpreter calls functions that perform the math, whatever that may be. If your statement were true, assembler would have completely disappeared long ago. It still exists and is still used for very time critical stuff. Believe me, Access, Word, Windows etc (at least the core of) is NOT written in VB for very good reasons. It is also probably not written in assembler, although pieces of it might be, where the speedup would warrant the development expense. John W. Colby www.ColbyConsulting.com Contribute your unused CPU cycles to a good cause: http://folding.stanford.edu/ -----Original Message----- From: accessd-bounces at databaseadvisors.com [mailto:accessd-bounces at databaseadvisors.com] On Behalf Of DWUTKA at marlow.com Sent: Wednesday, May 18, 2005 3:07 PM To: accessd at databaseadvisors.com Subject: RE: Integers was:RE: [AccessD] Global Variable VB compiles math functions to the same machine language that assembler will.....if you know differently, I'd love to see that.... Drew -----Original Message----- From: John W. Colby [mailto:jwcolby at colbyconsulting.com] Sent: Wednesday, May 18, 2005 1:55 PM To: 'Access Developers discussion and problem solving' Subject: RE: Integers was:RE: [AccessD] Global Variable ROTFL. Why? Look at his statement to see the scale of lack of understanding. >unless I'm mistaken, math in VB is going to be just as fast as >something in assembler Uh... No, by several orders of magnitude. John W. Colby www.ColbyConsulting.com Contribute your unused CPU cycles to a good cause: http://folding.stanford.edu/ -----Original Message----- From: accessd-bounces at databaseadvisors.com [mailto:accessd-bounces at databaseadvisors.com] On Behalf Of Hale, Jim Sent: Wednesday, May 18, 2005 2:22 PM To: 'Access Developers discussion and problem solving' Subject: RE: Integers was:RE: [AccessD] Global Variable I'm only trying to figure out your metric for "good" vs "bad" programming. Jim Hale -----Original Message----- From: DWUTKA at marlow.com [mailto:DWUTKA at marlow.com] Sent: Wednesday, May 18, 2005 12:25 PM To: accessd at databaseadvisors.com Subject: Integers was:RE: [AccessD] Global Variable Now does that make sense? Where is the value in using a slower variable (Integer) to represent, let's say a month. Sure, the value is going to be 1 through 12, unless the calendar itself changes. If you use a Long Integer, for the same value, can it not store 1 through 12 also? Running faster? It's not a different language, so you can't compare going to assembler, from VB, besides, unless I'm mistaken, math in VB is going to be just as fast as something in assembler.... Drew -----Original Message----- From: Hale, Jim [mailto:Jim.Hale at fleetpride.com] Sent: Wednesday, May 18, 2005 12:08 PM To: 'Access Developers discussion and problem solving' Subject: RE: [AccessD] Global Variable Okay Drew, you've completely confused me (which often is not all that hard to do). I thought it was always a "good" practice to type variables according to use. I use integers for things like months, loop counters (the infamous dim x),etc. and longs only when I know the number has a chance to exceed the integer limit. I hope you are not arguing integers are "bad" because they are less efficient, take up more cycles, etc. Using that standard we should all be programming using assembler. Jim Hale -----Original Message----- From: DWUTKA at marlow.com [mailto:DWUTKA at marlow.com] Sent: Wednesday, May 18, 2005 11:39 AM To: accessd at databaseadvisors.com Subject: RE: [AccessD] Global Variable LOL. Well, I did say that exceeding an Integer is possible, but that was a philosophical point. It could exceed 32k, in your example, if you decided to include an extended family tree. Either way, using an Integer is much slower then a Long Integer. Drew -----Original Message----- From: Scott Marcus [mailto:marcus at tsstech.com] Sent: Wednesday, May 18, 2005 7:41 AM To: Access Developers discussion and problem solving Subject: RE: [AccessD] Global Variable << Declaring a variables an Integer IS bad practice. It is bad practice because even if you think a variable will never go over 32k, or below -32k, it can, and probably will. Question: So when will the following declaration exceed the 32k, -32k limit? Dim intFamilyMembers as integer 'Number of immediate family members Answer: When you declare the variable as a Public (global) variable, then some other function written by some other developer changes its intended use causing the original function to possibly work incorrectly. Scott Marcus -----Original Message----- From: accessd-bounces at databaseadvisors.com [mailto:accessd-bounces at databaseadvisors.com] On Behalf Of DWUTKA at marlow.com Sent: Tuesday, May 17, 2005 7:05 PM To: accessd at databaseadvisors.com Subject: RE: [AccessD] Global Variable I guess I'm not seeing the same definition from John, though it was closer in the last few posts. Yes, 'bad practice' sends me into a tail spin, when there is no reason for calling something bad practice. Declaring a variable as an Integer IS bad practice. It is bad practice because even if you think a variable will never go over 32k, or below -32k, it can, and probably will. But more importantly, an Integer is a 16 bit variable, and it takes longer to process an Integer then it does a Long Integer, on a 32 bit system. The first reason is a philosophy. The second reason is a FACT! I have yet to hear a fact, as to why Globals are 'bad practice'. What gets my goat, though, is that this is a forum where developers of all skill level meet. If opinions are given as facts, developers who are learning something new could be hampered by prejudice. Ever run into an IT shop that refuses to allow applications to be developed in Access, because 'it's not a database', or 'it's not secure', or something else, that is just ignorance repeated through 'tribal knowledge'? (There is also usually power involved...and IT shop has more power and control involved when something is on a server side db.) That's why I rail on this stuff, because invalid tribal knowledge can be dangerous! Drew *********************************************************************** The information transmitted is intended solely for the individual or entity to which it is addressed and may contain confidential and/or privileged material. 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