I have two more things to say firstly i wonna talk about some misunderstanding point in the links that you gave.What does "make conservative guess" mean ? In the sentence i read from mail said that. <pre>"The "conservative" part means "guess a bit about which stack, heap, and register words represent live pointers" i dont know anything how to be used heap or register by garbage collector.But fortunately i know something about stack. Stack is a structure that works with LIFO sense.Let say we wrote a factorial function that takes 50 as input.In that stack factorial makes a job until finding fact of 50.But after some point machine cant make any calculation because stack will be full.But if we write that function CPS version,tail recursive version machine works until finding fact of 50.I mean stack is filled until it is full.When it is full,garbage collector starts clearing up that stack.I dunno my knowledge is true with 100 percentage.If i make a mistake please let me know.But that mail talks about "whick stack or heap or register represent live pointers.So i have two question ? How many stack or heap or register are there in memory ? If There are more than one.Why machine cannot calculate some value or having trouble in calculating s some value ? And If more than one stack there are,How can it be decided,which one is used ? Are there some rules ? Thats why it is concervative because of rules ?Sorry for my bad english.I hope i can tell my point.I am just newbie in programming.I try to learn the environment. "The advantage of conservative garbage collection (CGC) is that it's relatively easy to interoperate with C. For that reason, CGC was a reasonable choice for the way that we originally constructed DrScheme, and it remains extremely useful to those of you who develop C-based extensions to import C libraries." I know that Drscheme was written in C language.And mail said it is using CGC and said easy to interprete with C. My question is Drscheme is written in C and mail said CGC is easy to interprete in C.So both drscheme and CGC is suitable foe each other. Because both of them is written in C. "[Boehm, POPL'02]" Can someone explain this problem more clearly or can someone suggest anything because i wonder that problem. And mail said the problem is for for GUI program why is that ? I dont understand shot-living-object and long-living object.I try to understand that mail but i am newbie so there are lots of foreign thing for me. But can queue be used for Garbage collector.I mean instead of Lifo using fifo ca be reasonable choice. Anyway sorry for being busing mailling list. </pre><pre> </pre> <div class="gmail_quote">On Sun, Apr 5, 2009 at 2:38 AM, Marek Kubica <<a href="mailto:marek@xivilization.net">marek@xivilization.net</a>> wrote: <blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">Hi, Sorry, while digging in the sources I found another GC backend which is the SenoraGC (SGC) but it is not really recommended to use and not mentioned very much. On Sun, 5 Apr 2009 02:10:06 +0300 <div class="im">emre berat nebiođlu <<a href="mailto:beratn@gmail.com">beratn@gmail.com</a>> wrote: </div><div class="im">> What are the difference between CGC and 3m.Both has some advantage or > disadvantage ? Or It is just about running time or compilation time. </div>Yes, they have both some advantages and other disadvantages, for more details you could take a look at this mail <<a href="http://www.cs.brown.edu/pipermail/plt-scheme/2006-June/013840.html" target="_blank">http://www.cs.brown.edu/pipermail/plt-scheme/2006-June/013840.html</a>> which explains how 3m works. <div class="im"> > I dont know the whole issue on running time and compilation time. > Running time is same with compilation time.? </div>No, to run MzScheme, you first have to compile it. At that point, you can decide whether your to-be-compiled MzScheme should use CGC, SGC or 3m as garbage collector [1]. You then compile MzScheme with your desired GC and then can run programs on MzScheme. The garbage collector is fixed by this time, so you cannot just switch in the middle of the program which Garbage Collector to use. <div class="im"> > For example running time of merge sort is nlogn .This nlogn include > only time until array is sorted(I assume array is unsorted in first > time) or include this plus "clearing shared memory". </div>The Big-O notation describes the time-complexity of an algorithm, not actually how long it will take exactly. As such, your algorithm will be O(n log n) on 3m and on CGC. The actual time that your program runs will change too, for course but usually not in a way that you'd get another time-complexity. What also changes is the amount of memory that MzScheme will use while it runs your program/algorithm. <div class="im"> > But i just wonder about CGC and 3m. What do we exactly focus on > "garbage collector". </div>On the efficient management of memory. regards, Marek [1] technically, even when selecting 3m, a CGC-version of MzScheme will be built, too </blockquote></div>