How Does Garbage Collection in Perl Work?
Perl is reference counting, and it's famous not to free garbage at all. It's recycling unused variables, variables which went out of scope, but it's never giving back memory to the OS. Even the final global destruction phase does by default shortcuts for performance. It only walks through all objects and IO objects to call its DESTROY methods and close IO handles, but it doesn't actually free memory, esp. not the code OPs. Variables (SVs) are kept in arena pools, which are also not recycled, only individual SV members in the pool are recycled, but an empty pool never. So youll never see a perl application go down in memory usage, only up.I once started working on a GC branch to actually free arena pools and unload unused shared libs, but it was too complicated at the first attempt. • Other QuestionsDo you use a collection agency for your overdue invoices? Why or why not?3rd party collections agency should be last resort, no a way of doing business.First, it is expensive (10%50% fee).Second, you will lose the client.Third, it is time consuming.Best practice is to have a collections policy and follow up with the client (e-mail,text,call) . Statistically, in US, you will be able to collect over 90% of invoices this way.If this doesn't work you can stop the service (make sure your contract allows that) to the client and notify them you are passing matter to a collections agency.Many times that will pay.An operationally good business should forward less than 2% to collections agency.For increased results you can automate the whole receivables process with invoice and debtor tracking software. A good solution will automate all of it, from checking in with client regarding upcoming invoice, to reminding about past due balance to forwarding it to a collections agency.------What is the best way to sell a MtG collection?There are no good ways, so choosing a 'best' one is simply choosing one that is least bad.A collection is a large, valuable asset with very low liquidity that is difficult to ship around the world.Your best bet is to get some expert advice (if the collection is not your own) and split it into several smaller sections that will have a better shot of selling individually.You can also try attending large events with your collection (or most valuable parts of it) in order to contact potential buyers physically. Not having to deal with shipping is also a huge advantage when it somes to selling anything MTG related.After you get rid of anything of value from your collection, you can sell the rest at bulk value to some MTG shop, use the cards to plaster your watercloset walls and/or give the cards to local kids. I would recommend the latter.------What albums are a must in any music collection?Rubber Soul, Revolver, Cheap Thrills, Blood On The Tracks, Bringing It All Back Home, Highway 61 Revisited, The Times They Are A-Changin, The Clash, London Calling, Sandinista, Freash Cream, Disraeli Gears, The Rise and Fall of Ziggy Stardust, Catch the Wind, Sunshine Superman, Wa-Do-Dem, My AIM Is True, This Years Model, Hot Rats, Howlin Wind, GP, Grievous Angel, Living In The Flood, Live At The Apollo, Surrealistic Pillow, Are You Experienced?, Axis: Bold As Love, The Harder They Come, Diamonds and Rust, LED Zeppelin (14), Bass Culture, Broken English, Mezzanine, World War III, In Search Of The Lost Chord, Nazz, Yellow Moon, Otis Redding - Live in Europe, Horses, Easter, Equal Rights, Ummagumma, Controversy, 1999, Under Heavy Manners, Come On In, Mixed Bag, Aftermath, Decembers Children, Sticky Fingers, Out Of Our Heads, Never Mind The Bollocks, Electric Warrior, Astral Weeks, Moondance, Pay It All Back, Vol. 3, Velvet Underground, White Heat White Light, Excitable Boy, Whos Next, Quadrophenia, Psychedelic World of the 13th Floor Elevators, Paris au Printemps------In what ways are we as Muslims collectively doing wrong?We waste too much time on cooking and relishing gourmet food and consequently that time better spent in discussing religion or course books is taken away from parents and children. As a community we dont believe in buying assets, but that doesnt mean we should spent it all on clothes and food. We need to invest in books, in touring and travelling to different places, in the education of our children.As a community we need to stop spending lavishly in weddings again more on education and less on such non productive stuff.Then we need to learn to live as a community and help our poor brethren. Each capable household should sponsor the education of at least one poor child-if that is not possible then educate poor children for free.Dissemination of Arabic is al so important. The upper classes discouraged Arabic and encouraged Persian/Urdu and that disempowered the masses. With better understanding of the Quran the poor would become aware of their rights.------What is it that engineering students in India are collectively doing wrong?Not following our passion : I have many friends in IIT, NIT, BITS , other state institutions, private colleges etc. I rarely come across someone who has chosen his branch according to his interests. Mostly the choice is biased towards better colleges & so-called popular streams. Believe me , going to a slightly lower ranked college with a branch you are passionate about is far better than going to a better college with a stream you never cared about.( this holds mostly for tier-3 colleges) : Just studying for the sake of degree & jobs. I've seen people who have no clue about what they are doing.Placement oriented attitudeVery limited interest in R&DVery few people actually understand what programming is & it's importance.Too much interest in almost everything except engineering . I agree that , one should have an enjoyable , healthy life for survival , but too much interest in not so necessary things has never been beneficial for anybody .------How much of Greece's problem could be solved by proper tax collection?Nikos Lekkas, the director of Tax Control in Greece, says yearly tax avoidance amounts to 40 to 45 billion Euro! Enough to pull back the budget to equilibrium and then some...Now of course you want to tackle a big chunk of sociological habits: corruption, complicity and self-preservation of elites, old cultural habits... this takes time, demographic time...Now OTOH I've heard a lot of anecdotes from Greek and German Friends, that run this way: Greek student goes abroad to find work (Germany, France, Belgium in our cases); does find work; and experiences... an administration that works, civil servants that explain, money that's being paid on time, power when you turn lights on...People who respect rules... And they say "OMG! When I think back of Greece" But they also say "When I'm back home, I want to make this happen, I can't take the 'old habits' anymore..." So...de "Frau Lagarde hat ganz recht!"fr Grce : le contrleur fiscal dnonce la corruption------Does the IRS have collection agencies contact debtors?Dan O'Connell pretty well explained it. However I think he left out one thing. If you do not want the collection agencies collecting on your taxes then all you have to do to have your case moved back to the IRS is send the collections agency a letter telling them that you want the IRS to handle your case. After they receive your letter they must return it back to IRS inventory. It will take about 4 - 6 weeks.Why would you want that? Because they have very limited collections ability and they can only agree on full pay installment agreements. Often contacting a Tax Resolution Specialist like me will get you a resolution other than full pay.It would be in your interest to have a Tax Resolution Specialist review your case before agreeing to anything. If you already made an agreement you can have the agreement changed if you qualify.Don't tell the collection agency anything about your finances, or the IRS, without help------What is a collective behavior?The term Collective behavior refers to behaviors which do not reflect social norms (laws, social mores, conventional social values, and etc.), and may occur spontaneously, and can be very destructive, and/or dangerous as well. The best examples I can think of, are actions historically taken by the Ku Klux Klan against African Americans. The bank robbery committed by Patty Hearst, and the Symbonese Liberation Army, in the early 70′s, is another example that comes to mind. I researched the answer online to find the answer, and there is quite a lot of information there. The site "Wikapedia" was where I found the answer, if you want to know more about Collective behavior. I certainly am glad you asked the C.b. question, because honestly I had never heard the term. Thankyou Yousaf, for providing me an opportunity to learn something new today. The term was first used in 1908.What is collective behaviour?------How does garbage collection work in Android 4.2 Jelly Bean Dalvik? - please see the commentIn Android Dalvik, every process runs in its own virtual machine and every application has its own process and heap. Also, every application has own Garbage collector, even if it is sharing memory with other applications.Dalvik Garbage Collector uses Mark and Sweep approach. Here is how it works -1. Maintain a free list that contains all the heap memory blocks that are free.2. If a process requests a free block and the free list is empty, then invoke the Garbage Collector which works as follows - a. Mark the bits for objects that are in use and hence should not be garbage collected. These mark bits are stored separate from other heap memory. b.Sweep and collect all unmarked heap blocks and put them back to the free list. You can refer to the following link for more details on Mark and Sweep - Mark-and-Sweep Garbage Collection------What's the best way to sell a stamp collection?Start by doing some basic research and find out if you have a collection with interesting items in it or one that is referred to as a school boy collection (means common stamps, no value). You can opt to find a reputable stamp auction and ask them for a value. If you like what you hear, let them put it to auction. Auctions are hit and miss. You might get quoted value, you might get under the valuation. Other option: find someone interested in purchasing your collection. Again, this is where you need a reputable dealer. He/she will evaluate the collection and offer a price. Note: you will not get catalogue value for your collection. The dealer is in it to make money. Last option is to spend time researching what you have and break the collection down and sell it on eBay or another auction site. This takes far more work on your part, but you keep a larger part of the profit------Why is garbage collection an important programming language feature?Probably the greatest benefit of Java's garbage collection, in retrospect, is that it enabled the creation of high quality libraries.Before garbage collection, there had to be strong (yet runtime-unenforced) contracts between a library and its consumer regarding memory management. Whichever one allocated memory and other resources also had to free that memory and those resources. In C, this led to convoluted handle-based libraries, tricky error handling, and many different ways to shoot one's self in one's foot.With garbage collection, the "contract" is enforced by the runtime, because memory and resources are automatically freed when they are no longer used. Suddenly it was possible to pass things into and out of a library without worrying about memory leaks, and most (but not all!) resource lifecycle issues were dramatically simplified.I discuss this in more depth in this QCon presentation: Keynote: How the 10 Key Lessons from Java and CHistory Inform the Cloud
