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  • The Sound of Two Toilets Flushing: Constructive Criticism for Virgin Atlantic Complaints Department

    - by Geertjan
    I recently had the experience of flying from London to Johannesburg and back with Virgin Atlantic. The good news was that it was the cheapest flight available and that the take off and landing were absolutely perfect. Hence I really have no reason to complain. Instead, I'd like to offer some constructive criticism which hopefully Richard Branson will find sometime while googling his name. Or maybe someone from the Virgin Atlantic Complaints Department will find it, whatever, just want to put this information out there. Arrangement of restroom facilities. Maybe next time you design an airplane, consider not putting your toilets at a right angle right next to your rows of seats. Being able to reach, without even needing to stretch your arm, from your seat to close, yet again, a toilet door that someone, someone obviously sitting very far from the toilets, carelessly forgot to close is not an indicator of quality interior design. Have you noticed how all other airplanes have their toilets in a cubicle separated from the rows of seats? On those airplanes, people sitting in the seats near the toilets are not constantly being woken up throughout the night whenever someone enters/exits the toilet, whenever the light in the toilet is suddenly switched on, and whenever one of the toilets flushes. Bonus points for Virgin Atlantic passengers in the seats adjoining the toilets is when multiple toilets are flushed simultaneously and multiple passengers enter/exit them at the same time, a bit like an unasked for low budget musical of suddenly illuminated grumpy people in crumpled clothes. What joy that brings at 3 AM is hard to describe. Seats with extra leg room. You know how other airplanes have the seats with the extra leg room? You know what those seats tend to have? Extra leg room. It's really interesting how Virgin Atlantic's seats with extra leg room actually have no extra leg room at all. It should have been a give away, the fact that these special seats are found in the same rows as the standard seats, rather than on the cusp of real glory which is where most airlines put their extra leg room seats, with the only actual difference being that they have a slightly different color. Had you called them "seats with a different color" (i.e., almost not quite green, rather than something vaguely hinting at blue), at least I'd have known what I was getting. Picture the joy at 3 AM, rudely awakened from nightmarish slumber, partly grateful to have been released from a grayish dream of faceless zombies resembling one or two of those in a recent toilet line, by multiple adjoining toilets flushing simultaneously, while you're sitting in a seat with extra leg room that has exactly as much leg room as the seats in neighboring rows. You then have a choice of things to be sincerely annoyed about. Food from the '80's. In the '80's, airplane food came in soggy containers and even breakfast, the most important meal of the day, was a sad heap of vaguely gray colors. The culinary highlight tended to be a squashed tomato, which must have been mashed to a pulp with a brick prior to being regurgitated by a small furry animal, and there was also always a piece of immensely horrid pumpkin, as well as a slice of spongy something you'd never seen before. Sausages and mash at 6 AM on an airplane was always a heavy lump of horribleness. Thankfully, all airlines throughout the world changed from this puke inducing strategy around 1987 sometime. Not Virgin Atlantic, of course. The fatty sausages and mash are still there, bringing you flashbacks to Duran Duran, which is what you were listening to (on your walkman) the last time you saw it in an airplane. Even the golden oldie "squashed tomato attached by slime to three wet peas" is on the menu. How wonderful to have all this in a cramped seat with a long row of early morning bleariness lined up for the toilets, right at your side, bumping into your elbow, groggily, one by one, one after another, more and more, fumble-open-door-silence-flush-fumble-open-door, and on and on, while you tentatively push your fork through a soggy pile of colorless mush, fighting the urge to throw up on the stinky socks of whatever nightmarish zombie is bumping into your elbow at the time. But, then again, the plane landed without a hitch, in fact, extremely smoothly, so I'm certainly not blaming the pilots.

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  • SEO Package Deals Make a Change From Flushing the Toilet on Your Business

    SEO package deals could save your business from being flushed away - almost literally. Rather than using SEO package deals, does your online marketing go a little like this: save up enough money to pay for an article service to create a whole batch of custom SEO articles, submitting them all across the web, then do nothing for weeks while you save up for the next assault? If so, then your article marketing strategy is what I tend to refer to as lavatorial.

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  • Page cache flushing behavior under heavy append load

    - by Bryce
    I'm trying to understand the behavior of the Linux pdflush daemon when: The page cache is initially pretty much empty There is a large amount of free memory The system starts undergoing heavy write load My understanding right now is that the vm.dirty_ratio and vm.dirty_background_ratio that control page cache flushing behavior are with respect to the present size of the page cache, which means that my writes will flush earlier than they would if the page cache was pre-populated (even with dummy data from some random file), and thus throughput will be lower. Is this accurate?

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  • CentOS I/O blocking flushing dirtypages

    - by user3662224
    I have an Apache webserver on CentOS. It is not doing anything fantastic or complicated at all but it does at intervals experience a high load (120 for 4 CPUs) for some reason. During this time I see high waits and write durations. I have narrowed this down to flushing of dirtypages to disk to make room for new data. I have tried many things and talked to the developers who are also puzzled by this. I am stumped. Details: vmware virtual guest server 4 cpus 12G RAM Apache PHP I have 40 servers in this cluster that share the same disk structure. Only the webservers are experiencing this issue. Any ideas?

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  • Flushing disk cache for performance benchmarks?

    - by Ido Hadanny
    I'm doing some performance benchmark on some heavy SQL script running on postgres 8.4 on a ubuntu box (natty). I'm experiencing some pretty un-stable performance, even though I'm supposed to be the only one running on the machine (the same script on the exact same data might run in 20m and then 40m for no specific reason). So, remembering my distant DBA training, I decided I should flush the postgres cache, using sudo /etc/init.d/postgresql restart, but it's still shaky! My question: maybe I'm missing some caches in my disk/os? I'm using a netapp appliance as my storage. Am I on the right track? Do I even want to make sure I get repeatable performance before I start tuning?

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  • Named pipe is not flushing in Python

    - by BrainCore
    I have a named pipe created via the os.mkfifo() command. I have two different Python processes accessing this named pipe, process A is reading, and process B is writing. Process A uses the select function to determine when there is data available in the fifo/pipe. Despite the fact that process B flushes after each write call, process A's select function does not always return (it keeps blocking as if there is no new data). After looking into this issue extensively, I finally just programmed process B to add 5KB of garbage writes before and after my real call, and likewise process A is programmed to ignore those 5KB. Now everything works fine, and select is always returning appropriately. I came to this hack-ish solution by noticing that process A's select would return if process B were to be killed (after it was writing and flushing, it would sleep on a read pipe). Is there a problem with flush in Python for named pipes?

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  • save the transient instance before flushing

    - by eugenn
    Exception: object references an unsaved transient instance - save the transient instance before flushing: Child How to reproduce issue: 1. Hibernate is load the entity "Parent". The property "child" is null 2. The "Parent" is rendered on the screen and after that the "child" property is auto instantiated. So I have the following graph: Parent.child != null Parent.child.childId = null Parent.child.childKey = "" Parent.child.childName = "" Question: How I could to force the Hibernate to ignore updating or inserting Child entity WHEN childId = null? If childId != null I would like just create relation. <hibernate-mapping> <class name="com.test.Parent" entity-name="ParentObject" table="parent" dynamic-insert="false" dynamic-update="true" optimistic-lock="version"> <id name="rowId" type="long"> <column name="RowID" /> <generator class="native" /> </id> <version name="versionSequence" type="integer" unsaved-value="null" generated="never" insert="false"> <column name="VersionSequence" /> </version> <many-to-one name="child" entity-name="Child" fetch="select" optimistic-lock="true" embed-xml="false" update="true" insert="false"> <column name="ChildID" /> </many-to-one> <property name="dateCreated" type="timestamp"> <column name="DateCreated" length="0" /> </property> <property name="dateUpdated" type="timestamp" update="false"> <column name="DateUpdated" length="0" /> </property> </class> </hibernate-mapping> <hibernate-mapping> <class name="com.Child" entity-name="Child" table="Child" dynamic-insert="false" dynamic-update="true" optimistic-lock="version"> <id name="childId" type="long" > <column name="ChildID" /> <generator class="native" /> </id> <version name="versionSequence" type="integer" insert="false" generated="never" > <column name="VersionSequence" /> </version> <property name="childKey" type="string" > <column name="ChildKey" length="20" /> </property> <property name="childName" type="string" > <column name="ChildName" length="30" /> </property> <property name="childNumber" type="string" > <column name="ChildNumber" /> </property> <property name="dateCreated" type="timestamp"> <column name="DateCreated" /> </property> <property name="dateUpdated" type="timestamp" update="false"> <column name="DateUpdated" /> </property> </class> </hibernate-mapping>

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  • flushing database cache in SWI-Prolog

    - by JPro
    We are using swi-prolog to run our testcases. Whenever the test starts, I am opening the connection to MYSQL database and storing the Name of the Test hat is being done and then closing the DB. These tests run for about 2 days continuously. After the tests are done, the results basically gets stored in folder in the server. There is a predicate in another prolog file that is called to update the results to the MYSQL database. The code is simple, I use odbc library and just call odbc_* predicates to connect and update the mysql by issuing direct queries. The actual problem is : If I try to call the Predicate from the same Prolog window, where the test just got completed, I get an error as updating to the DB server. Although I do not get any error in the connection. If I close the session of that prolog with halt and closing all the open prolog windows , then open an other complete new instance of Prolog and run the predicate the update goes well. I have a feeling that there is some connection reference to the MySQL DB in Prolog database. Is there any way to clear the database in prolog so that I can run the same predicate without closing any existing prolog windows? Any ideas appreciated. Thanks.

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  • Flushing a queue using AMQP, Rabbit, and Ruby

    - by jeffshantz
    I'm developing a system in Ruby that is going to make use of RabbitMQ to send messages to a queue as it does some work. I am using: Ruby 1.9.1 Stable RabbitMQ 1.7.2 AMQP gem v0.6.7 (http://github.com/tmm1/amqp) Most of the examples I have seen on this gem have their publish calls in an EM.add_periodic_timer block. This doesn't work for what I suspect is a vast majority of use cases, and certainly not for mine. I need to publish a message as I complete some work, so putting a publish statement in an add_periodic_timer block doesn't suffice. So, I'm trying to figure out how to publish a few messages to a queue, and then "flush" it, so that any messages I've published are then delivered to my subscribers. To give you an idea of what I mean, consider the following publisher code: #!/usr/bin/ruby require 'rubygems' require 'mq' MESSAGES = ["hello","goodbye","test"] AMQP.start do queue = MQ.queue('testq') messages_published = 0 while (messages_published < 50) if (rand() < 0.4) message = MESSAGES[rand(MESSAGES.size)] puts "#{Time.now.to_s}: Publishing: #{message}" queue.publish(message) messages_published += 1 end sleep(0.1) end AMQP.stop do EM.stop end end So, this code simply loops, publishing a message with 40% probability on each iteration of the loop, and then sleeps for 0.1 seconds. It does this until 50 messages have been published, and then stops AMQP. Of course, this is just a proof of concept. Now, my subscriber code: #!/usr/bin/ruby require 'rubygems' require 'mq' AMQP.start do queue = MQ.queue('testq') queue.subscribe do |header, msg| puts "#{Time.now.to_s}: Received #{msg}" end end So, we just subscribe to the queue, and for each message received, we print it out. Great, except that the subscriber only receives all 50 messages when the publisher calls AMQP.stop. Here's the output from my publisher. It has been truncated in the middle for brevity: $ ruby publisher.rb 2010-04-14 21:45:42 -0400: Publishing: test 2010-04-14 21:45:42 -0400: Publishing: hello 2010-04-14 21:45:42 -0400: Publishing: test 2010-04-14 21:45:43 -0400: Publishing: test 2010-04-14 21:45:44 -0400: Publishing: test 2010-04-14 21:45:44 -0400: Publishing: goodbye 2010-04-14 21:45:45 -0400: Publishing: goodbye 2010-04-14 21:45:45 -0400: Publishing: test 2010-04-14 21:45:45 -0400: Publishing: test . . . 2010-04-14 21:45:55 -0400: Publishing: test 2010-04-14 21:45:55 -0400: Publishing: test 2010-04-14 21:45:55 -0400: Publishing: test 2010-04-14 21:45:55 -0400: Publishing: goodbye Next, the output from my subscriber: $ ruby consumer.rb 2010-04-14 21:45:56 -0400: Received test 2010-04-14 21:45:56 -0400: Received hello 2010-04-14 21:45:56 -0400: Received test 2010-04-14 21:45:56 -0400: Received test 2010-04-14 21:45:56 -0400: Received test 2010-04-14 21:45:56 -0400: Received goodbye 2010-04-14 21:45:56 -0400: Received goodbye 2010-04-14 21:45:56 -0400: Received test 2010-04-14 21:45:56 -0400: Received test . . . 2010-04-14 21:45:56 -0400: Received test 2010-04-14 21:45:56 -0400: Received test 2010-04-14 21:45:56 -0400: Received test 2010-04-14 21:45:56 -0400: Received goodbye If you note the timestamps in the output, the subscriber only receives all of the messages once the publisher has stopped AMQP and exited. So, being an AMQP newb, how can I get my messages to deliver immediately? I tried putting AMQP.start and AMQP.stop in the body of the while loop of the publisher, but then only the first message gets delivered -- though strangely, if I turn on logging, there are no error messages reported by the server and the messages do get sent to the queue, but never get received by the subscriber. Suggestions would be much appreciated. Thanks for reading.

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  • OpenJPA - not flushing before queries

    - by Ales
    hi all, how can i set openjpa to flush before query. When i change some values in database i want to propagate these changes into application. I tried this settings in persistence.xml: <property name="openjpa.FlushBeforeQueries" value="true" /> <property name="openjpa.IgnoreChanges" value="false"/> false/true - same behavior to my case <property name="openjpa.DataCache" value="false"/> <property name="openjpa.RemoteCommitProvider" value="sjvm"/> <property name="openjpa.ConnectionRetainMode" value="always"/> <property name="openjpa.QueryCache" value="false"/> Any idea? Thanks

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  • bash: flushing stdin (standard input)

    - by rahul
    I have a bash script that gets some input as stdin. After processing, I copy a file using "-i" (interactive). However, this never gets executed since (I guess) standard input has not been flushed. To simplify with an example: #!/bin/bash while read line do echo $line done # the next line does not execute read -p "y/n" x echo "got $x" Place this in t.sh, and execute with: ls | ./t.sh The read is not executed. I need to flush stdin before the read. How could it do this?

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  • Flushing writes in buffer of Memory Controller to DDR device

    - by Rohit
    At some point in my code, I need to push the writes in my code all the way to the DIMM or DDR device. My requirement is to ensure the write reaches the row,ban,column of the DDR device on the DIMM. I need to read what I've written to the main memory. I do not want caching to get me the value. Instead after writing I want to fetch this value from main memory(DIMM's). So far I've been using Intel's x86 instruction wbinvd(write back and invalidate cache). However this means the caches and TLB are flushed. Write-back requests go to the main memory. However, there is a reasonable amount of time this data might reside in the write buffer of the Memory Controller( Intel calls it integrated memory controller or IMC). The Memory Controller might take some more time depending on the algorithm that runs in the Memory Controller to handle writes. Is there a way I force all existing or pending writes in the write buffer of the memory controller to the DRAM devices ?? What I am looking for is something more direct and more low-level than wbinvd. If you could point me to right documents or specs that describe this I would be grateful. Generally, the IMC has a several registers which can be written or read from. From looking at the specs for that for the chipset I could not find anything useful. Thanks for taking the time to read this.

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  • Flushing JDBC connection pools

    - by Matt
    Does anyone know the best (or any) way to flush a JDBC connection pool? I can't find anything obvious in the documentation. It appears connection pools aren't meant to ever be deleted. My current thought is to delete all DataSources from the hash we store them in, which will trigger our code to make new ones. However, my first attempt throws a ConcurrentModificationException.

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  • Streaming HTTP response, flushing to the browser

    - by synic
    I've got a view like the following: from django.views.decorators.http import condition def stream(): for i in range(0, 40): yield " " * 1024 yield "%d" % i time.sleep(1) @condition(etag_func=None): def view(request): return HttpResponse(stream(), mimetype='text/html') However, it definitely doesn't seem to be streaming at all. All the data is dumped at once, at the end, after about 40 seconds. How can I get it to flush correctly?

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  • Can I output/flush data to screen while processing ajax page?

    - by Bee
    I need to display on my page a list of records pulled from a table. Ajax works fine (I query the database and put all the data inside a on the main page) but if I have lots of records (say 500+) it will hang until data is fully loaded, THEN it will be sent back to the page and correctly displayed. I would like to be able to display the records on the page while getting them, instead of being forced to wait until completion. I am trying with flush(); inside the remote (ajax) page but it still waits until full data is loaded. This is what I currently have inside the ajax page: At the very beginning: @apache_setenv('no-gzip', 1); @ini_set('zlib.output_compression', 0); @ini_set('implicit_flush', 1); for ($i = 0; $i < ob_get_level(); $i++) { ob_end_flush(); } ob_implicit_flush(1); Then whenever I have a echo call: ob_flush(); Now if I load the ajax page alone... it will list the records while reading them from the database. But if I call the same page via Ajax, it will hang and send all the data at once. Any idea? This is the function I use to get the ajax content ('id' is the target , 'url' refers to the ajax page that runs the database query to list the records): function ajax(id,url) { xmlhttp=new XMLHttpRequest(); xmlhttp.open("GET",url,false); xmlhttp.send(null); document.getElementById(id).innerHTML = parseScript(xmlhttp.responseText); }

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  • How to flush output after each `echo` call?

    - by CuSS
    Hi all! I've a php script that only produces logs to the client. When I echo something, i wan't it to be transfered to client on-the-fly. (Because while the script is processing, the page is blank) I had already played arround with ob_start() and ob_flush(), but they didn't worked. What's the best solution? PS: it is a little dirty to put a flush at the end of the echo call... EDIT: Neither the Answers worked, PHP or Apache Fault? Thanks in advance, José Moreira Sorry for my bad English. ;)

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  • How should flushing be handled in a doctrine EntityManager instance shared across different services in symfony2?

    - by Jbm
    I have defined several services in symfony 2 which persist changes to the database. These services have the doctrine instance as one of their dependencies: a.given.service: class: Acme\TestBundle\Service\AGivenService arguments: [@doctrine] If I have two different services and both of them persist objects through the EntityManager, which is obtained like this from the doctrine instance: $em = $doctrine->getEntityManager(); Would all services always share the same EntityManager? If so, how should I handle flushing if I wanted to handle all the changes in a single transaction? I have checked this: http://docs.doctrine-project.org/projects/doctrine-orm/en/2.0.x/reference/transactions-and-concurrency.html and it explains how to handle different transactions in a request, but I want to achieve the opposite, which is having different changes in different services handled as a single transaction. Is there a better approach to handle multiple changes in different services? For now my best bet is having a front-end service in charge of calling the other services and doing the flushing afterwards. Backend services would persist objects but would not do any flushing.

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  • Is "Turn Off Windows write-cache buffer flushing" safe on a laptop?

    - by Earlz
    my laptop's internal harddrive is a bit slow. I looked at the drive properties and there are two options: [X] Enable write caching on the device [ ] Turn off windows write-cache buffer flushing on the device As you can see, the first option is checked already, but the second option isn't. I've heard the second option can really speed things up, but it also sounds very risky. Is it safe to do on a laptop that rarely is off of AC power? (but still has battery as well)

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  • What does flushing thread local memory to global memory mean?

    - by Jack Griffith
    Hi, I am aware that the purpose of volatile variables in Java is that writes to such variables are immediately visible to other threads. I am also aware that one of the effects of a synchronized block is to flush thread-local memory to global memory. I have never fully understood the references to 'thread-local' memory in this context. I understand that data which only exists on the stack is thread-local, but when talking about objects on the heap my understanding becomes hazy. I was hoping that to get comments on the following points: When executing on a machine with multiple processors, does flushing thread-local memory simply refer to the flushing of the CPU cache into RAM? When executing on a uniprocessor machine, does this mean anything at all? If it is possible for the heap to have the same variable at two different memory locations (each accessed by a different thread), under what circumstances would this arise? What implications does this have to garbage collection? How aggressively do VMs do this kind of thing? Overall, I think am trying to understand whether thread-local means memory that is physically accessible by only one CPU or if there is logical thread-local heap partitioning done by the VM? Any links to presentations or documentation would be immensely helpful. I have spent time researching this, and although I have found lots of nice literature, I haven't been able to satisfy my curiosity regarding the different situations & definitions of thread-local memory. Thanks very much.

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  • Flushing iptables broke my pipe, how can I save my instance?

    - by Niels
    I was setting up my iptables when I performed a iptables -F and my ssh pipe broke. This is the last output of my session: root@alfapaints:~# iptables -L Chain INPUT (policy DROP) target prot opt source destination ACCEPT all -- anywhere anywhere ACCEPT tcp -- anywhere anywhere state NEW,ESTABLISHED tcp dpt:2222 ACCEPT tcp -- li465-68.members.linode.com anywhere state NEW,ESTABLISHED tcp dpt:nrpe ACCEPT tcp -- anywhere anywhere tcp dpt:9200 state NEW,ESTABLISHED ACCEPT tcp -- anywhere anywhere tcp dpt:http state NEW,ESTABLISHED ACCEPT udp -- anywhere anywhere udp spt:domain Chain FORWARD (policy DROP) target prot opt source destination Chain OUTPUT (policy DROP) target prot opt source destination ACCEPT all -- anywhere anywhere ACCEPT tcp -- anywhere anywhere state ESTABLISHED tcp spt:2222 ACCEPT tcp -- anywhere anywhere state ESTABLISHED tcp spt:nrpe ACCEPT tcp -- anywhere anywhere tcp spt:9200 state ESTABLISHED ACCEPT tcp -- anywhere anywhere tcp spt:http state ESTABLISHED ACCEPT udp -- anywhere anywhere udp dpt:domain root@alfapaints:~# iptables -F Write failed: Broken pipe I tested my connection just before and I was able to connect with ssh. Now I did a nmap scan and not a single port is open anymore. I know my VPS is running on VMWare ESXi, could a reboot help? Or if not could I attach and mount the disk to another vm to save the data? Does anybody have some advise? And maybe an explanation what happend or what could have cause my pipe to break? ps: I didn't save my rules on the config directories of iptables. But used a file I stored in ~/rules.config to apply my rules like this: iptables-restore < rules.config So probably a reboot would help? Thanks a lot in advance.

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  • Why is IIS 7.5 flushing file cache very often?

    - by Steffen
    We're running a Win 2008 R2 server with IIS 7.5 for serving image files. It's only used for static content, and file caching has been set up to cache files for 10 minutes. However the IIS frequently completely flushes the cache (seen by using Perfmon) It's not application pool recycling, it's not because the TTL has expired, so now I'm at a loss :-( I've included a screenshot of the perfmon graph where you can clearly see the issue. Is there anywhere I can see WHY it's doing these flushes ? (Note: I'm aware I could maybe detect it by attaching a debugger to the process, but that's not an option because it's a production server, and it cannot handle the slowdown a debugger would cause)

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  • Flushing stdin after every input - which approach is not buggy?

    - by Aseem Bansal
    While using scanf() in C there is always the problem of extra input lying in the input buffer. So I was looking for a function that I call after every scanf call to remedy this problem. I used this, this, this and this to get these answers //First approach scanf("%*[^\n]\n"); //2ndapproach scanf("%*[^\n]%*c"); //3rd approach int c; while((c = getchar()) != '\n' && c != EOF) /* discard */ ; All three are working as far as I could find by hit-and-trial and going by the references. But before using any of these in all of my codes I wanted to know whether any of these have any bugs?

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  • Clarification On Write-Caching Policy, Its Underlying Options And How It Applies To Hard Drives And Solid-State Drives

    - by Boris_yo
    In last week after doing more research on subject matter, I have been wondering about what I have been neglecting all those years to understand write-caching policy, always leaving it on default setting. Write-caching policy improves writing performance and consists of write-back caching and write-cache buffer flushing. This is how I understand all the above, but correct me if I erred somewhere: Write-through cache / Write-through caching itself is not a part of write caching policy per se and it's when data is written to both cache and storage device so if Windows will need that data later again, it is retrieved from cache and not from storage device which means only improved read performance as there is no need for waiting for storage device to read required data again. Since data is still written to storage device, write performance isn't improved and represents no risk of data loss or corruption in case of power failure or system crash while only data in cache gets lost. This option seems to be enabled by default and is recommended for removable devices with no need to use function of "Safely Remove Hardware" on user's part. Write-back caching is similar to above but without writing data to storage device, periodically releasing data from cache and writing to storage device when it is idle. In my opinion this option improves both read and write performance but represents risk if power failure or system crash occurs with the outcome of not only losing data eventually to be written to storage device, but causing file inconsistencies or corrupted file system. Write-back caching cannot be enabled together with write-through caching and it is not recommended to be enabled if no backup power supply is availabe. Write-cache buffer flushing I reckon is similar to write-back caching but enables immediate release and writing of data from cache to storage device right before power outage occurs but I don't know if it applies also to occasional system crash. This option seem to be complementary to write-back cache reducing or potentially eliminating risk of data loss or corruption of file system. I have questions about relevance of last 2 options to today's modern SSDs in order to get best performance and with less wear on SSDs: I know that traditional hard drives come with onboard cache (I wonder what type of cache that is), but do SSDs also come with cache? Assuming they do, is this cache faster than their NAND flash and system RAM and worth taking the risk of utilizing it by enabling write-back cache? I read somewhere that generally storage device's cache is faster than RAM, but I want to be sure. Additionally I read that write-caching should be enabled since current data that is to be written later to NAND flash is kept for a while in cache and provided there is data that gets modified a lot before finally being written, holding of this data and its periodic release reduces its write times to SSD thereby reducing its wearing. Now regarding to write-cache buffer flushing, I heard that SSD controllers are so fast by themselves that enabling this option is not required, because they manage flushing. However, once again, I don't know if SSDs have their own onboard cache and whether or not it is faster than their NAND flash and system RAM because if it is, keeping this option enabled would make sense. Recently I have posted question about issue with my Intel 330 SSD 120GB which was main reason to do deeper research having suspicion of write-caching policy being the culprit of SSD's freezing issue assuming data being released is what causes freezes. Currently I have write-cache enabled and write-cache buffer flushing disabled because I believe SSD controller's management of write-cache flushing and Windows write-cache buffer flushing are conflicting with each other: Since I want to troubleshoot in small steps to finally determine the source of issue, I have decided to start with write-caching policy and the move to drivers, switching to AHCI later on and finally disabling DIPM (device initiated power management) through registry modification thanks to @TomWijsman

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