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  • How to boost playback volume in real time on media recorded with a very low volume.

    - by L Marksman
    I have never heard a satisfactory answer to this often misunderstood question, let me explain. Lets say I have a sound card and earphones/speakers that can play back audio loud enough in most cases. This is great but the problem is that you always find people who do not know how to record audio, from Youtube video's to music. So now you end up with a audio playback that only uses 10% or less of the capacity of your sound hardware, in vista/win 7 you will see this frequently in the mixer with the volume pushed up to max but the green sound level only goes up a millimeter or two. I am looking for (preferably free) software or a method to boost the sound level of any audio from any source in real time to use more of my hardware capacity similar to what VLC media player can do. Oh and please, do not tell me it is impossible. I am not trying to boost the volume past what my hardware is capable of, I am just trying to use my hardware's full capacity. Also please do not tell met to buy new hardware, I know I can use hardware amplification, I don't want to (like many others) spend money on a simple little problem like this. Thanks!

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  • Windows XP VM on VMWare ESXi 4.1 "pausing" / blocked occasionally

    - by FelixD
    We have an issue with Windows XP SP3 VMs on VMWare ESXi 4.1.0 (the free version): They sometimes seem to "pause" for several minutes. This happens rarely (maybe once a month per VM, at least noticed only that often), but still is an issue for us. It happens for three different but similar VMs on three pretty different hosts (different hardware). I have the feeling that the "pausing" is not actually the CPU blocking, but probably the harddisks, but not 100% sure. The servers have one IDE disk (C:) and one SCSI (D:) and it might be either of the two. I have seen scheduled tasks simply not starting for up to 9 minutes and then running normally again with normal speed. They were totally blocked. This is not a load issue, the VMWare hosts have average load and the VMs in question already have reserved CPU resources plus high priorities for CPU and disk. The Windows boxes run mainly MySQL, Tomcat, FileZilla server, Cygwin stuff, Java + R applications, VMWare client, Elusiva Terminal Server pro, Nagios client. Not sure if this might be related with any of that software (e.g. Elusiva). Trying to debug this, there was nothing visible in Windows Event log, other logs in C:\Windows, VMWare events etc. Unfortunately the vmware.log file ends with "Log throttled". We found that we ran into 2 VMWare bugs there: The VMWare client writes lots on bogus messages in the vmware.log, which we now disabled (log level error setting) plus the bug that VMWare does not unthrottle the log (at least so far despite VM reboots). I know there is not much guidance and that may also be the reason why I so far didn't find anything related on the web or on ServerFault, but maybe some of this rings a bell with someone? Or please direct me to what more info to post. I hope that the vmware.logs get unthrottled eventually (can't easily restart the hosts at the moment). Thanks for any input!

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  • linux kernel buffer memory is zero

    - by user64772
    Hi all. There are one qestion that i can`t find in google. I have many linux boxes mostly with SLES or openSUSE, diffrent versions and kernels. On some of them i faced with slow oracle transactions problem. It time to time problem and when i log in the box on that time i see that oracle blocked in kernel function sync_page # while :; do ps axo stat,pid,cmd,wchan | egrep '^D|^R'; echo --; sleep 5; done D 3483 hald-addon-storage: polling ide_do_drive_cmd Ds 4635 ora_dbw0_orcl sync_page Ds 4637 ora_lgwr_orcl sync_page Ds 4639 ora_ckpt_orcl sync_page D 11210 oracleorcl (LOCAL=NO) sync_page D 12457 [smtpd] sync_page R+ 12458 ps axo stat,pid,cmd,wchan - -- Ds 4635 ora_dbw0_orcl sync_page Ds 4637 ora_lgwr_orcl sync_page Ds 4639 ora_ckpt_orcl sync_page D 11210 oracleorcl (LOCAL=NO) sync_page R+ 12501 ps axo stat,pid,cmd,wchan - -- Ds 4635 ora_dbw0_orcl sync_page Ds 4637 ora_lgwr_orcl sync_page Ds 4639 ora_ckpt_orcl sync_page D 11210 oracleorcl (LOCAL=NO) sync_page R+ 12535 ps axo stat,pid,cmd,wchan - -- Ds 4635 ora_dbw0_orcl sync_page Ds 4637 ora_lgwr_orcl sync_page Ds 4639 ora_ckpt_orcl sync_page D 11210 oracleorcl (LOCAL=NO) sync_page R+ 12570 ps axo stat,pid,cmd,wchan - -- so i think that box is run out of memory for disk buffers but memry is fine total used free shared buffers cached Mem: 4149084 3994552 154532 0 0 2424328 -/+ buffers/cache: 1570224 2578860 Swap: 3148700 750696 2398004 i think that this is the problem, buffer is zero and we must write directly to disk, but why buffer is zero ? - i try to google it and find nothing - is anyone can help ?

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  • Debian on HP ProLiant server hangs (disk i/o is my guess)

    - by Martin
    I installed Debian (2.6.32-5-amd64) on my HP ProLiant MicroServer (purchased recently.) I also added 3 2tb hd in zfs. I've experienced several server froze. Sometimes it showed Soft lockup CUP stuck for 61s! Today I experienced a different problem (I think) and the message looked like this [431336.200002] Call Trace: [431336.200002] [<ffffffff812fcc7c>] ? _write_lock+0xe/0xf [431336.200002] [<ffffffff810d7a86>] ? __vmalloc_node+0x99/0xe2 : : and (in different screen) [431354.222318] Node 0 DMA32 free: 2064kB min:5520kB low:69900kB high:8280kB active_anon:181648kB inactive_anon:61728kB active_file:313152kB inactive_file:832456kB unevictable: 0kB isolated(anon): 0kB isolated(file):0kB present:1922596kB mlocked:0kB dirty:72kB writeback:0kB mapped:25620kB shmem:344kB slab_reclaimable:34460kB slab_unreclaimable:31400kB kernel_stack:2288kB pagetables:7556kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? no [431354.222431] lowmem_reserve[]: 0 0 0 0 : : Is this a hardware problem? What tools/methods can I find out the source of the problem? I've used Debian for years but never had problem like this.

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  • VMworkstation Windows 7 vm from physical partition?

    - by rich
    Hi All, i have a machine with 2 disks. my secondary drive has two partitions, one of which is a windows 7 64 boot partition. I have VM workstation and i would like to make a VM from the physical partition (described above). Ideally this would boot from the live disk, but if i can make a vmdk from the two partitions on the secondary drive that would be fine. 1 issue is the drive is 140gig raptor of which the two partitions i want are 40g and 30g partitions. the rest of the space is unallocated. So if i make a vmdk i really need it to be fixed at say 80 gig. I have converter but i don't understand how i can make the vmdk using this... specs Drive 1: this drive is a 120 SSD, running the host OS (Windows 7 64bit) - i've got 95 gigs free on this Drive 2: 140 gig raptor, partition 1 40g is also a windows 7 64bit install, partition 2 is 35 gig with program files folder on it.. sorta of needed to get the vm to work. There is 65gig unallocated on this disk. Drive 1 will host drive 2 as a VM.. my hope.

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  • What's the proper way to prepare chroot to recover a broken Linux installation?

    - by ~quack
    This question relates to questions that are asked often. The procedure is frequently mentioned or linked to offsite, but is not often clearly and correctly stated. In an objective to concentrate useful information in one place, this question seeks to provide a clear, correct reference for this procedure. What are the proper steps to prepare a chroot environment for a recovery procedure? In many situations, repairing a broken Linux installation is best done from within the installation. But if the system won't boot, how do you fix it from within? Let's assume you manage to boot into an alternate system. Once there, you need to access your broken installation in order to fix it. Many recovery How-Tos recommend using chroot in order to run programs as if you are actually booted into the broken installation. What is the basic procedure? Are there accepted best-practices to follow? What variables need to be considered in order to adapt the basic preparation steps to a particular recovery task? As this is Community Wiki, feel free to edit this question to improve it as well.

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  • Faster caching method

    - by pataroulis
    I have a service that provides HTML code which at some point it is not updated anymore. The code is always generated dynamically from a database with 10 million entries so each HTML code page rendering searches there for say 60 or 70 of those entries and then renders the page. So, for those expired pages, I want to use a caching system which will be VERY simple (like just enter a record with the rendered HTML and (if I need) remove it). I tried to do it file-based but the search for the existence of a file and then passing it through php to actually render it , seems like too much for what I want to do. I was thinking of doing it on mysql with a table with MEDIUMBLOBs (each page is around 100k). It would hold about 150000 such records (for now, at least). My question is: Would it be faster to let mysql do the lookup of the file and the passing to php or is the file-based approach faster? The lookup code for the file based version looks like this: $page = @file_get_contents(getCacheFilename($pageId)); if($page!=NULL) { echo $page; } else { renderAndCachePage($pageId); } which does one lookup whether it finds the file or not. The mysql table would just have an ID (the page id) and the blob entry. The disk of the system is a simple SATA raid 1 , the mysql daemon can grab up to 2.5GB of memory (i have a proxy running too, eating the rest of the 16GB of the machine. ) In general the disk is quite busy already. My not using PEAR cache, is because I think (please feel free to correct me on this) it adds overhead I do not need because the page rendering code is called about 2M times per day and I wouldn't want to go through the whole code each time (and yes, I have eaccelerator to cache the code too). Any pointer to what direction I should go, would be greatly welcome. Thanks!

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  • please take a look at my server's ram usage

    - by user66779
    Hi, i am a noob with servers. I have a centos5.5 vps with 512mb ram. My goal is to have it host just one magento store. I've installed Magento on the server without any control panel, by just installing lamp myself and whatever php extensions were necessary to get Magento to install. As soon as i visit my magento store, suddenly the ram on the vps is almost completely used, with only about 100mb left. Please see this screenshot of htop taken after just myself visited the website. http://img714.imageshack.us/img714/1944/screenouv.png As you can see there's only around 100mb left. Is that normal? I'm wondering if i might have done something stupid with the server that makes it very resource hungry. I installed apache from the centos base repo, php version 5.3 from the ius repository and mysql 5.1 also from ius repo. I haven't changed any of the default config files for any of these except to make memory_minimum 256 in php.ini. Is there anything i can do to make more ram free? I'm clueless but i see each Apache daemon is using 8% of available ram, and AFAIK each visitor needs one Apache daemon. So i would run out of ram with just a handful of visitors. Thanks for your advice.

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  • What would prevent the same ActiveX control from downloading on one internal website but not another?

    - by ProfessionalAmateur
    We have two internal webservers for an application at my company, one is the development server and the other is production. This application server will deploy and install and ActiveX control to allow the use of specific functionality. The ActiveX control is the exact same on both servers. Last week suddenly when trying to install and run this ActiveX control from the development server stopped working. IE will still prompt the user to install it, but when select "Install this Add-on for all users on this computer", nothing happens. Another IE window pops open and immediately closes and that is it. It is almost as if a pop-up blocker is running (but it is not enabled). The kicker which has me completely stumped is that if we try the same thing on the Production server, everything works as we would expect. Items of interest: Both servers are in the 'Trusted Sites' No pop-up blocker in IE is activated ActiveX controls for Trusted and Intranet Sites are all enabled. Has anyone experienced something similar? I'm not a Windows administrator so please feel free to explain things as elementary as you see fit.

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  • Downloading Emails locally with Thunderbird

    - by r_honey
    I am using Gmail (web interface) for sometime now, and have well over 20 labels and some thousand mails there archived to different labels in Gmail. Now I want to have a local copy of all my mails and following points are important in the context: The Primary mail access mechanism would continue to be Gmail web for me. I just want a backup of my mail account locally. Ideally the mails should download locally in folders named after Gmail labels (I know this is possible via IMAP but probably not by POP) After all my mails are available locally, I will delete most of them in Gmail to free up space and because I want to archive them. The mails should continue to exist locally and should not be deleted when I delete when from Gmail web interface. I would be syncing my gmail account locally let's say every month. So, the new mails that I have sent/received during this period should come over to my local mailbox in the folders named after Gmail labels. I do understand that Gmail maintains a single copy of email having 2 different labels and such email would get duplicated locally in the 2 folders and I am okay with that. Essentially you can see I just want to archive my mails from the Gmail server to a local backup and then sync (one way from Gmail to locally) new mails at regular intervals. For some points above, POP seems to be the option while IMAP seems for the others. I am really confused and need help in deciding which of POP or IMAP would suit me best. I have currently chosen Thunderbird to be my local email client but would not have a problem switching to Outlook or anything else as long as I get my desired archiving functionality.

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  • Where does Firefox store cerificates and how to delete one?

    - by majid4466
    Hi all, The root cause of my problem is not known to me, whatever it is, I experience frequent DNS failures. When it happens I cannot browse to my Gmail inbox. I use two DNS settings. One is the public DNS server offered by OpenDNS, and the other is Google's free DNS server. When this happens I switch from the active setting to the other one and the problem goes away. But there is a side effect to this. When browsing to Gmail fails to load, after switching the DNS I receive an error saying the security certificate the site uses is only valid for OpenDNS. This my wild guess at what is going on: OpenDNS fails to resolve mail.google.com to its IP, My ISP sends me a page showing search results for 'mail.google.com' Since I have received some sort of page instead of a timeout, the browser, mistakenly, binds the certificate it has cached for 'mail.google.com' to the new domain. This search page is not served by https so not exception is thrown by the wrong binding After switching the DNS, the domain is correctly resolved to Gmail server's IP and since his is on https the handshake is triggered. Now, because of the wrong binding, which passed quietly as no handshake was involved, I receive the error saying the certificate used by 'mail.google.com' is only good for openDNS I don't know much about DNS, less about https and the process of establishing a secure connection. How correct is my explanation? How can I delete the wrong association and/or the certificate? Thanks for listening. P. S. The problem goes away by itself, but sometimes it takes several hours before Gmail works again.

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  • Where does Firefox store cerificates and how to delete one?

    - by majid4466
    Hi all, The root cause of my problem is not known to me, whatever it is, I experience frequent DNS failures. When it happens I cannot browse to my Gmail inbox. I use two DNS settings. One is the public DNS server offered by OpenDNS, and the other is Google's free DNS server. When this happens I switch from the active setting to the other one and the problem goes away. But there is a side effect to this. When browsing to Gmail fails to load, after switching the DNS I receive an error saying the security certificate the site uses is only valid for OpenDNS. This my wild guess at what is going on: 1. OpenDNS fails to resolve mail.google.com to its IP, 2. My ISP sends me a page showing search results for 'mail.google.com' 3. Since I have received some sort of page instead of a timeout, the browser, mistakenly, binds the certificate it has cached for 'mail.google.com' to the new domain. This search page is not served by https so not exception is thrown by the wrong binding 4. After switching the DNS, the domain is correctly resolved to Gmail server's IP and since his is on https the handshake is triggered. 5. Now, because of the wrong binding, which passed quietly as no handshake was involved, I receive the error saying the certificate used by 'mail.google.com' is only good for openDNS I don't know much about DNS, less about https and the process of establishing a secure connection. How correct is my explanation? How can I delete the wrong association and/or the certificate? Thanks for listening. P. S. The problem goes away by itself, but sometimes it takes several hours before Gmail works again.

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  • How do I re-configure grub options

    - by Ash
    I've searched this topic and I can't find an article with a plausable solution, to my problem. I installed windows 7 first, with 100gb of disk space. I created the necessary partitions via windows. Then I installed Ubuntu 12.04 on the remaining 400gb of disk space. During the Ubuntu installation I installed the ubuntu boot loader on /dev/sda3 which Windows (as expected never granted me the option pre-boot for which OS I wanted to boot). So I re-installed Ubuntu on that /dev/sda3 partition, overriding the windows 7 loader. Now when I boot windows 7, it runs GNU Grub, so like an infinite loop. How can I reconfigure grub to say: /dev/sda is the bootloader. /dev/sda2 is Windows. /dev/sda3 is Ubuntu. Re-installing windows and my partitions isn't an option, purchasing software for windows isn't an option (theres a reason I use linux, it's not because it's free, because you don't have to install lots of shit to get stuff working, and over-all it's a robust OS).

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  • Can I sort files A-Z and at the same time Z-A?

    - by The_Buff
    I am trying to sort and rename a large number of files that are labeled #####_## The LEFT side of the underscore are numbers (e.g., 32956715, 32956810, etc.) that do not repeat. The RIGHT side of the underscore are also numbers (e.g., 1, 2, 3, etc.) and they do repeat. (The left side is the number of a scan and the right side is the page of that particular scan.) I would like to be able to sort the left side of the underscore Z-A and the right side A-Z. Example: 3_1 3_2 3_3 2_1 2_2 2_3 1_1 1_2 1_3 I am using ReNamer by den4b (easily the best free renamer out there). It supports regular expressions so I believe there should be an easy way to do this, but I don't know how. (I've been trying to learn regular expressions but I don't use them enough to retain anything.) I'm open for any suggestions that achieve the same result. I've spent enough time trying to figure it out that I could have probably just sorted them myself already but this is a reccuring problem so hopefully someone has a solution that will save me lots of time in the long run. Thank You!

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  • I just deleted my backup file! How do I save it?

    - by Sammy
    I just accidentally deleted a backup file that I need to restore my system. It's an Acronis True Image TIB file. It was stored at H:\My backups and the name of the file was File_backup_2012-10-18.tib. I did a quick scan with Recuva 1.43.623 and it found the file using the recovery wizard, but it was unable to recover it. The "state" of the file is "unrecoverable". So the resulting file is 0 byte. I am trying to do a deep scan with Recuva right now but it takes a lot of time. If it should fail, what other recovery option do I have? Is there any other good file recovery software that's free to use for home users? I do have a second copy of the whole system partition, but I needed this file backup copy because it is more up to date. That's the file, right there! But why is Recuva unable to recover it?

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  • Linux RHEL : Making disk image efficiently

    - by TheProfoundGeek
    I have a linux box having RHEL. Its disk (hda1) is having free space of about 25GB. I have an another disk (hda2) which is of 250GB having another RHEL instance, it's partitioned for 200GB. Data on the disk occupies about 21GB of data. The image of hda2 needs to be taken and restored on other disk of same specs. What is the best way to make image file of the hda2? Ideally the images size should be around 25GBs as the actual data on the disk is just 21GB. I am aware about the following two methods. Method 1 : Raw Image dd if=/dev/hda2 of=/path/to/image dd if=/path/to/image of=/dev/hda3 Question 1 : Will the above method make a gigantic image of 250GBs? Is it efficient? Method 2 : Compressed Image. dd if=/dev/hda2 | gzip > /path/to/image.gz gzip -dc /path/to/image.gz | dd of=/dev/hda2 Question 2 : I tried the method 2, its taking too long. What are the pit falls of this methods? Which of the above method id efficient and why? Is there any other Linux utility which can do the job? Third party tools are no no.

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  • Mac OS X: Applications not responding

    - by Robot55
    This happens to me several times a day. I'll quit an app, the window will close, but the app won't finish shutting down. It stays open in the dock, and right clicking and force quit show not responding. Force quit won't work. I can't shut the app down. Starting any other app when this happens causes that app to behave in exactly the same way: the icon opens in the dock, but the app is non-responsive and can't be forced to quit. Can't access terminal when this happens, because it locks up just like all the apps. While I haven't tried to open every app, I think any app I try to open when this is happening will lock up. If I relaunch Finder, it too locks up and then the only thing left is to hold down the power button for a hard reboot. Any app that is running while this is happening will continue to run normally unless I try to shut it down. Repairing disk permissions has no effect. I also did a time machine and a full restore on a brand new MbP - and sure enough, after restore, the new MbP suffers form the same problem. Creating a new user has no effect. Any thoughts? Please help MacBook Pro 15" AG 2.53ghz i5 cpu 8gb RAM 500gb HD (over 200gb free)

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  • How to merge Windows registry hives directly without converting them to an intermediate text based file?

    - by Registrar
    Help! I'm going to get fired if I can't figure out how to do this by tomorrow. Microsoft Windows stores its registry databases (known as "registry hives" - there's actually a backstory to the origin of this name, but I digress) in a proprietary binary format. Answer this correctly or you lose your job: Let H-sub-A be the registry hive of Computer A, and let H-sub-B be the registry hive of Computer B. Create a registry hive H-sub-A-prime (in the native binary format) that contains all of the registry keys and values in both H-sub-A and H-sub-B. If there is overlap, let the value from H-sub-B overwrite the value in H-sub-A. Sure, you can import a text-based patch file (e.g., "FOO.REG") to modify the registry, but can you merge two registry hives in their native binary format? Answers that involve exporting the registry to a text file (e.g., "FOO.REG") will receive no credit. You may only use software included with Microsoft Windows (any version) and / or third-party tools that are free of charge.

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  • Do email providers have to tell me which (inter)national agencies/institutes are requesting legal access to my account data?

    - by Juve
    I know this question is not technical, but i did not find the "stackoverflow for legal issues" and I guess all you super users out there might know the answer. Here is my (potential) problem: I have a free email account at a (inter)national email provider. I used the words "wikileaks" and "twitter" lately in my email. Some over-ambitious national security organization legally requests access to all accounts that behaved similarly. Q1: Can I request the who-, when-, and why-information related to this legal request from my provider? Does he have to tell me which (inter)national organizations (legally) requested my account data? Q2: Does the situation change if I live in Germany (and have a German provider)? I guess here are some German users. And I know that such a legal policy exists for our national credit rating agency. I can request who got access to my data, they have to tell me. Please answer only if you know a good answer, I don't want to start a long discussion on this none-technical question. Best regards, Juve

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  • Modern Java alternatives

    - by Ralph
    I'm not sure if stackoverflow is the best forum for this discussion. I have been a Java developer for 14 years and have written an enterprise-level (~500,000 line) Swing application that uses most of the standard library APIs. Recently, I have become disappointed with the progress that the language has made to "modernize" itself, and am looking for an alternative for ongoing development. I have considered moving to the .NET platform, but I have issues with using something the only runs well in Windows (I know about Mono, but that is still far behind Microsoft). I also plan on buying a new Macbook Pro as soon as Apple releases their new rumored Arrandale-based machines and want to develop in an environment that will feel "at home" in Unix/Linux. I have considered using Python or Ruby, but the standard Java library is arguably the largest of any modern language. In JVM-based languages, I looked at Groovy, but am disappointed with its performance. Rumor has it that with the soon-to-be released JDK7, with its InvokeDynamic instruction, this will improve, but I don't know how much. Groovy is also not truly a functional language, although it provides closures and some of the "functional" features on collections. It does not embrace immutability. I have narrowed my search down to two JVM-based alternatives: Scala and Clojure. Each has its strengths and weaknesses. I am looking for the stackoverflow readerships' opinions. I am not an expert at either of these languages; I have read 2 1/2 books on Scala and am currently reading Stu Halloway's book on Clojure. Scala is strongly statically typed. I know the dynamic language folks claim that static typing is a crutch for not doing unit testing, but it does provide a mechanism for compile-time location of a whole class of errors. Scala is more concise than Java, but not as much as Clojure. Scala's inter-operation with Java seems to be better than Clojure's, in that most Java operations are easier to do in Scala than in Clojure. For example, I can find no way in Clojure to create a non-static initialization block in a class derived from a Java superclass. For example, I like the Apache commons CLI library for command line argument parsing. In Java and Scala, I can create a new Options object and add Option items to it in an initialization block as follows (Java code): final Options options = new Options() { { addOption(new Option("?", "help", false, "Show this usage information"); // other options } }; I can't figure out how to the same thing in Clojure (except by using (doit...)), although that may reflect my lack of knowledge of the language. Clojure's collections are optimized for immutability. They rarely require copy-on-write semantics. I don't know if Scala's immutable collections are implemented using similar algorithms, but Rich Hickey (Clojure's inventor) goes out of his way to explain how that language's data structures are efficient. Clojure was designed from the beginning for concurrency (as was Scala) and with modern multi-core processors, concurrency takes on more importance, but I occasionally need to write simple non-concurrent utilities, and Scala code probably runs a little faster for these applications since it discourages, but does not prohibit, "simple" mutability. One could argue that one-off utilities do not have to be super-fast, but sometimes they do tasks that take hours or days to complete. I know that there is no right answer to this "question", but I thought I would open it up for discussion. If anyone has a suggestion for another JVM-based language that can be used for enterprise level development, please list it. Also, it is not my intent to start a flame war. Thanks, Ralph

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  • Interactive Data Language, IDL: Does anybody care?

    - by Alex
    Anyone use a language called Interactive Data Language, IDL? It is popular with scientists. I think it is a poor language because it is proprietary (every terminal running it has to have an expensive license purchased) and it has minimal support (try searching for IDL, the language, right now on stack) . I am trying to convince my colleagues to stop using it and learn C/C++/Python/Fortran/Java/Ruby. Does anybody know about or even care about IDL enough to have opinions on it? What do you think of it? Should I tell my colleagues to stop wasting their time on it now? How can I convince them? Edit: People are getting the impression that I don't know or use IDL. Also, I said IDL has minimal support which is true in one sense, so I must clarify that the scientific libraries are indeed large. I use IDL all the time, but this is exactly the problem: I am only using IDL because colleagues use it. There is a file format IDL uses, the .sav, which can only be opened in IDL. So I must use IDL to work with this data and transfer the data back to colleagues, but I know I would be more efficient in another language. This is like someone sending you a microsoft word file in an email attachment and if you don't understand how wrong that is then you probably write too many words not enough code and you bought microsoft word. Edit: As an alternative to IDL Python is popular. Here is a list of The Pros of IDL (and the cons) from AstroBetter: Pros of IDL Mature many numerical and astronomical libraries available Wide astronomical user base Numerical aspect well integrated with language itself Many local users with deep experience Faster for small arrays Easier installation Good, unified documentation Standard GUI run/debug tool (IDLDE) Single widget system (no angst about which to choose or learn) SAVE/RESTORE capability Use of keyword arguments as flags more convenient Cons of IDL Narrow applicability, not well suited to general programming Slower for large arrays Array functionality less powerful Table support poor Limited ability to extend using C or Fortran, such extensions hard to distribute and support Expensive, sometimes problem collaborating with others that don’t have or can’t afford licenses. Closed source (only RSI can fix bugs) Very awkward to integrate with IRAF tasks Memory management more awkward Single widget system (useless if working within another framework) Plotting: Awkward support for symbols and math text Many font systems, portability issues (v5.1 alleviates somewhat) not as flexible or as extensible plot windows not intrinsically interactive (e.g., pan & zoom) Pros of Python Very general and powerful programming language, yet easy to learn. Strong, but optional, Object Oriented programming support Very large user and developer community, very extensive and broad library base Very extensible with C, C++, or Fortran, portable distribution mechanisms available Free; non-restrictive license; Open Source Becoming the standard scripting language for astronomy Easy to use with IRAF tasks Basis of STScI application efforts More general array capabilities Faster for large arrays, better support for memory mapping Many books and on-line documentation resources available (for the language and its libraries) Better support for table structures Plotting framework (matplotlib) more extensible and general Better font support and portability (only one way to do it too) Usable within many windowing frameworks (GTK, Tk, WX, Qt…) Standard plotting functionality independent of framework used plots are embeddable within other GUIs more powerful image handling (multiple simultaneous LUTS, optional resampling/rescaling, alpha blending, etc) Support for many widget systems Strong local influence over capabilities being developed for Python Cons of Python More items to install separately Not as well accepted in astronomical community (but support clearly growing) Scientific libraries not as mature: Documentation not as complete, not as unified Not as deep in astronomical libraries and utilities Not all IDL numerical library functions have corresponding functionality in Python Some numeric constructs not quite as consistent with language (or slightly less convenient than IDL) Array indexing convention “backwards” Small array performance slower No standard GUI run/debug tool Support for many widget systems (angst regarding which to choose) Current lack of function equivalent to SAVE/RESTORE in IDL matplotlib does not yet have equivalents for all IDL 2-D plotting capability (e.g., surface plots) Use of keyword arguments used as flags less convenient Plotting: comparatively immature, still much development going on missing some plot type (e.g., surface) 3-d capability requires VTK (though matplotlib has some basic 3-d capability)

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  • Scope quandary with namespaces, function templates, and static data

    - by Adrian McCarthy
    This scoping problem seems like the type of C++ quandary that Scott Meyers would have addressed in one of his Effective C++ books. I have a function, Analyze, that does some analysis on a range of data. The function is called from a few places with different types of iterators, so I have made it a template (and thus implemented it in a header file). The function depends on a static table of data, AnalysisTable, that I don't want to expose to the rest of the code. My first approach was to make the table a static const inside Analysis. namespace MyNamespace { template <typename InputIterator> int Analyze(InputIterator begin, InputIterator end) { static const int AnalysisTable[] = { /* data */ }; ... // implementation uses AnalysisTable return result; } } // namespace MyNamespace It appears that the compiler creates a copy of AnalysisTable for each instantiation of Analyze, which is wasteful of space (and, to a small degree, time). So I moved the table outside the function like this: namespace MyNamespace { const int AnalysisTable[] = { /* data */ }; template <typename InputIterator> int Analyze(InputIterator begin, InputIterator end) { ... // implementation uses AnalysisTable return result; } } // namespace MyNamespace There's only one copy of the table now, but it's exposed to the rest of the code. I'd rather keep this implementation detail hidden, so I introduced an unnamed namespace: namespace MyNamespace { namespace { // unnamed to hide AnalysisTable const int AnalysisTable[] = { /* data */ }; } // unnamed namespace template <typename InputIterator> int Analyze(InputIterator begin, InputIterator end) { ... // implementation uses AnalysisTable return result; } } // namespace MyNamespace But now I again have multiple copies of the table, because each compilation unit that includes this header file gets its own. If Analyze weren't a template, I could move all the implementation detail out of the header file. But it is a template, so I seem stuck. My next attempt was to put the table in the implementation file and to make an extern declaration within Analyze. // foo.h ------ namespace MyNamespace { template <typename InputIterator> int Analyze(InputIterator begin, InputIterator end) { extern const int AnalysisTable[]; ... // implementation uses AnalysisTable return result; } } // namespace MyNamespace // foo.cpp ------ #include "foo.h" namespace MyNamespace { const int AnalysisTable[] = { /* data */ }; } This looks like it should work, and--indeed--the compiler is satisfied. The linker, however, complains, "unresolved external symbol AnalysisTable." Drat! (Can someone explain what I'm missing here?) The only thing I could think of was to give the inner namespace a name, declare the table in the header, and provide the actual data in an implementation file: // foo.h ----- namespace MyNamespace { namespace PrivateStuff { extern const int AnalysisTable[]; } // unnamed namespace template <typename InputIterator> int Analyze(InputIterator begin, InputIterator end) { ... // implementation uses PrivateStuff::AnalysisTable return result; } } // namespace MyNamespace // foo.cpp ----- #include "foo.h" namespace MyNamespace { namespace PrivateStuff { const int AnalysisTable[] = { /* data */ }; } } Once again, I have exactly one instance of AnalysisTable (yay!), but other parts of the program can access it (boo!). The inner namespace makes it a little clearer that they shouldn't, but it's still possible. Is it possible to have one instance of the table and to move the table beyond the reach of everything but Analyze?

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  • Unresolved compilation problems -- can't use .jar files that I have created

    - by Mike
    I created a few .jar files and am trying to access them in another application - I have tried to use both Eclipse and IntelliJ and experience the same issue: java.lang.Error: Unresolved compilation problems: The import com.XXXX.XXXXXXXXX.project2 cannot be resolved The import com.XXXX.XXXXXXXXX.project2 cannot be resolved BeanFactory cannot be resolved to a type Author cannot be resolved to a type AuthorFactoryImpl cannot be resolved to a type Author cannot be resolved to a type Author cannot be resolved to a type I have been using Maven during this process and the jars compile fine. I have included them on the file path using both the Maven .pom file and directly assigning them. I also have unassigned the direct file path and left the reference in Maven and vise versa -- no difference. See below .jar file class info: file structure: Author.java BeanWithIdentityInterface Books Subject ie: Interface: package com.XXXX.training; /** * Created with IntelliJ IDEA. * User: kBPersonal * Date: 11/5/12 * Time: 3:16 PM * */ public interface BeanWithIdentityInterface <I> { I getId(); } Author.java: package com.XXXX.training; /** * Created with IntelliJ IDEA. * User: kBPersonal * Date: 10/25/12 * Time: 12:03 PM */ public class Author implements BeanWithIdentityInterface <Integer>{ private Integer id = null; private String name = null; private String picture = null; private String bio = null; public Author(Integer id, String bio, String name, String picture) { this.id = id; this.bio = bio; this.name = name; this.picture = picture; } public Author (){} @Override public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getPicture() { return picture; } public void setPicture(String picture) { this.picture = picture; } public String getBio() { return bio; } public void setBio(String bio) { this.bio = bio; } @Override public String toString() { return "\n\tAuthor Id: "+this.getId() + " | Bio:"+ this.getBio()+ " | Name:"+ this.getName()+ " | Picture: "+ this.getPicture(); } } implementing Servlet: package com.acentia.training.project3.controller; import com.acentia.training.*; import com.acentia.training.project2.AuthorFactoryImpl; import com.acentia.training.project2.BeanFactory; import javax.servlet.ServletException; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.io.IOException; import java.io.PrintWriter; /** * Created with IntelliJ IDEA. * User: kBPersonal * Date: 11/11/12 * Time: 6:34 PM * */ public class ListAuthorServlet extends AbstractBaseServlet { private static final long serialVersionUID = -6934109551750492182L; public void doProcess(final HttpServletRequest request, final HttpServletResponse response) throws IOException { final BeanFactory<Author, Integer> authorFactory = new AuthorFactoryImpl(); Author author = null; if (authorFactory != null) { author = (Author) authorFactory.getMember(5); } I can't pull the Author class. Any help would be greatly appreciated.

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  • The best cross platform (portable) arbitrary precision math library

    - by Siu Ching Pong - Asuka Kenji
    Dear ninjas / hackers / wizards, I'm looking for a good arbitrary precision math library in C or C++. Could you please give me some advices / suggestions? The primary requirements: It MUST handle arbitrarily big integers (my primary interest is on integers). In case that you don't know what the word arbitrarily big means, imagine something like 100000! (the factorial of 100000). The precision MUST NOT NEED to be specified during library initialization / object creation. The precision should ONLY be constrained by the available resources of the system. It SHOULD utilize the full power of the platform, and should handle "small" numbers natively. That means on a 64-bit platform, calculating 2^33 + 2^32 should use the available 64-bit CPU instructions. The library SHOULD NOT calculate this in the same way as it does with 2^66 + 2^65 on the same platform. It MUST handle addition (+), subtraction (-), multiplication (*), integer division (/), remainder (%), power (**), increment (++), decrement (--), gcd(), factorial(), and other common integer arithmetic calculations efficiently. Ability to handle functions like sqrt() (square root), log() (logarithm) that do not produce integer results is a plus. Ability to handle symbolic computations is even better. Here are what I found so far: Java's BigInteger and BigDecimal class: I have been using these so far. I have read the source code, but I don't understand the math underneath. It may be based on theories / algorithms that I have never learnt. The built-in integer type or in core libraries of bc / Python / Ruby / Haskell / Lisp / Erlang / OCaml / PHP / some other languages: I have ever used some of these, but I have no idea on which library they are using, or which kind of implementation they are using. What I have already known: Using a char as a decimal digit, and a char* as a decimal string and do calculations on the digits using a for-loop. Using an int (or a long int, or a long long) as a basic "unit" and an array of it as an arbitrary long integer, and do calculations on the elements using a for-loop. Booth's multiplication algorithm What I don't know: Printing the binary array mentioned above in decimal without using naive methods. Example of a naive method: (1) add the bits from the lowest to the highest: 1, 2, 4, 8, 16, 32, ... (2) use a char* string mentioned above to store the intermediate decimal results). What I appreciate: Good comparisons on GMP, MPFR, decNumber (or other libraries that are good in your opinion). Good suggestions on books / articles that I should read. For example, an illustration with figures on how a un-naive arbitrarily long binary to decimal conversion algorithm works is good. Any help. Please DO NOT answer this question if: you think using a double (or a long double, or a long long double) can solve this problem easily. If you do think so, it means that you don't understand the issue under discussion. you have no experience on arbitrary precision mathematics. Thank you in advance! Asuka Kenji

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  • How do I explain this to potential employers?

    - by ReferencelessBob
    Backstory: TL;DR: I've gained a lot of experience working for 5 years at one startup company, but it eventually failed. The company is gone and the owner MIA. When I left sixth-form college I didn't want to start a degree straight away, so when I met this guy who knew a guy who was setting up a publishing company and needed a 'Techie' I thought why not. It was a very small operation, he sent mailings to schools, waited for orders to start arriving, then ordered a short run of the textbooks to be printed, stuck them in an envelope posted them out. I was initially going to help him set up a computerized system for recording orders and payments, printing labels, really basic stuff and I threw it together in Access in a couple of weeks. He also wanted to start taking orders online, so I set up a website and a paypal business account. While I was doing this, I was also helping to do the day-to-day running of things, taking phone orders, posting products, banking cheques, ordering textbooks, designing mailings, filing end of year accounts, hiring extra staff, putting stamps on envelopes. I learned so much about things I didn't even know I needed to learn about. Things were pretty good, when I started we sold about £10,000 worth of textbooks and by my 4th year there we sold £250,000 worth of text books. Things were looking good, but we had a problem. Our best selling product had peaked and sales started to fall sharply, we introduced add on products through the website to boost sales which helped for a while, but we had simply saturated the market. Our plan was to enter the US with our star product and follow the same, slightly modified, plan as before. We setup a 1-866 number and had the calls forwarded to our UK offices. We contracted a fulfillment company, shipped over a few thousand textbooks, had a mailing printed and mailed, then sat by the phones and waited. Needless to say, it didn't work. We tried a few other things, at home and in the US, but nothing helped. We expanded in the good times, moving into bigger offices, taking on staff to do administrative and dispatch work, but now cashflow was becoming a problem and things got tougher. We did the only thing we could and scaled things right back, the offices went, the admin staff went, I stopped taking a wage and started working from home. Nothing helped. The business was wound up about about 2 years ago. In the end it turned out that the owner had built up considerable debt at the start of business and had not paid them off during good years, which left him in a difficult position when cashflow had started to dry up. I haven't been able to contact the owner since I found out. It took me a while to get back on my feet after that, but I'm now at University and doing a Computer Science degree. How do I show the experience I have without having to get into all the gory details of what happened?

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