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• In what language was MSDOS originally written in?

  - by nebukadnezzar

  In what language was MSDOS originally written in? The Wikipedia Article implies either C, QBasic or Pascal, but: * C was invented to write UNIX, so I don't believe it was used to write MSDOS * Pascal seems popular to teach programming, but not really popular to write Operating systems in * QBasic didn't seem to be very popular for Operating Systems at the time MSDOS was developed (or was *BASIC ever very popular to write Operating Systems in it?) Except these three languages there is also Assembly, but I assume that Microsoft already switched from Assembly to a "higher" level language? Since C was originally invented for UNIX, I still wouldn't think Microsoft is using C... although the Microsoft API is written in C (I find this kind-of oxymoronic, actually). Can anyone enlighten me on this topic?

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• Best way to check for null values in Java?

  - by Arty-fishL

  I need to check whether the function of an object returns true or false in Java, but that object may be null, so obviously then the function would throw a NullPointerException. This means I need to check if the object is null before checking the value of the function. What is the best way to go about this? I've listed some methods I considered, I just want to know the most sensible one, the one that is best programming practice for Java (opinion?). // method 1 if (foo != null) { if (foo.bar()) { etc... } } // method 2 if (foo != null ? foo.bar() : false) { etc... } // method 3 try { if (foo.bar()) { etc... } } catch (NullPointerException e) { } // method 4 // would this work all the time, would it still call foo.bar()? if (foo != null && foo.bar()) { etc... }

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• Is there any advantages to integrate Smarty with Zend?

  - by keisimone

  Hi, i am quite familiar with Smarty and recently decided to use Zend framework in implementation. because i am aware of the various advantages of Smarty, i insisted my contractor to integrate Smarty in. But now, i am questioning my assumptions. Should I integrate Smarty in with Zend framework? simply because I am familiar with Smarty syntax? I am also involved with the programming. I got the contractor to help in the architecture and with the prototype.

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• Encrypt text using a number

  - by Adam Matan

  Project Euler I have recently begun to solve some of the Project Euler riddles. I found the discussion forum in the site a bit frustrating (most of the discussions are closed and poorly-threaded), So I have decided to publish my Python solutions on launchpad for discussion. The problem is that it seems quite unethical to publish these solutions, as it would let other people gain reputation without doing the programming work, which the site deeply discourages. My Encryption problem I want to encrypt my answers so that only those who have already solved the riddles can see my code. The logical key would be the answer to the riddle, which is always numeric. In order to prevent brute-force attacks on my answers, I want to find an encryption algorithm that takes a significantly long time (few seconds) to run. Do you know any such algorithm? I would fancy a Python package, which I can attach to the code, over an external program that might have portability issues. Thanks, Adam

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• Hidden Features and Dark Corners of STL?

  - by Andrei

  C++ developers, all know the basics of C++: Declarations, conditionals, loops, operators, etc. Some of us even mastered the stuff like templates, object model, complex I/O, etc. But what are the most hidden features or tricks or dark corners of C++/STL that even C++ fans, addicts, and experts barely know? I am talking about a seasoned C++ programmer (be she/he a developer, student, fan, all three, etc), who thinks (s)he knows something 99% of us never heard or dreamed about. Something that not only makes his/her work easier, but also cool and hackish. After all, C++ is one of the most used programming languages in the world, thus it should have intricacies that only a few privileged know about and want to share with us. Boost is welcome too! One per post with an example please P.S Examples are important for other developers to copy and paste!

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• Consolidate loan, purchase & sale tables into one transaction table.

  - by Frank Computer

  INFORMIX-SE with ISQL 7.3: I have separate tables for Loan, Purchase & Sales transactions. Each tables rows are joined to their respective customer rows by: customer.id [serial] = loan.foreign_id [integer]; = purchase.foreign_id [integer]; = sale.foreign_id [integer]; I would like to consolidate the three tables into one table called "transaction", where a column: transaction.trx_type char(1) {L=Loan, P=Purchase, S=Sale} identifies the transaction type. Each transaction will be assigned a unique transaction number [serial]. Is this a good idea or is it better to keep them in separate tables? Storage space is not a concern, I think it would be easier programming & user-wise to have all types of transactions under one table, whenever possible. This implies denormalization.

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• How stable or unstable is symfony 2.0 ?

  - by Doron

  Well, I know it's a preview, and I know it says that it's not yet ready for production, and yet I dare ask the question. I need to start building a pretty big application, which is planned to go live at around sep-oct 2010. Lets say I will not release the application to production until the stable version of symfony 2.0 will be released - is it a good idea (well, I'll settle for a viable idea) for me to start building the application using the 2.0 version ? How big is the chance I will need to rewrite/replace code I've written due to core changes in the framework ? Thanks. Edit: the other option right now, is to use symfony 1.4. I have thought and tried Zend Framework, but I refuse to re-invent each and every module, which will cost me a lot of programming hours (if not days/weeks).

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• verilog or systemc for testbench

  - by Alphaneo

  I am assigned with the task of verifying some verilog based RTL code. Now, coding the RTL testbench using verilog seems to be very difficult (for me). So I would like to try one of the following. - Try providing a PLI interface to the RTL and thereby invoke 'C functions for testing - Using system 'C for interfacing the 'C functions PS: I already have a extensive 'C code that was used for testing the behavioral model. I am new to the world of hardware programming. Any pointers would be greatly appreciated.

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• Parallel Assignment operator in Ruby

  - by Bragaadeesh

  Hi, I was going through an example from Programming in Ruby book. This is that example def fib_up_to(max) i1, i2 = 1, 1 # parallel assignment (i1 = 1 and i2 = 1) while i1 <= max yield i1 i1, i2 = i2, i1+i2 end end fib_up_to(100) {|f| print f, " " } The above program simply prints the fibonacci numbers upto 100. Thats fine. My question here is when i replace the parallel assignment with something like this, i1 = i2 i2 = i1+i2 I am not getting the desired output. My question here is, is it advisable to use parallel assignments? (I come from Java background and it feels really wierd to see this type of assignment) One more doubt is : Is parallel assignment an operator?? Thanks

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• Rsync over ssh: "ERROR: module is read only" suddenly appeared

  - by user978548

  I've used from some time rsync/ssh to backup my shared host contents to my personal Synology NAS (212j for that matter), and it worked quite well. For information, I use a password-less ssh connection. 3 days ago, I updated my NAS software and since (or at least I believe it's since that), the backup won't work anymore. I get the following error on the host: rsync: writefd_unbuffered failed to write 4 bytes to socket [sender]: Broken pipe (32) ERROR: module is read only ..which I do not understand. beside that nothing changed that I know of in both source and destination that can be related to rsync or ssh, I did check a few things and all seems to be alright: I can still connect through ssh from the host to my NAS with the good user, so ssh stuff like keys haven't changed. I also have the correct file permissions on the NAS (I checked, and also tried to create files, directories, .. with the user used by rsync through ssh). I read here and there that the error means that I have to ensure that my rsyncd.conf have the right read only = no in it, but as far as I know, I never used rsyncd as well as I never configured anything for it and until now it worked like a charm.. I use the following command to do the backup: rsync -ab --recursive \ --files-from="$FILES_FROM" \ --backup-dir=backup_$SUFFIX \ --delete \ --filter='protect backup_*' \ $WDIRECTORY/ \ remote_backup:$REMOTE_BACKUP/ So I'm stuck and really can't figure out what happened. Edit: As suggested in comments, I also tried passing commands to ssh (but not from inside a ssh session), that worked as expected, and also tried a single rsync command, which didnt worked, failing just like the complete backup command. (sharedHost):hostuser:~ > touch test.txt (sharedHost):hostuser:~ > rsync test.txt remote_backup:backups/test.txt ERROR: module is read only rsync error: syntax or usage error (code 1) at main.c(1034) [Receiver=3.0.8] rsync: connection unexpectedly closed (9 bytes received so far) [sender] rsync error: error in rsync protocol data stream (code 12) at io.c(601) [sender=3.0.7] and (sharedHost):hostuser:~ > ssh remote_backup 'touch /abs_path_to_backups/backups/test2.txt && echo "ProoF" > /abs_path_to_backups/backups/test2.txt' (sharedHost):hostuser:~ > ssh remote_backup 'cat /abs_path_to_backups/backups/test2.txt' ProoF

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• In what language was MSDOS originally written?

  - by nebukadnezzar

  In what language was MSDOS originally written in? The Wikipedia Article implies either C, QBasic or Pascal, but: C was invented to write UNIX, so I don't believe it was used to write MSDOS Pascal seems popular to teach programming, but not really popular to write Operating systems in QBasic didn't seem to be very popular for Operating Systems at the time MSDOS was developed (or was *BASIC ever very popular to write Operating Systems in it?) Except these three languages there is also Assembly, but I assume that Microsoft already switched from Assembly to a "higher" level language? Since C was originally invented for UNIX, I still wouldn't think Microsoft is using C... although the Microsoft API is written in C (I find this kind-of oxymoronic, actually). Can anyone enlighten me on this topic?

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• Best way to return a user-generated file, AJAX or Forms?

  - by Bill Zimmerman

  Hi, I'm new to web programming, so I need some help. I am writing a custom file-creation app for my site. A user visits the page, clicks on some various options and toggles some checkboxes, and the presses a 'download now' link. I have a PHP backend which will be processing the submission, and generating a PDF file. After the user presses the download link, I want the download to start like it would for any static link. My question is: What is the best way to do this? From my limited understanding, I have a choice between using AJAX or somehow using forms to submit the data. What are the advantages/disadvantages of each? Does anyone have any good links to examples? Thanks

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• Good way to cache data during Android application lifecycle?

  - by sniurkst

  Hello, keeping my question short, I have creating application with 3 activities, where A - list of categories, B - list of items, C - single item. Data displayed in B and C is parsed from online XML. But, if I go trough A - B1 - C, then back to A and then back to B1 I would like to have it's data cached somewhere so I wouldn't have to request XML again. I'm new to Android and Java programming, I've googled a lot and still can't find (or simply do not have an idea where to look) a way to do what I want. Would storing all received data in main activity A (HashMaps? ContentProviders?) and then passing to B and C (if they get same request that was before) be a good idea?

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• Resources for TDD aimed at Python Web Development

  - by Null Route

  I am a hacker not and not a full-time programmer but am looking to start my own full application development experiment. I apologize if I am missing something easy here. I am looking for recommendations for books, articles, sites, etc for learning more about test driven development specifically compatible with or aimed at Python web application programming. I understand that Python has built-in tools to assist. What would be the best way to learn about these outside of RTFM? I have searched on StackOverflow and found the Kent Beck's and David Astels book on the subject. I have also bookmarked the Wikipedia article as it has many of these types of resources. Are there any particular ones you would recommend for this language/application?

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• What is the current state of Ubuntu's transition from init scripts to Upstart? [migrated]

  - by Adam Eberlin

  What is the current state of Ubuntu's transition from init.d scripts to upstart? I was curious, so I compared the contents of /etc/init.d/ to /etc/init/ on one of our development machines, which is running Ubuntu 12.04 LTS Server. # /etc/init.d/ # /etc/init/ acpid acpid.conf apache2 --------------------------- apparmor --------------------------- apport apport.conf atd atd.conf bind9 --------------------------- bootlogd --------------------------- cgroup-lite cgroup-lite.conf --------------------------- console.conf console-setup console-setup.conf --------------------------- container-detect.conf --------------------------- control-alt-delete.conf cron cron.conf dbus dbus.conf dmesg dmesg.conf dns-clean --------------------------- friendly-recovery --------------------------- --------------------------- failsafe.conf --------------------------- flush-early-job-log.conf --------------------------- friendly-recovery.conf grub-common --------------------------- halt --------------------------- hostname hostname.conf hwclock hwclock.conf hwclock-save hwclock-save.conf irqbalance irqbalance.conf killprocs --------------------------- lxc lxc.conf lxc-net lxc-net.conf module-init-tools module-init-tools.conf --------------------------- mountall.conf --------------------------- mountall-net.conf --------------------------- mountall-reboot.conf --------------------------- mountall-shell.conf --------------------------- mounted-debugfs.conf --------------------------- mounted-dev.conf --------------------------- mounted-proc.conf --------------------------- mounted-run.conf --------------------------- mounted-tmp.conf --------------------------- mounted-var.conf networking networking.conf network-interface network-interface.conf network-interface-container network-interface-container.conf network-interface-security network-interface-security.conf newrelic-sysmond --------------------------- ondemand --------------------------- plymouth plymouth.conf plymouth-log plymouth-log.conf plymouth-splash plymouth-splash.conf plymouth-stop plymouth-stop.conf plymouth-upstart-bridge plymouth-upstart-bridge.conf postgresql --------------------------- pppd-dns --------------------------- procps procps.conf rc rc.conf rc.local --------------------------- rcS rcS.conf --------------------------- rc-sysinit.conf reboot --------------------------- resolvconf resolvconf.conf rsync --------------------------- rsyslog rsyslog.conf screen-cleanup screen-cleanup.conf sendsigs --------------------------- setvtrgb setvtrgb.conf --------------------------- shutdown.conf single --------------------------- skeleton --------------------------- ssh ssh.conf stop-bootlogd --------------------------- stop-bootlogd-single --------------------------- sudo --------------------------- --------------------------- tty1.conf --------------------------- tty2.conf --------------------------- tty3.conf --------------------------- tty4.conf --------------------------- tty5.conf --------------------------- tty6.conf udev udev.conf udev-fallback-graphics udev-fallback-graphics.conf udev-finish udev-finish.conf udevmonitor udevmonitor.conf udevtrigger udevtrigger.conf ufw ufw.conf umountfs --------------------------- umountnfs.sh --------------------------- umountroot --------------------------- --------------------------- upstart-socket-bridge.conf --------------------------- upstart-udev-bridge.conf urandom --------------------------- --------------------------- ureadahead.conf --------------------------- ureadahead-other.conf --------------------------- wait-for-state.conf whoopsie whoopsie.conf To be honest, I'm not entirely sure if I'm interpreting the division of responsibilities properly, as I didn't expect to see any overlap (of what framework handles which services). So I was quite surprised to learn that there was a significant amount of overlap in service references, in addition to being unable to discern which of the two was intended to be the primary service framework. Why does there seem to be a fair amount of redundancy in individual service handling between init.d and upstart? Is something else at play here that I'm missing? What is preventing upstart from completely taking over for init.d? Is there some functionality that certain daemons require which upstart does not yet have, which are preventing some services from converting? Or is it something else entirely?

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• printing uid of a file on linux system

  - by neo730

  i am learning c programming. I am trying to make my own program similar to ls command but with less options.what i am doing is taking input directory/file name as argument and then gets all directory entry with dirent struct(if it is directory) . After it i use stat() to take all information of the file but here is my problem when i use write() to print these value its fine but when i want to print these with printf() i get warninng : format ‘%ld’ expects type ‘long int’, but argument 2 has type ‘__uid_t’. I don't know what should use at place of %ld and also for other special data types.

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• CMS common Architecture

  - by Shalan

  Hi there, I know this is a weird question to ask, but I would like to know if there is any documentation/blog-article out there that explains the architecture of a Website content management system? More particularly, I am interested to learn more about how "widgets" are implemented. I can't remember which system it was that I've seen tis one, but in the "Page Layout view" it had the ability to allow the end user to select a widget (thumbnail gallery, contact form, etc) from a list, and drag and drop it onto custom areas of the page. I know that this is not directly a programming question, but please could I seek advice/feedback on this. Thanks!

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• Redirect print in Python: val = print(arg) to output mixed iterable to file

  - by emcee

  So lets say I have an incredibly nested iterable of lists/dictionaries. I would like to print them to a file as easily as possible. Why can't I just redirect print to a file? val = print(arg) gets a SyntaxError. Is there a way to access stdinput? And why does print take forever with massive strings? Bad programming on my side for outputting massive strings, but quick debugging--and isn't that leveraging the strength of an interactive prompt? There's probably also an easier way than my gripe. Has the hive-mind an answer?

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• What tech stack/platform to use for a project?

  - by danny z

  Hey guys, This is a bit of a weird meta-programming question, but I've realized that my new project doesn't need a full MVC framework, and being a rails guy, I'm not sure what to use now. To give you a gist of the necessary functionality; this website will display static pages, but users will be able to log in and 'edit their current plans'. All purchasing and credit card editing is being handled by a recurring payment subscriber, I just need a page to edit their current plan. All of that will be done through (dynamic) XML API calls, so no database is necessary. Should I stick with my typical rails/nginx stack, or is there something I could use that would lighten the load, since I don't need the Rails heft. I'm familiar with python and PHP but would prefer not to go that route. Is Sinatra a good choice here? tl;dr: What's a good way to quickly serve mostly static pages, preferably in Ruby, with some pages requiring dynamic XML rendering?

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• Type patterns and generic classes in Haskell

  - by finnsson

  I'm trying to understand type patterns and generic classes in Haskell but can't seem to get it. Could someone explain it in laymen's terms? In [1] I've read that "To apply functions generically to all data types, we view data types in a uniform manner: except for basic predefined types such as Float, IO, and ?, every Haskell data type can be viewed as a labeled sum of possibly labeled products." and then Unit, :*: and :+: are mentioned. Are all data types in Haskell automatically versions of the above mentioned and if so how do I figure out how a specific data type is represented in terms of :*:, etc? The users guide for generic classes (ch. 7.16) at haskell.org doesn't mention the predefined types but shouldn't they be handled in every function if the type patterns should be exhaustive? [1] Comparing Approaches to Generic Programming in Haskell, Ralf Hinze, Johan Jeuring, and Andres Löh

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• How to get distinct values from a column with all its corresponding values in another column

  - by Vishnu

  I know the question is bit confusing. Please read below. I have a table table_categories (id INT(11), cname VARCHAR(25),survey_id INT(11)) I want to retrieve the values for the column cname without duplication, that is distinct values but with all the values in the other column. id cname survey_id -- -------- --------- 1 Trader 2 2 Beginner 2 25 Human 1 26 Human 2 From the above example I want to retrieve distinct cnames with all the values of the survey_id. I don't want to use any programming language. Is there any way by using a single query. Please give me a solution in MySQL.

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• Why the "mutable default argument fix" syntax is so ugly, asks python newbie

  - by Cawas

  Now following my series of "python newbie questions" and based on another question. Go to http://python.net/~goodger/projects/pycon/2007/idiomatic/handout.html#other-languages-have-variables and scroll down to "Default Parameter Values". There you can find the following: def bad_append(new_item, a_list=[]): a_list.append(new_item) return a_list def good_append(new_item, a_list=None): if a_list is None: a_list = [] a_list.append(new_item) return a_list So, question here is: why is the "good" syntax over a known issue ugly like that in a programming language that promotes "elegant syntax" and "easy-to-use"? Why not just something in the definition itself, that the "argument" name is attached to a "localized" mutable object like: def better_append(new_item, a_list=[].local): a_list.append(new_item) return a_list I'm sure there would be a better way to do this syntax, but I'm also almost positive there's a good reason to why it hasn't been done. So, anyone happens to know why?

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• Cross-platform GUI toolkits with WPF-style composition capabilities

  - by Alexey Romanov

  A huge advantage of WPF over, say, WinForms is its composability. To quote Programming WPF: One level up, WPF provides its “content model,” which allows any control to host any group of other controls. You don’t have to build special BitmapButton or IconComboBox classes; you put as many images, shapes, videos, 3D models, or whatever into a Button (or a ComboBox, ListBox, etc.) as suit your fancy. Are there any cross-platform GUI frameworks (preferably with Java bindings) out there which also let you do this?

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• Changing UINavigationBar font in Swift

  - by dcgoss

  I have a UINavigationBar with a title in the middle. I have added a custom font ("Comic_Andy.ttf") to my app (I have checked info.plist to make sure it's listed, and I have checked the Copy Bundle Resources to make sure it has been added), and I would like the title of the UINavigationBar to be displayed in that font. From what I can gather it seems as though I'm supposed to use this in my ViewController: myNavigationBar.titleTextAttributes = [NSFontAttributeName: UIFont(name: "Comic_Andy", size: 22)] I placed that method in the viewDidLoad function of the ViewController. I have also tried this in the didFinishLaunchingWithOptions function of the AppDelegate: UINavigationBar.appearance().titleTextAttributes = [NSFontAttributeName: UIFont(name: "Comic_Andy", size: 22)] I am programming in Swift, in XCode 6 Beta 6. Many resources regarding this task have mentioned using a method called setTitleTextAttributes, which is nowhere to be seen. I can't figure it out for the life of me - I've probably spent close to 3 hours on it by now - I have checked every StackOverflow answer, every website, so please do not mark this as a duplicate. Many thanks in advance!

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• A compiler for automata theory

  - by saadtaame

  I'm designing a programming language for automata theory. My goal is to allow programmers to use machines (DFA, NFA, etc...) as units in expressions. I'm confused whether the language should be compiled, interpreted, or jit-compiled! My intuition is that compilation is a good choice, for some operations might take too much time (converting NFA's to equivalent DFA's can be expensive). Translating to x86 seems good. There is one issue however: I want the user to be able to plot machines. Any ideas?

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