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• Getting kernel errors when manually mounting VirtualBox shared folders

  - by Ross

  Updated: I've rephrased this problem as I understand it a bit more now (and have encountered another problem). I'm using a Fedora 15 guest on a Windows 7 host using VirtualBox. I am trying to mount a partition on the host PC as a shared folder for use in the guest. The folder appears in /media and is accessible when I use the auto-mount feature when setting up the shared folder, but when I attempt to mount without auto-mount I get the following error: $ sudo mount.vboxsf data /mnt/host_data /sbin/mount.vboxsf: Could not add an entry to the mount table.: Invalid argument In addition a popup appears (part of Fedora/GNOME) reporting a crash in the kernel package: WARNING: at lib/list_debug.c:26 __list_add+0x3e/0x81() However the shared folder seems to work, I can certainly browse it (although everything seems to be executable, probably down to a Windows host). Is there something wrong with what I'm doing or is this a bug (and in which case should it be reported to the Linux Kernel team or VirtualBox)?

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• How to choose light version of database system

  - by adopilot

  I am starting one POS (Point of sale) project. Targeting system is going to be written in C# .NET 2 WinForms and as main database server We are going to use MS-SQL Server. As we have a lot of POS devices in chain for one store I will love to have backend local data base system on each POS device. Scenario are following: When main server goes down!! POS application should continue working "off-line" with local database, until connection to main server come up again. Now I am in dilemma which local database is going to be most adoptable for me. Here is some notes for helping me point me in right direction: To be Light "My POS devices art usually old and suffering with performances" To be Free "I have a lot of devices and I do not wont additional cost beside main SQL serer" One day Ill love to try all that port on Mono and Linux OS. Here is what I've researched so far: Simple XML "Light but I am afraid of performance, My main table of items is average of 10K records" SQL-Express "I am afraid that my POS devices is poor with hardware for SQLExpress, and also hard to install on each device and configure" Less known Advantage Database Server have free distribution of offline ADT system. DBF with extended Library,"Respect for good old DBFs but that era is behind Me with clipper and DBFs" MS Access Sqlite "Mostly like for now, but I am afraid how it is going to pair with MS SQL do they have same Data types". I know that in this SO is a lot of subjective data, but at least can someone recommended some others lite database system, or things that I shod most take attention before I choice database.

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• Using Comparable to compare objects and sorting them in a TreeMap

  - by arjacsoh

  II cannot understand how should the natural ordering of class be "consistent with equals" when implementing the Comparable interface. I deteted a flaw in my program and therefore I deteced that in the documentantion of the interface Comparable. My problem is that although two Objects are considered as distinct on the base of equals method, the TreeMap structure treats them as equal and consequently does not accept the second insert. The sample code is: public class Car implements Comparable<Car> { int weight; String name; public Car(int w, String n) { weight=w; name=n; } public boolean equals(Object o){ if(o instanceof Car){ Car d = (Car)o; return ((d.name.equals(name)) && (d.weight==weight)); } return false; } public int hashCode(){ return weight/2 + 17; } public String toString(){ return "I am " +name+ " !!!"; } public int compareTo(Car d){ if(this.weight>d.weight) return 1; else if(this.weight<d.weight) return -1; else return 0; } /*public int compareTo(Car d){ return this.name.compareTo(d.name); }*/ } public static void main(String[] args) { Car d1 = new Car(100, "a"); Car d2 = new Car(110, "b"); Car d3 = new Car(110, "c"); Car d4 = new Car(100, "a"); Map<Car, Integer> m = new HashMap<Car, Integer>(); m.put(d1, 1); m.put(d2, 2); m.put(d3, 3); m.put(d4, 16); for(Map.Entry<Car, Integer> me : m.entrySet()) System.out.println(me.getKey().toString() + " " +me.getValue()); TreeMap<Car, Integer> tm = new TreeMap<Car, Integer>(m); System.out.println("After Sorting: "); for(Map.Entry<Car, Integer> me : tm.entrySet()) System.out.println(me.getKey().toString() + " " +me.getValue()); } The output is : I am a !!! 16 I am c !!! 3 I am b !!! 2 After Sorting: I am a !!! 16 I am c !!! 2 That is, that the object c has replaced (somewhat) object b. If I comment the original equals method and uncomment the second equals method, which compares the objects according name, the output is the expected: I am a !!! 16 I am c !!! 3 I am b !!! 2 After Sorting: I am a !!! 16 I am b !!! 2 I am c !!! 3 Why does it come around in this way and what should I alter in order to insert and sort different objects with some attributes of equal value in a TreeMap?

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• Stop Munin messages from /var/log/syslog

  - by Sparsh Gupta

  Hello I am using munin on a system which is adding a log entry in syslog everytime the munin-node cron job executes. It is not an issue but it sometimes makes other errors spotting difficult. There are entries like Feb 28 07:05:01 li235-57 CRON[2634]: (root) CMD (if [ -x /etc/munin/plugins/apt_all ]; then /etc/munin/plugins/apt_all update 7200 12 >/dev/null; elif [ -x /etc/munin/plugins/apt ]; then /etc/munin/plugins/apt update 7200 12 >/dev/null; fi) every 5 minutes and I was wondering how can I stop the messages going into syslog. For munin specific errors I anyways have to keep an eye on /var/log/munin/* Thanks Sparsh

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• Missing management console for Symantec Antivirus, Corporate Edition

  - by Alex C.

  I work for a small (80 employees) non-profit organization. We have a Windows network with a domain. The file server is running Server 2003. A vendor recently installed Symantec Antivirus, Corporate Edition, ver. 10.1.8.8000. It used to be the case that when I logged in to the file server as administrator, I would see an icon on the desktop that took me to the management console for the antivirus software. I could check logs, statuses of client machines, set policies, etc. That icon is now missing, and I can't find anything relevant under the "Start" menu. There is an entry for Symantec Antivirus, but that only gives me the panel for the client process, not the overall management console for the whole network. I don't want to call the vendor back to fix this (I'm baffled how we lost the icon in the first place). Can someone offer some guidance?

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• Catch-all DNS record

  - by Christian Sciberras

  Intro Our users have the ability to buy a domain (eg: user1.com) and make it point to out website, (eg: example.com), by simply pointing user1.com to ns1/ns2.example.com . Issue So far everything's good, however, example.com does not like this; we need to set up WHM/cpanel to make the server accept user1.com . Problem is, we'd rather made this automatic, possibly without having to use WHM API. The question We need some sort of "catch-all" wildcard entry so that we capture all of our user's possible domains.

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• ExecutorService memory leak on exception

  - by TofuBeer

  I am having a hard time tracking this down since the profiler keeps crashing (hotspot error). Before I go too deep into figuring it out I'd like to know if I really have a problem or not :-) I have a few thread pools created via: Executors.newFixedThreadPool(10); The threads connect to different web sites and, on occasion, I get connection refused and wind up throwing an exception. When I later on call Future.get() to get the result it will then catch the ExecutionException that wraps the exception that was thrown when the connection could not be made. The program uses a fairly constant amount of memory up until the point in time that the exceptions get thrown (they tend to happen in batches when a particular site is overloaded). After that point the memory again remains constant but at a higher level. So my question is along the lines of is the memory behaviour (reported by "top" on Unix) expected because the exceptions just triggered something or do I probably have an actual leak that I'll need to track down? Additionally when Future.get() throws an exception is there anything else I need to do besides catch the exception (such as call Future.cancel() on it)?

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• Cannot change password for user postgres in postgresql

  - by dhaval

  I have made the following entry in pg_hba.conf local all all trust but still su postgres does not accept blank as password. I am not able to run psql nor pg_ctl for same reason as most of the files are owned by postgres. EDIT1 dhaval@ubuntu:~$ su -c "pg_ctl reload -D template1" Password: su: Authentication failure dhaval@ubuntu:~$ su -c psql Password: su: Authentication failure I am giving the root password above but I guess its expecting "postgres" superuser password. I dont have the same. I need to reset it. EDIt2 dhaval@ubuntu:~$ sudo -i -u postgres [sudo] password for dhaval: postgres@ubuntu:~$ psql Welcome to psql 8.3.7, the PostgreSQL interactive terminal. The above has taken me postgreSQL command prompt. But I am still not sure why the "trust" was not working.

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• iptables ACCEPT policy

  - by kamae

  In Redhat EL 6, iptables INPUT policy is ACCEPT but INPUT chain has REJECT entry in the end. /etc/syconfig/iptables is as below: *filter :INPUT ACCEPT [0:0] :FORWARD ACCEPT [0:0] :OUTPUT ACCEPT [0:0] -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT -A INPUT -p icmp -j ACCEPT -A INPUT -i lo -j ACCEPT -A INPUT -m state --state NEW -m tcp -p tcp --dport 22 -j ACCEPT -A INPUT -j REJECT --reject-with icmp-host-prohibited -A FORWARD -j REJECT --reject-with icmp-host-prohibited COMMIT Do you know why the policy is ACCEPT not DROP? I think setting DROP policy is safer than ACCEPT in case to make mistake in the chain. Actually the policy is not applied to any packet: # iptables -L -v Chain INPUT (policy ACCEPT 0 packets, 0 bytes)

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• Draw a position from a 2d Array on respected canvas location

  - by Anon

  Background: I have two 2d arrays. Each index within each 2d array represents a tile which is drawn on a square canvas suitable for 8 x 8 tiles. The first 2d array represents the ground tiles and is looped and drawn on the canvas using the following code: //Draw the map from the land 2d array map = new Canvas(mainFrame, 20, 260, 281, 281); for(int i=0; i < world.length; i++){ for(int j=0; j < world[i].length; j++){ for(int x=0; x < 280; x=x+35){ for(int y=0; y < 280; y=y+35){ Point p = new Point(x,y); map.add(new RectangleObject(p,35,35,Colour.green)); } } } } This creates a grid of green tiles 8 x 8 across as intended. The second 2d array represents the position on the ground. This 2d array has everyone of its indexes as null apart from one which is comprised of a Person class. Problem I am unsure of how I can draw the position on the grid. I was thinking of a similar loop, so it draws over the previous 2d array another set of 64 tiles. Only this time they are all transparent but the one tile which isn't null. In other words, the tile where Person is located. I wanted to use a search throughout the loop using a comparative if statement along the lines of if(!(world[] == null)){ map.add(new RectangleObject(p,35,35,Colour.red));} However my knowledge is limited and I am confused on how to implement it.

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• customized xkb layouts not working (in KDE?) after upgrade from Ubuntu 9.10 to 10.04

  - by Alan

  I customised my keyboard layout in 9.10 by editing the appropriate /usr/share/X11/xkb/symbols/ file. After upgrading to 10.04 I noticed it had overwritten all my modifications, so I recovered the layout and overwrote the symbol file's base entry. Sadly KDE (and, presumably, the entire OS) seems to ignore the files altogether. The help files don't mention anything about modifying layouts anyway (and the layout switcher seems to be using setxkbmap, which uses the above path according to its man page), so I'm at a bit of a loss. Do I need to compile this into some other format somehow or how do I get it to work?

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• Why does iChat Server keep connecting to proxy.eu.jabber.org?

  - by Tom Hamming

  I have OS X Server 10.6.5 running on a new Mac Mini (server model), serving several functions among which is iChat Server (iChat and Pidgin on Windows as clients). In the iChat log in Server Admin, I kept seeing entries about connecting to proxy.eu.jabber.org. It's for our office network and I wasn't excited about external access to it, so I disabled server-to-server XMPP federation and now the connections just time out. But why is it doing that in the first place? Sample log entry: (datetime) (servername)jabberd/resolver[portnum]: [xmpp-server._tcp.proxy.eu.jabber.org resolved to 208.68.163.220:5269 (300 seconds to live) then: sending dialback auth request for route '(full server hostname)/proxy.eu.jabber.org' A couple minutes later, it comes back with: dialback for outgoing route '(full server hostname)/proxy.eu.jabber.org' timed out

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• PHP: Best solution for links breaking in a mod_rewrite app

  - by psil

  I'm using mod rewrite to redirect all requests targeting non-existent files/directories to index.php?url=* This is surely the most common thing you do with mod_rewrite yet I have a problem: Naturally, if the page url is "mydomain.com/blog/view/1", the browser will look for images, stylesheets and relative links in the "virtual" directory "mydomain.com/blog/view/". Problem 1: Is using the base tag the best solution? I see that none of the PHP frameworks out there use the base tag, though. I'm currently having a regex replace all the relative links to point to the right path before output. Is that "okay"? Problem 2: It is possible that the server doesn't support mod_rewrite. However, all public files like images, stylesheets and the requests collector index.php are located in the directory /myapp/public. Normally mod_rewrite points all request to /public so it seems as if public was actually the root directory too all users. However if there is no mod_rewrite, I then have to point the users to /public from the root directory with a header() call. That means, however that all links are broken again because suddenly all images, etc. have to be called via /public/myimage.jpg Additional info: When there is no mod_rewrite the above request would look like this: mydomain.com/public/index.php/blog/view/1 What would be the best solutions for both problems?

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• wsgi django not working

  - by MaKo

  im installing django, the test for wsgi is ok, but when i point my default file to the django test, it doesnt work, this is the test that works fine: default: /etc/apache2/sites-available/default <VirtualHost *:80> ServerName www.example.com ServerAlias example.com ServerAdmin [email protected] DocumentRoot /var/www <Directory /var/www/documents> Order allow,deny Allow from all </Directory> WSGIScriptAlias / /home/ubuntu/djangoProj/micopiloto/application.wsgi <Directory /home/ubuntu/djangoProj/mysitio/wsgi_handler.py> Order allow,deny Allow from all </Directory> </VirtualHost> application.wsgi:: ~/djangoProj/micopiloto import os import sys sys.path.append('/srv/www/cucus/application') os.environ['PYTHON_EGG_CACHE'] = '/srv/www/cucus/.python-egg' def application(environ, start_response): status = '200 OK' output = 'Hello World!MK SS9 tkt kkk' response_headers = [('Content-type', 'text/plain'), ('Content-Length', str(len(output)))] start_response(status, response_headers) return [output] but if I change the default to point to application_sa.wsgi the django test, it doesnt work :( application_sa.wsgi import os, sys sys.path.append('/home/ubuntu/djangoProj/micopiloto') os.environ['DJANGO_SETTINGS_MODULE'] = 'micopiloto.settings' import django.core.handlers.wsgi application = django.core.handlers.wsgi.WSGIHandler() I restart the apache server every time i change the wsgi to test, so what im i missing? thanks a lot!

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• image appears larger than bounding rectangle?

  - by Kildareflare

  Hello I'm implementing a custom print preview control. One of the objects it needs to display is an image which can be several pages high and wide. I've successfully divided the image into pages and displayed them in the correct order. Each "page" is drawn within the marginbounds. (That is, each page is sized to be the same as the marginBounds.) The problem I have is that the image the page represents exceeds the bottom margin. However if I draw a rectangle with the same dimensions as the image, at the same position as the image, the rectangle matches the marginbounds. Thus when drawn to the page (in print preview and printed page) the image is larger than a rectangle drawn based on the image dimensions. I.e. The image is drawn at the same size as e.MarignBounds and is drawn at e.MarginBounds.Location yet exceeds the bottom margin. How is this? I've checked resoutions at each step of the process and they are all 96DPI. //... private List<Image> m_printImages = new List<Image>(); //... private void ImagePrintDocument_PrintPage(object sender, PrintPageEventArgs e) { PrepareImageForPrinting(e); e.Graphics.DrawImage(m_printImages[m_currentPage], new Point(e.MarginBounds.X, e.MarginBounds.Y); e.Graphics.DrawRectangle(new Pen(Color.Blue, 1.0F), new Rectangle( new Point(e.MarginBounds.X, e.MarginBounds.Y), new Size(m_printImages[m_currentPage].Width, m_printImages[m_currentPage].Height))); //rest of handler } PS Not able to show an image as free image hosting blocked here.

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• Questions on method to use: Facebook Business Page with Flash or Facebook Application?

  - by Jay

  Hi there, I'm new to Facebook's Graph API / FBML / etc. So if at any point in my post I make a mistake or wrong assumption, please point them out. One of the projects that I am working on has a need to get data/info from an existing web site in addition to the friends list and such that FB can provide. This is for a platform that allows people from all over the world to help out in small scale projects that will benefit various communities. These projects are usually to help out people in unfortunate / less than ideal situations / living conditions so that their environment improves. You can read about it in detail at http://www.getitdone.org. The initial idea was to develop a Business Page (this is the same as a Fan Page right?) for each Project with a Static FBML tag to do the displaying. However, iframes are not allowed in Pages (as far as I know, iframes are only allowed in an FB Application). So it is no longer possible to get data from the web site to be displayed in the FB Page. So one of the options is to embed a Flash in the Page's Tab. I am fairly certain that the Flash can retrieve data on the User's friends and connections in an Application's context (because of all of those darn FB games that I'm addicted to :p). However, I would like to confirm if it can do the same if it's embedded in a Business Page's Tab. Could someone please confirm on this issue? The other option that we arrived at was (if the earlier options fails) to have an Application built instead. However, this means that we would need to create an Application for each Project. Not an ideal situation. Is there any other option that we have missed that can help us achieve the desired result with as little hassle as possible? Any help that you can provide on this matter is most welcome. Thank you.

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• Broken characters in filenames only in some directories

  - by Kaivosukeltaja

  We have a web server running CentOS 5.8 that uses SVN for version control. When trying to switch to the latest revision, we got an error about the filenames of files in an upload directory: svn: Error converting entry in directory 'adm/emails/upload' to UTF-8 svn: Valid UTF-8 data (hex: 54 79) followed by invalid UTF-8 sequence (hex: f6 6b 69 72) Upon investigating, we noticed there were some files that had broken filenames: $ ls ~/public_html/adm/emails/upload/ Ty?el?m?trendit.csv Ty?kirja1.csv To get the update completed quickly, we simply mved the files into our home directory. Surprisingly, their filenames looked fine in their new location: $ ls ~/ Työelämätrendit.csv Työkirja1.csv After the update we moved them back to where they were and their filenames were broken again. What could cause this and how can we fix it? The system's locale is set to LANG=en_US.UTF-8.

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• How to set global PATH on OS X Server 10.6.6?

  - by Adam Lindberg

  I'm running Tomcat on OS X Server 10.6.6 under the normal Web component that comes with the OS. This has worked fine so far, but I need to add some entries to the $PATH environment variable for programs that I want access to from the web server (more specifically, I'm running Hudson under Tomcat which needs access to build tools that I have installed). Tomcat and the Web component seems to run under the user _appserver which has a different $PATH than the administrator account. What's the proper way to add a global entry to the $PATH in OS X Server for the Web component? Preferable it should be done only once so that both the _appserver and Administrator user can access the same $PATH.

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• Sendmail /etc/hosts and DNS ... what is the correct way?

  - by ben

  I found one tutorial on setting up sendmail that says that in the /etc/hosts file, "The entry for 127.0.0.1 must always be followed by the fully qualified domain name (FQDN) of the server." Like so: 127.0.0.1 bigboy.my-site.com localhost.localdomain localhost bigboy (This tutorial is here). However, I can't find anyone else suggesting something like that. instead most people seem to put some combination of localhost and localdomain.localhost after 127.0.0.1, and then some variant of the fully qualified domain name after the public ip address. What is the correct way?

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• WPF create a list of controls that can be scrolled via the mouse but still remain functional

  - by Mark

  I have a list of controls that I am displaying via a WrapPanel and it horizontally oriented. I have implemented a "Click and Drag" scrolling technique so that the user scrolls with the mouse via clicking and dragging. Like so: <Canvas x:Name="ParentCanvas" PreviewMouseDown="Canvas_MouseDown" MouseMove="Canvas_MouseMove"> <WrapPanel> <WrapPanel.RenderTransform> <TranslateTransform /> </WrapPanel.RenderTransform> <!-- controls are all in here ... --> </WrapPanel> </Canvas> Then in the code behind: private Point _mousePosition; private Point _lastMousePosition; private void Canvas_MouseDown(object sender, MouseButtonEventArgs e) { _lastMousePosition = e.GetPosition(ParentCanvas); e.Handled = true; } private void Canvas_MouseMove(object sender, MouseEventArgs e) { _mousePosition = e.GetPosition(ParentCanvas); var delta = _mousePosition - _lastMousePosition; if(e.LeftButton == MouseButtonState.Pressed && delta.X != 0) { var transform = ((TranslateTransform)_wrapPanel.RenderTransform).Clone(); transform.X += delta.X; _wrapPanel.RenderTransform = transform; _lastMousePosition = _mousePosition; } } This all works fine But what I want to do is make it so that when a users clicks to drag, the items within the WrapPanel dont respond (i.e. the user is only browsing), but when the user clicks (as in a full click) then they do respond to the click. Just like how the iphone works, when you press and drag directly on an app, it does not open the app, but rather scrolls the screen, but when you tap the app, it starts... I hope this makes sense. Cheers, Mark

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• Reshape linux md raid5 that is already being reshaped?

  - by smammy

  I just converted my RAID1 array to a RAID5 array and added a third disk to it. I'd like to add a fourth disk without waiting fourteen hours for the first reshape to complete. I just did this: mdadm /dev/md0 --add /dev/sdf1 mdadm --grow /dev/md0 --raid-devices=3 --backup-file=/root/md0_n3.bak The entry in /proc/mdstat looks like this: md0 : active raid5 sdf1[2] sda1[0] sdb1[1] 976759936 blocks super 0.91 level 5, 64k chunk, algorithm 2 [3/3] [UUU] [>....................] reshape = 1.8% (18162944/976759936) finish=834.3min speed=19132K/sec Now I'd like to do this: mdadm /dev/md0 --add /dev/sdd1 mdadm --grow /dev/md0 --raid-devices=4 --backup-file=/root/md8_n4.bak Is this safe, or do I have to wait for the first reshape operation to complete? P.S.: I know I should have added both disks first, and then reshaped from 2 to 4 devices, but it's a little late for that.

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• How to use sshd_config - PermitUserEnvironment option

  - by laks

  I have client1 and client2 both are linux machines. From client1: client1$ssh root@client2 "env" it displays list of ssh variables from client2. Things I did on client2: I want to add new variable to client2 . So I edited sshd_config to PermitUserEnvironment yes and created a file environment under ssh with following entry Hi=Hello then restart sshd /etc/init.d/sshd Now from client1 trying the same command client1$ssh root@client2 "env" didn't provide the new variable "Hi". ref: http://www.raphink.info/2008/09/forcing-environment-in-ssh.html http://www.netexpertise.eu/en/ssh/environment-variables-and-ssh.html/comment-page-1#comment-1703

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• Problem with setjmp/longjmp

  - by user294732

  The code below is just not working. Can anybody point out why #define STACK_SIZE 1524 static void mt_allocate_stack(struct thread_struct *mythrd) { unsigned int sp = 0; void *stck; stck = (void *)malloc(STACK_SIZE); sp = (unsigned int)&((stck)); sp = sp + STACK_SIZE; while((sp % 8) != 0) sp--; #ifdef linux (mythrd->saved_state[0]).__jmpbuf[JB_BP] = (int)sp; (mythrd->saved_state[0]).__jmpbuf[JB_SP] = (int)sp-500; #endif } void mt_sched() { fprintf(stdout,"\n Inside the mt_sched"); fflush(stdout); if ( current_thread->state == NEW ) { if ( setjmp(current_thread->saved_state) == 0 ) { mt_allocate_stack(current_thread); fprintf(stdout,"\n Jumping to thread = %u",current_thread->thread_id); fflush(stdout); longjmp(current_thread->saved_state, 2); } else { new_fns(); } } } All I am trying to do is to run the new_fns() on a new stack. But is is showing segmentation fault at new_fns(). Can anybody point me out what's wrong.

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• Testing DNS configuration of domain by using hosts file?

  - by Alex Blundell

  I'm currently migrating a website to another server, and want to test the DNS configuration (more specifically, email mx records) before moving the domain over. I've configured the DNS on the new server to have mx entries for Google Apps in the same way that it's configured on the old server. The domain is controlled by nameservers on the old server at the moment, so the change would simply be updating the nameservers to the new servers. (What I'm getting at is DNS is controlled at the server level, not registrar level). Since the website has quite a number of users, I want to make sure the configuration is right before flicking the switch. For this, can I add an entry to the hosts file of my local computer to point the domain to the new server? I've done this, and the web server works, but would this also test the email mx records on the new server?

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• Getting a handle on GIS math, where do I start?

  - by Joshua

  I am in charge of a program that is used to create a set of nodes and paths for consumption by an autonomous ground vehicle. The program keeps track of the locations of all items in its map by indicating the item's position as being x meters north and y meters east of an origin point of 0,0. In the real world, the vehicle knows the location of the origin's lat and long, as it is determined by a dgps system and is accurate down to a couple centimeters. My program is ignorant of any lat long coordinates. It is one of my goals to modify the program to keep track of lat long coords of items in addition to an origin point and items' x,y position in relation to that origin. At first blush, it seems that I am going to modify the program to allow the lat long coords of the origin to be passed in, and after that I desire that the program will automatically calculate the lat long of every item currently in a map. From what I've researched so far, I believe that I will need to figure out the math behind converting to lat long coords from a UTM like projection where I specify the origin points and meridians etc as opposed to whatever is defined already for UTM. I've come to ask of you GIS programmers, am I on the right track? It seems to me like there is so much to wrap ones head around, and I'm not sure if the answer isn't something as simple as, "oh yea theres a conversion from meters to lat long, here" Currently, due to the nature of DGPS, the system really doesn't need to care about locations more than oh, what... 40 km? radius away from the origin. Given this, and the fact that I need to make sure that the error on my coordinates is not greater than .5 meters, do I need anything more complex than a simple lat/long to meters conversion constant? I'm knee deep in materials here. I could use some pointers about what concepts to research. Thanks much!

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