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• Android 2.1 gallery not backward compatible with Cupcake version, now what?

  - by Schermvlieger

  I don't know why, but in Eclair, the default (non-fancy) gallery app changed its begaviour from the Cupcake version, and it broke one of my commercial applications :-( Firstly, when long-pressing a gallery and choosing "Diashow", it does not publish an Intent to be picked up by any application that implements the Intent filter anymore. Instead, it will directly call "com.android.gallery/com.android.camera.ViewImage" with extras. Question: is it still possible to intercept this intent and allow the user to choose my application to do the Diashow? Secondly, the intent extras for the VIEW intent are messed up (in my build of 2.1 anyway): Instead of providing the BucketId of the picture in the Intent's queryparameter. But in 2.1, the BucketId is moved to the Intent's extras. Except; it is not passing the BUCKET_ID, but the unlocalized BUCKET_DISPLAY_NAME instead :-/ Question: how can I still get the unique BUCKET_ID from the intent, so that I do not have to work with a potentially non-unique BUCKET_DISPLAY_NAME? Is there anybody out there who has come up with a working solution for these problems? I thought the whole idea of Android Intents was to be able to integrate your applications with the base Android environment, but my build of 2.1 proves that this idea still lives in the land of Theory :-(

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• How do I gather data from the same collumn in multiple worksheets in a single workbook?

  - by infiniteloop91

  Okay so here is what I want to accomplish. For this example I have a single workbook composed of 4 data sheets plus a totals sheet. Each of the 4 data sheets has a similar name following the same pattern where the only difference is the date. (Ex. 9854978_1009_US.txt, where 1009 is the date that changes while the rest of the file name is the same). In each of those documents column F contains a series of number that I would like to find the sum of but I will have no idea how many cells in F actually contain numbers. (However there will never be additional information below it the numbers so I could in theory just add the entire F column together). I will also add new files to the workbook over time and do not want to have to rewrite the code of which I gather my data from column F. Essentially what I would like to accomplish is for the 'totals' document to take every column F from documents in the workbook with the name of '9854978_????_US.txt', where the question marks change based on the file name. How would I go about doing this in pure Excel code?

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• Iterate Through JSON Data for Specific Element - Similar to XPath

  - by Highroller

  I am working on an embedded system and my theory of the overall process follows this methodology: 1. Send a command to the back end asking for account information in JSON format. 2. The back end writes a JSON file with all accounts and associated information (there could be 0 to 16 accounts). 3. Here's where I get stuck - use JavaScript (we are using the JQuery library) to iterate through the returned information for a specific element (similar to XPath) and build an array based on the number of elements found to populate a drop-down box to select the account you want to view and then do stuff with the account info. So my code looks like this: loadAccounts = function() { $.getJSON('/info?q=voip.accounts[]', function(result) { var sipAcnts = $("#sipacnts"); $(sipAcnts).empty(); // empty the dropdown (if necessarry) // Get the 'label' element and stick it in an array // build the array and append it to the sipAcnts dropdown // use array index to ref the accounts info and do stuff with it } So what I need is the JSON version of XPath to build the array of voip.accounts.label. The first account info looks something like this: { "result_set": { "voip.accounts[0]": { "label": "Dispatch1", "enabled": true, "user": "1234", "name": "Jane Doe", "type": "sip", "sip": { "lots and lots of stuff": }, } } } Am I over complicating the issue? Any wisdom anyone could thrown down would be greatly appreciated.

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• How to identify multiple identical pairs in two vectors

  - by Sacha Epskamp

  In my graph-package (as in graph theory, nodes connected by edges) I have a vector indicating for each edge the node of origin from, a vector indicating for each edge the node of destination to and a vector indicating the curve of each edge curve. By default I want edges to have a curve of 0 if there is only one edge between two nodes and curve of 0.2 if there are two edges between two nodes. The code that I use now is a for-loop, and it is kinda slow: curve <- rep(0,5) from<-c(1,2,3,3,2) to<-c(2,3,4,2,1) for (i in 1:length(from)) { if (any(from==to[i] & to==from[i])) { curve[i]=0.2 } } So basically I look for each edge (one index in from and one in to) if there is any other pair in from and to that use the same nodes (numbers). What I am looking for are two things: A way to identify if there is any pair of nodes that have two edges between them (so I can omit the loop if not) A way to speed up this loop # EDIT: To make this abit clearer, another example: from <- c(4L, 6L, 7L, 8L, 1L, 9L, 5L, 1L, 2L, 1L, 10L, 2L, 6L, 7L, 10L, 4L, 9L) to <- c(1L, 1L, 1L, 2L, 3L, 3L, 4L, 5L, 6L, 7L, 7L, 8L, 8L, 8L, 8L, 10L, 10L) cbind(from,to) from to [1,] 4 1 [2,] 6 1 [3,] 7 1 [4,] 8 2 [5,] 1 3 [6,] 9 3 [7,] 5 4 [8,] 1 5 [9,] 2 6 [10,] 1 7 [11,] 10 7 [12,] 2 8 [13,] 6 8 [14,] 7 8 [15,] 10 8 [16,] 4 10 [17,] 9 10 In these two vectors, pair 3 is identical to pair 10 (both 1 and 7 in different orders) and pairs 4 and 12 are identical (both 2 and 8). So I would want curve to become: [1,] 0.0 [2,] 0.0 [3,] 0.2 [4,] 0.2 [5,] 0.0 [6,] 0.0 [7,] 0.0 [8,] 0.0 [9,] 0.0 [10,] 0.2 [11,] 0.0 [12,] 0.2 [13,] 0.0 [14,] 0.0 [15,] 0.0 [16,] 0.0 [17,] 0.0 (as I vector, I transposed twice to get row numbers).

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• How do I do a table join on two fields in my second table?

  - by Cannonade

  I have two tables: Messages - Amongst other things, has a to_id and a from_id field. People - Has a corresponding person_id I am trying to figure out how to do the following in a single linq query: Give me all messages that have been sent to and from person x (idself). I had a couple of cracks at this. Not quite right MsgPeople = (from p in db.people join m in db.messages on p.person_id equals m.from_id where (m.from_id == idself || m.to_id == idself) orderby p.name descending select p).Distinct(); This almost works, except I think it misses one case: "people who have never received a message, just sent one to me" How this works in my head So what I really need is something like: join m in db.messages on (p.people_id equals m.from_id or p.people_id equals m.to_id) Gets me a subset of the people I am after It seems you can't do that. I have tried a few other options, like doing two joins: MsgPeople = (from p in db.people join m in AllMessages on p.person_id equals m.from_id join m2 in AllMessages on p.person_id equals m2.to_id where (m2.from_id == idself || m.to_id == idself) orderby p.name descending select p).Distinct(); but this gives me a subset of the results I need, I guess something to do with the order the joins are resolved. My understanding of LINQ (and perhaps even database theory) is embarrassingly superficial and I look forward to having some light shed on my problem.

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• Pointer and malloc issue

  - by Andy

  I am fairly new to C and am getting stuck with arrays and pointers when they refer to strings. I can ask for input of 2 numbers (ints) and then return the one I want (first number or second number) without any issues. But when I request names and try to return them, the program crashes after I enter the first name and not sure why. In theory I am looking to reserve memory for the first name, and then expand it to include a second name. Can anyone explain why this breaks? Thanks! #include <stdio.h> #include <stdlib.h> void main () { int NumItems = 0; NumItems += 1; char* NameList = malloc(sizeof(char[10])*NumItems); printf("Please enter name #1: \n"); scanf("%9s", NameList[0]); fpurge(stdin); NumItems += 1; NameList = realloc(NameList,sizeof(char[10])*NumItems); printf("Please enter name #2: \n"); scanf("%9s", NameList[1]); fpurge(stdin); printf("The first name is: %s",NameList[0]); printf("The second name is: %s",NameList[1]); return 0; }

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• How can I get a list of modified records from a SQL Server database?

  - by Pixelfish

  I am currently in the process of revamping my company's management system to run a little more lean in terms of network traffic. Right now I'm trying to figure out an effective way to query only the records that have been modified (by any user) since the last time I asked. When the application starts it loads the job information and caches it locally like the following: SELECT * FROM jobs. I am writing out the date/time a record was modified ala UPDATE jobs SET Widgets=@Widgets, LastModified=GetDate() WHERE JobID=@JobID. When any user requests the list of jobs I query all records that have been modified since the last time I requested the list like the following: SELECT * FROM jobs WHERE LastModified>=@LastRequested and store the date/time of the request to pass in as @LastRequest when the user asks again. In theory this will return only the records that have been modified since the last request. The issue I'm running into is when the user's date/time is not quite in sync with the server's date/time and also of server load when querying an un-indexed date/time column. Is there a more effective system then querying date/time information?

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• How to speed up a slow UPDATE query

  - by Mike Christensen

  I have the following UPDATE query: UPDATE Indexer.Pages SET LastError=NULL where LastError is not null; Right now, this query takes about 93 minutes to complete. I'd like to find ways to make this a bit faster. The Indexer.Pages table has around 506,000 rows, and about 490,000 of them contain a value for LastError, so I doubt I can take advantage of any indexes here. The table (when uncompressed) has about 46 gigs of data in it, however the majority of that data is in a text field called html. I believe simply loading and unloading that many pages is causing the slowdown. One idea would be to make a new table with just the Id and the html field, and keep Indexer.Pages as small as possible. However, testing this theory would be a decent amount of work since I actually don't have the hard disk space to create a copy of the table. I'd have to copy it over to another machine, drop the table, then copy the data back which would probably take all evening. Ideas? I'm using Postgres 9.0.0. UPDATE: Here's the schema: CREATE TABLE indexer.pages ( id uuid NOT NULL, url character varying(1024) NOT NULL, firstcrawled timestamp with time zone NOT NULL, lastcrawled timestamp with time zone NOT NULL, recipeid uuid, html text NOT NULL, lasterror character varying(1024), missingings smallint, CONSTRAINT pages_pkey PRIMARY KEY (id ), CONSTRAINT indexer_pages_uniqueurl UNIQUE (url ) ); I also have two indexes: CREATE INDEX idx_indexer_pages_missingings ON indexer.pages USING btree (missingings ) WHERE missingings > 0; and CREATE INDEX idx_indexer_pages_null ON indexer.pages USING btree (recipeid ) WHERE NULL::boolean; There are no triggers on this table, and there is one other table that has a FK constraint on Pages.PageId.

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• Collision Detection (Ground & Slopes) in 2D Platform Game using Pygame Rects

  - by RedCap

  Hi, First off, I am not after any instructions on logic for collision detection; I get it. What I am trying to work out is the least complicated way to do this with Pygame using Sprites & Rects. I want to be able to check collisions for the Player against ground, walls & slopes. In theory it is quite straight forward, but I'm having difficulty because it seems like you cannot do this with one Rect. One Rect is simple enough to get you collisions in the X plane against walls. The same Rect could be used also be used in the Y plane against solids, but not with slopes - since with the collision routines in Pygame it checks the whole Rect (or mask), rather than perhaps just the bottom middle of the Rect. It seems in addition you need to have a number of "sprites" to check collisions with, that are 1x1 pixel in various places around the Player. What's the easiest way to do this, without having a bunch of 3, 4, or more separate "collision pixels" to check against slopes? Geoff

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• "Find all tiles connected to this one" project

  - by Omega

  Remember MS Paint? The bucket tool? If you used it and clicked on a pixel, all pixels connected to this pixel that are the same are affected. The theory is, I suppose, to check if there is any pixel adjacent to the selected one. If such pixel is the same type as the selected one, check for more adjacent pixels in this one, and so on. I want to implement something similar in VB.NET. Basically I have a 2D array map which represents the map. Let's assume there are only two types of tile: 0 and 1. Now, I got pretty much everything ready: I got my 2d map and I can tell which tile is clicked and tell what array indexes are the ones that represent such tile. Now for the "painting" process. Whenever I think about it, I can't figure a convenient way to execute such iteration. Can someone help me choosing a correct design/way/tip to achieve this?

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• Can Visual Studio (should it be able to) compute a diff between any two changesets associated with a

  - by Hamish Grubijan

  Here is my use case: I start on a project XYZ, for which I create a work item, and I make frequent check-ins, easily 10-20 in total. ALL of the code changes will be code-read and code-reviewed. The change sets are not consecutive - other people check-in in-between my changes, although they are very unlikely to touch the exact same files. So ... at the en of the project I am interested in a "total diff" - as if there was a single check-in by me to complete the entire project. In theory this is computable. From the list of change sets associated with the work item, you get the list of all files that were affected. Then, the algorithm can aggregate individual diffs over each file and combine them into one. It is possible that a pure total diff is uncomputable due to the fact that someone else renamed files, or changed stuff around very closely, or in the same functions as me. I that case ... I suppose a total diff can include those changes by non-me as well, and warn me about the fact. I would find this very useful, but I do not know how to do t in practice. Can Visual Studio 2008/2010 (and/or TFS server) do it? Are there other source control systems capable of doing this? Thanks.

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• Is `super` local variable?

  - by Michael

  // A : Parent @implementation A -(id) init { // change self here then return it } @end A A *a = [[A alloc] init]; a. Just wondering, if self is a local variable or global? If it's local then what is the point of self = [super init] in init? I can successfully define some local variable and use like this, why would I need to assign it to self. -(id) init { id tmp = [super init]; if(tmp != nil) { //do stuff } return tmp; } b. If [super init] returns some other object instance and I have to overwrite self then I will not be able to access A's methods any more, since it will be completely new object? Am I right? c. super and self pointing to the same memory and the major difference between them is method lookup order. Am I right? sorry, don't have Mac to try, learning theory as for now...

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• Rails: Duplicate functionality across controllers? A humble plea.

  - by Alex

  So I'm working with authlogic, and I'm trying to duplicate the login functionality to the welcome page, so that you can log in by restful url or by just going to the main page. No, I don't know if we'll keep that feature, but I want to test it out anyway. Here's the error message: RuntimeError in Welcome#index Called id for nil, which would mistakenly be 4 -- if you really wanted the id of nil, use object_id The code is below. Basically, what's happening is the index view (the first code snippet) is sending the information from the form to the create method of user_sessions controller. At this point, in theory, it create should just pick up, but it doesn't. PLEASE help. Please. I've been doing this for about 8 hours. I checked Google. I checked IRC. I checked every book I could find. You don't even have to answer, I can to the grunt work if you just point me in the right direction. <% form_for @user_session, :url => user_sessions_path do |f| %> <%= f.text_field :email %><br /> <%= f.password_field :password %> <%= submit_tag 'Login' %> <% end %> class ApplicationController < ActionController::Base helper :all # include all helpers, all the time protect_from_forgery # See ActionController::RequestForgeryProtection for details # Scrub sensitive parameters from your log # filter_parameter_logging :password helper_method :current_user_session, :current_user before_filter :new_session_object protected def new_session_object unless current_user @user_session = UserSession.new(params[:user_session]) end end private def current_user_session return @current_user_session if defined?(@current_user_session) @current_user_session = UserSession.find end def current_user return @current_user if defined?(@current_user) @current_user = current_user_session && current_user_session.record end end

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• Heap Algorithmic Issue

  - by OberynMarDELL

  I am having this algorithmic problem that I want to discuss about. Its not about find a solution but about optimization in terms of runtime. So here it is: Suppose we have a race court of Length L and a total of N cars that participate on the race. The race rules are simple. Once a car overtakes an other car the second car is eliminated from the race. The race ends when no more overtakes are possible to happen. The tricky part is that the k'th car has a starting point x[k] and a velocity v[k]. The points are given in an ascending order, but the velocities may differ. What I've done so far: Given that a car can get overtaken only by its previous, I calculated the time that it takes for each car to reach its next one t = (x[i] - x[i+1])/(v[i] - v[i+1]) and I insert these times onto a min heap in O(n log n). So in theory I have to pop the first element in O(logn), find its previous, pop it as well , update its time and insert it in the heap once more, much like a priority queue. My main problem is how I can access specific points of a heap in O(log n) or faster in order to keep the complexity in O(n log n) levels. This program should be written on Haskell so I would like to keep things simple as far as possible EDIT: I Forgot to write the actual point of the race. The goal is to find the order in which cars exit the game

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• Quickly generate junk data of certain size in Javascript

  - by user1357607

  I am writing an upload speed test in Javascript. I am using Jquery (and Ajax) to send chunks of data to a server in order to time how long it takes to get a response. This should, in theory give an estimation, of the upload speed. Of course to cater for different bandwidths of the user I sequentially upload larger and larger amounts of junk data until a threshold duration is reached. Currently I generate the junk data using the following function, however, it is very slow when generation megabytes of data. function generate_random_data(size){ var chars = "abcdefghijklmnopqrstuvwxyz"; var random_data = ""; for (var i = 0; i < size; i++){ var random_num = Math.floor(Math.random() * char.length); random_data = random_data + chars.substring(random_num,random_num+1); } return random_data; Really all I am doing is generating a chunk of bytes to send to the server, however, this is the only way I could find out how in Javascript. Any help would be appreciated.

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• Need help making a div appear on the bottom of the screen while the rest of the divs scroll

  - by user1896600

  It's hard to describe my specific problem without just showing you the HTML code. The HTML source can be seen easily from clicking "View Source" while seeing the page http://techdot.us/projects/jeopardy/view.php. The CSS is located here: http://techdot.us/projects/jeopardy/style/gameStyle.css. My main goal is to have the main content table rows/columns appear on the majority of the screen (everything except 69px, to be exact). So, the bottom 69px contains an informational panel that is supposed to stay on the bottom of the screen, even when the user scrolls down the page. Scrolling is supposed to, in theory, trigger the majority of the content to go down the page normally, except the bottom bar which stays static. I have achieved this effect on the website. However, there is a big problem. On smaller screens (as you can simulate by resizing the window), some of the main table gets cut off. It seems that my CSS solution is a botch, and, in effect, does not accomplish my main goal. The bottom bar should not cut off part of the table from the main content div (gameTable), but the main content div should display all of its content in a scrollable fashion. My CSS at the moment works as long as the viewer's screen is a certain pixel height. This is definitely not permanent. Thank you SO much for the help. I really appreciate it and totally understand that I'm being a total pain by just throwing down tons of CSS and HTML code to edit.

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• Database PK-FK design for future-effective-date entries?

  - by Scott Balmos

  Ultimately I'm going to convert this into a Hibernate/JPA design. But I wanted to start out from purely a database perspective. We have various tables containing data that is future-effective-dated. Take an employee table with the following pseudo-definition: employee id INT AUTO_INCREMENT ... data fields ... effectiveFrom DATE effectiveTo DATE employee_reviews id INT AUTO_INCREMENT employee_id INT FK employee.id Very simplistic. But let's say Employee A has id = 1, effectiveFrom = 1/1/2011, effectiveTo = 1/1/2099. That employee is going to be changing jobs in the future, which would in theory create a new row, id = 2 with effectiveFrom = 7/1/2011, effectiveTo = 1/1/2099, and id = 1's effectiveTo updated to 6/30/2011. But now, my program would have to go through any table that has a FK relationship to employee every night, and update those FK to reference the newly-effective employee entry. I have seen various postings in both pure SQL and Hibernate forums that I should have a separate employee_versions table, which is where I would have all effective-dated data stored, resulting in the updated pseudo-definition below: employee id INT AUTO_INCREMENT employee_versions id INT AUTO_INCREMENT employee_id INT FK employee.id ... data fields ... effectiveFrom DATE effectiveTo DATE employee_reviews id INT AUTO_INCREMENT employee_id INT FK employee.id Then to get any actual data, one would have to actually select from employee_versions with the proper employee_id and date range. This feels rather unnatural to have this secondary "versions" table for each versioned entity. Anyone have any opinions, suggestions from your own prior work, etc? Like I said, I'm taking this purely from a general SQL design standpoint first before layering in Hibernate on top. Thanks!

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• Migrate from Oracle to MySQL

  - by Cassy

  Hi together. We ran into serious performance problems with our Oracle database and we would like to try to migrate to a MySQL-based database (either MySQL directly or, more preferrable, Infobright). The thing is, we need to let the old and the new system overlap for at least some weeks if not months, before we actually know, if all features of the new database match our needs. So, here is our situation: The Oracle database consists of multiple tables with each millions of rows. During the day, there are literally thousands of statements, which we cannot stop for migration. Every morning, new data is imported into the Oracle database, replacing some thousands of rows. Copying this process is not a problem, so we could, in theory, import in both databases in parallel. But, and here lies the challenge, for this to work, we need to have an export from the Oracle database with a consistent state from one day. (We cannot export some tables on Monday and some others on Tuesday, etc.) This means, that at least the export should be finished in less than one day. Our first thought was to dump the schema, but I wasn't able to find a tool to import an Oracle dump file into mysql. Exporting tables in CSV files might work, but I'm afraid it could take too long. So my question now is: What should I do? Is there any tool to import Oracle dump files into MySQL? Does anybody have any experience with such a large-scale migration? Thanks in advance, Cassy PS: Please, don't suggest performance optimization techniques for Oracle, we already tried a lot :-)

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• Setting up a transparent SSL proxy

  - by badunk

  I've got a linux box set up with 2 network cards to inspect traffic going through port 80. One card is used to go out to the internet, the other one is hooked up to a networking switch. The point is to be able to inspect all HTTP and HTTPS traffic on devices hooked up to that switch for debugging purposes. I've written the following rules for iptables: nat -A PREROUTING -i eth1 -p tcp -m tcp --dport 80 -j DNAT --to-destination 192.168.2.1:1337 -A PREROUTING -i eth1 -p tcp -m tcp --dport 80 -j REDIRECT --to-ports 1337 -A POSTROUTING -s 192.168.2.0/24 -o eth0 -j MASQUERADE On 192.168.2.1:1337, I've got a transparent http proxy using Charles (http://www.charlesproxy.com/) for recording. Everything's fine for port 80, but when I add similar rules for port 443 (SSL) pointing to port 1337, I get an error about invalid message through Charles. I've used SSL proxying on the same computer before with Charles (http://www.charlesproxy.com/documentation/proxying/ssl-proxying/), but have been unsuccessful with doing it transparently for some reason. Some resources I've googled say its not possible - I'm willing to accept that as an answer if someone can explain why. As a note, I have full access to the described set up including all the clients hooked up to the subnet - so I can accept self-signed certs by Charles. The solution doesn't have to be Charles-specific since in theory, any transparent proxy will do. Thanks! Edit: After playing with it a little, I was able to get it working for a specific host. When I modify my iptables to the following (and open 1338 in charles for reverse proxy): nat -A PREROUTING -i eth1 -p tcp -m tcp --dport 80 -j DNAT --to-destination 192.168.2.1:1337 -A PREROUTING -i eth1 -p tcp -m tcp --dport 80 -j REDIRECT --to-ports 1337 -A PREROUTING -i eth1 -p tcp -m tcp --dport 443 -j DNAT --to-destination 192.168.2.1:1338 -A PREROUTING -i eth1 -p tcp -m tcp --dport 443 -j REDIRECT --to-ports 1338 -A POSTROUTING -s 192.168.2.0/24 -o eth0 -j MASQUERADE I am able to get a response, but with no destination host. In the reverse proxy, if I just specify that everything from 1338 goes to a specific host that I wanted to hit, it performs the hand shake properly and I can turn on SSL proxying to inspect the communication. The setup is less than ideal because I don't want to assume everything from 1338 goes to that host - any idea why the destination host is being stripped? Thanks again

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• multiple webapps in tomcat -- what is the optimal architecture?

  - by rvdb

  I am maintaining a growing base of mainly Cocoon-2.1-based web applications [http://cocoon.apache.org/2.1/], deployed in a Tomcat servlet container [http://tomcat.apache.org/], and proxied with an Apache http server [http://httpd.apache.org/docs/2.2/]. I am conceptually struggling with the best way to deploy multiple web applications in Tomcat. Since I'm not a Java programmer and we don't have any sysadmin staff I have to figure out myself what is the most sensible way to do this. My setup has evolved through 2 scenarios and I'm considering a third for maximal separation of the distinct webapps. [1] 1 Tomcat instance, 1 Cocoon instance, multiple webapps -tomcat |_ webapps |_ webapp1 |_ webapp2 |_ webapp[n] |_ WEB-INF (with Cocoon libs) This was my first approach: just drop all web applications inside a single Cocoon webapps folder inside a single Tomcat container. This seemed to run fine, I did not encounter any memory issues. However, this poses a maintainability drawback, as some Cocoon components are subject to updates, which often affect the webapp coding. Hence, updating Cocoon becomes unwieldy: since all webapps share the same pool of Cocoon components, updating one of them would require the code in all web applications to be updated simultaneously. In order to isolate the web applications, I moved to the second scenario. [2] 1 Tomcat instance, each webapp in its dedicated Cocoon environment -tomcat |_ webapps |_ webapp1 | |_ WEB-INF (with Cocoon libs) |_ webapp1 | |_ WEB-INF (with Cocoon libs) |_ webapp[n] |_ WEB-INF (with Cocoon libs) This approach separates all webapps into their own Cocoon environment, run inside a single Tomcat container. In theory, this works fine: all webapps can be updated independently. However, this soon results in PermGenSpace errors. It seemed that I could manage the problem by increasing memory allocation for Tomcat, but I realise this isn't a structural solution, and that overloading a single Tomcat in this way is prone to future memory errors. This set me thinking about the third scenario. [3] multiple Tomcat instances, each with a single webapp in its dedicated Cocoon environment -tomcat |_ webapps |_ webapp1 |_ WEB-INF (with Cocoon libs) -tomcat |_ webapps |_ webapp2 |_ WEB-INF (with Cocoon libs) -tomcat |_ webapps |_ webapp[n] |_ WEB-INF (with Cocoon libs) I haven't tried this approach, but am thinking of the $CATALINA_BASE variable. A single Tomcat distribution can be multiply instanciated with different $CATALINA_BASE environments, each pointing to a Cocoon instance with its own webapp. I wonder whether such an approach could avoid the structural memory-related problems of approach [2], or will the same issues apply? On the other hand, this approach would complicate management of the Apache http frontend, as it will require the AJP connectors of the different Tomcat instances to be listening at different ports. Hence, Apache's worker configuration has to be updated and reloaded whenever a new webapp (in its own Tomcat instance) is added. And there seems no way to reload worker.properties without restarting the entire Apache http server. Is there perhaps another / more dynamic way of 'modularizing' multiple Tomcat-served webapps, or can one of these scenarios be refined? Any thoughts, suggestions, advice much appreciated. Ron

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• order of operations for environment variables

  - by alyda

  I want to understand how environment variables are set and reset (overridden). I'm running Apache/2.2.24 (Unix) PHP/5.4.14 on a mac . My theory is this: Environment vars can be set in bash, then they can be overwritten with httpd.conf preceding a VirtualHost directive that precedes php.ini, which can then be overwritten by .htaccess (if allowable) and finally by PHP I tried the following: setting environment variable in bash: I added export ENVIRONMENT='local' to my ~/.bashrc file, restarted apache and did not get any output from print_r($_ENV); (in a simple index.php file at the root of my webserver). I also tried putting ENVIRONMENT='local' into /etc/environment, and restarting apache, nothing, as well as /etc/bashrc, restart apache. still nothing. setting environment variable in httpd.conf: I added SetEnv ENVIRONMENT 'local-httpd to the end of my /etc/apache2/httpd.conf file (but before I load other conf files, such as virtual host [Include /private/etc/apache2/other/*.conf]). I now see the variable in the array print_r($_SERVER); but not print_r($_ENV);. setting environment variable in httpd-vhosts.conf: I added SetEnv ENVIRONMENT 'local-vhost to my /etc/apache2/extra/httpd-vhosts.conf file in my generic directive that points to my default document root. I now see the variable has been overwritten (to local-vhost from local-httpd, so I know where the variable is getting set). setting environment variable in php.ini: while searching for a proper place to put my environment variable, I noticed that variables_order = "GPCS" was set to the production value rather than EGPCS. I changed it, restarted my server and found that I was now getting output for print_r($_ENV); but not my expected custom variable. It also appears that I am not able to set a custom variable in this file. Please tell me if I am wrong setting environment variable in .htaccess: I added SetEnv ENVIRONMENT 'local-htaccess'. This worked as expected, overwriting all other values that were set. setting / overwriting environment variable in PHP: if (...) { putenv('ENVIRONMENT=local'); } I'm asking this question because I have a lot of local and remote testing servers, some of which may or may not allow me access to modify httpd, httpd-vhost, php.ini or environment variables. I want to understand what is best for those difference scenarios (shared hosting, heroku, local servers, etc) I obviously don't know how to properly set the environment variable in bash in a way that php can use it, I'd like to know how to do that (as I think Heroku does something similar with heroku config set...)

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• How to grow to be global sysadmin of an organization?

  - by user64729

  Bit of a non-technical question but I have seen questions of the career development type on here before so hopefully it is fine. I work for a fast growing but still small organization (~65 employees). I have been their external sysadmin for a while now, looking after hosted Linux servers and infrastructure. In the past 12 months I have been transforming into the internal sysadmin for our office too. I'm currently studying Cisco CCNA to cover the demands of being an internal sysadmin and looking after the office LAN, routers, switches and VPNs. Now they want me to look after the global sysadmin function of the organization as a whole. The organization has 3 offices in total, 2 in the UK and 1 in the US. I work in one of the UK offices. The other offices are primarily Windows desktops with AD domain shops. My office is primarily a Linux shop with a file-server and NFS/NIS (no AD domain for the Windows desktops yet but it's in the works). Each other office has a sysadmin which in theory I am supposed to supervise but in reality each is independent. I have a very competent junior sysadmin working with me who shares the day-to-day tasks and does some of the longer term projects with my supervision. My boss has asked me how to grow from being the external sysadmin to the global sysadmin. I am to ponder this and then report back to him on how to achieve this. My current thoughts are: Management training or professional development - eg. reading books such as "Influencer" and "7 Habits". Also I feel I should take steps to improving communication skills since a senior person is expected to talk and speak out more often. Learn more about Windows and Active Directory - I'm an LPI-certified guy and have a lot of experience in Linux (Ubuntu or desktop, Debian/Ubuntu as server). Since the other offices are mainly Windows-domains it makes sense to skill-up in that area so I can understand what the other admins are talking about. Talk to previous colleagues who have are are in this role already - to try and get the benefit of their experience. Produce an "IT Roadmap" or similar that maps out where we want the organization to be and when, plotted out over the next couple of years with regards to internal and external infrastructure. I have produced a "Security roadmap" already which does cover some of these things. I guess this can summed up as "thinking more strategically"? I'd appreciate comments from anyone who has been through a similar situation, thanks.

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• Preinstalled Windows 8 and Linux UEFI dual boot on a laptop

  - by itchy355

  I am trying to set up Windows 8 and Arch Linux on a new Sony Vaio E14 with preinstalled windows 8. So far: installed W8 to my new SSD (switched for the original HDD) using Recovery Media shrunk the W8 partition, deleted recovery partition, disabled swap confirmed W8 booting just fine On to Arch: disabled Secure Boot in bios confirmed W8 booting just fine Booted Arch off the CD and installed everything to 4th and 5th partition set up rEFInd for EFIstub kernel bootloader After that it got worse. I was unable to boot anything else than Windows 8 (although I was glad that they at least kept working just fine). Tried: creating EFI\refind\ and putting the .efi there (as per Arch manual overwriting EFI\boot\bootx64.efi overwriting EFI\Microsoft\Boot\bootmgr.efi overwriting EFI\Microsoft\Boot\bootmgfw.efi --- YAY rEFInd shown up! So far, so good. I've kept the whole W8 Boot\ directory in EFI\windows8 and set up a boot menuentry for it; and it booted just fine. But, upon restart, everything was wrong -- 'Operating system not found' instead of any bootloader (refind or w8). Booted back into Arch using the live CD to find out that the EFI partition had erroneous FAT table. fsck.vfat fixed it, and I've found that EFI\Microsoft\Boot was back to it's original state (all refind files deleted and replaced with W8 bootloaders). I've overwritten them again and got back to rEFInd showing up correctly and Arch being perfectly bootable. After that I've tried only renaming EFI\Microsoft\Boot\bootmgfw.efi to bootmgfw.001.efi (then copying refind's .efi to bootmgfw.efi and keeping EVERY OTHER file as it was), but with exactly the same result. Tried marking the GPT EFI partition as read-only, same result. Now I'm kinda out of luck. Arch boots fine, so does W8 but it destroys the EFI partition in the process. Thanks for any ideas, Googling brought me this far and I can't find any better. PS -- windows 8 MAYBE destroys the partition upon shutdown -- when I order a shutdown in W8, it takes unusually long (about half a minute instead of ~5 seconds). So in theory I could solve this by hard-resetting the laptop instead of a normal shutdown, but that's just not nice.

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• SAS Expanders vs Direct Attached (SAS)?

  - by jemmille

  I have a storage unit with 2 backplanes. One backplane holds 24 disks, one backplane holds 12 disks. Each backplane is independently connected to a SFF-8087 port (4 channel/12Gbit) to the raid card. Here is where my question really comes in. Can or how easily can a backplane be overloaded? All the disks in the machine are WD RE4 WD1003FBYX (black) drives that have average writes at 115MB/sec and average read of 125 MB/sec I know things would vary based on the raid or filesystem we put on top of that but it seems to be that a 24 disk backplane with only one SFF-8087 connector should be able to overload the bus to a point that might actually slow it down? Based on my math, if I had a RAID0 across all 24 disks and asked for a large file, I should, in theory should get 24*115 MB/sec wich translates to 22.08 GBit/sec of total throughput. Either I'm confused or this backplane is horribly designed, at least in a perfomance environment. I'm looking at switching to a model where each drive has it's own channel from the backplane (and new HBA's or raid card). EDIT: more details We have used both pure linux (centos), open solaris, software raid, hardware raid, EXT3/4, ZFS. Here are some examples using bonnie++ 4 Disk RAID-0, ZFS WRITE CPU RE-WRITE CPU READ CPU RND-SEEKS 194MB/s 19% 92MB/s 11% 200MB/s 8% 310/sec 194MB/s 19% 93MB/s 11% 201MB/s 8% 312/sec --------- ---- --------- ---- --------- ---- --------- 389MB/s 19% 186MB/s 11% 402MB/s 8% 311/sec 8 Disk RAID-0, ZFS WRITE CPU RE-WRITE CPU READ CPU RND-SEEKS 324MB/s 32% 164MB/s 19% 346MB/s 13% 466/sec 324MB/s 32% 164MB/s 19% 348MB/s 14% 465/sec --------- ---- --------- ---- --------- ---- --------- 648MB/s 32% 328MB/s 19% 694MB/s 13% 465/sec 12 Disk RAID-0, ZFS WRITE CPU RE-WRITE CPU READ CPU RND-SEEKS 377MB/s 38% 191MB/s 22% 429MB/s 17% 537/sec 376MB/s 38% 191MB/s 22% 427MB/s 17% 546/sec --------- ---- --------- ---- --------- ---- --------- 753MB/s 38% 382MB/s 22% 857MB/s 17% 541/sec Now 16 Disk RAID-0, it's gets interesting WRITE CPU RE-WRITE CPU READ CPU RND-SEEKS 359MB/s 34% 186MB/s 22% 407MB/s 18% 1397/sec 358MB/s 33% 186MB/s 22% 407MB/s 18% 1340/sec --------- ---- --------- ---- --------- ---- --------- 717MB/s 33% 373MB/s 22% 814MB/s 18% 1368/sec 20 Disk RAID-0, ZFS WRITE CPU RE-WRITE CPU READ CPU RND-SEEKS 371MB/s 37% 188MB/s 22% 450MB/s 19% 775/sec 370MB/s 37% 188MB/s 22% 447MB/s 19% 797/sec --------- ---- --------- ---- --------- ---- --------- 741MB/s 37% 376MB/s 22% 898MB/s 19% 786/sec 24 Disk RAID-1, ZFS WRITE CPU RE-WRITE CPU READ CPU RND-SEEKS 347MB/s 34% 193MB/s 22% 447MB/s 19% 907/sec 347MB/s 34% 192MB/s 23% 446MB/s 19% 933/sec --------- ---- --------- ---- --------- ---- --------- 694MB/s 34% 386MB/s 22% 894MB/s 19% 920/sec 28 Disk RAID-0, ZFS 32 Disk RAID-0, ZFS 36 Disk RAID-0, ZFS More details: Here is the exact unit: http://www.supermicro.com/products/chassis/4U/847/SC847E1-R1400U.cfm

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• Ubuntu Lucid: Erratic screen behaviour after boot

  - by fgysin

  In short: about 50% of the time I have a screwed up monitor setup after reboot. About 50% it is totally correct. Now the longer version: I updated my machine from 9.04 to 10.04 (via 9.10). At first I run into some monitor problems (I have a 3-monitor setup) because of the known bug in the new xserver driver for xinerama. This messes up behaviour if the mouse goes either left or above the screen number 0, i.e. I had to make my left-most monitor screen 0. Everything worked out fine finally, I got my 3-monitor setup back with xinerama enabled to get one big desktop streched over 3 screens. Now the fun part: Every time I start up my machine only one of the 3 monitors gets a signal and is woken up: it only recognizes the left-most monitor (screen 0) and crams all the desktop stuff into this one screen. If I go into nvidia settings I only see one physical device although all 3 are connected and have power. When I look into the xorg.conf I can still see my old setup with 3 devices, 3 screens, xinerama active etc... But I was totally unable to get 3 montitors to work. (I tried unplugging monitors, reconfiguring whole nvidia setup, ...) But it gets even better: When I restart my machine (i.e. choose the restart option from the Ubuntu menu) it shuts down and tries to restart. The restart then gets stuck after showing the Ubuntu splash screen with the 'loading bar' (the moving dots thingy) and I am forced to kill the machine by cutting power. But after the power cut the machine boots up normally and suddenly I get my 3 monitor setup back up working. That is until the next time I shut down and start up, where it all starts over again and I only have one monitor... (see above) I really have a hard time seeing where the error is. It must be that the restart boot somehow differs from the 'normal' boot. But the fact that it gets stuck and I need to cut power which then basically triggers a 'normal' boot does not really support this theory... My setup (please tell me if you need further info): 3 monitors as 3 screens as one desktop (with xinerama) 2 nvidia cards where screen 0 and 1 are on card 0 and screen 2 is on card 1 Ubuntu 10.04 Lucid Lynx (updated from 9.10, 9.04, ....) I would appreciate every idea on the subject, at the moment I really don't have any clue what to do...

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