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  • Finding the shortest path through a digraph that visits all nodes

    - by Boluc Papuccuoglu
    I am trying to find the shortest possible path that visits every node through a graph (a node may be visited more than once, the solution may pick any node as the starting node.). The graph is directed, meaning that being able to travel from node A to node B does not mean one can travel from node B to node A. All distances between nodes are equal. I was able to code a brute force search that found a path of only 27 nodes when I had 27 nodes and each node had a connection to 2 or 1 other node. However, the actual problem that I am trying to solve consists of 256 nodes, with each node connecting to either 4 or 3 other nodes. The brute force algorithm that solved the 27 node graph can produce a 415 node solution (not optimal) within a few seconds, but using the processing power I have at my disposal takes about 6 hours to arrive at a 402 node solution. What approach should I use to arrive at a solution that I can be certain is the optimal one? For example, use an optimizer algorithm to shorten a non-optimal solution? Or somehow adopt a brute force search that discards paths that are not optimal? EDIT: (Copying a comment to an answer here to better clarify the question) To clarify, I am not saying that there is a Hamiltonian path and I need to find it, I am trying to find the shortest path in the 256 node graph that visits each node AT LEAST once. With the 27 node run, I was able to find a Hamiltonian path, which assured me that it was an optimal solution. I want to find a solution for the 256 node graph which is the shortest.

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  • Ubuntu 12.04 boot degraded raid

    - by beacon_bonanza
    I've installed Ubuntu 12.04.1 in a new server and set up the 4 hard drives with 3 RAID 1 devices, the configuration is such that the first two drives have md0 (swap space) and md1 (/) with the third and fourth drives having md2 (/var). I've been testing the operation under a drive failure and found that the system boots fine if I remove disk two but if I remove disk one then the system gets to grub and then just restarts. I'm confused as to why grub appears to be loading properly from disk two but then the boot fails. I've tried to copy the MBR from disk 1 to 2: dd if=/dev/sda of=/dev/sdb bs=512 count=1 but this didn't make a difference. Any ideas how to get it to boot from just the second disk? fdisk -l Disk /dev/sda: 2000.4 GB, 2000398934016 bytes 255 heads, 63 sectors/track, 243201 cylinders, total 3907029168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x000ccfa5 Device Boot Start End Blocks Id System /dev/sda1 2048 31250431 15624192 fd Linux RAID autodetect /dev/sda2 * 31250432 3907028991 1937889280 fd Linux RAID autodetect Disk /dev/sdb: 2000.4 GB, 2000398934016 bytes 255 heads, 63 sectors/track, 243201 cylinders, total 3907029168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x000ccfa5 Device Boot Start End Blocks Id System /dev/sdb1 2048 31250431 15624192 fd Linux RAID autodetect /dev/sdb2 * 31250432 3907028991 1937889280 fd Linux RAID autodetect Disk /dev/sdd: 2000.4 GB, 2000398934016 bytes 255 heads, 63 sectors/track, 243201 cylinders, total 3907029168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00035b05 Device Boot Start End Blocks Id System /dev/sdd1 2048 3907028991 1953513472 fd Linux RAID autodetect Disk /dev/sdc: 2000.4 GB, 2000398934016 bytes 255 heads, 63 sectors/track, 243201 cylinders, total 3907029168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x000c73aa Device Boot Start End Blocks Id System /dev/sdc1 2048 3907028991 1953513472 fd Linux RAID autodetect Disk /dev/md1: 1984.3 GB, 1984264208384 bytes 2 heads, 4 sectors/track, 484439504 cylinders, total 3875516032 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Disk /dev/md2: 2000.3 GB, 2000263380992 bytes 2 heads, 4 sectors/track, 488345552 cylinders, total 3906764416 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Disk /dev/md0: 16.0 GB, 15990652928 bytes 2 heads, 4 sectors/track, 3903968 cylinders, total 31231744 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000

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  • optimal memory layout for read-only/write memory segments.

    - by aaa
    hello. Suppose I have two memory segments (equal size each, approximately 1kb in size) , one is read-only (after initialization), and other is read/write. what is the best layout in memory for such segments in terms of memory performance? one allocation, contiguous segments or two allocations (in general not contiguous). my primary architecture is linux Intel 64-bit. my feeling is former (cache friendlier) case is better. is there circumstances, where second layout is preferred? Thanks

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  • Is their an optimal config/format for a TIFF when using Tesseract or other OCR?

    - by Zando
    I'm having a bizarre problem with Tesseract. I have a name, "Janice" that is in a 200x40 pixel tiff, that Tesseract interprets as a blank. I'm running hundreds of names through Tesseract and they are processed fine. What I'm actually doing, though, is breaking up a larger TIFF into smaller tiffs of one word each. In the larger TIFF, tesseract recognizes "Janice". What could cause it to hiccup in a TIFF that solely contains that word (and there's enough space around the word to not truncate any of the pixels)? I'm using ImageMagick to split the big TIFF, are there options I should set when reconstituting the new TIFF files?

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  • How to figure out optimal C / Gamma parameters in libsvm?

    - by Cuga
    I'm using libsvm for multi-class classification of datasets with a large number of features/attributes (around 5,800 per each item). I'd like to choose better parameters for C and Gamma than the defaults I am currently using. I've already tried running easy.py, but for the datasets I'm using, the estimated time is near forever (ran easy.py at 20, 50, 100, and 200 data samples and got a super-linear regression which projected my necessary runtime to take years). Is there a way to more quickly arrive at better C and Gamma values than the defaults? I'm using the Java libraries, if that makes any difference.

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  • Most efficient algorithm for mesh-level, optimal occlusion culling?

    - by Fredriku73
    I am new to culling. On a first glance, it seems that most occlusion culling algorithms are object-level, not examining single meshes, which would be practical for game rendering. What I am looking for is an algorithm that culls all meshes within a single object that are occluded for a given viewpoint, with high accuracy. It needs to be at least O(n log n), a naive mesh-by-mesh comparison (O(n^2)) is too slow. I notice that the Blender GUI identifies the occluded meshes for you in real-time, even if you work with large objects of 10,000+ meshes. What algorithm is used there, pray tell?

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  • Optimal Activity Stack Order for a Main Menu button?

    - by kefs
    I'm developing an app that starts with a main menu, and then continues through three different steps (activities) to a final activity where the task is marked complete. On this last activity, i have several additional options (add note, share, etc..) and i also have a return to main menu button. My question is.. how do i stack the activities so that calling finish() on the final activity will return back to the first activity launched? i am currently just starting the new activity via an intent, so pressing back on this screen doesn't return me to home as i would like. Sorry in advance for being so convoluted in my desc

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  • Typical SVN repo structure seems to be sub-optimal for continuous integration...

    - by Dave
    I've set up our SVN repository like the Subversion book suggests, and this is also how my previous companies have done it. It looks something like this: /trunk /branches /tags /extlibs /docs where the first three are pretty obvious, and extlibs is for 3rd party assemblies that we wouldn't typically recompile ourselves. All of this works great for the daily development stuff. Now I've installed TeamCity and have builds, unit tests, code coverage, and code analysis running. Everything is great, except for the fact that this code structure results in too much code getting downloaded. So here's the catch 22, in my opinion: it's silly to download all of aforementioned folders from the SVN repo when I only need /trunk and /extlibs. But I can only specify one repo folder to download in the TeamCity VCS settings. So then the other possibility is to put the /extlibs folder into /trunk, but in order to compile branches, /extlibs would have to go into all of those as well (since I usually branch the trunk, and not individual subfolders... and this would seem infinitely more evil since /extlibs could actually be larger than /trunk and /branches, with all of the binaries stored there... Do you guys have any suggestions for me? Thanks!

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  • Most optimal way to detect if black (or any color pixels) exist in an image file?

    - by Zando
    What's the best and most flexible algorithm to detect any black (or colored pixel) in a given image file? Say I'm given an image file that could, say, have a blue background. And any non blue pixel, including a white pixel, is counted as a "mark". The function returns true if there are X number of pixels that deviate from each other at a certain threshold. I thought it'd be fastest to just simply iterate through every pixel and see if its color matches the last. But if it's the case that pixel (0,0) is deviant, and every other pixel is the same color (and I want to allow at least a couple deviated pixels before considering an image to be "marked), this won't work or be terribly efficient.

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  • In a C# app, what is the most optimal way to insert many records into sql server?

    - by Otter
    I need to perform a very large sql server insert from a c# application. Somewhere in the range of 20,000 through 50,000 records. What is the fastest way through SQL server to perform the insert? There are several options I know of, but I don't know which is the fastest. insert into MyTable(column1, column2, ..., column*) select 'value','value',...,'value' union select 'value','value',...,'value' VS insert into MyTable(column1, column2, ..., column*) exec('select ''value'',''value'',...,''value''' 'select ''value'',''value'',...,''value''') VS bulk insert from a data file VS Any better way that you know of :)

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  • How many SQL queries per HTTP request is optimal?

    - by Chris Kooken
    I know the answer to this question for the most part is "It Depends", however I wanted to see if anyone had some pointers. We execute queries each request in ASP.NET MVC. Each request we need to get user rights information, and Various data for the Views that we are displaying. How many is too much, I know I should be conscious to the number of queries i am executing. I would assume if they are small queries and optimized out, half-a-dozen should be okay? Am I right? What do you think?

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  • SQL SERVER – Example of Performance Tuning for Advanced Users with DB Optimizer

    - by Pinal Dave
    Performance tuning is such a subject that everyone wants to master it. In beginning everybody is at a novice level and spend lots of time learning how to master the art of performance tuning. However, as we progress further the tuning of the system keeps on getting very difficult. I have understood in my early career there should be no need of ego in the technology field. There are always better solutions and better ideas out there and we should not resist them. Instead of resisting the change and new wave I personally adopt it. Here is a similar example, as I personally progress to the master level of performance tuning, I face that it is getting harder to come up with optimal solutions. In such scenarios I rely on various tools to teach me how I can do things better. Once I learn about tools, I am often able to come up with better solutions when I face the similar situation next time. A few days ago I had received a query where the user wanted to tune it further to get the maximum out of the performance. I have re-written the similar query with the help of AdventureWorks sample database. SELECT * FROM HumanResources.Employee e INNER JOIN HumanResources.EmployeeDepartmentHistory edh ON e.BusinessEntityID = edh.BusinessEntityID INNER JOIN HumanResources.Shift s ON edh.ShiftID = s.ShiftID; User had similar query to above query was used in very critical report and wanted to get best out of the query. When I looked at the query – here were my initial thoughts Use only column in the select statements as much as you want in the application Let us look at the query pattern and data workload and find out the optimal index for it Before I give further solutions I was told by the user that they need all the columns from all the tables and creating index was not allowed in their system. He can only re-write queries or use hints to further tune this query. Now I was in the constraint box – I believe * was not a great idea but if they wanted all the columns, I believe we can’t do much besides using *. Additionally, if I cannot create a further index, I must come up with some creative way to write this query. I personally do not like to use hints in my application but there are cases when hints work out magically and gives optimal solutions. Finally, I decided to use Embarcadero’s DB Optimizer. It is a fantastic tool and very helpful when it is about performance tuning. I have previously explained how it works over here. First open DBOptimizer and open Tuning Job from File >> New >> Tuning Job. Once you open DBOptimizer Tuning Job follow the various steps indicates in the following diagram. Essentially we will take our original script and will paste that into Step 1: New SQL Text and right after that we will enable Step 2 for Generating Various cases, Step 3 for Detailed Analysis and Step 4 for Executing each generated case. Finally we will click on Analysis in Step 5 which will generate the report detailed analysis in the result pan. The detailed pan looks like. It generates various cases of T-SQL based on the original query. It applies various hints and available hints to the query and generate various execution plans of the query and displays them in the resultant. You can clearly notice that original query had a cost of 0.0841 and logical reads about 607 pages. Whereas various options which are just following it has different execution cost as well logical read. There are few cases where we have higher logical read and there are few cases where as we have very low logical read. If we pay attention the very next row to original query have Merge_Join_Query in description and have lowest execution cost value of 0.044 and have lowest Logical Reads of 29. This row contains the query which is the most optimal re-write of the original query. Let us double click over it. Here is the query: SELECT * FROM HumanResources.Employee e INNER JOIN HumanResources.EmployeeDepartmentHistory edh ON e.BusinessEntityID = edh.BusinessEntityID INNER JOIN HumanResources.Shift s ON edh.ShiftID = s.ShiftID OPTION (MERGE JOIN) If you notice above query have additional hint of Merge Join. With the help of this Merge Join query hint this query is now performing much better than before. The entire process takes less than 60 seconds. Please note that it the join hint Merge Join was optimal for this query but it is not necessary that the same hint will be helpful in all the queries. Additionally, if the workload or data pattern changes the query hint of merge join may be no more optimal join. In that case, we will have to redo the entire exercise once again. This is the reason I do not like to use hints in my queries and I discourage all of my users to use the same. However, if you look at this example, this is a great case where hints are optimizing the performance of the query. It is humanly not possible to test out various query hints and index options with the query to figure out which is the most optimal solution. Sometimes, we need to depend on the efficiency tools like DB Optimizer to guide us the way and select the best option from the suggestion provided. Let me know what you think of this article as well your experience with DB Optimizer. Please leave a comment. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Joins, SQL Optimization, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • Package upgrade on Ubuntu raid server and grub setup issue

    - by RecNes
    I have remote Ubuntu 10.10 server running on raid system. I did package upgrade yesterday night for security reasons. During the upgrade, grub installation screen appeared and asked me which partition I wanted to install grub. Options are sda,sdb,md1 and md2. I decide to install them on both sda and sdb partitions. I wondering, was I make true decision? If machine get reboot is it can be boot up safely? You can find fdisk output and fstab mount points below: Fstab: proc /proc proc defaults 0 0 none /dev/pts devpts gid=5,mode=620 0 0 /dev/md0 none swap sw 0 0 /dev/md1 /boot ext3 defaults 0 0 /dev/md2 / ext3 defaults 0 0 Fdisk: Disk /dev/sda: 750.2 GB, 750156374016 bytes 255 heads, 63 sectors/track, 91201 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00029bb5 Device Boot Start End Blocks Id System /dev/sda1 1 262 2102562 fd Linux raid autodetect /dev/sda2 263 295 265072+ fd Linux raid autodetect /dev/sda3 296 91201 730202445 fd Linux raid autodetect Disk /dev/md0: 2152 MB, 2152923136 bytes 2 heads, 4 sectors/track, 525616 cylinders Units = cylinders of 8 * 512 = 4096 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Disk /dev/md0 doesn't contain a valid partition table Disk /dev/md1: 271 MB, 271319040 bytes 2 heads, 4 sectors/track, 66240 cylinders Units = cylinders of 8 * 512 = 4096 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Disk /dev/md1 doesn't contain a valid partition table Disk /dev/md2: 747.7 GB, 747727224832 bytes 2 heads, 4 sectors/track, 182550592 cylinders Units = cylinders of 8 * 512 = 4096 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Disk /dev/md2 doesn't contain a valid partition table Disk /dev/sdb: 750.2 GB, 750156374016 bytes 255 heads, 63 sectors/track, 91201 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00088969 Device Boot Start End Blocks Id System /dev/sdb1 1 262 2102562 fd Linux raid autodetect /dev/sdb2 263 295 265072+ fd Linux raid autodetect /dev/sdb3 296 91201 730202445 fd Linux raid autodetect

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  • How to use Hardware RAID in Ubuntu Server

    - by user2071938
    I have an Adaptec RAID-Controller and created an RAID-1(Mirroring) succesfully. Now I have installed Ubuntu Server 12.04.3. When I type fdisk -l I get this output: bf@fileserver:~$ sudo fdisk -l Disk /dev/sda: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 4096 bytes / 4096 bytes Disk identifier: 0x00000000 Disk /dev/sda doesn't contain a valid partition table Disk /dev/sdb: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 4096 bytes / 4096 bytes Disk identifier: 0x00000000 Disk /dev/sdb doesn't contain a valid partition table Disk /dev/sdc: 80.0 GB, 80026361856 bytes 255 heads, 63 sectors/track, 9729 cylinders, total 156301488 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x0004c454 Device Boot Start End Blocks Id System /dev/sdc1 * 2048 499711 248832 83 Linux /dev/sdc2 501758 156301311 77899777 5 Extended /dev/sdc5 501760 156301311 77899776 8e Linux LVM Disk /dev/mapper/fileserver--vg-root: 75.6 GB, 75606523904 bytes 255 heads, 63 sectors/track, 9191 cylinders, total 147668992 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Disk /dev/mapper/fileserver--vg-root doesn't contain a valid partition table Disk /dev/mapper/ddf1_Data: 1000.1 GB, 1000065728512 bytes 255 heads, 63 sectors/track, 121584 cylinders, total 1953253376 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 4096 bytes / 4096 bytes Disk identifier: 0x00000000 Disk /dev/mapper/ddf1_Data doesn't contain a valid partition table Disk /dev/mapper/fileserver--vg-swap_1: 4160 MB, 4160749568 bytes 255 heads, 63 sectors/track, 505 cylinders, total 8126464 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Disk /dev/mapper/fileserver--vg-swap_1 doesn't contain a valid partition table The 80 GB HDD is for the System The 1000.2 GB HDD should be for my data. But I'm a bit confused becauser there are listed two 1000.2 GB HDDs, due the Hardware RAID shoudln't there be only one HDD vissible to the OS? (I have two 1000.2 GB HDDs in an Raid-1 Array) dmraid gives me bf@fileserver:~$ sudo dmraid -r /dev/sdb: ddf1, ".ddf1_disks", GROUP, ok, 1953253376 sectors, data@ 0 /dev/sda: ddf1, ".ddf1_disks", GROUP, ok, 1953253376 sectors, data@ 0 so It seems to be ok? But how do I partitionate this disks and which one should I mount(sdb or sda?) Hope you can help me thx Florian

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  • Recover RAID 5 data after created new array instead of re-using

    - by Brigadieren
    Folks please help - I am a newb with a major headache at hand (perfect storm situation). I have a 3 1tb hdd on my ubuntu 11.04 configured as software raid 5. The data had been copied weekly onto another separate off the computer hard drive until that completely failed and was thrown away. A few days back we had a power outage and after rebooting my box wouldn't mount the raid. In my infinite wisdom I entered mdadm --create -f... command instead of mdadm --assemble and didn't notice the travesty that I had done until after. It started the array degraded and proceeded with building and syncing it which took ~10 hours. After I was back I saw that that the array is successfully up and running but the raid is not I mean the individual drives are partitioned (partition type f8 ) but the md0 device is not. Realizing in horror what I have done I am trying to find some solutions. I just pray that --create didn't overwrite entire content of the hard driver. Could someone PLEASE help me out with this - the data that's on the drive is very important and unique ~10 years of photos, docs, etc. Is it possible that by specifying the participating hard drives in wrong order can make mdadm overwrite them? when I do mdadm --examine --scan I get something like ARRAY /dev/md/0 metadata=1.2 UUID=f1b4084a:720b5712:6d03b9e9:43afe51b name=<hostname>:0 Interestingly enough name used to be 'raid' and not the host hame with :0 appended. Here is the 'sanitized' config entries: DEVICE /dev/sdf1 /dev/sde1 /dev/sdd1 CREATE owner=root group=disk mode=0660 auto=yes HOMEHOST <system> MAILADDR root ARRAY /dev/md0 metadata=1.2 name=tanserv:0 UUID=f1b4084a:720b5712:6d03b9e9:43afe51b Here is the output from mdstat cat /proc/mdstat Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] md0 : active raid5 sdd1[0] sdf1[3] sde1[1] 1953517568 blocks super 1.2 level 5, 512k chunk, algorithm 2 [3/3] [UUU] unused devices: <none> fdisk shows the following: fdisk -l Disk /dev/sda: 80.0 GB, 80026361856 bytes 255 heads, 63 sectors/track, 9729 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x000bf62e Device Boot Start End Blocks Id System /dev/sda1 * 1 9443 75846656 83 Linux /dev/sda2 9443 9730 2301953 5 Extended /dev/sda5 9443 9730 2301952 82 Linux swap / Solaris Disk /dev/sdb: 750.2 GB, 750156374016 bytes 255 heads, 63 sectors/track, 91201 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x000de8dd Device Boot Start End Blocks Id System /dev/sdb1 1 91201 732572001 8e Linux LVM Disk /dev/sdc: 500.1 GB, 500107862016 bytes 255 heads, 63 sectors/track, 60801 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00056a17 Device Boot Start End Blocks Id System /dev/sdc1 1 60801 488384001 8e Linux LVM Disk /dev/sdd: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x000ca948 Device Boot Start End Blocks Id System /dev/sdd1 1 121601 976760001 fd Linux raid autodetect Disk /dev/dm-0: 1250.3 GB, 1250254913536 bytes 255 heads, 63 sectors/track, 152001 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Disk /dev/dm-0 doesn't contain a valid partition table Disk /dev/sde: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x93a66687 Device Boot Start End Blocks Id System /dev/sde1 1 121601 976760001 fd Linux raid autodetect Disk /dev/sdf: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0xe6edc059 Device Boot Start End Blocks Id System /dev/sdf1 1 121601 976760001 fd Linux raid autodetect Disk /dev/md0: 2000.4 GB, 2000401989632 bytes 2 heads, 4 sectors/track, 488379392 cylinders Units = cylinders of 8 * 512 = 4096 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 524288 bytes / 1048576 bytes Disk identifier: 0x00000000 Disk /dev/md0 doesn't contain a valid partition table Per suggestions I did clean up the superblocks and re-created the array with --assume-clean option but with no luck at all. Is there any tool that will help me to revive at least some of the data? Can someone tell me what and how the mdadm --create does when syncs to destroy the data so I can write a tool to un-do whatever was done? After the re-creating of the raid I run fsck.ext4 /dev/md0 and here is the output root@tanserv:/etc/mdadm# fsck.ext4 /dev/md0 e2fsck 1.41.14 (22-Dec-2010) fsck.ext4: Superblock invalid, trying backup blocks... fsck.ext4: Bad magic number in super-block while trying to open /dev/md0 The superblock could not be read or does not describe a correct ext2 filesystem. If the device is valid and it really contains an ext2 filesystem (and not swap or ufs or something else), then the superblock is corrupt, and you might try running e2fsck with an alternate superblock: e2fsck -b 8193 Per Shanes' suggestion I tried root@tanserv:/home/mushegh# mkfs.ext4 -n /dev/md0 mke2fs 1.41.14 (22-Dec-2010) Filesystem label= OS type: Linux Block size=4096 (log=2) Fragment size=4096 (log=2) Stride=128 blocks, Stripe width=256 blocks 122101760 inodes, 488379392 blocks 24418969 blocks (5.00%) reserved for the super user First data block=0 Maximum filesystem blocks=0 14905 block groups 32768 blocks per group, 32768 fragments per group 8192 inodes per group Superblock backups stored on blocks: 32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 4096000, 7962624, 11239424, 20480000, 23887872, 71663616, 78675968, 102400000, 214990848 and run fsck.ext4 with every backup block but all returned the following: root@tanserv:/home/mushegh# fsck.ext4 -b 214990848 /dev/md0 e2fsck 1.41.14 (22-Dec-2010) fsck.ext4: Invalid argument while trying to open /dev/md0 The superblock could not be read or does not describe a correct ext2 filesystem. If the device is valid and it really contains an ext2 filesystem (and not swap or ufs or something else), then the superblock is corrupt, and you might try running e2fsck with an alternate superblock: e2fsck -b 8193 <device> Any suggestions? Regards!

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  • swapon --all --verbose : 'read swap header failed: Invalid argument'

    - by user66088
    Recently ran through EnableHibernateWithEncryptedSwap and ran the following command: swapon --all --verbose and received: 'read swap header failed: Invalid argument' How do I fix this? Here's some more pertinent output... Output of sudo fdisk -l: Disk /dev/sda: 80.0 GB, 80026361856 bytes 255 heads, 63 sectors/track, 9729 cylinders, total 156301488 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00006d20 Device Boot Start End Blocks Id System /dev/sda1 * 2048 499711 248832 83 Linux /dev/sda2 501758 156301311 77899777 5 Extended /dev/sda5 501760 156301311 77899776 8e Linux LVM Disk /dev/mapper/ubuntu--t10194-root: 75.5 GB, 75539415040 bytes 255 heads, 63 sectors/track, 9183 cylinders, total 147537920 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Disk /dev/mapper/ubuntu--t10194-root doesn't contain a valid partition table Disk /dev/mapper/ubuntu--t10194-swap_1: 4227 MB, 4227858432 bytes 255 heads, 63 sectors/track, 514 cylinders, total 8257536 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x08040000 Disk /dev/mapper/ubuntu--t10194-swap_1 doesn't contain a valid partition table Disk /dev/mapper/cryptswap1: 4225 MB, 4225761280 bytes 255 heads, 63 sectors/track, 513 cylinders, total 8253440 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0xd2236983 Disk /dev/mapper/cryptswap1 doesn't contain a valid partition table Thanks for any and ALL help!

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  • mount another drive to the same directory

    - by Ken Autotron
    I recently purchased a server that was advertised as 2TB (2 1TB drives) in size, when I use it it reports only one of the drives, I would like to be able to use both as if one drive. here is the specs... sudo lshw -C disk *-disk description: ATA Disk product: TOSHIBA DT01ACA1 vendor: Toshiba physical id: 0.0.0 bus info: scsi@1:0.0.0 logical name: /dev/sda version: MS2O serial: 13EJ81XPS size: 931GiB (1TB) capabilities: partitioned partitioned:dos configuration: ansiversion=5 signature=0005b3dd *-disk description: ATA Disk product: TOSHIBA DT01ACA1 vendor: Toshiba physical id: 0.0.0 bus info: scsi@4:0.0.0 logical name: /dev/sdb version: MS2O serial: 13OX3TKPS size: 931GiB (1TB) capabilities: partitioned partitioned:dos configuration: ansiversion=5 signature=00030e86 and fdisk -l Disk /dev/sdb: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 4096 bytes / 4096 bytes Disk identifier: 0x00030e86 Device Boot Start End Blocks Id System /dev/sdb1 * 4096 41947135 20971520 fd Linux raid autodetect /dev/sdb2 41947136 1952468991 955260928 fd Linux raid autodetect /dev/sdb3 1952468992 1953519615 525312 82 Linux swap / Solaris Disk /dev/sda: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 4096 bytes / 4096 bytes Disk identifier: 0x0005b3dd Device Boot Start End Blocks Id System /dev/sda1 * 4096 41947135 20971520 fd Linux raid autodetect /dev/sda2 41947136 1952468991 955260928 fd Linux raid autodetect /dev/sda3 1952468992 1953519615 525312 82 Linux swap / Solaris Disk /dev/md2: 978.2 GB, 978187124736 bytes 2 heads, 4 sectors/track, 238815216 cylinders, total 1910521728 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 4096 bytes / 4096 bytes Disk identifier: 0x00000000 Disk /dev/md2 doesn't contain a valid partition table Disk /dev/md1: 21.5 GB, 21474770944 bytes 2 heads, 4 sectors/track, 5242864 cylinders, total 41942912 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 4096 bytes / 4096 bytes Disk identifier: 0x00000000 Disk /dev/md1 doesn't contain a valid partition table is it possible to mount both drives to say /Home/ so I would have 2TB of usable space?

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  • Optimization of time-varying parameters

    - by brama
    I need to find an optimal set of "n" parameter values that minimize an objective function (a 2-hr simulation of a system). I have looked at genetic algorithm and simulated annealing methods, but was wondering if there are any better algorithms and guidance on their merits and limitations. With the above optimization methods I can find the optimal parameter values that hold true for the entire simulation duration. Incase, I want to find the optimal "time varying" parameter values (parameter values change with time during the 2-hr simulation), are there any methods/ideas other than making each time varying parameter value a variable to optimize? Any thoughts?

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  • CD-ROM Cant Be Accessed After Installing VMware Tools on VMware Server 2.0.2

    - by Optimal Solutions
    Using VMware Server 2.02, I set up a new VM (Windows XP Pro) applied all of the updates, added Windows addons from the install CD, etc... I got it to a stable point and up through that point I was able to access the CD-ROM drive (E: on my host). What I never did before was install "VMware Tools" and since it claims to give better mouse and video support, I gave it a shot. What it does is it places the install package in a virtual CD-ROM drive. I ran the install, no errors and it wants a reboot. I log back in after reboot and pop in the install CD for Microsoft Office 2003 and I receive the message "Please Insert A Disc Into Drive D:". Drive D: would be the next logical drive after the C: drive where I chose to install the OS. The message box sits there and if I click "Cancel", to return to Windows Explorer, the status bar seems to blink ever 1/2 second - as if its polling for a CD-ROM drive or something. No bangs or exclamations in the Device Manager for any hardware. I had taken a snapshot prior to the VMware Tools install and upon restoring it, the CD-ROM is back. I made copies of two other VMs, installed the VMware Tools on those VMs and both experienced the same issues: Windows 2003 Server and Windows 7 (32-bit). Has anyone seen this issue and know of a fix for this? It would be nice to have the better graphics and better mouse control AND use my CD-ROM drive as well! Thank you.

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  • Hot Link To A Specific Cell Comment In Excel 2007

    - by Optimal Solutions
    Is there a way to create a comment for cell D7 (for example) such that when the user hovers over it the comment has a hot link or hyperlink to cell A100? I dont know what else to call it other than a hot link or hyperlink, however its not like the hyperlink we know of in HTML. Or, maybe it could it be? The effect that is desired is that when the user sees that comment, he/she can click on the link to cell A100 if they choose to do so. I do not wish to create a macro or use VBA behind a button, etc.. It must be within the comment box itself. One of the issues I have run into is that once you move the mouse, the comment goes away. The comment might be able to be displayed all the time if it needs to be for this to work.

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  • Convert a cassette tape recording to digital format

    - by Optimal Solutions
    Has anyone been successful with transferring audio cassette tape recordings to a digital format? I would like to preserve old cassette tape recordings of my grandparents to some digital format: MP3, WAV, etc... The quality of the tapes are mediocre. I think I can handle the quality restoration but getting the audio from tape to digital is my question. Below is a list of the hardware that I can work with: Cassette Deck: I have a Technics stereo cassette deck model RS-B12. It has separate left and right IN and OUT RCA type jacks on the back. In the front it has a headphone phono jack, plus left and right mic input phono jacks. On the computer side: -I have a Windows Vista PC with no additional software other than what came with the machine from Costco. No sound editing software that I can see. There is no sound card on the PC. On the front panel there is a mini-phono mic input jack and there are several different types of in/out mini-phono jacks on the back. In addition, USB and Firewire. I also have access to a new (2009) iMac with a mini-phono input jack for a powered mic or other audio source and GarageBand that has come with the computer. In addition, USB and Firewire. What are my options for getting these cassette recordings into a digital format? Whats the best format? What sort of wires would I need and will I want to utilize the USB or Firewire or can I simply use the audio inputs on the PC (or Mac) to receive the audio stream?

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  • Install Active Directory on Windows Server 2008 R2 for CRM 2011?

    - by Optimal Solutions
    I have just set up a VM for Windows Server 2008 R2 and want to install Microsoft CRM 2011 to play around with it. CRM 2011 seems to require Active Directory to be configured and running on the server. I've never gotten involved with Active Directory and I know that I need to install it and get it going for the CRM 2011 to continue. Does anyone have any quick pointers and/or resources for someone with no Active Directory experience, so that I can get CRM 2011 installed?

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