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clear explanation sought: throw() and stack unwinding

- by Jerry Gagelman

I'm not a programmer but have learned a lot watching others. I am writing wrapper classes to simplify things with a really technical API that I'm working with. Its routines return error codes, and I have a function that converts those to strings: static const char* LibErrString(int errno); For uniformity I decided to have member of my classes throw an exception when an error is encountered. I created a class: struct MyExcept : public std::exception { const char* errstr_; const char* what() const throw() {return errstr_;} MyExcept(const char* errstr) : errstr_(errstr) {} }; Then, in one of my classes: class Foo { public: void bar() { int err = SomeAPIRoutine(...); if (err != SUCCESS) throw MyExcept(LibErrString(err)); // otherwise... } }; The whole thing works perfectly: if SomeAPIRoutine returns an error, a try-catch block around the call to Foo::bar catches a standard exception with the correct error string in what(). Then I wanted the member to give more information: void Foo::bar() { char adieu[128]; int err = SomeAPIRoutine(...); if (err != SUCCESS) { std::strcpy(adieu,"In Foo::bar... "); std::strcat(adieu,LibErrString(err)); throw MyExcept((const char*)adieu); } // otherwise... } However, when SomeAPIRoutine returns an error, the what() string returned by the exception contains only garbage. It occurred to me that the problem could be due to adieu going out of scope once the throw is called. I changed the code by moving adieu out of the member definition and making it an attribute of the class Foo. After this, the whole thing worked perfectly: a try-call block around a call to Foo::bar that catches an exception has the correct (expanded) string in what(). Finally, my question: what exactly is popped off the stack (in sequence) when the exception is thrown in the if-block when the stack "unwinds?" As I mentioned above, I'm a mathematician, not a programmer. I could use a really lucid explanation of what goes onto the stack (in sequence) when this C++ gets converted into running machine code.

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Database Firewall

- by ???02

Database Firewall?????SQL????????SQL????????????WEB?????HTTP??????SQL????????SQL????????????????????????????????????????????????????????????SQL??????????????????????????????????????·WEB???????????????????·??????????????????WEB???????????WEB??????????Web?????????????????IPA???????????SQL?????????????????????SQL??????????????????????SQL????????????????WEB??????????????????????????????????????????????????????????????????????????????????????????????WEB????????????????????????????????????????B to B?B to C???WEB????????????????????????????????????????????????????????????????????????????WEB?????????????????????WEB??????????????????·??????????????????????????????????????????????????????????????????????????????????????????WEB???????SQL?????????????????????????????Oracle Database Firewall???SQL??????????????????????????????????????????????????????????????????????????????2011?Oracle Database Firewall?????????·????????????????????????????????????????Oracle Database Firewall??????????????????SQL?????????·?????????????????????? Oracle Database Fireawall ?Oracle Database Firewall???????????????????????????????????????????????????????????SQL??????????????????????????????????????????2????????????????????SQL???Pass?Block????????????SQL?????????????????????????????????????????????????????????????????????????????????SQL????????????????????????????????????????????????????????????????????????????????????????????SQL?Oracle Database Firewall???????????????????SQL????????????????WEB??????????Oracle Database Firewall???????????????????????????????????Oracle Database??????SQL Server?DB2?Sybase??????????2????????Oracle Database Firewall?????????????????????????????????????????????????Oracle Database Firewall?????????????????????????????????????????????SQL???????????????????????????????????????????????????????????SPAN???(?????????)?????????????????????????????????SQL???????????????????????????????????????????SQL?Block???Pass??????????????????????????????????IDS?IPS????????????????????WAF (Web Application Firewall)? ??????????????????????????????????Database Firewall???????????????SQL????????????SQL????400????????????????(ISO/IEC 9075)??????????Oracle Database Firewall???????????????????????????????????????????SQL?????????????????????SQL??????Oracle Database Firewall??Oracle Database, SQL Server, DB2??????????????????????SQL???????????????????SQL??????????????????????????????????SQL???????????????????????????????????SQL????????????????????????????????????Oracle Database Firewall???SQL??????Oracle Database Firewall?????????????????????????????????????????????????????????????????????????????(Oracle Database???10gR2??XML??????????????????????????????????????????????????????????????Oracle Database???????????????????Oracle Database???????????????????????????????)???Oracle Database Firewall??????????????????????????????????????????????????????????????Oracle Database Firewall????????????????????????????????????????????????????????? ?????? Oracle Direct

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Do backlinks to blocked content add value?

- by David Fisher

We've been debating the following SEO question at our office: If you block bot access to a page either via robots.txt or on-page noindex metadata, does that negate the value of any backlinks to that page? We have a client who wants to block some event booking form pages from being indexed as each booking form page has a unique URL parameter and the pages are "clogging up" the Google index; however lots of websites link to those booking form pages and we wouldn't want to lose the value of those links. Any opinions welcomed.

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What should we tell our unsupported IE6 users?

- by Dan Fabulich

In the upcoming version of our web app, we've broken IE6, and we don't intend to fix it. We've had a clear warning posted for IE6 users for some months; we've decided it's time not to support it. My question is: how should we communicate this to our users? Some people here feel that we should block IE6 users who would try to access the web app, because it's not going to work for them. Others feel that we should just leave up a warning, saying "This doesn't work in IE6," but not block them; instead, if they click to dismiss the warning, just let them in to the broken site to see for themselves that it doesn't work. Who is right? Is there a better way?

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how to resize an encrypted logical volume?

- by Nirmik

I installed Ubuntu with encryption and LVM on my entire haddisk... Now I want to resize it. How do I do This... Following this link gave me errors on step 2 - How to resize a LVM partition? error ubuntu@ubuntu:~$ sudo e2fsck -f /dev/sda5 e2fsck 1.42.5 (29-Jul-2012) ext2fs_open2: Bad magic number in super-block e2fsck: Superblock invalid, trying backup blocks... e2fsck: Bad magic number in super-block while trying to open /dev/sda5 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 what do I do?

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xsltproc killed, out of memory

- by David Parks

I'm trying to split up a 13GB xml file into small ~50MB xml files with this XSLT style sheet. But this process kills xsltproc after I see it taking up over 1.7GB of memory (that's the total on the system). Is there any way to deal with huge XML files with xsltproc? Can I change my style sheet? Or should I use a different processor? Or am I just S.O.L.? <xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0" xmlns:exsl="http://exslt.org/common" extension-element-prefixes="exsl" xmlns:fn="http://www.w3.org/2005/xpath-functions"> <xsl:output method="xml" indent="yes"/> <xsl:strip-space elements="*"/> <xsl:param name="block-size" select="75000"/> <xsl:template match="/"> <xsl:copy> <xsl:apply-templates select="mysqldump/database/table_data/row[position() mod $block-size = 1]" /> </xsl:copy> </xsl:template> <xsl:template match="row"> <exsl:document href="chunk-{position()}.xml"> <add> <xsl:for-each select=". | following-sibling::row[position() < $block-size]" > <doc> <xsl:for-each select="field"> <field> <xsl:attribute name="name"><xsl:value-of select="./@name"/></xsl:attribute> <xsl:value-of select="."/> </field> <xsl:text>
</xsl:text> </xsl:for-each> </doc> </xsl:for-each> </add> </exsl:document> </xsl:template>

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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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Is there any reason to allow Yahoo! Slurp to crawl my site?

- by James Skemp

I thought a year or more ago Yahoo! would be using another search engine for results, and no longer using their own Slurp bot. However, a couple of the sites I manage Yahoo! Slurp continues to crawl pages, and seems to ignore the Gone status code when returned (as it keeps coming back). Is there any reason why I wouldn't want to block Yahoo! Slurp via robots.txt or by IP (since it tends to ignore robots.txt in some cases anyways)? I've confirmed that when the bot does hit it is from Yahoo! IPs, so I believe this is a legit instance of the bot. Is Yahoo Search the same as Bing Search now? is a related question, but I don't think it completely answers whether one should add a new block of the bot.

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Increasing deadlocks with NoLock

- by Dave Ballantyne

One on my personnel pet issues is with inappropriate use of the NOLOCK hint (and read uncommitted) . Dont get me wrong, I have used it in exceptional circumstances , but as a general statement it is a bad thing. Mostly , when NOLOCK, is used the discussion is around a single statement, “it runs faster with nolock for XYZ reason”, however ,IMO, this is quite a shorted sighted view. What about the Transaction ? What about other concurrent users ? What is good for one statement in isolation , does not mean that it is good for the system as a whole. I have seen on a number of occasions deadlocks happen, when tasks that would of(and should of) be blocked continue to execute, only for a deadlock to occur at a later data writing (INSERT,UPDATE,DELETE) statement. Writers will block writers regardless of isolation level. By Way of (fairly contrived ) example , lets generate some dummy tables and populate with some data drop table a go drop table b go Create Table a ( col1 integer ) go insert into a values(1) insert into a values(2) go Create Table b ( col1 integer ) go insert into b values(1) insert into b values(2) go Now make two connections. In connection one execute set transaction isolation level read committed BEGIN TRAN Select * from a Select * from b delete from a In connection two execute set transaction isolation level read committed BEGIN TRAN Select * from a Select * from b delete from b Right now the ‘select from a’ in connection two is being blocked by the ‘delete from a’ in connection one. This is ,IMO, quite a healthy and natural thing to be happening , some see this as a ‘slow down’, a drop in performance. So, lets reach for our ‘NOLOCK’ magic pill. Cancel the blocked query and ROLLBACK both transactions, then in connection one execute set transaction isolation level read uncommitted BEGIN TRAN Select * from a Select * from b delete from b and then in connection two execute set transaction isolation level read uncommitted BEGIN TRAN Select * from a Select * from b delete from a We have now solved out performance problem , no more blocking. Lets finish the work required by the transaction, in connection one , execute delete from a Oh, ‘ performance problem’ again , its now being blocked. Still, lets complete the work in connection two…. delete from b DEADLOCK!! It is important to be clear about the role of the select statements. They do not participate within the deadlock, but are preventing code executing that would of. Additionally, without the select readers to block, a deadlock would occur on the deletes with READ COMMITTED. Naturally, other isolation levels will exhibit different behaviour as to where and when they will and wont block, and I would encourage you to read BOL and satisfy yourself that you really do NEED to NOLOCK.

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Robots.txt never downloaded but some blocked URLs in GWT

- by Zistoloen

There is something I don't understand in Google Webmaster Tools (GWT) for my Wordpress site. In menu "Blocked URLs", it mention that my robots.txt has never been downloaded but there are some blocked URLs. It's kind of weird and not logical. Am i missing something? User-agent : * Disallow: /*? Disallow: /wp-login.php Disallow: /wp-admin Disallow: /wp-includes Disallow: /wp-content Allow: /wp-content/uploads Disallow: */trackback Disallow: /*/feed Disallow: /*/comments Disallow: /cgi-bin Disallow: /*.php$ Disallow: /*.inc$ Disallow: /*.gz$ Disallow: /*.cgi$ Disallow: /author/* I'm afraid my robots.txt doesn't block several URLs I want to block.

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Simplified Performance Counters for Timed Operations

A generalized code block which can be used in a common scenario for simple performance benchmarking.

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Why does an error appear every time I try to open the Ubuntu Software Center? [duplicate]

- by askubuntu7639

This question already has an answer here: How do I remove a broken software source? 3 answers There is a glitch on the Ubuntu Software Center and whenever I open it an error appears and it keeps loading and never opens. Why does this happen? I have installed Ubuntu 13.04 on a disk and partitioned it. Please help me and ask for excess information if you need it. If you know of any duplicates please show me them!! This is the output of a question someone asked me. SystemError: E:Type '<!DOCTYPE' is not known on line 1 in source list /etc/apt/sources.list.d/medibuntu.list This next output is the output of cat /etc/apt/sources.list.d/medibuntu.list </div> <div style="float:left;"> <div class="textwidget"><script type="text/javascript"> </div> Unixmen Archive Select Month September 2013 August 2013 July 2013 June 2013 May 2013 April 2013 March 2013 February 2013 January 2013 December 2012 November 2012 October 2012 September 2012 August 2012 July 2012 June 2012 May 2012 April 2012 March 2012 February 2012 January 2012 December 2011 November 2011 October 2011 September 2011 August 2011 July 2011 June 2011 May 2011 April 2011 March 2011 February 2011 January 2011 December 2010 November 2010 October 2010 September 2010 August 2010 July 2010 June 2010 May 2010 April 2010 March 2010 February 2010 January 2010 December 2009 November 2009 October 2009 September 2009 August 2009 July 2009 June 2009 May 2009 April 2009 March 2009 February 2009 January 2009 December 2008 Tags Cloudandroid apache browser Centos chrome command line Debian eyecandy Fedora firefox games gaming gnome google karmic koala kde libreoffice Linux linux distribution LinuxMint lucid lynx maverick meerkat mysql news oneiric ocelot openoffice opensource opensuse oracle ppa Precise Pangolin release RHEL security server software themes tools ubuntu unix upgrade virtualbox vlc windows wine Unixmen Twitts Firefox 16, a treat for developers http://t.co/cnd27CzT Ubuntu 12.10 ‘Quantal Quetzal’: Beta 2 Sneak Peek http://t.co/hd4LwDOy Top 5 security Myths about Linux; and their realities http://t.co/zO1LgHST About Us Advertising Sitemap Privacy Contact Us Hire Us Copyright © 2008-2013 Unixmen.com . Maintained by Unixmen . /* */ jQuery(document).on('ready post-load', easy_fancybox_handler ); http://www.w3-edge.com/wordpress-plugins/ Page Caching using apc Database Caching 3/186 queries in 0.035 seconds using apc Content Delivery Network via 180016988.r.cdn77.net Served from: www.unixmen.com @ 2013-09-25 01:38:14 by W3 Total Cache

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Why do operating systems do low level stuff in C and C++? Why not just C++?

- by Cole Johnson

On the Wikipedia page for Windows, it states the Windows is written in Assembly for the bootloader and task switcher, and C and C++ for kernel routines. This confuses me because AFAIK, you can call C++ functions from an extern "C"'d block as C++ is just C with extra features (all of which can be rewritten in C if you wanted to AFAIK). I can get using C for the kernel functions so pure C apps can use them (like printf and such), but if they can just be wrapped in an extern "C " block, then why code in C? So my question is: Why would a kernel be written in both C and C++ instead of just C++

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Designing Algorithm Flowchart Application

- by l46kok

I need to develop an GUI application in C# where users can freely add conditional/statement blocks on the algorithm flowchart like the one shown below. By freely, I mean users can add a block on wherever the arrows are. I'm having some problems brainstorming how to approach this problem, especially what to choose for my datastructure to store the blocks. I was thinking LinkedList since everything follows a linear fashion and every node always has a head and tail, but the If/Else block (ba) has two branches (heads) to store, so this complicates things a little bit. How would a smart one approach problems like this? My apologies if this question isn't suited for Programmers stackexchange, but this is more of a conceptual problem rather than implementation problem so I figured this place was appropriate for the question.

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Can I safely delete the Ubuntu 12.04 partition and use the unallocated space for my Elementary OS?

- by d4ryl3

I have this setup: I've decided to switch to Elementary OS Luna (fork of Ubuntu 12.04) as my main Linux distro. Now I need to delete my Ubuntu partition so I could add capacity to my eOS which only has 10Gb. Currently my eOS is in /dev/sda9, and Ubuntu in /dev/sda8/. I forgot where my bootloader is installed, so I ran bootinfoscript, which returned this: `============================= Boot Info Summary: =============================== = Grub2 (v1.99) is installed in the MBR of /dev/sda and looks at sector 1 of the same hard drive for core.img. core.img is at this location and looks in partition 94 for . sda1: __________________________________________ File system: ntfs Boot sector type: Windows Vista/7: NTFS Boot sector info: No errors found in the Boot Parameter Block. Operating System: Boot files: /bootmgr /Boot/BCD sda2: __________________________________________ File system: ntfs Boot sector type: Windows Vista/7: NTFS Boot sector info: No errors found in the Boot Parameter Block. Operating System: Windows 7 Boot files: /bootmgr /Boot/BCD /Windows/System32/winload.exe sda3: __________________________________________ File system: ntfs Boot sector type: Windows Vista/7: NTFS Boot sector info: No errors found in the Boot Parameter Block. Operating System: Boot files: /bootmgr /boot/bcd sda4: __________________________________________ File system: Extended Partition Boot sector type: - Boot sector info: sda5: __________________________________________ File system: ntfs Boot sector type: Windows Vista/7: NTFS Boot sector info: According to the info in the boot sector, sda5 starts at sector 2048. Operating System: Boot files: sda6: __________________________________________ File system: swap Boot sector type: - Boot sector info: sda7: __________________________________________ File system: ext4 Boot sector type: Grub2 (v1.99) Boot sector info: Grub2 (v1.99) is installed in the boot sector of sda7 and looks at sector 851823520 of the same hard drive for core.img, but core.img can not be found at this location. Operating System: Boot files: /grub/grub.cfg /extlinux/extlinux.conf sda8: __________________________________________ File system: ext4 Boot sector type: Grub2 (v1.99) Boot sector info: Grub2 (v1.99) is installed in the boot sector of sda8 and looks at sector 860224256 of the same hard drive for core.img. core.img is at this location and looks for (,msdos9)/boot/grub on this drive. Operating System: Ubuntu 13.04 Boot files: /etc/fstab sda9: __________________________________________ File system: ext4 Boot sector type: - Boot sector info: Operating System: elementary OS Luna Boot files: /boot/grub/grub.cfg /etc/fstab /boot/grub/core.img` I need advice as to how to proceed. I mean, could I simply delete /dev/sda7/ and /dev/sda8/? Please help, thank you.

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Ubuntu btrfs: how to remove rootflags=subvol=@ from grub.cfg

- by mnpria

When i mount "btrfs" as a root filesytem, the mount info is as below: root@ubuntu1304Btrfs:~# mount /dev/mapper/ubuntu1304Btrfs--vg-root on / type btrfs (rw,subvol=@) Is there a way to have a mount info without the "subvol" information ? I have tried executing what was mentioned here. I also updated the grub.cfg. Still rootflags=subvol=@ is not removed. Is there a way to remove this subvol information ? root@ubuntu1304Btrfs:/home# mount /dev/mapper/ubuntu1304Btrfs--vg-root on / type btrfs (rw,subvol=@) /dev/mapper/ubuntu1304Btrfs--vg-root on /home type btrfs (rw,subvol=@home) root@ubuntu1304Btrfs:/# stat / File: ‘/’ Size: 262 Blocks: 0 IO Block: 4096 directory Device: 12h/18d Inode: 256 Links: 1 Access: (0755/drwxr-xr-x) Uid: ( 0/ root) Gid: ( 0/ root) Access: 2013-11-11 19:56:04.548121873 +0530 Modify: 2013-11-11 19:55:18.008120103 +0530 Change: 2013-11-11 19:55:18.008120103 +0530 Birth: - root@ubuntu1304Btrfs:/# stat /home/ File: ‘/home/’ Size: 230 Blocks: 0 IO Block: 4096 directory Device: 19h/25d Inode: 256 Links: 1 Access: (0755/drwxr-xr-x) Uid: ( 0/ root) Gid: ( 0/ root) Access: 2013-11-12 12:24:52.346377976 +0530 Modify: 2013-11-12 12:24:50.338377900 +0530 Change: 2013-11-12 12:24:50.338377900 +0530 Birth: -

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AWR Performance Report and Read by Other Session Waits

- by user702295

For the questions regarding "read by other session" and its relation to "db file sequential/scattered read", the logic is like this: When a "db file sequential/scattered read" is done, the blocks are either already in the cache or on the disk. Since any operation on blocks is done in the cache and since and the issue is "read by other session" I will relate to the case the blocks are on the disk. Process A is reading the needed block from the disk to the cache. During that time, if process B (and C and others) need the same block, it will wait on "read by other session". A and B can be threads of the same process running in parallel or unrelated processes. For example two processes doing full table scan on mdp_matrix etc. Solutions for that can be lowering the number of processes competing on the same blocks, increasing PCTFREE. If it is a full table scan, maybe an index is missing that can result in less blocks being read from the cache and so on.

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Is this how dynamic language copes with dynamic requirement?

- by Amumu

The question is in the title. I want to have my thinking verified by experienced people. You can add more or disregard my opinion, but give me a reason. Here is an example requirement: Suppose you are required to implement a fighting game. Initially, the game only includes fighters, who can attack each other. Each fighter can punch, kick or block incoming attacks. Fighters can have various fighting styles: Karate, Judo, Kung Fu... That's it for the simple universe of the game. In an OO like Java, it can be implemented similar to this way: abstract class Fighter { int hp, attack; void punch(Fighter otherFighter); void kick(Fighter otherFighter); void block(Figther otherFighter); }; class KarateFighter extends Fighter { //...implementation...}; class JudoFighter extends Fighter { //...implementation... }; class KungFuFighter extends Fighter { //...implementation ... }; This is fine if the game stays like this forever. But, somehow the game designers decide to change the theme of the game: instead of a simple fighting game, the game evolves to become a RPG, in which characters can not only fight but perform other activities, i.e. the character can be a priest, an accountant, a scientist etc... At this point, to make it more generic, we have to change the structure of our original design: Fighter is not used to refer to a person anymore; it refers to a profession. The specialized classes of Fighter (KaraterFighter, JudoFighter, KungFuFighter) . Now we have to create a generic class named Person. However, to adapt this change, I have to change the method signatures of the original operations: class Person { int hp, attack; List<Profession> skillSet; }; abstract class Profession {}; class Fighter extends Profession { void punch(Person otherFighter); void kick(Person otherFighter); void block(Person otherFighter); }; class KarateFighter extends Fighter { //...implementation...}; class JudoFighter extends Fighter { //...implementation... }; class KungFuFighter extends Fighter { //...implementation ... }; class Accountant extends Profession { void calculateTax(Person p) { //...implementation...}; void calculateTax(Company c) { //...implementation...}; }; //... more professions... Here are the problems: To adapt to the method changes, I have to fix the places where the changed methods are called (refactoring). Every time a new requirement is introduced, the current structural design has to be broken to adapt the changes. This leads to the first problem. Rigid structure makes it hard for code reuse. A function can only accept the predefined types, but it cannot accept future unknown types. A written function is bound to its current universe and has no way to accommodate to the new types, without modifications or rewrite from scratch. I see Java has a lot of deprecated methods. OO is an extreme case because it has inheritance to add up the complexity, but in general for statically typed language, types are very strict. In contrast, a dynamic language can handle the above case as follow: ;;fighter1 punch fighter2 (defun perform-punch (fighter1 fighter2) ...implementation... ) ;;fighter1 kick fighter2 (defun perform-kick (fighter1 fighter2) ...implementation... ) ;;fighter1 blocks attacks from fighter2 (defun perform-block (fighter1 fighter2) ...implementation... ) fighter1 and fighter2 can be anything as long as it has the required data for calculation; or methods (duck typing). You don't have to change from the type Fighter to Person. In the case of Lisp, because Lisp only has a single data structure: list, it's even easier to adapt to changes. However, other dynamic languages can have similar behaviors as well. I work primarily with static languages (mainly C and Java, but working with Java was a long time ago). I started learning Lisp and some other dynamic languages this year. I can see how it helps improving my productivity.

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Installation of 11.10 on new drive (no OS)

- by Jeffrey Vincent

I have a Dell Dimension 600 XPS Phoenix BIOS version A03, the original HD crashed and burned. Dell didn't send OS disks (was on the original drive and no back up disks), so I am trying to install Ubuntu 11.10 on the new drive. The new drive is a Western Digital 1TB. I formatted the new drive by putting it in an enclosure and formatting it with Windows 7 on my HP system. When I put the cd in the cdrom it boots to the cd with the Advanced user screen (won't boot into the usually Windows GUI). When I try to install (or run from live Cd) I get the same error message. Same with trying the various boot options. The message is: VFS: cannot open root device "(NULL)" or unknown-block(8,1) Please append a correct "root=" boot option: Here are the available partitions: Kernal Panic- not syncing: VFS: Unable to mount rootfs on unknown-block(8,1) and then it lists Trace messages then freezing. Any help or suggestions are appreciated in advance.

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Ubuntu missing from the Grub menu

- by varevarao

Recently I've had some audio issues with Ubuntu (using precise), and in the process of trying to resolve that I ran a dist-upgrade. Everything went just fine, and the sound seemed good, until I rebooted my machine for the first time since the dist-upgrade. All I see now in the Grub menu at startup is memtest86+, another memtest variant, and Windows 7. It's not showing any of the linux kernels that Ubuntu is running on. I am attaching my bootinfoscript: Boot Info Script 0.61.full + Boot-Repair extra info [Boot-Info November 20th 2012] ============================= Boot Info Summary: =============================== => Grub2 (v1.99) is installed in the MBR of /dev/sda and looks at sector 1 of the same hard drive for core.img. core.img is at this location and looks for (,msdos6)/boot/grub on this drive. sda1: __________________________________________________________________________ File system: vfat Boot sector type: Dell Utility: FAT16 Boot sector info: No errors found in the Boot Parameter Block. Operating System: Boot files: sda2: __________________________________________________________________________ File system: ntfs Boot sector type: Windows Vista/7: NTFS Boot sector info: No errors found in the Boot Parameter Block. Operating System: Boot files: sda3: __________________________________________________________________________ File system: ntfs Boot sector type: Windows Vista/7: NTFS Boot sector info: No errors found in the Boot Parameter Block. Operating System: Windows 7 Boot files: sda4: __________________________________________________________________________ File system: Extended Partition Boot sector type: Unknown Boot sector info: sda5: __________________________________________________________________________ File system: ntfs Boot sector type: Windows Vista/7: NTFS Boot sector info: According to the info in the boot sector, sda5 starts at sector 2048. Operating System: Boot files: sda6: __________________________________________________________________________ File system: ext4 Boot sector type: Grub2 (v1.99-2.00) Boot sector info: Grub2 (v1.99) is installed in the boot sector of sda6 and looks at sector 220046240 of the same hard drive for core.img. core.img is at this location and looks for (,msdos6)/boot/grub on this drive. Operating System: Ubuntu 12.04.1 LTS Boot files: /boot/grub/grub.cfg /etc/fstab /boot/grub/core.img sda7: __________________________________________________________________________ File system: swap Boot sector type: - Boot sector info: ============================ Drive/Partition Info: ============================= Drive: sda _____________________________________________________________________ Disk /dev/sda: 320.1 GB, 320072933376 bytes 255 heads, 63 sectors/track, 38913 cylinders, total 625142448 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes Partition Boot Start Sector End Sector # of Sectors Id System /dev/sda1 63 273,104 273,042 de Dell Utility /dev/sda2 * 274,432 19,406,847 19,132,416 7 NTFS / exFAT / HPFS /dev/sda3 19,406,848 218,274,364 198,867,517 7 NTFS / exFAT / HPFS /dev/sda4 218,275,838 625,139,711 406,863,874 f W95 Extended (LBA) /dev/sda5 328,630,272 625,139,711 296,509,440 7 NTFS / exFAT / HPFS /dev/sda6 218,275,840 324,030,463 105,754,624 83 Linux /dev/sda7 324,032,512 328,626,175 4,593,664 82 Linux swap / Solaris "blkid" output: ________________________________________________________________ Device UUID TYPE LABEL /dev/loop0 squashfs /dev/sda1 07DA-0512 vfat DellUtility /dev/sda2 8834146034145392 ntfs RECOVERY /dev/sda3 48E2189DE21890F4 ntfs OS /dev/sda5 BC2A44C02A447982 ntfs Varshneya /dev/sda6 34731459-4b0f-46ac-a9bf-cb360a2c947c ext4 /dev/sda7 dcb9ce9b-799a-4c65-b008-887b01775670 swap /dev/sr0 iso9660 Ubuntu 12.04.1 LTS i386 ================================ Mount points: ================================= Device Mount_Point Type Options /dev/loop0 /rofs squashfs (ro,noatime) /dev/sda6 /mnt ext4 (rw) /dev/sr0 /cdrom iso9660 (ro,noatime) =========================== sda6/boot/grub/grub.cfg: =========================== -------------------------------------------------------------------------------- # # DO NOT EDIT THIS FILE # # It is automatically generated by grub-mkconfig using templates # from /etc/grub.d and settings from /etc/default/grub # ### BEGIN /etc/grub.d/00_header ### if [ -s $prefix/grubenv ]; then set have_grubenv=true load_env fi set default="0" if [ "${prev_saved_entry}" ]; then set saved_entry="${prev_saved_entry}" save_env saved_entry set prev_saved_entry= save_env prev_saved_entry set boot_once=true fi function savedefault { if [ -z "${boot_once}" ]; then saved_entry="${chosen}" save_env saved_entry fi } function recordfail { set recordfail=1 if [ -n "${have_grubenv}" ]; then if [ -z "${boot_once}" ]; then save_env recordfail; fi; fi } function load_video { insmod vbe insmod vga insmod video_bochs insmod video_cirrus } insmod part_msdos insmod ext2 set root='(hd0,msdos6)' search --no-floppy --fs-uuid --set=root 34731459-4b0f-46ac-a9bf-cb360a2c947c if loadfont /boot/grub/unicode.pf2 ; then set gfxmode=auto load_video insmod gfxterm insmod part_msdos insmod ext2 set root='(hd0,msdos6)' search --no-floppy --fs-uuid --set=root 34731459-4b0f-46ac-a9bf-cb360a2c947c set locale_dir=($root)/boot/grub/locale set lang=en_US insmod gettext fi terminal_output gfxterm if [ "${recordfail}" = 1 ]; then set timeout=-1 else set timeout=10 fi ### END /etc/grub.d/00_header ### ### BEGIN /etc/grub.d/05_debian_theme ### set menu_color_normal=white/black set menu_color_highlight=black/light-gray ### END /etc/grub.d/05_debian_theme ### ### BEGIN /etc/grub.d/10_linux ### function gfxmode { set gfxpayload="${1}" if [ "${1}" = "keep" ]; then set vt_handoff=vt.handoff=7 else set vt_handoff= fi } if [ "${recordfail}" != 1 ]; then if [ -e ${prefix}/gfxblacklist.txt ]; then if hwmatch ${prefix}/gfxblacklist.txt 3; then if [ ${match} = 0 ]; then set linux_gfx_mode=keep else set linux_gfx_mode=text fi else set linux_gfx_mode=text fi else set linux_gfx_mode=keep fi else set linux_gfx_mode=text fi export linux_gfx_mode if [ "${linux_gfx_mode}" != "text" ]; then load_video; fi ### END /etc/grub.d/10_linux ### ### BEGIN /etc/grub.d/20_linux_xen ### ### END /etc/grub.d/20_linux_xen ### ### BEGIN /etc/grub.d/20_memtest86+ ### menuentry "Memory test (memtest86+)" { insmod part_msdos insmod ext2 set root='(hd0,msdos6)' search --no-floppy --fs-uuid --set=root 34731459-4b0f-46ac-a9bf-cb360a2c947c linux16 /boot/memtest86+.bin } menuentry "Memory test (memtest86+, serial console 115200)" { insmod part_msdos insmod ext2 set root='(hd0,msdos6)' search --no-floppy --fs-uuid --set=root 34731459-4b0f-46ac-a9bf-cb360a2c947c linux16 /boot/memtest86+.bin console=ttyS0,115200n8 } ### END /etc/grub.d/20_memtest86+ ### ### BEGIN /etc/grub.d/30_os-prober ### menuentry "Windows 7 (loader) (on /dev/sda2)" --class windows --class os { insmod part_msdos insmod ntfs set root='(hd0,msdos2)' search --no-floppy --fs-uuid --set=root 8834146034145392 chainloader +1 } ### END /etc/grub.d/30_os-prober ### ### BEGIN /etc/grub.d/40_custom ### # This file provides an easy way to add custom menu entries. Simply type the # menu entries you want to add after this comment. Be careful not to change # the 'exec tail' line above. ### END /etc/grub.d/40_custom ### ### BEGIN /etc/grub.d/41_custom ### if [ -f $prefix/custom.cfg ]; then source $prefix/custom.cfg; fi ### END /etc/grub.d/41_custom ### -------------------------------------------------------------------------------- =============================== sda6/etc/fstab: ================================ -------------------------------------------------------------------------------- # /etc/fstab: static file system information. # # Use 'blkid -o value -s UUID' to print the universally unique identifier # for a device; this may be used with UUID= as a more robust way to name # devices that works even if disks are added and removed. See fstab(5). # # <file system> <mount point> <type> <options> <dump> <pass> proc /proc proc nodev,noexec,nosuid 0 0 # / was on /dev/sda6 during installation UUID=34731459-4b0f-46ac-a9bf-cb360a2c947c / ext4 errors=remount-ro,user_xattr 0 1 # swap was on /dev/sda7 during installation UUID=dcb9ce9b-799a-4c65-b008-887b01775670 none swap sw 0 0 -------------------------------------------------------------------------------- =================== sda6: Location of files loaded by Grub: ==================== GiB - GB File Fragment(s) 104.851909637 = 112.583880704 boot/grub/core.img 1 121.191410065 = 130.128285696 boot/grub/grub.cfg 1 ======================== Unknown MBRs/Boot Sectors/etc: ======================== Unknown BootLoader on sda4 00000000 eb 0f 2a 5d f4 b7 75 f2 e9 56 12 b8 50 b4 79 ec |..*]..u..V..P.y.| 00000010 89 91 ca c3 16 40 31 d0 ae c4 53 3d c7 dd d7 98 |[email protected]=....| 00000020 bd a4 f2 a4 e8 ab fc ea 36 30 1b 34 cf 8a 28 30 |........60.4..(0| 00000030 43 95 6c 31 3e 76 93 58 84 37 99 c3 ae 3a 88 a3 |C.l1>v.X.7...:..| 00000040 c2 a6 36 2a f8 e0 e1 03 91 8d a1 50 cd ad b0 b5 |..6*.......P....| 00000050 ad 69 3a 49 63 1f 4a 33 97 6e 0c 71 bf 7d bd 35 |.i:Ic.J3.n.q.}.5| 00000060 86 c5 17 93 b4 9f e5 af e0 c4 6f f4 6f f9 4b dd |..........o.o.K.| 00000070 14 39 e2 9e b9 36 ca b1 56 5b d9 b1 66 2c 05 b2 |.9...6..V[..f,..| 00000080 5d 5b 99 c0 db e6 81 27 ab c2 e1 55 00 ac 0b 2c |][.....'...U...,| 00000090 24 d3 8e 54 b0 3d ab 58 e4 23 fc 3a 79 93 fb 5e |$..T.=.X.#.:y..^| 000000a0 94 5a 3a c2 16 4e 56 cb 1b 7f 7e b3 4c 38 ca 5b |.Z:..NV...~.L8.[| 000000b0 ca ab c1 2c 2a 64 e7 77 fe 2a ba ee 08 33 b5 9b |...,*d.w.*...3..| 000000c0 d0 c2 b4 a8 fc 73 4f 01 fd 03 61 75 eb 6d 1a 74 |.....sO...au.m.t| 000000d0 5f 79 31 7f ed e6 f5 99 21 36 16 ed 25 d9 6d 2b |_y1.....!6..%.m+| 000000e0 5f f4 42 b8 9d 01 89 10 fe df a4 98 e7 ab ab ea |_.B.............| 000000f0 1d 1c 44 e1 49 d9 19 c9 ab f5 41 eb 4a 32 c2 39 |..D.I.....A.J2.9| 00000100 87 57 f6 f6 f3 b5 4d 17 72 f2 b1 16 19 aa ec 24 |.W....M.r......$| 00000110 39 bd e3 b1 68 b3 b0 7f fa 2a 3a 2e 99 ed db 8a |9...h....*:.....| 00000120 f8 61 b4 ef 9d 7d 85 95 ed ad eb 9e 71 f4 27 d3 |.a...}......q.'.| 00000130 f3 04 8b 8a 69 98 02 72 df e1 f9 83 27 5b 01 4c |....i..r....'[.L| 00000140 d4 9a b9 3b db ca 1e 40 35 db 6f c1 52 c0 7f 27 |...;[email protected]..'| 00000150 8a 1d bc 34 89 24 b6 e3 fd ec a1 2a e5 9e d1 8f |...4.$.....*....| 00000160 77 e0 d5 52 c0 4c c4 38 38 3c 28 19 bf 20 f0 03 |w..R.L.88<(.. ..| 00000170 38 a4 b1 b5 ed 6a b8 f7 a9 7b 65 b1 7b 64 4a 33 |8....j...{e.{dJ3| 00000180 66 1a 60 29 38 1d 5b 52 40 31 de a5 0c 0f cc 6f |f.`)8.[[email protected]| 00000190 dd 31 6d 3d f0 2a 32 85 67 66 ca 4f 02 aa 0d 30 |.1m=.*2.gf.O...0| 000001a0 66 c9 b2 33 c2 4b 8a fa 3c 7b 52 02 00 88 8e cf |f..3.K..<{R.....| 000001b0 67 1e d4 20 49 1d 1a b8 71 ad c2 d4 37 9d 00 fe |g.. I...q...7...| 000001c0 ff ff 07 fe ff ff 02 e0 93 06 00 60 ac 11 00 fe |...........`....| 000001d0 ff ff 05 fe ff ff 01 00 00 00 01 b0 4d 06 00 00 |............M...| 000001e0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 000001f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.| 00000200 ADDITIONAL INFORMATION : =================== log of boot-repair 2012-11-24__09h45 =================== boot-repair version : 3.195~ppa2~precise boot-sav version : 3.195~ppa2~precise glade2script version : 3.2.2~ppa45~precise boot-sav-extra version : 3.195~ppa2~precise boot-repair is executed in live-session (Ubuntu 12.04.1 LTS, precise, Ubuntu, i686) CPU op-mode(s): 32-bit, 64-bit file=/cdrom/preseed/ubuntu.seed boot=casper initrd=/casper/initrd.lz quiet splash -- =================== os-prober: /dev/sda2:Windows 7 (loader):Windows:chain /dev/sda6:Ubuntu 12.04.1 LTS (12.04):Ubuntu:linux =================== blkid: /dev/sda1: SEC_TYPE="msdos" LABEL="DellUtility" UUID="07DA-0512" TYPE="vfat" /dev/sda2: LABEL="RECOVERY" UUID="8834146034145392" TYPE="ntfs" /dev/sda3: LABEL="OS" UUID="48E2189DE21890F4" TYPE="ntfs" /dev/sda5: LABEL="Varshneya" UUID="BC2A44C02A447982" TYPE="ntfs" /dev/loop0: TYPE="squashfs" /dev/sda6: UUID="34731459-4b0f-46ac-a9bf-cb360a2c947c" TYPE="ext4" /dev/sda7: UUID="dcb9ce9b-799a-4c65-b008-887b01775670" TYPE="swap" /dev/sr0: LABEL="Ubuntu 12.04.1 LTS i386" TYPE="iso9660" 1 disks with OS, 2 OS : 1 Linux, 0 MacOS, 1 Windows, 0 unknown type OS. Windows not detected by os-prober on sda3. Warning: extended partition does not start at a cylinder boundary. DOS and Linux will interpret the contents differently. =================== /mnt/etc/default/grub : # If you change this file, run 'update-grub' afterwards to update # /boot/grub/grub.cfg. # For full documentation of the options in this file, see: # info -f grub -n 'Simple configuration' GRUB_DEFAULT=0 GRUB_HIDDEN_TIMEOUT=0 GRUB_HIDDEN_TIMEOUT_QUIET=true GRUB_TIMEOUT=10 GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian` GRUB_CMDLINE_LINUX_DEFAULT="quiet splash" GRUB_CMDLINE_LINUX="" # Uncomment to enable BadRAM filtering, modify to suit your needs # This works with Linux (no patch required) and with any kernel that obtains # the memory map information from GRUB (GNU Mach, kernel of FreeBSD ...) #GRUB_BADRAM="0x01234567,0xfefefefe,0x89abcdef,0xefefefef" # Uncomment to disable graphical terminal (grub-pc only) #GRUB_TERMINAL=console # The resolution used on graphical terminal # note that you can use only modes which your graphic card supports via VBE # you can see them in real GRUB with the command `vbeinfo' #GRUB_GFXMODE=640x480 # Uncomment if you don't want GRUB to pass "root=UUID=xxx" parameter to Linux #GRUB_DISABLE_LINUX_UUID=true # Uncomment to disable generation of recovery mode menu entries #GRUB_DISABLE_RECOVERY="true" # Uncomment to get a beep at grub start #GRUB_INIT_TUNE="480 440 1" =================== /mnt/etc/grub.d/ : drwxr-xr-x 2 root root 4096 Nov 22 16:15 grub.d total 56 -rwxr-xr-x 1 root root 6743 Sep 12 20:19 00_header -rwxr-xr-x 1 root root 5522 Sep 12 20:05 05_debian_theme -rwxr-xr-x 1 root root 7407 Sep 12 20:19 10_linux -rwxr-xr-x 1 root root 6335 Sep 12 20:19 20_linux_xen -rwxr-xr-x 1 root root 1588 Sep 24 2010 20_memtest86+ -rwxr-xr-x 1 root root 7603 Sep 12 20:19 30_os-prober -rwxr-xr-x 1 root root 214 Sep 12 20:19 40_custom -rwxr-xr-x 1 root root 95 Sep 12 20:19 41_custom -rw-r--r-- 1 root root 483 Sep 12 20:19 README =================== No kernel in /mnt/boot: grub memtest86+.bin memtest86+_multiboot.bin =================== UEFI/Legacy mode: This live-session is not EFI-compatible. SecureBoot maybe enabled. =================== PARTITIONS & DISKS: sda1 : sda, not-sepboot, no-grubenv nogrub, no-docgrub, no-update-grub, 32, no-boot, no-os, not--efi--part, part-has-no-fstab, part-has-no-fstab, no-nt, no-winload, no-recov-nor-hid, no-bmgr, notwinboot, nopakmgr, nogrubinstall, no---usr, part-has-no-fstab, not-sep-usr, standard, not-far, /mnt/boot-sav/sda1. sda2 : sda, not-sepboot, no-grubenv nogrub, no-docgrub, no-update-grub, 32, no-boot, is-os, not--efi--part, part-has-no-fstab, part-has-no-fstab, no-nt, no-winload, no-recov-nor-hid, bootmgr, is-winboot, nopakmgr, nogrubinstall, no---usr, part-has-no-fstab, not-sep-usr, standard, not-far, /mnt/boot-sav/sda2. sda3 : sda, not-sepboot, no-grubenv nogrub, no-docgrub, no-update-grub, 32, no-boot, is-os, not--efi--part, part-has-no-fstab, part-has-no-fstab, no-nt, haswinload, no-recov-nor-hid, no-bmgr, notwinboot, nopakmgr, nogrubinstall, no---usr, part-has-no-fstab, not-sep-usr, standard, farbios, /mnt/boot-sav/sda3. sda5 : sda, not-sepboot, no-grubenv nogrub, no-docgrub, no-update-grub, 32, no-boot, no-os, not--efi--part, part-has-no-fstab, part-has-no-fstab, no-nt, no-winload, no-recov-nor-hid, no-bmgr, notwinboot, nopakmgr, nogrubinstall, no---usr, part-has-no-fstab, not-sep-usr, standard, farbios, /mnt/boot-sav/sda5. sda6 : sda, not-sepboot, grubenv-ok grub2, grub-pc, update-grub, 64, no-kernel, is-os, not--efi--part, fstab-without-boot, fstab-without-efi, no-nt, no-winload, no-recov-nor-hid, no-bmgr, notwinboot, apt-get, grub-install, with--usr, fstab-without-usr, not-sep-usr, standard, farbios, /mnt. sda : not-GPT, BIOSboot-not-needed, has-no-EFIpart, not-usb, has-os, 63 sectors * 512 bytes =================== parted -l: Model: ATA ST9320423AS (scsi) Disk /dev/sda: 320GB Sector size (logical/physical): 512B/512B Partition Table: msdos Number Start End Size Type File system Flags 1 32.3kB 140MB 140MB primary fat16 diag 2 141MB 9936MB 9796MB primary ntfs boot 3 9936MB 112GB 102GB primary ntfs 4 112GB 320GB 208GB extended lba 6 112GB 166GB 54.1GB logical ext4 7 166GB 168GB 2352MB logical linux-swap(v1) 5 168GB 320GB 152GB logical ntfs Model: HL-DT-ST DVD+-RW GA31N (scsi) Disk /dev/sr0: 4700MB Sector size (logical/physical): 2048B/2048B Partition Table: msdos Number Start End Size Type File system Flags 1 131kB 2916MB 2916MB primary boot, hidden =================== parted -lm: BYT; /dev/sda:320GB:scsi:512:512:msdos:ATA ST9320423AS; 1:32.3kB:140MB:140MB:fat16::diag; 2:141MB:9936MB:9796MB:ntfs::boot; 3:9936MB:112GB:102GB:ntfs::; 4:112GB:320GB:208GB:::lba; 6:112GB:166GB:54.1GB:ext4::; 7:166GB:168GB:2352MB:linux-swap(v1)::; 5:168GB:320GB:152GB:ntfs::; BYT; /dev/sr0:4700MB:scsi:2048:2048:msdos:HL-DT-ST DVD+-RW GA31N; 1:131kB:2916MB:2916MB:::boot, hidden; =================== mount: /cow on / type overlayfs (rw) proc on /proc type proc (rw,noexec,nosuid,nodev) sysfs on /sys type sysfs (rw,noexec,nosuid,nodev) udev on /dev type devtmpfs (rw,mode=0755) devpts on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=0620) tmpfs on /run type tmpfs (rw,noexec,nosuid,size=10%,mode=0755) /dev/sr0 on /cdrom type iso9660 (ro,noatime) /dev/loop0 on /rofs type squashfs (ro,noatime) none on /sys/fs/fuse/connections type fusectl (rw) none on /sys/kernel/debug type debugfs (rw) none on /sys/kernel/security type securityfs (rw) tmpfs on /tmp type tmpfs (rw,nosuid,nodev) none on /run/lock type tmpfs (rw,noexec,nosuid,nodev,size=5242880) none on /run/shm type tmpfs (rw,nosuid,nodev) gvfs-fuse-daemon on /home/ubuntu/.gvfs type fuse.gvfs-fuse-daemon (rw,nosuid,nodev,user=ubuntu) /dev/sda6 on /mnt type ext4 (rw) /dev on /mnt/dev type none (rw,bind) /proc on /mnt/proc type none (rw,bind) /sys on /mnt/sys type none (rw,bind) /usr on /mnt/usr type none (rw,bind) /dev/sda1 on /mnt/boot-sav/sda1 type vfat (rw) /dev/sda2 on /mnt/boot-sav/sda2 type fuseblk (rw,nosuid,nodev,allow_other,blksize=4096) /dev/sda3 on /mnt/boot-sav/sda3 type fuseblk (rw,nosuid,nodev,allow_other,blksize=4096) /dev/sda5 on /mnt/boot-sav/sda5 type fuseblk (rw,nosuid,nodev,allow_other,blksize=4096) =================== ls: /sys/block/sda (filtered): alignment_offset bdi capability dev device discard_alignment events events_async events_poll_msecs ext_range holders inflight power queue range removable ro sda1 sda2 sda3 sda4 sda5 sda6 sda7 size slaves stat subsystem trace uevent /sys/block/sr0 (filtered): alignment_offset bdi capability dev device discard_alignment events events_async events_poll_msecs ext_range holders inflight power queue range removable ro size slaves stat subsystem trace uevent /dev (filtered): autofs block bsg btrfs-control bus cdrom cdrw char console core cpu cpu_dma_latency disk dri dvd dvdrw ecryptfs fb0 fd full fuse fw0 hidraw0 hpet input kmsg log mapper mcelog mei mem net network_latency network_throughput null oldmem port ppp psaux ptmx pts random rfkill rtc rtc0 sda sda1 sda2 sda3 sda4 sda5 sda6 sda7 sg0 sg1 shm snapshot snd sr0 stderr stdin stdout uinput urandom usbmon0 usbmon1 usbmon2 v4l vga_arbiter video0 zero ls /dev/mapper: control =================== df -Th: Filesystem Type Size Used Avail Use% Mounted on /cow overlayfs 1.9G 113M 1.8G 6% / udev devtmpfs 1.9G 12K 1.9G 1% /dev tmpfs tmpfs 777M 872K 776M 1% /run /dev/sr0 iso9660 696M 696M 0 100% /cdrom /dev/loop0 squashfs 667M 667M 0 100% /rofs tmpfs tmpfs 1.9G 20K 1.9G 1% /tmp none tmpfs 5.0M 0 5.0M 0% /run/lock none tmpfs 1.9G 176K 1.9G 1% /run/shm /dev/sda6 ext4 51G 27G 22G 56% /mnt /dev/sda1 vfat 134M 9.1M 125M 7% /mnt/boot-sav/sda1 /dev/sda2 fuseblk 9.2G 5.6G 3.6G 61% /mnt/boot-sav/sda2 /dev/sda3 fuseblk 95G 80G 16G 84% /mnt/boot-sav/sda3 /dev/sda5 fuseblk 142G 130G 12G 92% /mnt/boot-sav/sda5 =================== fdisk -l: Disk /dev/sda: 320.1 GB, 320072933376 bytes 255 heads, 63 sectors/track, 38913 cylinders, total 625142448 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: 0xb8000000 Device Boot Start End Blocks Id System /dev/sda1 63 273104 136521 de Dell Utility /dev/sda2 * 274432 19406847 9566208 7 HPFS/NTFS/exFAT /dev/sda3 19406848 218274364 99433758+ 7 HPFS/NTFS/exFAT /dev/sda4 218275838 625139711 203431937 f W95 Ext'd (LBA) /dev/sda5 328630272 625139711 148254720 7 HPFS/NTFS/exFAT /dev/sda6 218275840 324030463 52877312 83 Linux /dev/sda7 324032512 328626175 2296832 82 Linux swap / Solaris Partition table entries are not in disk order =================== Repair blockers 64bits detected. Please use this software in a 64bits session. (Please use Ubuntu-Secure-Remix-64bits (www.sourceforge.net/p/ubuntu-secured) which contains a 64bits-compatible version of this software.) This will enable this feature. =================== Final advice in case of recommended repair The boot files of [Ubuntu 12.04.1 LTS] are far from the start of the disk. Your BIOS may not detect them. You may want to retry after creating a /boot partition (EXT4, >200MB, start of the disk). This can be performed via tools such as gParted. Then select this partition via the [Separate /boot partition:] option of [Boot Repair]. (https://help.ubuntu.com/community/BootPartition) =================== Default settings Recommended-Repair This setting would reinstall the grub2 of sda6 into the MBR of sda, using the following options: kernel-purge Additional repair would be performed: unhide-bootmenu-10s fix-windows-boot =================== Settings chosen by the user Boot-Info This setting will not act on the MBR. No change has been performed on your computer. See you soon! pastebinit packages needed dpkg-preconfigure: unable to re-open stdin: No such file or directory pastebin.com ko (), using paste.ubuntu Please report this message to [email protected] Any help would be great, I'm really missing Ubuntu (hate being stuck in the Windows world).

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ASMLib

- by wcoekaer

Oracle ASMlib on Linux has been a topic of discussion a number of times since it was released way back when in 2004. There is a lot of confusion around it and certainly a lot of misinformation out there for no good reason. Let me try to give a bit of history around Oracle ASMLib. Oracle ASMLib was introduced at the time Oracle released Oracle Database 10g R1. 10gR1 introduced a very cool important new features called Oracle ASM (Automatic Storage Management). A very simplistic description would be that this is a very sophisticated volume manager for Oracle data. Give your devices directly to the ASM instance and we manage the storage for you, clustered, highly available, redundant, performance, etc, etc... We recommend using Oracle ASM for all database deployments, single instance or clustered (RAC). The ASM instance manages the storage and every Oracle server process opens and operates on the storage devices like it would open and operate on regular datafiles or raw devices. So by default since 10gR1 up to today, we do not interact differently with ASM managed block devices than we did before with a datafile being mapped to a raw device. All of this is without ASMLib, so ignore that one for now. Standard Oracle on any platform that we support (Linux, Windows, Solaris, AIX, ...) does it the exact same way. You start an ASM instance, it handles storage management, all the database instances use and open that storage and read/write from/to it. There are no extra pieces of software needed, including on Linux. ASM is fully functional and selfcontained without any other components. In order for the admin to provide a raw device to ASM or to the database, it has to have persistent device naming. If you booted up a server where a raw disk was named /dev/sdf and you give it to ASM (or even just creating a tablespace without asm on that device with datafile '/dev/sdf') and next time you boot up and that device is now /dev/sdg, you end up with an error. Just like you can't just change datafile names, you can't change device filenames without telling the database, or ASM. persistent device naming on Linux, especially back in those days ways to say it bluntly, a nightmare. In fact there were a number of issues (dating back to 2004) : Linux async IO wasn't pretty persistent device naming including permissions (had to be owned by oracle and the dba group) was very, very difficult to manage system resource usage in terms of open file descriptors So given the above, we tried to find a way to make this easier on the admins, in many ways, similar to why we started working on OCFS a few years earlier - how can we make life easier for the admins on Linux. A feature of Oracle ASM is the ability for third parties to write an extension using what's called ASMLib. It is possible for any third party OS or storage vendor to write a library using a specific Oracle defined interface that gets used by the ASM instance and by the database instance when available. This interface offered 2 components : Define an IO interface - allow any IO to the devices to go through ASMLib Define device discovery - implement an external way of discovering, labeling devices to provide to ASM and the Oracle database instance This is similar to a library that a number of companies have implemented over many years called libODM (Oracle Disk Manager). ODM was specified many years before we introduced ASM and allowed third party vendors to implement their own IO routines so that the database would use this library if installed and make use of the library open/read/write/close,.. routines instead of the standard OS interfaces. PolyServe back in the day used this to optimize their storage solution, Veritas used (and I believe still uses) this for their filesystem. It basically allowed, in particular, filesystem vendors to write libraries that could optimize access to their storage or filesystem.. so ASMLib was not something new, it was basically based on the same model. You have libodm for just database access, you have libasm for asm/database access. Since this library interface existed, we decided to do a reference implementation on Linux. We wrote an ASMLib for Linux that could be used on any Linux platform and other vendors could see how this worked and potentially implement their own solution. As I mentioned earlier, ASMLib and ODMLib are libraries for third party extensions. ASMLib for Linux, since it was a reference implementation implemented both interfaces, the storage discovery part and the IO part. There are 2 components : Oracle ASMLib - the userspace library with config tools (a shared object and some scripts) oracleasm.ko - a kernel module that implements the asm device for /dev/oracleasm/* The userspace library is a binary-only module since it links with and contains Oracle header files but is generic, we only have one asm library for the various Linux platforms. This library is opened by Oracle ASM and by Oracle database processes and this library interacts with the OS through the asm device (/dev/asm). It can install on Oracle Linux, on SuSE SLES, on Red Hat RHEL,.. The library itself doesn't actually care much about the OS version, the kernel module and device cares. The support tools are simple scripts that allow the admin to label devices and scan for disks and devices. This way you can say create an ASM disk label foo on, currently /dev/sdf... So if /dev/sdf disappears and next time is /dev/sdg, we just scan for the label foo and we discover it as /dev/sdg and life goes on without any worry. Also, when the database needs access to the device, we don't have to worry about file permissions or anything it will be taken care of. So it's a convenience thing. The kernel module oracleasm.ko is a Linux kernel module/device driver. It implements a device /dev/oracleasm/* and any and all IO goes through ASMLib - /dev/oracleasm. This kernel module is obviously a very specific Oracle related device driver but it was released under the GPL v2 so anyone could easily build it for their Linux distribution kernels. Advantages for using ASMLib : A good async IO interface for the database, the entire IO interface is based on an optimal ASYNC model for performance A single file descriptor per Oracle process, not one per device or datafile per process reducing # of open filehandles overhead Device scanning and labeling built-in so you do not have to worry about messing with udev or devlabel, permissions or the likes which can be very complex and error prone. Just like with OCFS and OCFS2, each kernel version (major or minor) has to get a new version of the device drivers. We started out building the oracleasm kernel module rpms for many distributions, SLES (in fact in the early days still even for this thing called United Linux) and RHEL. The driver didn't make sense to get pushed into upstream Linux because it's unique and specific to the Oracle database. As it takes a huge effort in terms of build infrastructure and QA and release management to build kernel modules for every architecture, every linux distribution and every major and minor version we worked with the vendors to get them to add this tiny kernel module to their infrastructure. (60k source code file). The folks at SuSE understood this was good for them and their customers and us and added it to SLES. So every build coming from SuSE for SLES contains the oracleasm.ko module. We weren't as successful with other vendors so for quite some time we continued to build it for RHEL and of course as we introduced Oracle Linux end of 2006 also for Oracle Linux. With Oracle Linux it became easy for us because we just added the code to our build system and as we churned out Oracle Linux kernels whether it was for a public release or for customers that needed a one off fix where they also used asmlib, we didn't have to do any extra work it was just all nicely integrated. With the introduction of Oracle Linux's Unbreakable Enterprise Kernel and our interest in being able to exploit ASMLib more, we started working on a very exciting project called Data Integrity. Oracle (Martin Petersen in particular) worked for many years with the T10 standards committee and storage vendors and implemented Linux kernel support for DIF/DIX, data protection in the Linux kernel, note to those that wonder, yes it's all in mainline Linux and under the GPL. This basically gave us all the features in the Linux kernel to checksum a data block, send it to the storage adapter, which can then validate that block and checksum in firmware before it sends it over the wire to the storage array, which can then do another checksum and to the actual DISK which does a final validation before writing the block to the physical media. So what was missing was the ability for a userspace application (read: Oracle RDBMS) to write a block which then has a checksum and validation all the way down to the disk. application to disk. Because we have ASMLib we had an entry into the Linux kernel and Martin added support in ASMLib (kernel driver + userspace) for this functionality. Now, this is all based on relatively current Linux kernels, the oracleasm kernel module depends on the main kernel to have support for it so we can make use of it. Thanks to UEK and us having the ability to ship a more modern, current version of the Linux kernel we were able to introduce this feature into ASMLib for Linux from Oracle. This combined with the fact that we build the asm kernel module when we build every single UEK kernel allowed us to continue improving ASMLib and provide it to our customers. So today, we (Oracle) provide Oracle ASMLib for Oracle Linux and in particular on the Unbreakable Enterprise Kernel. We did the build/testing/delivery of ASMLib for RHEL until RHEL5 but since RHEL6 decided that it was too much effort for us to also maintain all the build and test environments for RHEL and we did not have the ability to use the latest kernel features to introduce the Data Integrity features and we didn't want to end up with multiple versions of asmlib as maintained by us. SuSE SLES still builds and comes with the oracleasm module and they do all the work and RHAT it certainly welcome to do the same. They don't have to rebuild the userspace library, it's really about the kernel module. And finally to re-iterate a few important things : Oracle ASM does not in any way require ASMLib to function completely. ASMlib is a small set of extensions, in particular to make device management easier but there are no extra features exposed through Oracle ASM with ASMLib enabled or disabled. Often customers confuse ASMLib with ASM. again, ASM exists on every Oracle supported OS and on every supported Linux OS, SLES, RHEL, OL withoutASMLib Oracle ASMLib userspace is available for OTN and the kernel module is shipped along with OL/UEK for every build and by SuSE for SLES for every of their builds ASMLib kernel module was built by us for RHEL4 and RHEL5 but we do not build it for RHEL6, nor for the OL6 RHCK kernel. Only for UEK ASMLib for Linux is/was a reference implementation for any third party vendor to be able to offer, if they want to, their own version for their own OS or storage ASMLib as provided by Oracle for Linux continues to be enhanced and evolve and for the kernel module we use UEK as the base OS kernel hope this helps.

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The proper use and disposal of WCF channels. (or CommunicationObjectFaultedException ?!*#*$)

In this post I explore the subtle but disastrous consequences of expecting a 'using' block to clean up your WCF channels.

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Clicks counting and crawler bots

- by Dennis

I am currently running a small affiliate-program for Facebook users. We use an auto-poster to publish links to fan pages. Every hit is stored in our database and we have included a 24 hour reload block for the IP-addresses. My problem right now is that the PHP script also stores every hit from all the bots that crawls my website. Now I was thinking to block those bots with the robots.txt of my website but I am afraid that this will have a negative effect on my AdSense ads. Does anybody have an idea for me how to work this out?

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Static Class Values Are Valid Even Without a Main Method

This example shows how a static block can work even without a main method.

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Static Class Values Are Valid Even Without a Main Method

This example shows how a static block can work even without a main method.

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