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  • When Google gives up recrawling 301 that led to 404?

    - by Easy Life
    I've transferred a domain and made a mistake in the redirects (the URL structure is identical). Even though they went to the new domain, the error caused a 404 when crawled by Google bot. 10 days after I saw and corrected my redirect mistake, and now the site should (hopefully) redirect to proper pages. Q1: The URLs of the 404 pages in the Webmaster Tools all bear the mistake and will never be available at the new site. I marked them as fixed in the tools. Do I need to do something about that, like 301 rewrite them with a condition to fix the error? Q2: Does Google bot attempt to recrawl 301 pages that pointed to a 404?

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  • Problem with Bibtex

    - by Tim
    Hi, I just wonder why this item not shown properly in bibliography? @misc{Nilsson96introductionto, author = {Nilsson, Nils J.}, citeulike-article-id = {6995464}, howpublished = {\url{http://robotics.stanford.edu/people/nilsson/mlbook.html}}, keywords = {*file-import-10-04-11}, posted-at = {2010-04-11 06:52:28}, priority = {2}, title = {Introduction to Machine Learning: An Early Draft of a Proposed Textbook.}, year = {1996} } [12] Nils J. Nilsson. Introduction to machine learn- ing: An early draft of a proposed textbook. http://robotics.stanford.edu/people/nilsson/mlbook.html, 1996. Thanks and regards!

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  • Learn C# now or finish up with Java and then learn C#?

    - by Sahat
    Ok here is my situation. I've studied Java in my college for 2 semesters. But you know they teach you jack in there, just the basics. We skipped half of our textbook and even then our professors don't teach from section to section of each chapter. I don't blame them. It's hard as it is for new students to understand even the basic concepts of programming. Now this is a community college we are talking about and not Stanford, MIT or Berkeley. So like I said I've done 2 semester of Java. I really like our textbook because it has some challenging projects to do at the end of each chapter. This textbook is pretty clear and i have no problem understanding it (although 2-D and 3-D Arrays have given me some trouble). I have tried reading a few C# books such as Pro C# 2008 and .NET 3.5 and C# 4.0 in a Nutshell. I found these books to be dry and overloaded with information that put me to sleep (No offense to the authors of those 2 wonderful, according to amazon ratings, books). Would you suggest I finish my Java textbook, brush up my knowledge of Arrays, Polymorphism, and etc that are universal to most programming languages. And then switch to C#, plus the syntax is very similar so it should be easy to switch. Or should I just start learning C# right now from the very beginning? If it's the latter then could you recommend some free online resources that will keep me engaged and at the same time teach me everything I need to know about C#. Someone has recommended me to learn .NET first, but I found it to be not the brightest idea. .NET is just a big monster full of libraries. How am I going to apply it if I don't even know the C# or VB!? Anyway back to my question: Master Java and switch to C# or just go with C#? DISCLAIMER: I don't want to start .NET vs J2EE or C# vs Java flame war. I am going with C#. I've decided that I want to work in a Microsoft shop in the future. .NET is what I want to learn. Thanks! Will be waiting for the answers.

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  • xml schema construction

    - by amanrahahla
    in xml can any concept inhert the attribute of the main concept as an example: book( -author -title -isbn -price) and textbook as a subconcept from book can textbook take the same attribute of book and how?

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  • How to recover from failed Mysql schema update, with replication?

    - by OmerGertel
    I have two MySQL servers configured with master-slave replication. Before we deploy a new application version we: 1) STOP SLAVE 2) Take a MySQL dump of the slave. However, if a mistake is done during the deployment of the new schema version (a table is dropped by mistake, for example), having the slave intact doesn't help. Our service is write-intensive, so we can't turn it back up until we have a master working. If we now load the mysql dump back into the master, it will take a long time during which our service remains down. What is the best-practice to recover from such a mistake? How can I setup the system so I can easily promote the slave, turn on our service and only then tend to the broken database? Mainly, I'm worried with re-syncing the slave and the master after changes are done on the slave.

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  • How do I make the PolicyKit authentication agent window not dissapear when I enter faulty password in Ubuntu 12.04?

    - by Petar
    As far as I remember in previous versions of Ubuntu, whenever authentication was required and when the PolicyKit authentication agent window was presented, it stayed there even after I would enter a faulty password. But now, whenever I make a mistake, the window is closed immediately. I find this behaviour irritating. For instance I use Synaptic rather frequently, and I prefer to start it using Synapse. I press Ctrl+Space to invoke Synapse, then I enter "syn" (s-shows SMplayer, sy- shows System Monitor) and than I press Enter so that Synaptic is invoked. Then I'm presented with the PolicyKit authentication agent window. As my password is rather complicated - using special characters and big letters, it's easy to make a mistake. If I do make a mistake while typing my password, I'm forced to redo all the previous steps. It's annoying as hell, knowing that this is not the way the PolicyKit authentication agent window behaved before. It used to warn me that the password was not correct and than wait for the correct input. I'm not sure if it allowed trying for the correct password indefinitely, or it was limited to 3 retries which is a much saner behaviour than the current one. I'm using Gnome 3, but the same thing happens in Unity too, although the window looks different.

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  • Inspiring People

    - by barrem23
    So I work with a few people that I feel are intelligent but don't seem to be working out well. After working with them for a while I have seen the flashes of brilliance but mostly I see a reliance on others. What I mean by this is that most times it seems like at the first moment of trouble they go ask for help. Now personally I am all for helping and spend a significant portion of time helping others with whatever they need, but after helping others for so long I have noticed a disturbing trend. These people seem terrified that they might make a mistake and because of this they don't try. So my question is how can I motivate someone who is afraid of making a mistake? In my career I have always learned the most by making mistakes and learning from them. Personally I feel that if I hadn't learned so much I would never have made it as far as I have. So how can I get them to discover that they have the ability to figure it out themselves and that if they make a mistake and learn from it they will be better off. I feel that if I can discover some way to properly motivate them that we all will be better off.

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  • How is the MTU is 65535 in UDP but ethernet does not allow frame size more than 1500 bytes

    - by nikku
    I am using a fast ethernet of 100 Mbps, whose frame size is less than 1500 bytes (1472 bytes for payload as per my textbook). In that, I was able to send and receive a UDP packet of message size 65507 bytes, which means the packet size was 65507 + 20 (IP Header) + 8 (UDP Header) = 65535. If the frame's payload size itself is maximum of 1472 bytes (as per my textbook), how can the packet size of IP be greater than that which here is 65535? I used sender code as char buffer[100000]; for (int i = 1; i < 100000; i++) { int len = send (socket_id, buffer, i); printf("%d\n", len); } Receiver code as while (len = recv (socket_id, buffer, 100000)) { printf("%d\n". len); } I observed that send returns -1 on i > 65507 and recv prints or receives a packet of maximum of length 65507.

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  • How is the MTU is 65535 in UDP but ethernet does not allow frame size more than 1500 bytes

    - by nikku
    I am using a fast ethernet of 100 Mbps, whose frame size is less than 1500 bytes (1472 bytes for payload as per my textbook). In that, I was able to send and receive a UDP packet of message size 65507 bytes, which means the packet size was 65507 + 20 (IP Header) + 8 (UDP Header) = 65535. If the frame's payload size itself is maximum of 1472 bytes (as per my textbook), how can the packet size of IP be greater than that which here is 65535? I used sender code as char buffer[100000]; for (int i = 1; i < 100000; i++) { int len = send (socket_id, buffer, i); printf("%d\n", len); } Receiver code as while (len = recv (socket_id, buffer, 100000)) { printf("%d\n". len); } I observed that send returns -1 on i > 65507 and recv prints or receives a packet of maximum of length 65507.

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  • In retrospect, has it been a good idea to use three-valued logic for SQL NULL comparisons?

    - by Heinzi
    In SQL, NULL means "unknown value". Thus, every comparison with NULL yields NULL (unknown) rather than TRUE or FALSE. From a conceptional point of view, this three-valued logic makes sense. From a practical point of view, every learner of SQL has, one time or another, made the classic WHERE myField = NULL mistake or learned the hard way that NOT IN does not do what one would expect when NULL values are present. It is my impression (please correct me if I am wrong) that the cases where this three-valued logic helps (e.g. WHERE myField IS NOT NULL AND myField <> 2 can be shortened to WHERE myField <> 2) are rare and, in those cases, people tend to use the longer version anyway for clarity, just like you would add a comment when using a clever, non-obvious hack. Is there some obvious advantage that I am missing? Or is there a general consensus among the development community that this has been a mistake?

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  • Unreal 3 Editor (Unreal Tournament 3) Why does the X Y Z translations now rotate along with my static meshes?

    - by Gareth Jones
    So I was making a map for UT3, using the Unreal 3 Editor provided, and all was going well. However I was doing some work with InterpActors and Vehicle Spawners, when I must have hit a key by mistake (or other wise somehow changed something) by mistake. Now the X Y Z translations that are used to move objects around in the editor will rotate along with the object (Ive put images down below to help show what I mean) - This is very annoying because it also changes the direction the arrow keys move a rotated object, in the example below, the Down arrow key will now move the object to the right. How can I fix this? (Note both images are taken from the same viewpoint) Before Rotation: After Rotation: P.S. If someone could please provide me with the correct / better name for the X Y Z "things" it would be much appreciated, thanks!

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  • what's the point of method overloading?

    - by David
    I am following a textbook in which I have just come across method overloading. It briefly described method overloading as: when the same method name is used with different parameters its called method overloading. From what I've learned so far in OOP is that if I want different behaviors from an object via methods, I should use different method names that best indicate the behavior, so why should I bother with method overloading in the first place?

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  • SQLSaturday 33 Observations

    - by Geoff N. Hiten
    Along with a lot of my colleagues, I went to SQLSaturday #33 in Charlotte this last weekend.  Overall a really good event, especially for a first-time organizer.  There is some controversy over certain events where my name got mentioned so I thought I would clear the air. Before I get to the core controversy, let's get the details out of the way.  The Microsoft Offices in Charlotte were an excellent venue for this event.  I really appreciated the Microsoft employees that helped out by letting us in and out of normally secure areas.  This is definitely above and beyond on their part. Thanks to the organizers (especially Greg and Peter) for the great hospitality they showed to the speakers.  Now for the specifics.  Like most events of this type, there was a raffle at the end for some cool swag.  As a speaker I got raffle tickets just like any other attendee.  The raffle was clearly promoted as "must be present to win".  The problem is that for various reasons, the raffle kicked off immediately after the last speaker finished in the largest room.  That room was across the parking lot from all the other rooms for the event.  I happened to have one of the last sessions of the day, and not in the main room.  I also ran long since the audience was very interactive and there were a lot of follow-up questions.  (BTW, thanks to everyone who came and stayed for my session.  Sorry it cost you the chance to win too.).  My name was drawn for an very nice piece of swag (iPod Touch if you insist).  Since I wasn't there, I didn't win. Several folks mentioned I was still speaking and was "here" (as in at the event) just not "here in the room". Yes, I was mad when I found out about it. I think that was handled poorly.  I personally lost out as did my audience (dunno if anyone specific lost anything, but it is the idea that counts).  It was a mistake. Mistakes happen.  Nobody acted maliciously.  Heck, the guys running the event who made the decision are my friends and remain so.  I got over my mad.  We talked about this privately and we are all OK with what happened.  I am not going to let a gadget get in the way of a couple of good friendships. I think the mistake was mostly due to a lack of unity between the venue buildings   Pam Shaw had a similar challenge in Tampa a few weeks ago, including a speaker who ran long on the last session (not me that time).  She had a couple of teenage volunteers to act as gofers/runners.  They counted heads in sessions, pointed people to last-minute room and session changes, and generally helped connect the organizers to what was actually happening.  Note that this was not Pam's first SQLSaturday event.  She knew but the knowledge had not been institutionalized.  We (The SQL community in general and SQLSaturday organizers in particular) now know how essential gofers are to success. I know I spent most of this post focusing on the controversy, but I wanted to clear everything up.  I don't want to let a minor mistake, made in good faith, overshadow what was a tremendously good event for the community. As for the iPod Touch, someone in the SQL community is enjoying it, so it is not a total loss.  And if losing out on it is the price I pay so we can learn this, then that is what a community leader does.  Consider it a gift.  Besides, I really wanted a Zune 120 :)

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  • Mercurial hg Subrepository Problem - "abort: unknown revision'

    - by Tex
    Note: I asked this yesterday over at kiln.stackexchange.com, but haven't gotten an answer, and it's holding up my work. So I figured I'd give it a shot here. My main mercurial repository has a bunch of subrepositories in it. During initial setup, I made a mistake in my .hgsub. Namely, I pointed two subrepositories to the same directory. What I should have had: sites/1=sites/1 sites/2=sites/2 sites/3=sites/3 What I actually had: sites/1=sites/1 sites/2=sites/2 sites/2=sites/3 Stupid copy/paste error. I committed the incorrect .hgsub, not realizing my error. A few revisions later, while adding a some new subrespositories to .hgsub, I noticed the mistake and fixed it inside .hgsub. I committed and kept rolling along. I've committed a reasonable amount of work that I'd prefer not to redo since I 'fixed' the mistake in .hgsub. Now we come to the actual problem: I've made some changes inside the subrepository sites/3, and when I try to commit the main repository, I get the following error: abort: unknown revision 'LongGUIDLookingString' I found this discussion, which seems to address the same problem I'm having, but I can't quite work out how bos fixed it. What do I need to do in order to fix this?

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  • C++0x rvalue references and temporaries

    - by Doug
    (I asked a variation of this question on comp.std.c++ but didn't get an answer.) Why does the call to f(arg) in this code call the const ref overload of f? void f(const std::string &); //less efficient void f(std::string &&); //more efficient void g(const char * arg) { f(arg); } My intuition says that the f(string &&) overload should be chosen, because arg needs to be converted to a temporary no matter what, and the temporary matches the rvalue reference better than the lvalue reference. This is not what happens in GCC and MSVC. In at least G++ and MSVC, any lvalue does not bind to an rvalue reference argument, even if there is an intermediate temporary created. Indeed, if the const ref overload isn't present, the compilers diagnose an error. However, writing f(arg + 0) or f(std::string(arg)) does choose the rvalue reference overload as you would expect. From my reading of the C++0x standard, it seems like the implicit conversion of a const char * to a string should be considered when considering if f(string &&) is viable, just as when passing a const lvalue ref arguments. Section 13.3 (overload resolution) doesn't differentiate between rvalue refs and const references in too many places. Also, it seems that the rule that prevents lvalues from binding to rvalue references (13.3.3.1.4/3) shouldn't apply if there's an intermediate temporary - after all, it's perfectly safe to move from the temporary. Is this: Me misreading/misunderstand the standard, where the implemented behavior is the intended behavior, and there's some good reason why my example should behave the way it does? A mistake that the compiler vendors have somehow all made? Or a mistake based on common implementation strategies? Or a mistake in e.g. GCC (where this lvalue/rvalue reference binding rule was first implemented), that was copied by other vendors? A defect in the standard, or an unintended consequence, or something that should be clarified?

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  • mdadm raid5 recover double disk failure - with a twist (drive order)

    - by Peter Bos
    Let me acknowledge first off that I have made mistakes, and that I have a backup for most but not all of the data on this RAID. I still have hope of recovering the rest of the data. I don't have the kind of money to take the drives to a recovery expert company. Mistake #0, not having a 100% backup. I know. I have a mdadm RAID5 system of 4x3TB. Drives /dev/sd[b-e], all with one partition /dev/sd[b-e]1. I'm aware that RAID5 on very large drives is risky, yet I did it anyway. Recent events The RAID become degraded after a two drive failure. One drive [/dev/sdc] is really gone, the other [/dev/sde] came back up after a power cycle, but was not automatically re-added to the RAID. So I was left with a 4 device RAID with only 2 active drives [/dev/sdb and /dev/sdd]. Mistake #1, not using dd copies of the drives for restoring the RAID. I did not have the drives or the time. Mistake #2, not making a backup of the superblock and mdadm -E of the remaining drives. Recovery attempt I reassembled the RAID in degraded mode with mdadm --assemble --force /dev/md0, using /dev/sd[bde]1. I could then access my data. I replaced /dev/sdc with a spare; empty; identical drive. I removed the old /dev/sdc1 from the RAID mdadm --fail /dev/md0 /dev/sdc1 Mistake #3, not doing this before replacing the drive I then partitioned the new /dev/sdc and added it to the RAID. mdadm --add /dev/md0 /dev/sdc1 It then began to restore the RAID. ETA 300 mins. I followed the process via /proc/mdstat to 2% and then went to do other stuff. Checking the result Several hours (but less then 300 mins) later, I checked the process. It had stopped due to a read error on /dev/sde1. Here is where the trouble really starts I then removed /dev/sde1 from the RAID and re-added it. I can't remember why I did this; it was late. mdadm --manage /dev/md0 --remove /dev/sde1 mdadm --manage /dev/md0 --add /dev/sde1 However, /dev/sde1 was now marked as spare. So I decided to recreate the whole array using --assume-clean using what I thought was the right order, and with /dev/sdc1 missing. mdadm --create /dev/md0 --assume-clean -l5 -n4 /dev/sdb1 missing /dev/sdd1 /dev/sde1 That worked, but the filesystem was not recognized while trying to mount. (It should have been EXT4). Device order I then checked a recent backup I had of /proc/mdstat, and I found the drive order. md0 : active raid5 sdb1[0] sde1[4] sdd1[2] sdc1[1] 8790402048 blocks super 1.2 level 5, 512k chunk, algorithm 2 [4/4] [UUUU] I then remembered this RAID had suffered a drive loss about a year ago, and recovered from it by replacing the faulty drive with a spare one. That may have scrambled the device order a bit...so there was no drive [3] but only [0],[1],[2], and [4]. I tried to find the drive order with the Permute_array script: https://raid.wiki.kernel.org/index.php/Permute_array.pl but that did not find the right order. Questions I now have two main questions: I screwed up all the superblocks on the drives, but only gave: mdadm --create --assume-clean commands (so I should not have overwritten the data itself on /dev/sd[bde]1. Am I right that in theory the RAID can be restored [assuming for a moment that /dev/sde1 is ok] if I just find the right device order? Is it important that /dev/sde1 be given the device number [4] in the RAID? When I create it with mdadm --create /dev/md0 --assume-clean -l5 -n4 \ /dev/sdb1 missing /dev/sdd1 /dev/sde1 it is assigned the number [3]. I wonder if that is relevant to the calculation of the parity blocks. If it turns out to be important, how can I recreate the array with /dev/sdb1[0] missing[1] /dev/sdd1[2] /dev/sde1[4]? If I could get that to work I could start it in degraded mode and add the new drive /dev/sdc1 and let it resync again. It's OK if you would like to point out to me that this may not have been the best course of action, but you'll find that I realized this. It would be great if anyone has any suggestions.

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  • Selected wrong OS from bootloader settings and now can't do anything

    - by Eric
    I'm trying to help a friend out with an urgent issue he is having. He has two Windows 7 installations when he was starting up his computer so the bootloader menu was making him select an OS every time he restarted. One installation is functional and the other is not. He wanted to make it so that he did not have to select the correct OS every time he booted up. He chose the wrong (non-functional) operating system in the windows settings and set the time to select an operating system int he bootloader menu to 0 seconds. Now, his computer attempts to boot into a non-working operating system and he has no way of selecting the correct operating system so that he can fix his mistake. What can he do to get into the functional OS so that he can fix his mistake? Thanks so much.

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  • Disabling the command enter shortcut on Mac Entourage.

    - by Bruce
    It seems like disabling a shortcut should not be such a big deal, but I cannot seem to be able to do it for any shortcuts and specifically not for the combination that I keep hitting by mistake, every single day. The smaller space bar makes it very easy to hit the command key by mistake, and the return is a commonly used key when typing. I keep sending important e-mails before I am done typing, or worse, before I am done editing. I do not necessarily want to disable all the shortcuts, but that one for sure. The choices for changing anything in Entourage seem very limited. [Entourage for Mac 2008. Version 12.2.8. (101117) ESD] It is easy enough just to hit "send." This short cut causes a lot more trouble than it saves. Help.

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  • Why would a process monitoring script use exit 1; on finding no problems?

    - by user568458
    General question: On a Linux (Centos) server, if a process monitoring script run by cron is set to close with exit 1; rather than exit 0; on finding that everything is okay and that no action is needed, is that a mistake? Or are there legitimate reasons for calling exit 1; instead of exit 0; on the "Everything's fine, no action needed" condition? exit 0; on finding no problems seems to me to be more appropriate. But maybe there's something I'm not aware of. For example, maybe there's something specific to Cron? Or maybe there's a convention in process monitoring scripts that 'failure' means 'this script failed to need to fix a problem' (rather than what I would expect which is that exit 1; would mean 'the process being monitored has failed'?) My specific case: I'm looking at a process monitoring script written by my web hosting company. By process monitoring script, I mean a script executed by Cron on a regular basis that checks if an important system process is running, and if it isn't running, takes actions such as mailing an administrator or restarting the process. Here's the (generalised) structure of their script, for a service running on port 8080 (in this case, Apache Tomcat): SERVICE=$(/usr/sbin/lsof -i tcp:8080 | wc -l); if [ $SERVICE != 0 ]; then exit 1; else #take action fi Seems simple enough even for someone with limited knowledge like me, except the exit 1; part seems odd. As I understand it, exit 0; closes a program and signifies to the parent that executed the program that everything is fine, exit n; where n0 and n<127 signifies that there has been some kind of error or problem. Here, their script seems to go against that rule - it calls exit 1; in the condition where everything is fine, and doesn't exit after taking remedial action in the problem condition. To me, this looks like a mistake - but my experience in this area is limited. Are there cases where calling exit 1; in the "Everything's fine, no action needed" condition is more appropriate than calling exit 0;? Or is it a mistake? Wider context is pretty simple. It's a Centos VPS, running Plesk. The script is being called by Cron via Plesk's "Scheduled tasks" Cron manager. There's no custom layer between Cron and this script that would respond in an unusual way to the exit call. It's a fairly average, almost out-of-the box Plesk-managed Centos VPS (in so far as there is such a thing). The process being monitored by this script is Apache Tomcat.

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  • Back up Linux environment

    - by joesavage
    I'm currently in the process of installing a bunch of stuff I need and getting setup my Linode that I recently purchased. Being a Linux newbie, I'm doing pretty well - but one small mistake can screw everything up for me. I've currently got apache2 and some other things successfully installed and setup how I want them, and DO NOT want this to be ruined by some newbie mistake. What is the easiest way to backup the actual environment itself so that I can restore the backed up environment (with apache2 and things fully working) if I mess up?

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