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• HP UX can not boot from Ignite Tape

  - by Spirit

  We have hp rp2470 server running hp-ux 11.00, with LVM mirroring. As for redundancy we have second rp2470 same hw (same two processors, same ram, same two hdd’s, same number of lan cards). I want to clone first one to the second. For that purpose I am making ignite tape with the following command: make_tape_recovery -x inc_entire=vg00 Ignite tape finishes without problems. When I boot second server from this ignate tape, server is starting to boot, and ignite restore finishes without any errors, only few notes, which are normal. However vmunix is not booting and when restore finishes, it boot to ISL prompt. From this I cannot boot /stand/vmunix. I tried to run recovery shell but no success. When recovery shell ask to do frecover to restore critical files, then I receive error: frecover(5405): unable to open /dev/rmt/0m At first I thought that the problem might be in the difference of the firmware version of the servers: fw version of production server is: Firmware Version 43.50 and fw version of backup server is: Firmware Version 42.19 So i did a fw upgrade of my backup server so that both servers are v43.50, and tried a recovery but again cant boot the system. Next I did another archive tape with -I (Interactive) flag: make_tape_recovery -I -x inc_entire=vg00 and tried recovery with it, again no good. I cannot find any error or warnings on ignite log, and I cannot boot hpux. I am only on ISL prompt. This is what i've noticed on the gsp logs: ************* SYSTEM ALERT ************** SYSTEM NAME: mcnfwim1 DATE: 07/27/2003 TIME: 10:18:49 ALERT LEVEL: 6 = Boot possible, pending failure - action required REASON FOR ALERT SOURCE: 8 = I/O SOURCE DETAIL: 6 = disk SOURCE ID: 0 PROBLEM DETAIL: 0 = no problem detail LEDs: RUN ATTENTION FAULT REMOTE POWER FLASH OFF ON ON ON LED State: Boot Failed. Running non-OS code. Check Chassis and Console Logs for error messages. 0x00000060860010B0 00000000 00000000 - type 0 = Data Field Unused 0x58000860860010B0 00006706 1B0A1231 - type 11 = Timestamp 07/27/2003 10:18:49 And another gsp log: Log Entry # 3 : SYSTEM NAME: mcnfwim1 DATE: 07/27/2003 TIME: 10:12:20 ALERT LEVEL: 6 = Boot possible, pending failure - action required SOURCE: 8 = I/O SOURCE DETAIL: 6 = disk SOURCE ID: 0 PROBLEM DETAIL: 0 = no problem detail CALLER ACTIVITY: 1 = test STATUS: 0 CALLER SUBACTIVITY: 0B = implementation dependent REPORTING ENTITY TYPE: 0 = system firmware REPORTING ENTITY ID: 00 0x00000060860010B0 00000000 00000000 type 0 = Data Field Unused 0x58000860860010B0 00006706 1B0A0C14 type 11 = Timestamp 07/27/2003 10:12:20 Type CR for next entry, - CR for previous entry, Q CR to quit. Please note that I can not change anything on the production server. I can only make changes to the backup server. Any help is appreciated.

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• What is the current state of Ubuntu's transition from init scripts to Upstart? [migrated]

  - by Adam Eberlin

  What is the current state of Ubuntu's transition from init.d scripts to upstart? I was curious, so I compared the contents of /etc/init.d/ to /etc/init/ on one of our development machines, which is running Ubuntu 12.04 LTS Server. # /etc/init.d/ # /etc/init/ acpid acpid.conf apache2 --------------------------- apparmor --------------------------- apport apport.conf atd atd.conf bind9 --------------------------- bootlogd --------------------------- cgroup-lite cgroup-lite.conf --------------------------- console.conf console-setup console-setup.conf --------------------------- container-detect.conf --------------------------- control-alt-delete.conf cron cron.conf dbus dbus.conf dmesg dmesg.conf dns-clean --------------------------- friendly-recovery --------------------------- --------------------------- failsafe.conf --------------------------- flush-early-job-log.conf --------------------------- friendly-recovery.conf grub-common --------------------------- halt --------------------------- hostname hostname.conf hwclock hwclock.conf hwclock-save hwclock-save.conf irqbalance irqbalance.conf killprocs --------------------------- lxc lxc.conf lxc-net lxc-net.conf module-init-tools module-init-tools.conf --------------------------- mountall.conf --------------------------- mountall-net.conf --------------------------- mountall-reboot.conf --------------------------- mountall-shell.conf --------------------------- mounted-debugfs.conf --------------------------- mounted-dev.conf --------------------------- mounted-proc.conf --------------------------- mounted-run.conf --------------------------- mounted-tmp.conf --------------------------- mounted-var.conf networking networking.conf network-interface network-interface.conf network-interface-container network-interface-container.conf network-interface-security network-interface-security.conf newrelic-sysmond --------------------------- ondemand --------------------------- plymouth plymouth.conf plymouth-log plymouth-log.conf plymouth-splash plymouth-splash.conf plymouth-stop plymouth-stop.conf plymouth-upstart-bridge plymouth-upstart-bridge.conf postgresql --------------------------- pppd-dns --------------------------- procps procps.conf rc rc.conf rc.local --------------------------- rcS rcS.conf --------------------------- rc-sysinit.conf reboot --------------------------- resolvconf resolvconf.conf rsync --------------------------- rsyslog rsyslog.conf screen-cleanup screen-cleanup.conf sendsigs --------------------------- setvtrgb setvtrgb.conf --------------------------- shutdown.conf single --------------------------- skeleton --------------------------- ssh ssh.conf stop-bootlogd --------------------------- stop-bootlogd-single --------------------------- sudo --------------------------- --------------------------- tty1.conf --------------------------- tty2.conf --------------------------- tty3.conf --------------------------- tty4.conf --------------------------- tty5.conf --------------------------- tty6.conf udev udev.conf udev-fallback-graphics udev-fallback-graphics.conf udev-finish udev-finish.conf udevmonitor udevmonitor.conf udevtrigger udevtrigger.conf ufw ufw.conf umountfs --------------------------- umountnfs.sh --------------------------- umountroot --------------------------- --------------------------- upstart-socket-bridge.conf --------------------------- upstart-udev-bridge.conf urandom --------------------------- --------------------------- ureadahead.conf --------------------------- ureadahead-other.conf --------------------------- wait-for-state.conf whoopsie whoopsie.conf To be honest, I'm not entirely sure if I'm interpreting the division of responsibilities properly, as I didn't expect to see any overlap (of what framework handles which services). So I was quite surprised to learn that there was a significant amount of overlap in service references, in addition to being unable to discern which of the two was intended to be the primary service framework. Why does there seem to be a fair amount of redundancy in individual service handling between init.d and upstart? Is something else at play here that I'm missing? What is preventing upstart from completely taking over for init.d? Is there some functionality that certain daemons require which upstart does not yet have, which are preventing some services from converting? Or is it something else entirely?

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• Suggestions for splitting server roles amongst Hyper-V virtual servers / RAID6 or RAID10? / AppAssure

  - by Anon

  We have 2 Hyper-V hosts at present running 1 virtual server that was converted from a physical box running all roles. My plan is to split the roles over various virtual machines, upgrading to the latest software versions as I go, and use the backup server as a standby in case the main server fails. AppAssure backup software has a feature called Virtual Standby, so the VHD's can be ready to be fired up on the backup server if necessary. Off-site backups will be done via external USB drive for now. I'm just seeking some input/suggestions into how I'm planning to split the roles out amongst various virtual servers. Also, I'm curious how to setup the storage on the servers. We do not have any NAS's, SAN'S or any budget for this. What would the best RAID level be to use? I'm thinking either RAID6 (which is currently used) however I'm concerned about the write speeds, or RAID10 but again I'm worried that I can only lose 1 drive (from the same mirror) as opposed to any 2 with RAID6. I realise I have a hot swap for this, but what if a further drive fails during a rebuild? Is the write penalty of RAID6 worth the extra reliability over RAID10? Or will it be too slow with all the roles I am planning, therefore RAID10 is my only real option? The reason for the needed redundancy is I am the only technician and I'm not always on-site. Options I've considered: 1) 5 drives in RAID6 set, 200gb for host OS, rest for VM storage. 1 drive for hot swap - this is how it is currently setup 2) 4 drives in RAID10 set, 200gb for host OS, rest for VM storage. 2 drives for hot swap 3) 4 drives in RAID10 set for VM storage, 2 drives in RAID1 set for host OS. No drives for hot swap - While this is probably the best option with the amount of drives I have, I don't like the idea of having no hot swap 4) 3 drives in RAID6 set for VM storage, 2 drives in RAID1 set for host OS. 1 drive for hot swap All options give us enough storage capacity for our files, etc. We don't have any budget for extra drives or extra hot swap HD chassis for the servers. We have about 70 clients and about 150 users. MAIN SERVER Intel Xeon 5520 @ 2.27 GHz (2 processors) 16GB RAM 6 x 1TB Seagate Barracuda ES.2 Enterprise SATA drives Intel SRCSATAWB RAID controller Virtual machine workload using Hyper-V on Windows Server 2008 R2: DC01 - Active Directory Domain Controller / DNS server / Global catalog - 1GB RAM DC02 - Active Directory Domain Controller / DNS server / Global catalog - 1GB RAM Member Server - DHCP server, File server, Print server - 1GB RAM SCCM Member Server - 4GB RAM Third Party Software Member Server - A/V server, Ticketing software, etc - 4GB RAM Exchange 2007 - 4GB RAM - however we are probably migrating to a hosted solution, therefore freeing up resources BACKUP SERVER Intel Xeon E5410 @ 2.33GHz (2 processors) 16GB RAM 6 x 2TB WD RE4 SATA drives Intel SRCSASRB RAID controller Virtual machine workload using Hyper-V on Windows Server 2008 R2: AppAssure backup software - 8GB RAM

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• What Sort of Server Setup Am I Likely to Need? - School A/V streaming

  - by DeathMagus

  My prior experience with servers has generally been limited to home file-sharing servers, low-traffic web-servers, and the like. This leaves me with the technical knowledge of how to set up a system, but little experience in terms of scaling said system. My current project, however, has me as the technical lead in setting up a school for online audio and video streaming. The difficulty I'm running into is that I don't quite have the experience to guess what they'll need, and they don't have the experience to tell me - so I've tried to ask as many pertinent questions about what they want to do with their server, and here's what I found out: About 1000 simultaneous users, and hoping to expand (possibly significantly) Both video and audio streaming, at obviously the highest quality possible Support for both live and playlist-based streaming. Probably only one channel, but as it's an educational opportunity, I imagine letting them have a few more wouldn't hurt. No word on whether they're locked into Windows or whether Linux is acceptable. Approximate budget - $7000. It may actually be about $2k less than this, because of a mishap with another technology firm (they ordered a $7000 DV tape deck for some reason, and now the company wants them to pay a 30% restocking fee). The tentative decisions I've already made: I'm planning on using Icecast 2 for my streaming server, fed by VLC Shoutcast encoding. Since the school already has a DMZ set up, I plan on placing the Icecast server in there, and feeding it through their intranet from a simple workstation computer in their studios. This system isn't in any way mission critical - it's an education tool (they're a media magnet school), so I figure redundancy is not worthwhile to them from a cost:benefit perspective. What I don't know is this: How powerful of a server will I need? What is likely to be my major throttle - bandwidth? How can I mitigate that? Will I need anything special for the encoding workstation other than professional video and audio capture cards and a copy of VLC? Are there any other considerations that I'm simply missing? Thanks a lot for any help - if there's more information you need, let me know and I'll tell you all I can.

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• What happens to missed writes after a zpool clear?

  - by Kevin

  I am trying to understand ZFS' behaviour under a specific condition, but the documentation is not very explicit about this so I'm left guessing. Suppose we have a zpool with redundancy. Take the following sequence of events: A problem arises in the connection between device D and the server. This causes a large number of failures and ZFS therefore faults the device, putting the pool in degraded state. While the pool is in degraded state, the pool is mutated (data is written and/or changed.) The connectivity issue is physically repaired such that device D is reliable again. Knowing that most data on D is valid, and not wanting to stress the pool with a resilver needlessly, the admin instead runs zpool clear pool D. This is indicated by Oracle's documentation as the appropriate action where the fault was due to a transient problem that has been corrected. I've read that zpool clear only clears the error counter, and restores the device to online status. However, this is a bit troubling, because if that's all it does, it will leave the pool in an inconsistent state! This is because mutations in step 2 will not have been successfully written to D. Instead, D will reflect the state of the pool prior to the connectivity failure. This is of course not the normative state for a zpool and could lead to hard data loss upon failure of another device - however, the pool status will not reflect this issue! I would at least assume based on ZFS' robust integrity mechanisms that an attempt to read the mutated data from D would catch the mistakes and repair them. However, this raises two problems: Reads are not guaranteed to hit all mutations unless a scrub is done; and Once ZFS does hit the mutated data, it (I'm guessing) might fault the drive again because it would appear to ZFS to be corrupting data, since it doesn't remember the previous write failures. Theoretically, ZFS could circumvent this problem by keeping track of mutations that occur during a degraded state, and writing them back to D when it's cleared. For some reason I suspect that's not what happens, though. I'm hoping someone with intimate knowledge of ZFS can shed some light on this aspect.

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• What DNS server to use for dynamic load-balancing of website?

  - by Marki555

  I will have 2 servers in different datacenters (different countries) and I want to use DNS load-balancing mainly for High Availability of website hosted on those 2 servers. It is just ad tracking site, which records hit in local database and returns few lines on html code. I want to return 2 A records each time because of DNS pinning in browsers (if one server fails, browser will try second A record which it has already cached). Both servers will be acting also as DNS servers for redundancy. Now comes my proposed solution: I will use BIND and have both servers as a master for that zone. On each server there will be running script, which will periodically test availability (http) of both servers and remove IP from DNS in case of failure. Now the questions :) 1) Is BIND suitable for this solution? I think BIND performance is good and it is easy to manipulate the zone file via script. And as I will modify the zone only in case of failure/maintenance, the modifications (and thus bind reload) won't be often. 2) I plan to use TTL of 5 minutes. The website will have about 1000-3000 req/s but from distinct clients (each IP only 1-3 requests), so I think the DNS load won't be too much. I suppose their ISPs will cache the responses for those 5 mins. Is there any reason to lower the TTL even more? 3) Is my master-master approach good? Or should I make one of the servers master and the other one slave? Right now each server can monitor both itself and the other one. If only webservice fails, both DNS nodes will notice it. If the whole server fails, then the remaining DNS node will notice it and the failed node will not answer DNS queries anyway. 4) Is it a big issue when one NS server does not respond to queries? If yes, I can make a third DNS, so anytime at least 2 of them would accept queries... 5) Should I rewrite the zone file via script, or just use dynamic DNS update (for example via nsupdateutility)?

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• Server to server replication and CPU and 32k\ corrupt doc

  - by nick wall

  Summary: if database contains a doc with 32K issue or corrupt, on server to server replication it causes marked increase in CPU in nserver.exe task, which effectively causes our server(s) to slow right down. We have a 5 server cluster (1 "hub" and 4 HTTP servers accessed via reverse proxy and SSO for load balancing and redundancy). All are physically located next to each other on network, they don't have dedicated network\ ports for cluster or replication. I realise IBM recommendation is dedicated port for cluster. Cluster queues are in tolerance and under heavy application user load, i.e. the maximum number of documents are being created, edited, deleted, the replication times between servers are negligible. Normally, all is well. Of the servers in the cluster, 1 is considered the "hub", and imitates a PUSH-PULL replication with it's cluster mates every 60mins, so that the replication load is taken by the hub and not cluster mates. The problem we have: every now and then we get a slow replication time from the hub to a cluster mate, sometimes up to 30mins. This maxes out the nserver.exe task on the "cluster mate" which causes it to respond to http requests very slowly. In the past, we have found that if a corrupt document is in the DB, it can have this affect, but on those occasions, the server log will show the corrupt doc noteId, we run fixup, all well. But we are not now seeing any record of corrupt docs. What we have noticed is if a doc with the 32K issue is present, the same thing can happen. Our only solution in that case is to run a : fixup mydb.nsf -V, which shows it is purging a 32K doc. Luckily we run a reverse proxy, so we can shut HTTP servers down without users noticing, but users do notice when a server has the problem! Has anyone else seen this occur? I have set up DDM event handlers for many of the replication events. I have set the replication time out limit to 5 mins (the max we usually see under full user load is 0.1min), to prevent it rep'ing for 30mins as before. This ia a temporary work around. Does anyone know of a DDM event to trap the 32K issue? we could at least then send alert. Regarding 32K issue: this prob needs another thread, but we are finding this relatively hard to find the source of the issue as the 32K event is fairly rare. Our app is fairly complex, interacting with various other external web services, with 2 way data transfer. But if we do encounter a 32K doc, we can't look at field properties, so we can't work out which field has issue which would give us a clue as to which process is culprit. As above, we run a fixup -V. Any help\ comments on this would be gratefully received.

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• SQL – Quick Start with Explorer Sections of NuoDB – Query NuoDB Database

  - by Pinal Dave

  This is the third post in the series of the blog posts I am writing about NuoDB. NuoDB is very innovative and easy-to-use product. I can clearly see how one can scale-out NuoDB with so much ease and confidence. In my very first blog post we discussed how we can install NuoDB (link), and in my second post I discussed how we can manage the NuoDB database transaction engines and storage managers with a few clicks (link). Note: You can Download NuoDB from here. In this post, we will learn how we can use the Explorer feature of NuoDB to do various SQL operations. NuoDB has a browser-based Explorer, which is very powerful and has many of the features any IDE would normally have. Let us see how it works in the following step-by-step tutorial. Let us go to the NuoDBNuoDB Console by typing the following URL in your browser: http://localhost:8080/ It will bring you to the QuickStart screen. Make sure that you have created the sample database. If you have not created sample database, click on Create Database and create it successfully. Now go to the NuoDB Explorer by clicking on the main tab, and it will ask you for your domain username and password. Enter the username as a domain and password as a bird. Alternatively you can also enter username as a quickstart and password as a quickstart. Once you enter the password you will be able to see the databases. In our example we have installed the Sample Database hence you will see the Test database in our Database Hierarchy screen. When you click on database it will ask for the database login. Note that Database Login is different from Domain login and you will have to enter your database login over here. In our case the database username is dba and password is goalie. Once you enter a valid username and password it will display your database. Further expand your database and you will notice various objects in your database. Once you explore various objects, select any database and click on Open. When you click on execute, it will display the SQL script to select the data from the table. The autogenerated script displays entire result set from the database. The NuoDB Explorer is very powerful and makes the life of developers very easy. If you click on List SQL Statements it will list all the available SQL statements right away in Query Editor. You can see the popup window in following image. Here is the cool thing for geeks. You can even click on Query Plan and it will display the text based query plan as well. In case of a SELECT, the query plan will be much simpler, however, when we write complex queries it will be very interesting. We can use the query plan tab for performance tuning of the database. Here is another feature, when we click on List Tables in NuoDB Explorer.  It lists all the available tables in the query editor. This is very helpful when we are writing a long complex query. Here is a relatively complex example I have built using Inner Join syntax. Right below I have displayed the Query Plan. The query plan displays all the little details related to the query. Well, we just wrote multi-table query and executed it against the NuoDB database. You can use the NuoDB Admin section and do various analyses of the query and its performance. NuoDB is a distributed database built on a patented emergent architecture with full support for SQL and ACID guarantees.  It allows you to add Transaction Engine processes to a running system to improve the performance of your system.  You can also add a second Storage Engine to your running system for redundancy purposes.  Conversely, you can shut down processes when you don’t need the extra database resources. NuoDB also provides developers and administrators with a single intuitive interface for centrally monitoring deployments. If you have read my blog posts and have not tried out NuoDB, I strongly suggest that you download it today and catch up with the learnings with me. Trust me though the product is very powerful, it is extremely easy to learn and use. Reference: Pinal Dave (http://blog.sqlauthority.com)   Filed under: Big Data, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: NuoDB

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• Windows Azure Recipe: Enterprise LOBs

  - by Clint Edmonson

  Enterprises are more and more dependent on their specialized internal Line of Business (LOB) applications than ever before. Naturally, the more software they leverage on-premises, the more infrastructure they need manage. It’s frequently the case that our customers simply can’t scale up their hardware purchases and operational staff as fast as internal demand for software requires. The result is that getting new or enhanced applications in the hands of business users becomes slower and more expensive every day. Being able to quickly deliver applications in a rapidly changing business environment while maintaining high standards of corporate security is a challenge that can be met right now by moving enterprise LOBs out into the cloud and leveraging Azure’s Access Control services. In fact, we’re seeing many of our customers (both large and small) see huge benefits from moving their web based business applications such as corporate help desks, expense tracking, travel portals, timesheets, and more to Windows Azure. Drivers Cost Reduction Time to market Security Solution Here’s a sketch of how many Windows Azure Enterprise LOBs are being architected and deployed: Ingredients Web Role – this will host the core of the application. Each web role is a virtual machine hosting an application written in ASP.NET (or optionally php, or node.js). The number of web roles can be scaled up or down as needed to handle peak and non-peak traffic loads. Many Java based applications are also being deployed to Windows Azure with a little more effort. Database – every modern web application needs to store data. SQL Azure databases look and act exactly like their on-premise siblings but are fault tolerant and have data redundancy built in. Access Control – this service is necessary to establish federated identity between the cloud hosted application and an enterprise’s corporate network. It works in conjunction with a secure token service (STS) that is hosted on-premises to establish the corporate user’s identity and credentials. The source code for an on-premises STS is provided in the Windows Azure training kit and merely needs to be customized for the corporate environment and published on a publicly accessible corporate web site. Once set up, corporate users see a near seamless single sign-on experience. Reporting – businesses live and die by their reports and SQL Azure Reporting, based on SQL Server Reporting 2008 R2, can serve up reports with tables, charts, maps, gauges, and more. These reports can be accessed from the Windows Azure Portal, through a web browser, or directly from applications. Service Bus (optional) – if deep integration with other applications and systems is needed, the service bus is the answer. It enables secure service layer communication between applications hosted behind firewalls in on-premises or partner datacenters and applications hosted inside Windows Azure. The Service Bus provides the ability to securely expose just the information and services that are necessary to create a simpler, more secure architecture than opening up a full blown VPN. Data Sync (optional) – in cases where the data stored in the cloud needs to be shared internally, establishing a secure one-way or two-way data-sync connection between the on-premises and off-premises databases is a perfect option. It can be very granular, allowing us to specify exactly what tables and columns to synchronize, setup filters to sync only a subset of rows, set the conflict resolution policy for two-way sync, and specify how frequently data should be synchronized Training Labs These links point to online Windows Azure training labs where you can learn more about the individual ingredients described above. (Note: The entire Windows Azure Training Kit can also be downloaded for offline use.) Windows Azure (16 labs) Windows Azure is an internet-scale cloud computing and services platform hosted in Microsoft data centers, which provides an operating system and a set of developer services which can be used individually or together. It gives developers the choice to build web applications; applications running on connected devices, PCs, or servers; or hybrid solutions offering the best of both worlds. New or enhanced applications can be built using existing skills with the Visual Studio development environment and the .NET Framework. With its standards-based and interoperable approach, the services platform supports multiple internet protocols, including HTTP, REST, SOAP, and plain XML SQL Azure (7 labs) Microsoft SQL Azure delivers on the Microsoft Data Platform vision of extending the SQL Server capabilities to the cloud as web-based services, enabling you to store structured, semi-structured, and unstructured data. Windows Azure Services (9 labs) As applications collaborate across organizational boundaries, ensuring secure transactions across disparate security domains is crucial but difficult to implement. Windows Azure Services provides hosted authentication and access control using powerful, secure, standards-based infrastructure. See my Windows Azure Resource Guide for more guidance on how to get started, including links web portals, training kits, samples, and blogs related to Windows Azure.

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• Manage Your Amazon S3 Account with CloudBerry Explorer

  - by Mysticgeek

  If you have an Amazon S3 account you’re using to backup your data, you might want an easy way to manage it. CloudBerry Explorer is a free app that runs on your desktop an provides an easy way to manage your S3 account. Installation and Setup Just download and install the application with the defaults. When the application launches you’ll be prompted to enter in your username and email to get a registration key. Or you can continue on by clicking Register later. Now you will want to set up your Amazon S3 account. Click on File \ Amazon S3 Accounts. Double-click on the New Account icon.   Next enter in your Amazon account Access and Secret keys, select SSL if you want, then click the Test Connection button. Provided everything was entered correctly, you’ll see the Connection Success screen, just close out of it. Browse and Manage files Once you have your account setup through the Explorer, you can start viewing and managing your files on S3. The left pane shows your S3 buckets and stored files, while the right side shows your local computer. This allows you to manage your files in your Amazon S3 buckets directly from your desktop! It’s very easy to use, and you can drag and drop files from your computer to the S3 account or vice versa. There is also the ability to transfer files between Amazon S3 accounts from within the explorer. Go into Tools and Content Types and you can control the file types by adding, removing, or editing them. If you end up messing something up along the lines, you can always select Reset to defaults and everything will be back to normal. There is a multiple tabbed view so you can easily keep track of your different accounts and local machine. It allows the ability to create new storage buckets directly in the Explorer. Or you can delete buckets as well… Different actions can be accessed from the toolbars or by right-clicking and selecting from the context menu. Here we see a cool option that lets you move your data inside Amazon S3. It is faster and doesn’t cost money by moving the files to your computer first, then to another account. However, if you want data moved to your local machine first, you have that option as well.   Not all features are available in the free version, and if it’s not, you’ll be prompted to purchase a license for the Pro version. We will have a comprehensive review of the Pro version in the near future.    If you ever need help with CloudBerry Explorer, go to Tools \ Diagnostics. It will run a quick diagnostics check and you can send the information to the CloudBerry team for assistance. Delete Files from Amazon S3 To delete a file from you Amazon S3 account, simply highlight the files or folder you want to get rid of then click Delete on the toolbar. You can also right-click the file and select Delete from the Context Menu. Click Yes to the confirmation dialog box… Then you can watch the progress as your files are deleted in the bottom section of the explorer. Conclusion CloudBerry Explorer free version has several neat features that will allow you easy and basic control over you Amazon S3 account. The free version may be enough for basic users, but power users will want to upgrade to the pro version, as it includes a lot more features. Using the free version allows you to get a feel for what CloudBerry Explorer has to offer, and is a good starting point. Keep in mind that Amazon S3 is introducing Reduced Redundancy Storage which will lower the price of data stored. The price drops from $0.15 per GB to only $0.10 per GB. If you’re a Windows Home Server user, check out our review of CloudBerry Online Backup 1.5 for WHS. Download CloudBerry Explorer Free for Amazon S3 Similar Articles Productive Geek Tips CloudBerry Online Backup 1.5 for Windows Home ServerReopen Closed Tabs in Internet ExplorerPreview and Purchase Ebooks with Kindle for PCTroubleshoot and Manage Addons in Internet Explorer 8Beginner Geek: Delete User Accounts in Windows 7 TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips All My Movies 5.9 CloudBerry Online Backup 1.5 for Windows Home Server Snagit 10 VMware Workstation 7 Google TV The iPod Revolution Ultimate Boot CD can help when disaster strikes Windows Firewall with Advanced Security – How To Guides Sculptris 1.0, 3D Drawing app AceStock, a Tiny Desktop Quote Monitor

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• Easing the Journey to the Private Cloud with Oracle Consulting

  - by MichaelM-Oracle

  By Sanjai Marimadaiah, Senior Director, Strategy & Business Development – Cloud Solutions, Oracle Consulting Services Business leaders are now leading the charge on how their firms can profit from cloud solutions. Agility and innovation are becoming the primary drivers of the business case for the cloud, even more than the anticipated cost savings. Leaders need to find the right strategy and optimize the use of cloud-based applications across their enterprise-computing infrastructure. The Problem – Current State With prevalent IT practices, many organizations find that they run multiple IT solutions serving similar business needs. This has led to the proliferation of technology stacks, for example: Oracle 10g on Sun T4 running Solaris 9; Oracle 11g on Exadata running Linux; or Oracle 12c on commodity x86 servers. This variance has a huge impact on an organization’s agility and expenses, and requires IT professionals with varied skills as well as on-going training for different systems and tools. Fortunately there is a practical business strategy to overcome this unneeded redundancy. Thus begins a journey to the right cloud computing solution. The Solution – Cloud Services from Oracle Consulting Services (OCS) Oracle Consulting Services (OCS ) works closely with our clients as trusted advisors to proactively respond to business needs and IT concerns. OCS understands that making the transition to cloud solutions begins with a strategic conversation, based on its deep expertise for successfully completing private cloud service engagements with several companies. For a journey to the cloud, Oracle Consulting Services leads the client through four phases– standardization, consolidation, service delivery, and enterprise cloud – to achieve optimal returns. Phase 1 - Standardization Oracle Consulting Services (OCS) works with clients to evaluate their business requirements and propose a set of standard solutions stacks for various IT solutions. This is an opportune time to evaluate cloud ready solutions, such as Oracle 12c, Oracle Exadata, and the Oracle Database Appliance (ODA). The OCS consultants, together with the delivery team, then turn to upgrading and migrating existing solution stacks to standardized offerings. OCS has the expertise and tools to complete this stage in a fraction of the time required by other IT services companies. Clients quickly realize cost savings in tools, processes, and type/number of resources required. This standardization also improves agility of the IT organizations and their abilities to respond to the needs of various business units. Phase 2 - Consolidation During the consolidation phase, OCS consultants programmatically consolidate hundreds of databases into a smaller number of servers to improve utilization, reduce floor space, and optimize maintenance costs. Consolidation helps clients realize huge savings in CapEx investments and shrink OpEx costs. The use of engineered systems, such as Oracle Exadata, greatly reduces the client’s risk of moving to a new solution stack. OCS recommends clients to pursue Phase 1 (Standardization) and Phase 2 (Consolidation) simultaneously to reduce the overall time, effort, and expense of the cloud journey. Phase 3 - Service Delivery Once a client is on a path of standardization and consolidation, OCS consultants create Service Catalogues based on the SLAs requirements and the criticality of the solutions. The number and types of Service Catalogues (Platinum, Gold, Silver, Bronze, etc.) vary from client to client. OCS consultants also implement a variety of value-added cloud solutions, including monitoring, metering, and charge-back solutions. At this stage, clients are able to achieve a high level of understanding in their cloud journey. Their IT organizations are operating efficiently and are more agile in responding to the needs of business units. Phase 4 - Enterprise Cloud In the final phase of the cloud journey, the economics of the IT organizations change. Business units can request services on-demand; applications can be deployed and consumed on a pay-as-you-go model. OCS has the expertise and capabilities to establish processes, programs, and solutions required for IT organizations to transform how they interact with business units. The Promise of Cloud Solutions Depending the size and complexity of their business model, some clients are able to abbreviate some phases of their cloud journey. Cloud solutions are still evolving and there is rapid pace of innovation to transform how IT organizations operate. The lesson is clear. Cloud solutions hold a lot of promise for business agility. Business leaders can now leverage an additional set of capabilities and services. They can ramp up their pace of innovation. With cloud maturity, they can compete more effectively in their respective markets. But there are certainly challenges ahead. A skilled consulting services partner can play a pivotal role as a trusted advisor in the successful adoption of cloud solutions. Oracle Consulting Services has expertise and a portfolio of services to help clients succeed on their journey to the cloud.

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• Checksum Transformation

  The Checksum Transformation computes a hash value, the checksum, across one or more columns, returning the result in the Checksum output column. The transformation provides functionality similar to the T-SQL CHECKSUM function, but is encapsulated within SQL Server Integration Services, for use within the pipeline without code or a SQL Server connection. As featured in The Microsoft Data Warehouse Toolkit by Joy Mundy and Warren Thornthwaite from the Kimbal Group. Have a look at the book samples especially Sample package for custom SCD handling. All input columns are passed through the transformation unaltered, those selected are used to generate the checksum which is passed out through a single output column, Checksum. This does not restrict the number of columns available downstream from the transformation, as columns will always flow through a transformation. The Checksum output column is in addition to all existing columns within the pipeline buffer. The Checksum Transformation uses an algorithm based on the .Net framework GetHashCode method, it is not consistent with the T-SQL CHECKSUM() or BINARY_CHECKSUM() functions. The transformation does not support the following Integration Services data types, DT_NTEXT, DT_IMAGE and DT_BYTES. ChecksumAlgorithm Property There ChecksumAlgorithm property is defined with an enumeration. It was first added in v1.3.0, when the FrameworkChecksum was added. All previous algorithms are still supported for backward compatibility as ChecksumAlgorithm.Original (0). Original - Orginal checksum function, with known issues around column separators and null columns. This was deprecated in the first SQL Server 2005 RTM release. FrameworkChecksum - The hash function is based on the .NET Framework GetHash method for object types. This is based on the .NET Object.GetHashCode() method, which unfortunately differs between x86 and x64 systems. For that reason we now default to the CRC32 option. CRC32 - Using a standard 32-bit cyclic redundancy check (CRC), this provides a more open implementation. The component is provided as an MSI file, however to complete the installation, you will have to add the transformation to the Visual Studio toolbox by hand. This process has been described in detail in the related FAQ entry for How do I install a task or transform component?, just select Checksum from the SSIS Data Flow Items list in the Choose Toolbox Items window. Downloads The Checksum Transformation is available for SQL Server 2005, SQL Server 2008 (includes R2) and SQL Server 2012. Please choose the version to match your SQL Server version, or you can install multiple versions and use them side by side if you have more than one version of SQL Server installed. Checksum Transformation for SQL Server 2005 Checksum Transformation for SQL Server 2008 Checksum Transformation for SQL Server 2012 Version History SQL Server 2012 Version 3.0.0.27 – SQL Server 2012 release. Includes upgrade support for both 2005 and 2008 packages to 2012. (5 Jun 2010) SQL Server 2008 Version 2.0.0.27 – Fix for CRC-32 algorithm that inadvertently made it sort dependent. Fix for race condition which sometimes lead to the error Item has already been added. Key in dictionary: '79764919' . Fix for upgrade mappings between 2005 and 2008. (19 Oct 2010) Version 2.0.0.24 - SQL Server 2008 release. Introduces the new CRC-32 algorithm, which is consistent across x86 and x64.. The default algorithm is now CRC32. (29 Oct 2008) Version 2.0.0.6 - SQL Server 2008 pre-release. This version was released by mistake as part of the site migration, and had known issues. (20 Oct 2008) SQL Server 2005 Version 1.5.0.43 – Fix for CRC-32 algorithm that inadvertently made it sort dependent. Fix for race condition which sometimes lead to the error Item has already been added. Key in dictionary: '79764919' . (19 Oct 2010) Version 1.5.0.16 - Introduces the new CRC-32 algorithm, which is consistent across x86 and x64. The default algorithm is now CRC32. (20 Oct 2008) Version 1.4.0.0 - Installer refresh only. (22 Dec 2007) Version 1.4.0.0 - Refresh for minor UI enhancements. (5 Mar 2006) Version 1.3.0.0 - SQL Server 2005 RTM. The checksum algorithm has changed to improve cardinality when calculating multiple column checksums. The original algorithm is still available for backward compatibility. Fixed custom UI bug with Output column name not persisting. (10 Nov 2005) Version 1.2.0.1 - SQL Server 2005 IDW 15 June CTP. A user interface is provided, as well as the ability to change the checksum output column name. (29 Aug 2005) Version 1.0.0 - Public Release (Beta). (30 Oct 2004) Screenshot

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• Myths about Coding Craftsmanship part 2

  - by tom

  Myth 3: The source of all bad code is inept developers and stupid people When you review code is this what you assume?  Shame on you.  You are probably making assumptions in your code if you are assuming so much already.  Bad code can be the result of any number of causes including but not limited to using dated techniques (like boxing when generics are available), not following standards (“look how he does the spacing between arguments!” or “did he really just name that variable ‘bln_Hello_Cats’?”), being redundant, using properties, methods, or objects in a novel way (like switching on button.Text between “Hello World” and “Hello World “ //clever use of space character… sigh), not following the SOLID principals, hacking around assumptions made in earlier iterations / hacking in features that should be worked into the overall design.  The first two issues, while annoying are pretty easy to spot and can be fixed so easily.  If your coding team is made up of experienced professionals who are passionate about staying current then these shouldn’t be happening.  If you work with a variety of skills, backgrounds, and experience then there will be some of this stuff going on.  If you have an opportunity to mentor such a developer who is receptive to constructive criticism don’t be a jerk; help them and the codebase will improve.  A little patience can improve the codebase, your work environment, and even your perspective. The novelty and redundancy I have encountered has often been the use of creativity when language knowledge was perceived as unavailable or too time consuming.  When developers learn on the job you get a lot of this.  Rather than going to MSDN developers will use what they know.  Depending on the constraints of their assignment hacking together what they know may seem quite practical.  This was not stupid though I often wonder how much time is actually “saved” by hacking.  These issues are often harder to untangle if we ever do.  They can also grow out of control as we write hack after hack to make it work and get back to some development that is satisfying. Hacking upon an existing hack is what I call “feeding the monster”.  Code monsters are anti-patterns and hacks gone wild.  The reason code monsters continue to get bigger is that they keep growing in scope, touching more and more of the application.  This is not the result of dumb developers. It is probably the result of avoiding design, not taking the time to understand the problems or anticipate or communicate the vision of the product.  If our developers don’t understand the purpose of a feature or product how do we expect potential customers to do so? Forethought and organization are often what is missing from bad code.  Developers who do not use the SOLID principals should be encouraged to learn these principals and be given guidance on how to apply them.  The time “saved” by giving hackers room to hack will be made up for and then some. Not as technical debt but as shoddy work that if not replaced will be struggled with again and again.  Bad code is not the result of dumb developers (usually) it is the result of trying to do too much without the proper resources and neglecting the right thing that needs doing with the first thoughtless thing that comes into our heads. Object oriented code is all about relationships between objects.  Coders who believe their coworkers are all fools tend to write objects that are difficult to work with, not eager to explain themselves, and perform erratically and irrationally.  If you constantly find you are surrounded by idiots you may want to ask yourself if you are being unreasonable, if you are being closed minded, of if you have chosen the right profession.  Opening your mind up to the idea that you probably work with rational, well-intentioned people will probably make you a better coder and it might even make you less grumpy.  If you are surrounded by jerks who do not engage in the exchange of ideas who do not care about their customers or the durability of the code you are building together then I suggest you find a new place to work.  Myth 4: Customers don’t care about “beautiful” code Craftsmanship is customer focused because it means that the job was done right, the product will withstand the abuse, modifications, and scrutiny of our customers.  Users can appreciate a predictable timeline for a release, a product delivered on time and on budget, a feature set that does not interfere with the task(s) it is supporting, quick turnarounds on exception messages, self healing issues, and less issues.  These are all hindered by skimping on craftsmanship.  When we write data access and when we write reusable code.   What do you think?  Does bad code come primarily from low IQ individuals?  Do customers care about beautiful code?

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• "RFC 2833 RTP Event" Consecutive Events and the E "End" Bit

  - by brian_d

  Hello, I can send out a RFC 2833 dtmf event as outlined at http://www.ietf.org/rfc/rfc2833.txt When I do set the E "End" bit, but leave it as 0, I get the following behaviour: If for example keys 7874556332111111145855885#3 were pressed, then ALL events would be sent and show up in a program like wireshark, however only 87456321458585#3 would sound. So the first key (which I figure could be a separate issue) and any repeats of an event (ie 11111) are failing to sound. In section 3.9, figure 2 of the above linked document, they give a 911 example. Here all but the last event have the E bit set. When I set the bit for all numbers, I never get an event to sound. I have thought of a couple possible thing but do not know if they are the reason: 1) figure 2 shows payload types of 96 and 97 sent. I have not nor know how to exactly. In section 3.8, codes 96 and 97 are described as "the dynamic payload types 96 and 97 have been assigned for the redundancy mechanism and the telephone event payload respectively" 2) In section 3.5, "E:", "A sender MAY delay setting the end bit until retransmitting the last packet for a tone, rather than on its first transmission" Does anyone have an idea of how to actually do this? I have also fiddled around with timestamp intervals and the RTP marker. Any help is greatly appreciated. Here is a sample wireshark event capture of the relevant areas: 6590 31.159045000 xx.x.x.xxx --.--.---.-- RTP EVENT Payload type=RTP Event, DTMF Pound # (end) Real-Time Transport Protocol Stream setup by SDP (frame 6225) Setup frame: 6225 Setup Method: SDP 10.. .... = Version: RFC 1889 Version (2) ..0. .... = Padding: False ...0 .... = Extension: False .... 0000 = Contributing source identifiers count: 0 0... .... = Marker: False Payload type: telephone-event (101) Sequence number: 0 Extended sequence number: 65536 Timestamp: 0 Synchronization Source identifier: 0x15f27104 (368210180) RFC 2833 RTP Event Event ID: DTMF Pound # (11) 1... .... = End of Event: True .0.. .... = Reserved: False ..00 0000 = Volume: 0 Event Duration: 2048

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• Write binary stream to browser using PHP

  - by Dave Jarvis

  Background Trying to stream a PDF report written using iReport through PHP to the browser. The general problem is: how do you write binary data to the browser using PHP? Working Code The following code does the job, but (for many reasons) it is not as efficient as it should be (the code writes a file then sends the file contents the browser). // Load the MySQL database driver. // java( 'java.lang.Class' )->forName( 'com.mysql.jdbc.Driver' ); // Attempt a database connection. // $conn = java( 'java.sql.DriverManager' )->getConnection( "jdbc:mysql://localhost:3306/climate?user=$user&password=$password" ); // Extract parameters. // $params = new java('java.util.HashMap'); $params->put('DistrictCode', '101'); $params->put('StationCode', '0066'); $params->put('CategoryCode', '010'); // Use the fill manager to produce the report. // $fm = java('net.sf.jasperreports.engine.JasperFillManager'); $pm = $fm->fillReport($report, $params, $conn); header('Cache-Control: no-cache private'); header('Content-Description: File Transfer'); header('Content-Disposition: attachment, filename=climate-report.pdf'); header('Content-Type: application/pdf'); header('Content-Transfer-Encoding: binary'); header('Content-Length: ' . strlen( $result ) ); $path = realpath( "." ) . "/output.pdf"; $em = java('net.sf.jasperreports.engine.JasperExportManager'); $result = $em->exportReportToPdfFile($pm,$path); readfile( $path ); $conn->close(); Non-working Code To remove the slight redundancy (i.e., write directly to the browser), the following code looks like it should work, but it does not: $em = java('net.sf.jasperreports.engine.JasperExportManager'); $result = $em->exportReportToPdf($pm); header('Content-Length: ' . strlen( $result ) ); echo $result; Content is sent to the browser, but the file is corrupt (it begins with the PDF header) and cannot be read by any PDF reader. Question How can I take out the middle step of writing to the file and write directly to the browser so that the PDF is not corrupted? Thank you!

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• Avoiding Redundancies in XML documents

  - by MarceloRamires

  I was working with a certain XML where there were no redundancies <person> <eye> <eye_info> <eye_color> blue </eye_color> </eye_info> </eye> <hair> <hair_info> <hair_color> blue </hair_color> </hair_info> </hair> </person> As you can see, the sub-tag eye-color makes reference to eye in it's name, so there was no need to avoid redundancies, I could get the eye color in a single line after loading the XML into a dataset: dataset.ReadXml(path); value = dataset.Tables("eye_info").Rows(0)("eye_color"); I do realise it's not the smartest way of doing so, and this situation I'm having now wasn't unforeseen. Now, let's say I have to read xml's that are in this format: <person> <eye> <info> <color> blue </color> </info> </eye> <hair> <info> <color> blue </color> </info> </hair> </person> So If I try to call it like this: dataset.ReadXml(path); value = dataset.Tables("info").Rows(0)("color"); There will be a redundancy, because I could only go as far as one up level to identify a single field in a XML with my previous method, and the 'disambiguator' is three levels above. Is there a practical way to reach with no mistake a single field given all the above (or at least a few) fields ?

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• architecture python question

  - by tom smith

  hi. creating a distributed crawling python app. it consists of a master server, and associated client apps that will run on client servers. the purpose of the client app is to run across a targeted site, to extract specific data. the clients need to go "deep" within the site, behind multiple levels of forms, so each client is specifically geared towards a given site. each client app looks something like main: parse initial url call function level1 (data1) function level1 (data) parse the url, for data1 use the required xpath to get the dom elements call the next function call level2 (data) function level2 (data2) parse the url, for data2 use the required xpath to get the dom elements call the next function call level3 function level3 (dat3) parse the url, for data3 use the required xpath to get the dom elements call the next function call level4 function level4 (data) parse the url, for data4 use the required xpath to get the dom elements at the final function.. --all the data output, and eventually returned to the server --at this point the data has elements from each function... my question: given that the number of calls that is made to the child function by the current function varies, i'm trying to figure out the best approach. each function essentialy fetches a page of content, and then parses the page using a number of different XPath expressions, combined with different regex expressions depending on the site/page. if i run a client on a single box, as a sequential process, it'll take awhile, but the load on the box is rather small. i've thought of attempting to implement the child functions as threads from the current function, but that could be a nightmare, as well as quickly bring the "box" to its knees! i've thought of breaking the app up in a manner that would allow the master to essentially pass packets to the client boxes, in a way to allow each client/function to be run directly from the master. this process requires a bit of rewrite, but it has a number of advantages. a bunch of redundancy, and speed. it would detect if a section of the process was crashing and restart from that point. but not sure if it would be any faster... i'm writing the parsing scripts in python.. so... any thoughts/comments would be appreciated... i can get into a great deal more detail, but didn't want to bore anyone!! thanks! tom

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• Recursive N-way merge/diff algorithm for directory trees?

  - by BobMcGee

  What algorithms or Java libraries are available to do N-way, recursive diff/merge of directories? I need to be able to generate a list of folder trees that have many identical files, and have subdirectories with many similar files. I want to be able to use 2-way merge operations to quickly remove as much redundancy as possible. Goals: Find pairs of directories that have many similar files between them. Generate short list of directory pairs that can be synchronized with 2-way merge to eliminate duplicates Should operate recursively (there may be nested duplicates of higher-level directories) Run time and storage should be O(n log n) in numbers of directories and files Should be able to use an embedded DB or page to disk for processing more files than fit in memory (100,000+). Optional: generate an ancestry and change-set between folders Optional: sort the merge operations by how many duplicates they can elliminate I know how to use hashes to find duplicate files in roughly O(n) space, but I'm at a loss for how to go from this to finding partially overlapping sets between folders and their children. EDIT: some clarification The tricky part is the difference between "exact same" contents (otherwise hashing file hashes would work) and "similar" (which will not). Basically, I want to feed this algorithm at a set of directories and have it return a set of 2-way merge operations I can perform in order to reduce duplicates as much as possible with as few conflicts possible. It's effectively constructing an ancestry tree showing which folders are derived from each other. The end goal is to let me incorporate a bunch of different folders into one common tree. For example, I may have a folder holding programming projects, and then copy some of its contents to another computer to work on it. Then I might back up and intermediate version to flash drive. Except I may have 8 or 10 different versions, with slightly different organizational structures or folder names. I need to be able to merge them one step at a time, so I can chose how to incorporate changes at each step of the way. This is actually more or less what I intend to do with my utility (bring together a bunch of scattered backups from different points in time). I figure if I can do it right I may as well release it as a small open source util. I think the same tricks might be useful for comparing XML trees though.

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• Template function as a template argument

  - by Kos

  I've just got confused how to implement something in a generic way in C++. It's a bit convoluted, so let me explain step by step. Consider such code: void a(int) { // do something } void b(int) { // something else } void function1() { a(123); a(456); } void function2() { b(123); b(456); } void test() { function1(); function2(); } It's easily noticable that function1 and function2 do the same, with the only different part being the internal function. Therefore, I want to make function generic to avoid code redundancy. I can do it using function pointers or templates. Let me choose the latter for now. My thinking is that it's better since the compiler will surely be able to inline the functions - am I correct? Can compilers still inline the calls if they are made via function pointers? This is a side-question. OK, back to the original point... A solution with templates: void a(int) { // do something } void b(int) { // something else } template<void (*param)(int) > void function() { param(123); param(456); } void test() { function<a>(); function<b>(); } All OK. But I'm running into a problem: Can I still do that if a and b are generics themselves? template<typename T> void a(T t) { // do something } template<typename T> void b(T t) { // something else } template< ...param... > // ??? void function() { param<SomeType>(someobj); param<AnotherType>(someotherobj); } void test() { function<a>(); function<b>(); } I know that a template parameter can be one of: a type, a template type, a value of a type. None of those seems to cover my situation. My main question is hence: How do I solve that, i.e. define function() in the last example? (Yes, function pointers seem to be a workaround in this exact case - provided they can also be inlined - but I'm looking for a general solution for this class of problems).

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• PHP 5.3: Late static binding doesn't work for properties when defined in parent class while missing in child class

  - by DavidPesta

  Take a look at this example, and notice the outputs indicated. <?php class Mommy { protected static $_data = "Mommy Data"; public static function init( $data ) { static::$_data = $data; } public static function showData() { echo static::$_data . "<br>"; } } class Brother extends Mommy { } class Sister extends Mommy { } Brother::init( "Brother Data" ); Sister::init( "Sister Data" ); Brother::showData(); // Outputs: Sister Data Sister::showData(); // Outputs: Sister Data ?> My understanding was that using the static keyword would refer to the child class, but apparently it magically applies to the parent class whenever it is missing from the child class. (This is kind of a dangerous behavior for PHP, more on that explained below.) I have the following two things in mind for why I want to do this: I don't want the redundancy of defining all of the properties in all of the child classes. I want properties to be defined as defaults in the parent class and I want the child class definition to be able to override these properties wherever needed. The child class needs to exclude properties whenever the defaults are intended, which is why I don't define the properties in the child classes in the above example. However, if we are wanting to override a property at runtime (via the init method), it will override it for the parent class! From that point forward, child classes initialized earlier (as in the case of Brother) unexpectedly change on you. Apparently this is a result of child classes not having their own copy of the static property whenever it isn't explicitly defined inside of the child class--but instead of throwing an error it switches behavior of static to access the parent. Therefore, is there some way that the parent class could dynamically create a property that belongs to the child class without it appearing inside of the child class definition? That way the child class could have its own copy of the static property and the static keyword can refer to it properly, and it can be written to take into account parent property defaults. Or is there some other solution, good, bad, or ugly?

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• Why does std::map operator[] create an object if the key doesn't exist?

  - by n1ck

  Hi, I'm pretty sure I already saw this question somewhere (comp.lang.c++? Google doesn't seem to find it there either) but a quick search here doesn't seem to find it so here it is: Why does the std::map operator[] create an object if the key doesn't exist? I don't know but for me this seems counter-intuitive if you compare to most other operator[] (like std::vector) where if you use it you must be sure that the index exists. I'm wondering what's the rationale for implementing this behavior in std::map. Like I said wouldn't it be more intuitive to act more like an index in a vector and crash (well undefined behavior I guess) when accessed with an invalid key? Refining my question after seeing the answers: Ok so far I got a lot of answers saying basically it's cheap so why not or things similar. I totally agree with that but why not use a dedicated function for that (I think one of the comment said that in java there is no operator[] and the function is called put)? My point is why doesn't map operator[] work like a vector? If I use operator[] on an out of range index on a vector I wouldn't like it to insert an element even if it was cheap because that probably mean an error in my code. My point is why isn't it the same thing with map. I mean, for me, using operator[] on a map would mean: i know this key already exist (for whatever reason, i just inserted it, I have redundancy somewhere, whatever). I think it would be more intuitive that way. That said what are the advantage of doing the current behavior with operator[] (and only for that, I agree that a function with the current behavior should be there, just not operator[])? Maybe it give clearer code that way? I don't know. Another answer was that it already existed that way so why not keep it but then, probably when they (the ones before stl) choose to implement it that way they found it provided an advantage or something? So my question is basically: why choose to implement it that way, meaning a somewhat lack of consistency with other operator[]. What benefit do it give? Thanks

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• Difference between Cloud and Virtualization

  - by Akash Kava

  Ops: This does not belong to ServerFault because it focuses on Programing Architecture. I have following questions regarding differences between Cloud and Virtualization.. How Cloud is different then Virtualization? Currently I tried to find out pricing of Rackspace, Amazone and all similar cloud providers, I found that our current 6 dedicated servers came cheaper then their pricing. So how one can claim cloud is cheaper? Is it cheaper only in comparison of normal hosting? We re organized our infrastructure in virtual environment to reduce or configuration overhead at time of failure, we did not have to rewrite any peice of code that is already written for earlier setup. So moving to virtualization does not require any re programming. But cloud is absoltely different and it will require entire reprogramming right? Is it really worth to recode when our current IT costs are 3-4 times lower then cloud hosting including raid backups and all sort of clustering for high availability? New programming architecture means new overheads of training staff, new methods of testing and new deployment schemes, does it justify over "on demand resource usage" words of cloud? We are having current development architecture with simple Server side ASP.NET WebServices with no local context and on client side Flex/Silverlight which offers pretty good REST architecture and its highly scalable. How does cloud differs from REST model of deployment? On storage, SQL Server or MySQL offers pretty good replication and high availibility then what is advantage in cloud? Data guarantee, one of our vendor hosting some other customer's app on cloud (one of most used), lost Entire Hard Disk (the virtual) and entire module in first 6 months. Second provider said its your duty to take backup, fine I agree, but no provider gives SLA for data guarantee, they give 99% uptime. However in most business apps, uptime is less important then data integrity. In our 10 years of dedicated hosting experience we had only one hard disk crash. This makes me little skeptical to go for cloud and loosing control over data. And I feel its just a big marketing buzz to sell virtulization in different form. Size of data, currently all providers charge very heavy for large data, if you are hosting only below 100GB cloud can be good alternative, but I think virtual servers and dedicated servers above 100GB to few TBs are still cheaper. Why would want to pay so high on cloud when there is no data guarentee as well as it doesnt say anything about redundancy. (I wish SO had something for spell check for Internet Explorer, sorry for wrong spellings in my post)

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• Dynamic Dispatch without Virtual Functions

  - by Kristopher Johnson

  I've got some legacy code that, instead of virtual functions, uses a kind field to do dynamic dispatch. It looks something like this: // Base struct shared by all subtypes // Plain-old data; can't use virtual functions struct POD { int kind; int GetFoo(); int GetBar(); int GetBaz(); int GetXyzzy(); }; enum Kind { Kind_Derived1, Kind_Derived2, Kind_Derived3 }; struct Derived1: POD { Derived1(): kind(Kind_Derived1) {} int GetFoo(); int GetBar(); int GetBaz(); int GetXyzzy(); // plus other type-specific data and function members }; struct Derived2: POD { Derived2(): kind(Kind_Derived2) {} int GetFoo(); int GetBar(); int GetBaz(); int GetXyzzy(); // plus other type-specific data and function members }; struct Derived3: POD { Derived3(): kind(Kind_Derived3) {} int GetFoo(); int GetBar(); int GetBaz(); int GetXyzzy(); // plus other type-specific data and function members }; and then the POD class's function members are implemented like this: int POD::GetFoo() { // Call kind-specific function switch (kind) { case Kind_Derived1: { Derived1 *pDerived1 = static_cast<Derived1*>(this); return pDerived1->GetFoo(); } case Kind_Derived2: { Derived2 *pDerived2 = static_cast<Derived2*>(this); return pDerived2->GetFoo(); } case Kind_Derived3: { Derived3 *pDerived3 = static_cast<Derived3*>(this); return pDerived3->GetFoo(); } default: throw UnknownKindException(kind, "GetFoo"); } } POD::GetBar(), POD::GetBaz(), POD::GetXyzzy(), and other members are implemented similarly. This example is simplified. The actual code has about a dozen different subtypes of POD, and a couple dozen methods. New subtypes of POD and new methods are added pretty frequently, and so every time we do that, we have to update all these switch statements. The typical way to handle this would be to declare the function members virtual in the POD class, but we can't do that because the objects reside in shared memory. There is a lot of code that depends on these structs being plain-old-data, so even if I could figure out some way to have virtual functions in shared-memory objects, I wouldn't want to do that. So, I'm looking for suggestions as to the best way to clean this up so that all the knowledge of how to call the subtype methods is centralized in one place, rather than scattered among a couple dozen switch statements in a couple dozen functions. What occurs to me is that I can create some sort of adapter class that wraps a POD and uses templates to minimize the redundancy. But before I start down that path, I'd like to know how others have dealt with this.

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• Database design advice needed.

  - by user346271

  Hi all, I'm a lone developer for a telecoms company, and am after some database design advice from anyone with a bit of time to answer. I am inserting into one table ~2 million rows each day, these tables then get archived and compressed on a monthly basis. Each monthly table contains ~15,000,000 rows. Although this is increasing month on month. For every insert I do above I am combining the data from rows which belong together and creating another "correlated" table. This table is currently not being archived, as I need to make sure I never miss an update to the correlated table. (Hope that makes sense) Although in general this information should remain fairly static after a couple of days of processing. All of the above is working perfectly. However my company now wishes to perform some stats against this data, and these tables are getting too large to provide the results in what would be deemed a reasonable time. Even with the appropriate indexes set. So I guess after all the above my question is quite simple. Should I write a script which groups the data from my correlated table into smaller tables. Or should I store the queries result sets in something like memcache? I'm already using mysqls cache, but due to having limited control over how long the data is stored for, it's not working ideally. The main advantages I can see of using something like memcache: No blocking on my correlated table after the query has been cashed. Greater flexibility of sharing the collected data between the backend collector and front end processor. (i.e custom reports could be written in the backend and the results of these stored in the cache under a key which then gets shared with anyone who would want to see the data of this report) Redundancy and scalability if we start sharing this data with a large amount of customers. The main disadvantages I can see of using something like memcache: Data is not persistent if machine is rebooted / cache is flushed. The main advantages of using MySql Persistent data. Less code changes (although adding something like memcache is trivial anyway) The main disadvantages of using MySql Have to define table templates every time I want to store provide a new set of grouped data. Have to write a program which loops through the correlated data and fills these new tables. Potentially will still grow slower as the data continues to be filled. Apologies for quite a long question. It's helped me to write down these thoughts here anyway, and any advice/help/experience with dealing with this sort of problem would be greatly appreciated. Many thanks. Alan

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• My webpage ignores changes in CSS file

  - by Pavel

  No matter what I change in my .css file, the page remains the same - what's more, neither changing the link tag so that it points to another .css file nor deleting it completely makes no difference. Other changes in html code are applied. The sourcecode of the webpage shows everything as it should be. This behavior started when I redirected the link tag from previous file to the one I use now (plus there have been some changes in the tag while this problem occured, to test the behavior of my webpage); changes in neither file affect the page. For the first time when this happened, this was caused by copies of head tag in included chunks of code (for header, left menu etc. - their head part overrode the head part of the main page) and the problem was solved by removing these redundant heads from these files. But it happened again when I changed the link tag for the next time. I couldn't find any head parts in my included files, but the problem lasts (only solution I can see now is to delete the included files and copy the code directly to the file, but this would mean lots of redundant code). How can I solve this problem, so that my page response to changes in .css files without increasing redundancy? How to ensure that I can change the link to .css file just on one place with no such problems? Do I have to unload the CSS file somehow? I saw this problem both in Firefox and in Chrome. I use PSPad to write the code, just in case it would play role. EDIT: I have cleared browser cache now, and I changed the link to .css files from one to another before, but nothing helped. Now I accept the best answer saying the problem is in caching and I start a related question to find out how to solve the caching issue. If the other question's answers would say that in this case I can be sure that problem isn't in caching (very unlikely, but fail of ordinary methods of caching-problems-solving is unlikely too), I'd update this question and start searching for other possible problems, but now the message seems to be clear: when webpage ignores changes in .css files, caching is to blame.

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