Search Results

Search found 13692 results on 548 pages for 'bad practices'.

Page 175/548 | < Previous Page | 171 172 173 174 175 176 177 178 179 180 181 182  | Next Page >

  • Network speed between a VM and another machine which is not residing on the same host, is 11MB/s at most

    - by Henno
    Problem Network speed between a VM and another machine which is not residing on the same host, is 11MB/s at most. Topology Facts ESXi5 version is 5.0.0.504890 VM has the latest Vmware Tools installed VM is using E1000 network driver Physical box has Win Srv 2008 R2 as the OS CrystalDiskMark says the drive on physical box can read/write 100MB/s vCenter is another vm on esx both vm and physical box are showing 1Gbps link speed Configuration Networking shows vmnic0 as 1000 Full NTttcp is a client/server tool from Microsoft for measuring pure network throughput Here's what I've done so far: Test1: VM is running Filezilla FTP Server (default settings, one user account made) Physical box is running Filezilla FTP Client (default settings) Physical box is uploading a big file to FTP server Transfer speed (as observed by Windows Task Manager on both machines): ~11MB/s (bad) Physical box is downloading that file from FTP server Transfer speed (as observed by Windows Task Manager on both machines): still ~11MB/s (bad) Could it be disk performance issue? Test2: Physical box is running ntttcpr.exe -a 6 -m 6,0,VM_IP_ADDRESS VM is running ntttcps.exe -a 6 -m 6,0,PHY_BOX_IP_ADDRESS Transfer speed (as observed by Windows Task Manager on both machines): ~11MB/s (bad) Could it be switch performance issue? Test3: physical box is running vSphere Client I open Summary Storage datastore Browse Datastore... from physical box and upload a file to datastore Transfer speed (as observed by Windows Task Manager on physical box): ~26-36MB/s (good) Could it be a vm specific issue? Test4: Installed ntttcp to another vm on the same esx server Measured network performance between vms on the same esx server with NTttcp Transfer speed (as observed by Windows Task Manager on physical box): ~90-120MB/s (excellent :) Test5: I have another esx server on the same site, connecting to the same datastore and same switch. Those two ESX servers have both 2 NICs. One NIC goes to switch while the other goes directly to the other ESX server. vMotioned one of the testing vms off to the other ESX host Measured network performance between vms on different esx servers with NTttcp Transfer speed (as observed by Windows Task Manager on physical box): ~11MB/s (bad) While I'm aware of these: ESXi 4.1 slow file transfer ESXi 5 network performance is slow Debian Etch and ESXi slow network speeds VMWare ESXi slow file copy to guest they did not help (or I must have been missed something)

    Read the article

  • Configure IIS to pass-through CGI output without any conditioning

    - by Daniel Watrous
    I'm building a web service on Windows 2008 R2 with IIS 7.5 and Python 2.5. Right now I have the Handler Mappings and everything else setup just fine, Except that IIS is modifying what it gets back from the CGI script before sending it along the the client. Here's an example: I wrote the following CGI script: # hello.py print "Status: 400 Bad Request" print "Content-Type: text/html" print print "Error Message" According to the HTTP spec this should be fine and a Status of 400 should allow for a description of the error message in the body of the response. When the server response actually comes back to me I get the following: Status: 400 Bad Request Date: Fri, 11 Feb 2011 17:58:30 GMT X-Powered-By: ASP.NET Connection: close Content-Length: 11 Server: Microsoft-IIS/7.5 Content-Type: text/html Bad Request I've seen on this forum and others where I can change or eliminate the X-Powered-By header element, but I would like IIS to leave it alone altogether. I'm not sure why it takes my response, deletes "Error Message" from the body and replaces it with "Bad Request" and then adds all that other junk in. Is there some way to tell IIS to just send the response along without making any changes at all?

    Read the article

  • Comments on Comments

    - by Joe Mayo
    I almost tweeted a reply to Capar Kleijne's question about comments on Twitter, but realized that my opinion exceeded 140 characters. The following is based upon my experience with extremes and approaches that I find useful in code comments. There are a couple extremes that I've seen and reasons why people go the distance in each approach. The most common extreme is no comments in the code at all.  A few bad reasons why this happens is because a developer is in a hurry, sloppy, or is interested in job preservation. The unfortunate result is that the code is difficult to understand and hard to maintain. The drawbacks to no comments in code are a primary reason why teachers drill the need for commenting code into our heads.  This viewpoint assumes the lack of comments are bad because the code is bad, but there is another reason for not commenting that is gaining more popularity. I've heard/and read that code should be self documenting. Following this thought pattern, if code is well written with meaningful names, there should not be a reason for comments.  An addendum to this argument is that comments are often neglected and get out-of-date, but the code is what is kept up-to-date. Presumably, if code contained very good naming, it would be easy to maintain.  This is a noble perspective and I like the practice of meaningful naming of identifiers. However, I think it's also an extreme approach that doesn't cover important cases.  i.e. If an identifier is named badly (subjective differences in opinion) or not changed appropriately during maintenance, then the badly named identifier is no more useful than a stale comment. These were the two no-comment extremes, so let's look at the too many comments extreme. On a regular basis, I'll see cases where the code is over-commented; not nearly as often as the no-comment scenarios, but still prevalent.  These are examples of where every single line in the code is commented.  These comments make the code harder to read because they get in the way of the algorithm.  In most cases, the comments parrot what each line of code does.  If a developer understands the language, then most statements are immediately intuitive.  i.e. what use is it to say that I'm assigning foo to bar when it's clear what the code is doing. I think that over-commenting code is a waste of time that slows down initial development and maintenance.  Understandably, the developer's intentions are admirable because they've had it beaten into their heads that they must comment. However, I think it's an extreme and prefer a more moderate approach. I don't think the extremes do justice to code because each can make maintenance harder.  No comments on bad code is obviously a problem, but the other two extremes are subtle and require qualification to address properly. The problem I see with the code-as-documentation approach is that it doesn't lift the developer out of the algorithm to identify dependencies, intentions, and hacks. Any developer can read code and follow an algorithm, but they still need to know where it fits into the big picture of the application. Because of indirections with language features like interfaces, delegates, and virtual members, code can become complex.  Occasionally, it's useful to point out a nuance or reason why a piece of code is there. i.e. If you've building an app that communicates via HTTP, you'll have certain headers to include for the endpoint, and it could be useful to point out why the code for setting those header values is there and how they affect the application. An argument against this could be that you should extract that code into a separate method with a meaningful name to describe the scenario.  My problem with such an approach would be that your code base becomes even more difficult to navigate and work with because you have all of this extra code just to make the code more meaningful. My opinion is that a simple and well-stated comment stating the reasons and intention for the code is more natural and convenient to the initial developer and maintainer.  I just don't agree with the approach of going out of the way to avoid making a comment.  I'm also concerned that some developers would take this approach as an excuse to not comment their bad code. Another area where I like comments is on documentation comments.  Java has it and so does C# and VB.  It's convenient because we can build automated tools that extract these comments.  These extracted comments are often much better than no documentation at all.  The "go read the code" answer always doesn't fulfill the need for a quick summary of an API. To summarize, I think that the extremes of no comments and too many comments are less than desirable approaches. I prefer documentation comments to explain each class and member (API level) and code comments as necessary to supplement well-written code. Joe

    Read the article

  • 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?

    Read the article

  • cannot access a site from Mac OSX Lion but can from other machines on network?

    - by house9
    SOLVED: The issue is with the hamachi client, hamachi is hi-jacking all of the 5.0.0.0/8 address block http://en.wikipedia.org/wiki/Hamachi_(software)#Criticism http://b.logme.in/2012/11/07/changes-to-hamachi-on-november-19th/ The fix on Mac LogMeIn Hamachi Preferences Settings Advanced Peer Connections IP protocol mode IPv6 only (default is both) If you can only connect to some of your network over IPv4 this 'fix' will NOT work for you ----- A few weeks ago I started using a service - https://semaphoreapp.com I think they made DNS changes a week ago and ever since I cannot access the site from my Mac OSX Lion (10.7.4) machine (my main development machine) but I can access the site from other machines on my network ipad windows machine MacMini (10.6.8) After some google searching I tried both of these dscacheutil -flushcache sudo killall -HUP mDNSResponder but no go, I've contacted semaphoreapp as well, but nothing so far - also of interest, one of my colleagues has the exact same problem, cannot access via Mac OSX Lion but can via windows machine, we work remotely and are not on the same ISP some additional info Lion (10.7.4) cannot access site host semaphoreapp.com semaphoreapp.com has address 5.9.53.16 ping semaphoreapp.com PING semaphoreapp.com (5.9.53.16): 56 data bytes Request timeout for icmp_seq 0 Request timeout for icmp_seq 1 Request timeout for icmp_seq 2 Request timeout for icmp_seq 3 ping: sendto: No route to host Request timeout for icmp_seq 4 ping: sendto: Host is down Request timeout for icmp_seq 5 ping: sendto: Host is down Request timeout for icmp_seq 6 ping: sendto: Host is down Request timeout for icmp_seq 7 .... traceroute semaphoreapp.com traceroute to semaphoreapp.com (5.9.53.16), 64 hops max, 52 byte packets 1 * * * 2 * * * traceroute: sendto: No route to host 3 traceroute: wrote semaphoreapp.com 52 chars, ret=-1 *traceroute: sendto: Host is down traceroute: wrote semaphoreapp.com 52 chars, ret=-1 .... and MacMini (10.6.8) can access it host semaphoreapp.com semaphoreapp.com has address 5.9.53.16 ping semaphoreapp.com PING semaphoreapp.com (5.9.53.16): 56 data bytes 64 bytes from 5.9.53.16: icmp_seq=0 ttl=44 time=191.458 ms 64 bytes from 5.9.53.16: icmp_seq=1 ttl=44 time=202.923 ms 64 bytes from 5.9.53.16: icmp_seq=2 ttl=44 time=180.746 ms 64 bytes from 5.9.53.16: icmp_seq=3 ttl=44 time=200.616 ms 64 bytes from 5.9.53.16: icmp_seq=4 ttl=44 time=178.818 ms .... traceroute semaphoreapp.com traceroute to semaphoreapp.com (5.9.53.16), 64 hops max, 52 byte packets 1 192.168.0.1 (192.168.0.1) 1.677 ms 1.446 ms 1.445 ms 2 * LOCAL ISP 11.957 ms * 3 etc... 10.704 ms 14.183 ms 9.341 ms 4 etc... 32.641 ms 12.147 ms 10.850 ms 5 etc.... 44.205 ms 54.563 ms 36.243 ms 6 vlan139.car1.seattle1.level3.net (4.53.145.165) 50.136 ms 45.873 ms 30.396 ms 7 ae-32-52.ebr2.seattle1.level3.net (4.69.147.182) 31.926 ms 40.507 ms 49.993 ms 8 ae-2-2.ebr2.denver1.level3.net (4.69.132.54) 78.129 ms 59.674 ms 49.905 ms 9 ae-3-3.ebr1.chicago2.level3.net (4.69.132.62) 99.019 ms 82.008 ms 76.074 ms 10 ae-1-100.ebr2.chicago2.level3.net (4.69.132.114) 96.185 ms 75.658 ms 75.662 ms 11 ae-6-6.ebr2.washington12.level3.net (4.69.148.145) 104.322 ms 105.563 ms 118.480 ms 12 ae-5-5.ebr2.washington1.level3.net (4.69.143.221) 93.646 ms 99.423 ms 96.067 ms 13 ae-41-41.ebr2.paris1.level3.net (4.69.137.49) 177.744 ms ae-44-44.ebr2.paris1.level3.net (4.69.137.61) 199.363 ms 198.405 ms 14 ae-47-47.ebr1.frankfurt1.level3.net (4.69.143.141) 176.876 ms ae-45-45.ebr1.frankfurt1.level3.net (4.69.143.133) 170.994 ms ae-46-46.ebr1.frankfurt1.level3.net (4.69.143.137) 177.308 ms 15 ae-61-61.csw1.frankfurt1.level3.net (4.69.140.2) 176.769 ms ae-91-91.csw4.frankfurt1.level3.net (4.69.140.14) 178.676 ms 173.644 ms 16 ae-2-70.edge7.frankfurt1.level3.net (4.69.154.75) 180.407 ms ae-3-80.edge7.frankfurt1.level3.net (4.69.154.139) 174.861 ms 176.578 ms 17 as33891-net.edge7.frankfurt1.level3.net (195.16.162.94) 175.448 ms 185.658 ms 177.081 ms 18 hos-bb1.juniper4.rz16.hetzner.de (213.239.240.202) 188.700 ms 190.332 ms 188.196 ms 19 hos-tr4.ex3k14.rz16.hetzner.de (213.239.233.98) 199.632 ms hos-tr3.ex3k14.rz16.hetzner.de (213.239.233.66) 185.938 ms hos-tr2.ex3k14.rz16.hetzner.de (213.239.230.34) 182.378 ms 20 * * * 21 * * * 22 * * * any ideas? EDIT: adding tcpdump MacMini (which can connect) while running - ping semaphoreapp.com sudo tcpdump -v -i en0 dst semaphoreapp.com Password: tcpdump: listening on en0, link-type EN10MB (Ethernet), capture size 65535 bytes 17:33:03.337165 IP (tos 0x0, ttl 64, id 20153, offset 0, flags [none], proto ICMP (1), length 84, bad cksum 0 (->3129)!) 192.168.0.6 > static.16.53.9.5.clients.your-server.de: ICMP echo request, id 61918, seq 0, length 64 17:33:04.337279 IP (tos 0x0, ttl 64, id 26049, offset 0, flags [none], proto ICMP (1), length 84, bad cksum 0 (->1a21)!) 192.168.0.6 > static.16.53.9.5.clients.your-server.de: ICMP echo request, id 61918, seq 1, length 64 17:33:05.337425 IP (tos 0x0, ttl 64, id 47854, offset 0, flags [none], proto ICMP (1), length 84, bad cksum 0 (->c4f3)!) 192.168.0.6 > static.16.53.9.5.clients.your-server.de: ICMP echo request, id 61918, seq 2, length 64 17:33:06.337548 IP (tos 0x0, ttl 64, id 24772, offset 0, flags [none], proto ICMP (1), length 84, bad cksum 0 (->1f1e)!) 192.168.0.6 > static.16.53.9.5.clients.your-server.de: ICMP echo request, id 61918, seq 3, length 64 17:33:07.337670 IP (tos 0x0, ttl 64, id 8171, offset 0, flags [none], proto ICMP (1), length 84, bad cksum 0 (->5ff7)!) 192.168.0.6 > static.16.53.9.5.clients.your-server.de: ICMP echo request, id 61918, seq 4, length 64 17:33:08.337816 IP (tos 0x0, ttl 64, id 35810, offset 0, flags [none], proto ICMP (1), length 84, bad cksum 0 (->f3ff)!) 192.168.0.6 > static.16.53.9.5.clients.your-server.de: ICMP echo request, id 61918, seq 5, length 64 17:33:09.337948 IP (tos 0x0, ttl 64, id 31120, offset 0, flags [none], proto ICMP (1), length 84, bad cksum 0 (->652)!) 192.168.0.6 > static.16.53.9.5.clients.your-server.de: ICMP echo request, id 61918, seq 6, length 64 ^C 7 packets captured 1047 packets received by filter 0 packets dropped by kernel OSX Lion (cannot connect) while running - ping semaphoreapp.com # wireless ~ $ sudo tcpdump -v -i en1 dst semaphoreapp.com Password: tcpdump: listening on en1, link-type EN10MB (Ethernet), capture size 65535 bytes ^C 0 packets captured 262 packets received by filter 0 packets dropped by kernel and # wired ~ $ sudo tcpdump -v -i en0 dst semaphoreapp.com tcpdump: listening on en0, link-type EN10MB (Ethernet), capture size 65535 bytes ^C 0 packets captured 219 packets received by filter 0 packets dropped by kernel above output after Request timeout for icmp_seq 25 or 30 times from ping. I don't know much about tcpdump, but to me it doesn't seem like the ping requests are leaving my machine?

    Read the article

  • what's the differences between rsync applications to use for backups?

    - by Thr4wn
    There are many concerns about backing up servers (naturally), and the best responses I found for "backing up best practices" was http://serverfault.com/questions/512/best-practices-to-keep-your-computers-backed-up-efficiently/1076#1076. However, Many people recommended 'rsync', but there are many rsync applications out there (like rsync-backup and duplicity, etc), and I want to know the trade-offs and recommendations for which one to use. Is there one that simply is newer and technically superior to all the rest?

    Read the article

  • Chroot for Mysql running on Ubuntu 10.10?

    - by Calvin Froedge
    Prompted from a question about MySQL server security best practices, I've been running through this list (with a few minor alterations) to properly secure my server database server: http://www.greensql.net/publications/mysql-security-best-practices On step 10, I'm told to change the root directory for the mysql user using chroot, but very few specifics are provided and I'm not sure where to start. Does anyone know of a good resource for walking me through the steps to properly create a chrooted environment for Ubuntu 10.10?

    Read the article

  • Is there a Telecommunications Reference Architecture?

    - by raul.goycoolea
    @font-face { font-family: "Arial"; }@font-face { font-family: "Courier New"; }@font-face { font-family: "Wingdings"; }@font-face { font-family: "Cambria"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraph, li.MsoListParagraph, div.MsoListParagraph { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpFirst, li.MsoListParagraphCxSpFirst, div.MsoListParagraphCxSpFirst { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpMiddle, li.MsoListParagraphCxSpMiddle, div.MsoListParagraphCxSpMiddle { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpLast, li.MsoListParagraphCxSpLast, div.MsoListParagraphCxSpLast { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }div.Section1 { page: Section1; }ol { margin-bottom: 0cm; }ul { margin-bottom: 0cm; } Abstract   Reference architecture provides needed architectural information that can be provided in advance to an enterprise to enable consistent architectural best practices. Enterprise Reference Architecture helps business owners to actualize their strategies, vision, objectives, and principles. It evaluates the IT systems, based on Reference Architecture goals, principles, and standards. It helps to reduce IT costs by increasing functionality, availability, scalability, etc. Telecom Reference Architecture provides customers with the flexibility to view bundled service bills online with the provision of multiple services. It provides real-time, flexible billing and charging systems, to handle complex promotions, discounts, and settlements with multiple parties. This paper attempts to describe the Reference Architecture for the Telecom Enterprises. It lays the foundation for a Telecom Reference Architecture by articulating the requirements, drivers, and pitfalls for telecom service providers. It describes generic reference architecture for telecom enterprises and moves on to explain how to achieve Enterprise Reference Architecture by using SOA.   Introduction   A Reference Architecture provides a methodology, set of practices, template, and standards based on a set of successful solutions implemented earlier. These solutions have been generalized and structured for the depiction of both a logical and a physical architecture, based on the harvesting of a set of patterns that describe observations in a number of successful implementations. It helps as a reference for the various architectures that an enterprise can implement to solve various problems. It can be used as the starting point or the point of comparisons for various departments/business entities of a company, or for the various companies for an enterprise. It provides multiple views for multiple stakeholders.   Major artifacts of the Enterprise Reference Architecture are methodologies, standards, metadata, documents, design patterns, etc.   Purpose of Reference Architecture   In most cases, architects spend a lot of time researching, investigating, defining, and re-arguing architectural decisions. It is like reinventing the wheel as their peers in other organizations or even the same organization have already spent a lot of time and effort defining their own architectural practices. This prevents an organization from learning from its own experiences and applying that knowledge for increased effectiveness.   Reference architecture provides missing architectural information that can be provided in advance to project team members to enable consistent architectural best practices.   Enterprise Reference Architecture helps an enterprise to achieve the following at the abstract level:   ·       Reference architecture is more of a communication channel to an enterprise ·       Helps the business owners to accommodate to their strategies, vision, objectives, and principles. ·       Evaluates the IT systems based on Reference Architecture Principles ·       Reduces IT spending through increasing functionality, availability, scalability, etc ·       A Real-time Integration Model helps to reduce the latency of the data updates Is used to define a single source of Information ·       Provides a clear view on how to manage information and security ·       Defines the policy around the data ownership, product boundaries, etc. ·       Helps with cost optimization across project and solution portfolios by eliminating unused or duplicate investments and assets ·       Has a shorter implementation time and cost   Once the reference architecture is in place, the set of architectural principles, standards, reference models, and best practices ensure that the aligned investments have the greatest possible likelihood of success in both the near term and the long term (TCO).     Common pitfalls for Telecom Service Providers   Telecom Reference Architecture serves as the first step towards maturity for a telecom service provider. During the course of our assignments/experiences with telecom players, we have come across the following observations – Some of these indicate a lack of maturity of the telecom service provider:   ·       In markets that are growing and not so mature, it has been observed that telcos have a significant amount of in-house or home-grown applications. In some of these markets, the growth has been so rapid that IT has been unable to cope with business demands. Telcos have shown a tendency to come up with workarounds in their IT applications so as to meet business needs. ·       Even for core functions like provisioning or mediation, some telcos have tried to manage with home-grown applications. ·       Most of the applications do not have the required scalability or maintainability to sustain growth in volumes or functionality. ·       Applications face interoperability issues with other applications in the operator's landscape. Integrating a new application or network element requires considerable effort on the part of the other applications. ·       Application boundaries are not clear, and functionality that is not in the initial scope of that application gets pushed onto it. This results in the development of the multiple, small applications without proper boundaries. ·       Usage of Legacy OSS/BSS systems, poor Integration across Multiple COTS Products and Internal Systems. Most of the Integrations are developed on ad-hoc basis and Point-to-Point Integration. ·       Redundancy of the business functions in different applications • Fragmented data across the different applications and no integrated view of the strategic data • Lot of performance Issues due to the usage of the complex integration across OSS and BSS systems   However, this is where the maturity of the telecom industry as a whole can be of help. The collaborative efforts of telcos to overcome some of these problems have resulted in bodies like the TM Forum. They have come up with frameworks for business processes, data, applications, and technology for telecom service providers. These could be a good starting point for telcos to clean up their enterprise landscape.   Industry Trends in Telecom Reference Architecture   Telecom reference architectures are evolving rapidly because telcos are facing business and IT challenges.   “The reality is that there probably is no killer application, no silver bullet that the telcos can latch onto to carry them into a 21st Century.... Instead, there are probably hundreds – perhaps thousands – of niche applications.... And the only way to find which of these works for you is to try out lots of them, ramp up the ones that work, and discontinue the ones that fail.” – Martin Creaner President & CTO TM Forum.   The following trends have been observed in telecom reference architecture:   ·       Transformation of business structures to align with customer requirements ·       Adoption of more Internet-like technical architectures. The Web 2.0 concept is increasingly being used. ·       Virtualization of the traditional operations support system (OSS) ·       Adoption of SOA to support development of IP-based services ·       Adoption of frameworks like Service Delivery Platforms (SDPs) and IP Multimedia Subsystem ·       (IMS) to enable seamless deployment of various services over fixed and mobile networks ·       Replacement of in-house, customized, and stove-piped OSS/BSS with standards-based COTS products ·       Compliance with industry standards and frameworks like eTOM, SID, and TAM to enable seamless integration with other standards-based products   Drivers of Reference Architecture   The drivers of the Reference Architecture are Reference Architecture Goals, Principles, and Enterprise Vision and Telecom Transformation. The details are depicted below diagram. @font-face { font-family: "Cambria"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoCaption, li.MsoCaption, div.MsoCaption { margin: 0cm 0cm 10pt; font-size: 9pt; font-family: "Times New Roman"; color: rgb(79, 129, 189); font-weight: bold; }div.Section1 { page: Section1; } Figure 1. Drivers for Reference Architecture @font-face { font-family: "Arial"; }@font-face { font-family: "Courier New"; }@font-face { font-family: "Wingdings"; }@font-face { font-family: "Cambria"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraph, li.MsoListParagraph, div.MsoListParagraph { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpFirst, li.MsoListParagraphCxSpFirst, div.MsoListParagraphCxSpFirst { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpMiddle, li.MsoListParagraphCxSpMiddle, div.MsoListParagraphCxSpMiddle { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpLast, li.MsoListParagraphCxSpLast, div.MsoListParagraphCxSpLast { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }div.Section1 { page: Section1; }ol { margin-bottom: 0cm; }ul { margin-bottom: 0cm; } Today’s telecom reference architectures should seamlessly integrate traditional legacy-based applications and transition to next-generation network technologies (e.g., IP multimedia subsystems). This has resulted in new requirements for flexible, real-time billing and OSS/BSS systems and implications on the service provider’s organizational requirements and structure.   Telecom reference architectures are today expected to:   ·       Integrate voice, messaging, email and other VAS over fixed and mobile networks, back end systems ·       Be able to provision multiple services and service bundles • Deliver converged voice, video and data services ·       Leverage the existing Network Infrastructure ·       Provide real-time, flexible billing and charging systems to handle complex promotions, discounts, and settlements with multiple parties. ·       Support charging of advanced data services such as VoIP, On-Demand, Services (e.g.  Video), IMS/SIP Services, Mobile Money, Content Services and IPTV. ·       Help in faster deployment of new services • Serve as an effective platform for collaboration between network IT and business organizations ·       Harness the potential of converging technology, networks, devices and content to develop multimedia services and solutions of ever-increasing sophistication on a single Internet Protocol (IP) ·       Ensure better service delivery and zero revenue leakage through real-time balance and credit management ·       Lower operating costs to drive profitability   Enterprise Reference Architecture   The Enterprise Reference Architecture (RA) fills the gap between the concepts and vocabulary defined by the reference model and the implementation. Reference architecture provides detailed architectural information in a common format such that solutions can be repeatedly designed and deployed in a consistent, high-quality, supportable fashion. This paper attempts to describe the Reference Architecture for the Telecom Application Usage and how to achieve the Enterprise Level Reference Architecture using SOA.   • Telecom Reference Architecture • Enterprise SOA based Reference Architecture   Telecom Reference Architecture   Tele Management Forum’s New Generation Operations Systems and Software (NGOSS) is an architectural framework for organizing, integrating, and implementing telecom systems. NGOSS is a component-based framework consisting of the following elements:   ·       The enhanced Telecom Operations Map (eTOM) is a business process framework. ·       The Shared Information Data (SID) model provides a comprehensive information framework that may be specialized for the needs of a particular organization. ·       The Telecom Application Map (TAM) is an application framework to depict the functional footprint of applications, relative to the horizontal processes within eTOM. ·       The Technology Neutral Architecture (TNA) is an integrated framework. TNA is an architecture that is sustainable through technology changes.   NGOSS Architecture Standards are:   ·       Centralized data ·       Loosely coupled distributed systems ·       Application components/re-use  ·       A technology-neutral system framework with technology specific implementations ·       Interoperability to service provider data/processes ·       Allows more re-use of business components across multiple business scenarios ·       Workflow automation   The traditional operator systems architecture consists of four layers,   ·       Business Support System (BSS) layer, with focus toward customers and business partners. Manages order, subscriber, pricing, rating, and billing information. ·       Operations Support System (OSS) layer, built around product, service, and resource inventories. ·       Networks layer – consists of Network elements and 3rd Party Systems. ·       Integration Layer – to maximize application communication and overall solution flexibility.   Reference architecture for telecom enterprises is depicted below. @font-face { font-family: "Arial"; }@font-face { font-family: "Courier New"; }@font-face { font-family: "Wingdings"; }@font-face { font-family: "Cambria"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoCaption, li.MsoCaption, div.MsoCaption { margin: 0cm 0cm 10pt; font-size: 9pt; font-family: "Times New Roman"; color: rgb(79, 129, 189); font-weight: bold; }p.MsoListParagraph, li.MsoListParagraph, div.MsoListParagraph { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpFirst, li.MsoListParagraphCxSpFirst, div.MsoListParagraphCxSpFirst { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpMiddle, li.MsoListParagraphCxSpMiddle, div.MsoListParagraphCxSpMiddle { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpLast, li.MsoListParagraphCxSpLast, div.MsoListParagraphCxSpLast { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }div.Section1 { page: Section1; }ol { margin-bottom: 0cm; }ul { margin-bottom: 0cm; } Figure 2. Telecom Reference Architecture   The major building blocks of any Telecom Service Provider architecture are as follows:   1. Customer Relationship Management   CRM encompasses the end-to-end lifecycle of the customer: customer initiation/acquisition, sales, ordering, and service activation, customer care and support, proactive campaigns, cross sell/up sell, and retention/loyalty.   CRM also includes the collection of customer information and its application to personalize, customize, and integrate delivery of service to a customer, as well as to identify opportunities for increasing the value of the customer to the enterprise.   The key functionalities related to Customer Relationship Management are   ·       Manage the end-to-end lifecycle of a customer request for products. ·       Create and manage customer profiles. ·       Manage all interactions with customers – inquiries, requests, and responses. ·       Provide updates to Billing and other south bound systems on customer/account related updates such as customer/ account creation, deletion, modification, request bills, final bill, duplicate bills, credit limits through Middleware. ·       Work with Order Management System, Product, and Service Management components within CRM. ·       Manage customer preferences – Involve all the touch points and channels to the customer, including contact center, retail stores, dealers, self service, and field service, as well as via any media (phone, face to face, web, mobile device, chat, email, SMS, mail, the customer's bill, etc.). ·       Support single interface for customer contact details, preferences, account details, offers, customer premise equipment, bill details, bill cycle details, and customer interactions.   CRM applications interact with customers through customer touch points like portals, point-of-sale terminals, interactive voice response systems, etc. The requests by customers are sent via fulfillment/provisioning to billing system for ordering processing.   2. Billing and Revenue Management   Billing and Revenue Management handles the collection of appropriate usage records and production of timely and accurate bills – for providing pre-bill usage information and billing to customers; for processing their payments; and for performing payment collections. In addition, it handles customer inquiries about bills, provides billing inquiry status, and is responsible for resolving billing problems to the customer's satisfaction in a timely manner. This process grouping also supports prepayment for services.   The key functionalities provided by these applications are   ·       To ensure that enterprise revenue is billed and invoices delivered appropriately to customers. ·       To manage customers’ billing accounts, process their payments, perform payment collections, and monitor the status of the account balance. ·       To ensure the timely and effective fulfillment of all customer bill inquiries and complaints. ·       Collect the usage records from mediation and ensure appropriate rating and discounting of all usage and pricing. ·       Support revenue sharing; split charging where usage is guided to an account different from the service consumer. ·       Support prepaid and post-paid rating. ·       Send notification on approach / exceeding the usage thresholds as enforced by the subscribed offer, and / or as setup by the customer. ·       Support prepaid, post paid, and hybrid (where some services are prepaid and the rest of the services post paid) customers and conversion from post paid to prepaid, and vice versa. ·       Support different billing function requirements like charge prorating, promotion, discount, adjustment, waiver, write-off, account receivable, GL Interface, late payment fee, credit control, dunning, account or service suspension, re-activation, expiry, termination, contract violation penalty, etc. ·       Initiate direct debit to collect payment against an invoice outstanding. ·       Send notification to Middleware on different events; for example, payment receipt, pre-suspension, threshold exceed, etc.   Billing systems typically get usage data from mediation systems for rating and billing. They get provisioning requests from order management systems and inquiries from CRM systems. Convergent and real-time billing systems can directly get usage details from network elements.   3. Mediation   Mediation systems transform/translate the Raw or Native Usage Data Records into a general format that is acceptable to billing for their rating purposes.   The following lists the high-level roles and responsibilities executed by the Mediation system in the end-to-end solution.   ·       Collect Usage Data Records from different data sources – like network elements, routers, servers – via different protocol and interfaces. ·       Process Usage Data Records – Mediation will process Usage Data Records as per the source format. ·       Validate Usage Data Records from each source. ·       Segregates Usage Data Records coming from each source to multiple, based on the segregation requirement of end Application. ·       Aggregates Usage Data Records based on the aggregation rule if any from different sources. ·       Consolidates multiple Usage Data Records from each source. ·       Delivers formatted Usage Data Records to different end application like Billing, Interconnect, Fraud Management, etc. ·       Generates audit trail for incoming Usage Data Records and keeps track of all the Usage Data Records at various stages of mediation process. ·       Checks duplicate Usage Data Records across files for a given time window.   4. Fulfillment   This area is responsible for providing customers with their requested products in a timely and correct manner. It translates the customer's business or personal need into a solution that can be delivered using the specific products in the enterprise's portfolio. This process informs the customers of the status of their purchase order, and ensures completion on time, as well as ensuring a delighted customer. These processes are responsible for accepting and issuing orders. They deal with pre-order feasibility determination, credit authorization, order issuance, order status and tracking, customer update on customer order activities, and customer notification on order completion. Order management and provisioning applications fall into this category.   The key functionalities provided by these applications are   ·       Issuing new customer orders, modifying open customer orders, or canceling open customer orders; ·       Verifying whether specific non-standard offerings sought by customers are feasible and supportable; ·       Checking the credit worthiness of customers as part of the customer order process; ·       Testing the completed offering to ensure it is working correctly; ·       Updating of the Customer Inventory Database to reflect that the specific product offering has been allocated, modified, or cancelled; ·       Assigning and tracking customer provisioning activities; ·       Managing customer provisioning jeopardy conditions; and ·       Reporting progress on customer orders and other processes to customer.   These applications typically get orders from CRM systems. They interact with network elements and billing systems for fulfillment of orders.   5. Enterprise Management   This process area includes those processes that manage enterprise-wide activities and needs, or have application within the enterprise as a whole. They encompass all business management processes that   ·       Are necessary to support the whole of the enterprise, including processes for financial management, legal management, regulatory management, process, cost, and quality management, etc.;   ·       Are responsible for setting corporate policies, strategies, and directions, and for providing guidelines and targets for the whole of the business, including strategy development and planning for areas, such as Enterprise Architecture, that are integral to the direction and development of the business;   ·       Occur throughout the enterprise, including processes for project management, performance assessments, cost assessments, etc.     (i) Enterprise Risk Management:   Enterprise Risk Management focuses on assuring that risks and threats to the enterprise value and/or reputation are identified, and appropriate controls are in place to minimize or eliminate the identified risks. The identified risks may be physical or logical/virtual. Successful risk management ensures that the enterprise can support its mission critical operations, processes, applications, and communications in the face of serious incidents such as security threats/violations and fraud attempts. Two key areas covered in Risk Management by telecom operators are:   ·       Revenue Assurance: Revenue assurance system will be responsible for identifying revenue loss scenarios across components/systems, and will help in rectifying the problems. The following lists the high-level roles and responsibilities executed by the Revenue Assurance system in the end-to-end solution. o   Identify all usage information dropped when networks are being upgraded. o   Interconnect bill verification. o   Identify where services are routinely provisioned but never billed. o   Identify poor sales policies that are intensifying collections problems. o   Find leakage where usage is sent to error bucket and never billed for. o   Find leakage where field service, CRM, and network build-out are not optimized.   ·       Fraud Management: Involves collecting data from different systems to identify abnormalities in traffic patterns, usage patterns, and subscription patterns to report suspicious activity that might suggest fraudulent usage of resources, resulting in revenue losses to the operator.   The key roles and responsibilities of the system component are as follows:   o   Fraud management system will capture and monitor high usage (over a certain threshold) in terms of duration, value, and number of calls for each subscriber. The threshold for each subscriber is decided by the system and fixed automatically. o   Fraud management will be able to detect the unauthorized access to services for certain subscribers. These subscribers may have been provided unauthorized services by employees. The component will raise the alert to the operator the very first time of such illegal calls or calls which are not billed. o   The solution will be to have an alarm management system that will deliver alarms to the operator/provider whenever it detects a fraud, thus minimizing fraud by catching it the first time it occurs. o   The Fraud Management system will be capable of interfacing with switches, mediation systems, and billing systems   (ii) Knowledge Management   This process focuses on knowledge management, technology research within the enterprise, and the evaluation of potential technology acquisitions.   Key responsibilities of knowledge base management are to   ·       Maintain knowledge base – Creation and updating of knowledge base on ongoing basis. ·       Search knowledge base – Search of knowledge base on keywords or category browse ·       Maintain metadata – Management of metadata on knowledge base to ensure effective management and search. ·       Run report generator. ·       Provide content – Add content to the knowledge base, e.g., user guides, operational manual, etc.   (iii) Document Management   It focuses on maintaining a repository of all electronic documents or images of paper documents relevant to the enterprise using a system.   (iv) Data Management   It manages data as a valuable resource for any enterprise. For telecom enterprises, the typical areas covered are Master Data Management, Data Warehousing, and Business Intelligence. It is also responsible for data governance, security, quality, and database management.   Key responsibilities of Data Management are   ·       Using ETL, extract the data from CRM, Billing, web content, ERP, campaign management, financial, network operations, asset management info, customer contact data, customer measures, benchmarks, process data, e.g., process inputs, outputs, and measures, into Enterprise Data Warehouse. ·       Management of data traceability with source, data related business rules/decisions, data quality, data cleansing data reconciliation, competitors data – storage for all the enterprise data (customer profiles, products, offers, revenues, etc.) ·       Get online update through night time replication or physical backup process at regular frequency. ·       Provide the data access to business intelligence and other systems for their analysis, report generation, and use.   (v) Business Intelligence   It uses the Enterprise Data to provide the various analysis and reports that contain prospects and analytics for customer retention, acquisition of new customers due to the offers, and SLAs. It will generate right and optimized plans – bolt-ons for the customers.   The following lists the high-level roles and responsibilities executed by the Business Intelligence system at the Enterprise Level:   ·       It will do Pattern analysis and reports problem. ·       It will do Data Analysis – Statistical analysis, data profiling, affinity analysis of data, customer segment wise usage patterns on offers, products, service and revenue generation against services and customer segments. ·       It will do Performance (business, system, and forecast) analysis, churn propensity, response time, and SLAs analysis. ·       It will support for online and offline analysis, and report drill down capability. ·       It will collect, store, and report various SLA data. ·       It will provide the necessary intelligence for marketing and working on campaigns, etc., with cost benefit analysis and predictions.   It will advise on customer promotions with additional services based on loyalty and credit history of customer   ·       It will Interface with Enterprise Data Management system for data to run reports and analysis tasks. It will interface with the campaign schedules, based on historical success evidence.   (vi) Stakeholder and External Relations Management   It manages the enterprise's relationship with stakeholders and outside entities. Stakeholders include shareholders, employee organizations, etc. Outside entities include regulators, local community, and unions. Some of the processes within this grouping are Shareholder Relations, External Affairs, Labor Relations, and Public Relations.   (vii) Enterprise Resource Planning   It is used to manage internal and external resources, including tangible assets, financial resources, materials, and human resources. Its purpose is to facilitate the flow of information between all business functions inside the boundaries of the enterprise and manage the connections to outside stakeholders. ERP systems consolidate all business operations into a uniform and enterprise wide system environment.   The key roles and responsibilities for Enterprise System are given below:   ·        It will handle responsibilities such as core accounting, financial, and management reporting. ·       It will interface with CRM for capturing customer account and details. ·       It will interface with billing to capture the billing revenue and other financial data. ·       It will be responsible for executing the dunning process. Billing will send the required feed to ERP for execution of dunning. ·       It will interface with the CRM and Billing through batch interfaces. Enterprise management systems are like horizontals in the enterprise and typically interact with all major telecom systems. E.g., an ERP system interacts with CRM, Fulfillment, and Billing systems for different kinds of data exchanges.   6. External Interfaces/Touch Points   The typical external parties are customers, suppliers/partners, employees, shareholders, and other stakeholders. External interactions from/to a Service Provider to other parties can be achieved by a variety of mechanisms, including:   ·       Exchange of emails or faxes ·       Call Centers ·       Web Portals ·       Business-to-Business (B2B) automated transactions   These applications provide an Internet technology driven interface to external parties to undertake a variety of business functions directly for themselves. These can provide fully or partially automated service to external parties through various touch points.   Typical characteristics of these touch points are   ·       Pre-integrated self-service system, including stand-alone web framework or integration front end with a portal engine ·       Self services layer exposing atomic web services/APIs for reuse by multiple systems across the architectural environment ·       Portlets driven connectivity exposing data and services interoperability through a portal engine or web application   These touch points mostly interact with the CRM systems for requests, inquiries, and responses.   7. Middleware   The component will be primarily responsible for integrating the different systems components under a common platform. It should provide a Standards-Based Platform for building Service Oriented Architecture and Composite Applications. The following lists the high-level roles and responsibilities executed by the Middleware component in the end-to-end solution.   ·       As an integration framework, covering to and fro interfaces ·       Provide a web service framework with service registry. ·       Support SOA framework with SOA service registry. ·       Each of the interfaces from / to Middleware to other components would handle data transformation, translation, and mapping of data points. ·       Receive data from the caller / activate and/or forward the data to the recipient system in XML format. ·       Use standard XML for data exchange. ·       Provide the response back to the service/call initiator. ·       Provide a tracking until the response completion. ·       Keep a store transitional data against each call/transaction. ·       Interface through Middleware to get any information that is possible and allowed from the existing systems to enterprise systems; e.g., customer profile and customer history, etc. ·       Provide the data in a common unified format to the SOA calls across systems, and follow the Enterprise Architecture directive. ·       Provide an audit trail for all transactions being handled by the component.   8. Network Elements   The term Network Element means a facility or equipment used in the provision of a telecommunications service. Such terms also includes features, functions, and capabilities that are provided by means of such facility or equipment, including subscriber numbers, databases, signaling systems, and information sufficient for billing and collection or used in the transmission, routing, or other provision of a telecommunications service.   Typical network elements in a GSM network are Home Location Register (HLR), Intelligent Network (IN), Mobile Switching Center (MSC), SMS Center (SMSC), and network elements for other value added services like Push-to-talk (PTT), Ring Back Tone (RBT), etc.   Network elements are invoked when subscribers use their telecom devices for any kind of usage. These elements generate usage data and pass it on to downstream systems like mediation and billing system for rating and billing. They also integrate with provisioning systems for order/service fulfillment.   9. 3rd Party Applications   3rd Party systems are applications like content providers, payment gateways, point of sale terminals, and databases/applications maintained by the Government.   Depending on applicability and the type of functionality provided by 3rd party applications, the integration with different telecom systems like CRM, provisioning, and billing will be done.   10. Service Delivery Platform   A service delivery platform (SDP) provides the architecture for the rapid deployment, provisioning, execution, management, and billing of value added telecom services. SDPs are based on the concept of SOA and layered architecture. They support the delivery of voice, data services, and content in network and device-independent fashion. They allow application developers to aggregate network capabilities, services, and sources of content. SDPs typically contain layers for web services exposure, service application development, and network abstraction.   SOA Reference Architecture   SOA concept is based on the principle of developing reusable business service and building applications by composing those services, instead of building monolithic applications in silos. It’s about bridging the gap between business and IT through a set of business-aligned IT services, using a set of design principles, patterns, and techniques.   In an SOA, resources are made available to participants in a value net, enterprise, line of business (typically spanning multiple applications within an enterprise or across multiple enterprises). It consists of a set of business-aligned IT services that collectively fulfill an organization’s business processes and goals. We can choreograph these services into composite applications and invoke them through standard protocols. SOA, apart from agility and reusability, enables:   ·       The business to specify processes as orchestrations of reusable services ·       Technology agnostic business design, with technology hidden behind service interface ·       A contractual-like interaction between business and IT, based on service SLAs ·       Accountability and governance, better aligned to business services ·       Applications interconnections untangling by allowing access only through service interfaces, reducing the daunting side effects of change ·       Reduced pressure to replace legacy and extended lifetime for legacy applications, through encapsulation in services   ·       A Cloud Computing paradigm, using web services technologies, that makes possible service outsourcing on an on-demand, utility-like, pay-per-usage basis   The following section represents the Reference Architecture of logical view for the Telecom Solution. The new custom built application needs to align with this logical architecture in the long run to achieve EA benefits.   Packaged implementation applications, such as ERP billing applications, need to expose their functions as service providers (as other applications consume) and interact with other applications as service consumers.   COT applications need to expose services through wrappers such as adapters to utilize existing resources and at the same time achieve Enterprise Architecture goal and objectives.   The following are the various layers for Enterprise level deployment of SOA. This diagram captures the abstract view of Enterprise SOA layers and important components of each layer. Layered architecture means decomposition of services such that most interactions occur between adjacent layers. However, there is no strict rule that top layers should not directly communicate with bottom layers.   The diagram below represents the important logical pieces that would result from overall SOA transformation. @font-face { font-family: "Arial"; }@font-face { font-family: "Courier New"; }@font-face { font-family: "Wingdings"; }@font-face { font-family: "Cambria"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoCaption, li.MsoCaption, div.MsoCaption { margin: 0cm 0cm 10pt; font-size: 9pt; font-family: "Times New Roman"; color: rgb(79, 129, 189); font-weight: bold; }p.MsoListParagraph, li.MsoListParagraph, div.MsoListParagraph { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpFirst, li.MsoListParagraphCxSpFirst, div.MsoListParagraphCxSpFirst { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpMiddle, li.MsoListParagraphCxSpMiddle, div.MsoListParagraphCxSpMiddle { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpLast, li.MsoListParagraphCxSpLast, div.MsoListParagraphCxSpLast { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }div.Section1 { page: Section1; }ol { margin-bottom: 0cm; }ul { margin-bottom: 0cm; } Figure 3. Enterprise SOA Reference Architecture 1.          Operational System Layer: This layer consists of all packaged applications like CRM, ERP, custom built applications, COTS based applications like Billing, Revenue Management, Fulfilment, and the Enterprise databases that are essential and contribute directly or indirectly to the Enterprise OSS/BSS Transformation.   ERP holds the data of Asset Lifecycle Management, Supply Chain, and Advanced Procurement and Human Capital Management, etc.   CRM holds the data related to Order, Sales, and Marketing, Customer Care, Partner Relationship Management, Loyalty, etc.   Content Management handles Enterprise Search and Query. Billing application consists of the following components:   ·       Collections Management, Customer Billing Management, Invoices, Real-Time Rating, Discounting, and Applying of Charges ·       Enterprise databases will hold both the application and service data, whether structured or unstructured.   MDM - Master data majorly consists of Customer, Order, Product, and Service Data.     2.          Enterprise Component Layer:   This layer consists of the Application Services and Common Services that are responsible for realizing the functionality and maintaining the QoS of the exposed services. This layer uses container-based technologies such as application servers to implement the components, workload management, high availability, and load balancing.   Application Services: This Service Layer enables application, technology, and database abstraction so that the complex accessing logic is hidden from the other service layers. This is a basic service layer, which exposes application functionalities and data as reusable services. The three types of the Application access services are:   ·       Application Access Service: This Service Layer exposes application level functionalities as a reusable service between BSS to BSS and BSS to OSS integration. This layer is enabled using disparate technology such as Web Service, Integration Servers, and Adaptors, etc.   ·       Data Access Service: This Service Layer exposes application data services as a reusable reference data service. This is done via direct interaction with application data. and provides the federated query.   ·       Network Access Service: This Service Layer exposes provisioning layer as a reusable service from OSS to OSS integration. This integration service emphasizes the need for high performance, stateless process flows, and distributed design.   Common Services encompasses management of structured, semi-structured, and unstructured data such as information services, portal services, interaction services, infrastructure services, and security services, etc.   3.          Integration Layer:   This consists of service infrastructure components like service bus, service gateway for partner integration, service registry, service repository, and BPEL processor. Service bus will carry the service invocation payloads/messages between consumers and providers. The other important functions expected from it are itinerary based routing, distributed caching of routing information, transformations, and all qualities of service for messaging-like reliability, scalability, and availability, etc. Service registry will hold all contracts (wsdl) of services, and it helps developers to locate or discover service during design time or runtime.   • BPEL processor would be useful in orchestrating the services to compose a complex business scenario or process. • Workflow and business rules management are also required to support manual triggering of certain activities within business process. based on the rules setup and also the state machine information. Application, data, and service mediation layer typically forms the overall composite application development framework or SOA Framework.   4.          Business Process Layer: These are typically the intermediate services layer and represent Shared Business Process Services. At Enterprise Level, these services are from Customer Management, Order Management, Billing, Finance, and Asset Management application domains.   5.          Access Layer: This layer consists of portals for Enterprise and provides a single view of Enterprise information management and dashboard services.   6.          Channel Layer: This consists of various devices; applications that form part of extended enterprise; browsers through which users access the applications.   7.          Client Layer: This designates the different types of users accessing the enterprise applications. The type of user typically would be an important factor in determining the level of access to applications.   8.          Vertical pieces like management, monitoring, security, and development cut across all horizontal layers Management and monitoring involves all aspects of SOA-like services, SLAs, and other QoS lifecycle processes for both applications and services surrounding SOA governance.     9.          EA Governance, Reference Architecture, Roadmap, Principles, and Best Practices:   EA Governance is important in terms of providing the overall direction to SOA implementation within the enterprise. This involves board-level involvement, in addition to business and IT executives. At a high level, this involves managing the SOA projects implementation, managing SOA infrastructure, and controlling the entire effort through all fine-tuned IT processes in accordance with COBIT (Control Objectives for Information Technology).   Devising tools and techniques to promote reuse culture, and the SOA way of doing things needs competency centers to be established in addition to training the workforce to take up new roles that are suited to SOA journey.   Conclusions   Reference Architectures can serve as the basis for disparate architecture efforts throughout the organization, even if they use different tools and technologies. Reference architectures provide best practices and approaches in the independent way a vendor deals with technology and standards. Reference Architectures model the abstract architectural elements for an enterprise independent of the technologies, protocols, and products that are used to implement an SOA. Telecom enterprises today are facing significant business and technology challenges due to growing competition, a multitude of services, and convergence. Adopting architectural best practices could go a long way in meeting these challenges. The use of SOA-based architecture for communication to each of the external systems like Billing, CRM, etc., in OSS/BSS system has made the architecture very loosely coupled, with greater flexibility. Any change in the external systems would be absorbed at the Integration Layer without affecting the rest of the ecosystem. The use of a Business Process Management (BPM) tool makes the management and maintenance of the business processes easy, with better performance in terms of lead time, quality, and cost. Since the Architecture is based on standards, it will lower the cost of deploying and managing OSS/BSS applications over their lifecycles.

    Read the article

  • 640 enterprise library caching threads - how?

    - by JohnW
    We have an application that is undergoing performance testing. Today, I decided to take a dump of w3wp & load it in windbg to see what is going on underneath the covers. Imagine my surprise when I ran !threads and saw that there are 640 background threads, almost all of which seem to say the following: OS Thread Id: 0x1c38 (651) Child-SP RetAddr Call Site 0000000023a9d290 000007ff002320e2 Microsoft.Practices.EnterpriseLibrary.Caching.ProducerConsumerQueue.WaitUntilInterrupted() 0000000023a9d2d0 000007ff00231f7e Microsoft.Practices.EnterpriseLibrary.Caching.ProducerConsumerQueue.Dequeue() 0000000023a9d330 000007fef727c978 Microsoft.Practices.EnterpriseLibrary.Caching.BackgroundScheduler.QueueReader() 0000000023a9d380 000007fef9001552 System.Threading.ExecutionContext.runTryCode(System.Object) 0000000023a9dc30 000007fef72f95fd System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object) 0000000023a9dc80 000007fef9001552 System.Threading.ThreadHelper.ThreadStart() If i had to give a guess, I'm thinkign that one of these threads are getting spawned for each run of our app - we have 2 app servers, 20 concurrent users, and ran the test approximately 30 times...it's in the neighborhood. Is this 'expected behavior', or perhaps have we implemented something improperly? The test ran hours ago, so i would have expected any timeouts to have occurred already.

    Read the article

  • .NET Single Line Logging (ala Trace.Write/WriteLine) using Instrumentation.Logging

    - by KnownColor
    Hello Everyone, My question is whether it is possible to get line/multiline (very unsure of correct term for this) behaviour of the Trace.Write and Trace.WriteLine methods but using the Microsoft Instrumentation Logging framework in .NET 2.0. Desired Output Hello World! Oh Hai. What I Currently Have Trace.Write("Hello "); Trace.WriteLine("World!"); Trace.Write("Oh Hai."); I would prefer to use instrumentation to log rather than writing to a log file using Debug.Trace. EDIT: By Instrumentation Logging I mean using a 'loggingConfiguration' block in my App.config and writing Log Entries using using Microsoft.Practices.EnterpriseLibrary.Logging.Logger.Write(LogEntry logEntry); Microsoft.Practices.EnterpriseLibrary.Logging.Configuration.FlatFileTraceListenerData, Microsoft.Practices.EnterpriseLibrary.Logging, Version=2.0.0.0 for example. Ta, KnownColor

    Read the article

  • C++ Mock/Test boost::asio::io_stream - based Asynch Handler

    - by rbellamy
    I've recently returned to C/C++ after years of C#. During those years I've found the value of Mocking and Unit testing. Finding resources for Mocks and Units tests in C# is trivial. WRT Mocking, not so much with C++. I would like some guidance on what others do to mock and test Asynch io_service handlers with boost. For instance, in C# I would use a MemoryStream to mock an IO.Stream, and am assuming this is the path I should take here. C++ Mock/Test best practices boost::asio::io_service Mock/Test best practices C++ Async Handler Mock/Test best practices I've started the process with googlemock and googletest.

    Read the article

  • Visual Studio 2008 resolving wrong reference

    - by e28Makaveli
    In my project file, I have the following entry: <Reference Include="Microsoft.Practices.Unity, Version=1.2.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35, processorArchitecture=MSIL"> <HintPath>..\..\..\..\Libraries\Microsoft.Practices.Unity.dll</HintPath> </Reference> which in absolute terms translates to: C:\dev\LUT600 2.1.1\OCC600\Libraries Somehow, when I try to compile the project, Visual Studio loads a reference from a totally different path: /reference:"C:\Program Files\Microsoft Enterprise Library 4.1 - October 2008\Bin\Microsoft.Practices.Unity.dll. How it resolves to this location is a complete mystery as this DLL is not referenced anywhere in this project. I have set Specific Verion to true but it still resolves the reference from this location. Any ideas? TIA. Klaus

    Read the article

  • HTTP/1.1 Status Codes 400 and 417, cannot choose which

    - by TheDeadLike
    I have been referred to here that it might be of better help, I've got a processing file which handles the user sent data, before that, however, it compares the input from client to the expected values to ensure no client-side data change. I can say I don't know lot about HTTP status codes, but I have made up some research on it, and to choose which one is the best for unexpected input handling. So I came up with: 400 Bad Request: The request cannot be fulfilled due to bad syntax 417 Expectation Failed: The server cannot meet the requirements of the Expect request-header field Now, I cannot be really sure which one to use, I have seen 400 Bad Request being used alot, however, whatI get from explanation is that the error is due to an unexistent request rather than an illegal input. On the other side 417 Expectation Failed seems to just fit for my use, however, I have never seen or experimented this header status before. I need your experience and opinions, thanks alot! For a full detailed with form/process page drafts, and my experiments, follow this link.

    Read the article

  • fsck: FILE SYSTEM WAS MODIFIED after each check with -c, why?

    - by Chris
    Hi I use a script to partition and format CF cards (connected with a USB card writer) in an automated way. After the main process I check the card again with fsck. To check bad blocks I also tried the '-c' switch, but I always get a return value != 0 and the message "FILE SYSTEM WAS MODIFIED" (see below). I get the same result when checking the very same drive several times... Does anyone know why a) the file system is modified at all and b) why this seems to happen every time I check and not only in case of an error (like bad blocks)? Here's the output: linux-box# fsck.ext3 -c /dev/sdx1 e2fsck 1.40.2 (12-Jul-2007) Checking for bad blocks (read-only test): done Pass 1: Checking inodes, blocks, and sizes Pass 2: Checking directory structure Pass 3: Checking directory connectivity Pass 4: Checking reference counts Pass 5: Checking group summary information Volume (/dev/sdx1): ***** FILE SYSTEM WAS MODIFIED ***** Volume (/dev/sdx1): 5132/245760 files (1.2% non-contiguous), 178910/1959896 blocks Thanks, Chris

    Read the article

  • SSD install - what do I need to watch out for when reconfiguring SATA ports?

    - by tim11g
    I installed a Samsung 840 SSD in a Windows 7 machine. It seems to be working fine, but I'm not seeing the expected performance. The AS SSD benchmark gives 76 for read and 138 for write. At the upper left of the benchmark it says "pciide - BAD" and "31K - BAD". I'm assuming the "pciide BAD" means the motherboard (Gigabyte GA-P35-DS4) is configured as IDE emulation and needs to change to native SATA. I don't know what the "31K" refers to. The bios settings look like this: I saw this article that indicates that changing the SATA mode of the boot drive can cause problems (Blue Screen): Error message occurs after you change the SATA mode of the boot drive What is the correct procedure to change the SATA Mode without causing a system failure? Apply the registry change from the MSFT article above first, then reboot and change the SATA mode? Will the SATA mode change in the BIOS affect other drives?

    Read the article

  • fsck: FILE SYSTEM WAS MODIFIED after each check with -c, why?

    - by Chris
    I use a script to partition and format CF cards (connected with a USB card writer) in an automated way. After the main process I check the card again with fsck. To check bad blocks I also tried the '-c' switch, but I always get a return value != 0 and the message "FILE SYSTEM WAS MODIFIED" (see below). I get the same result when checking the very same drive several times... Does anyone know why a) the file system is modified at all and b) why this seems to happen every time I check and not only in case of an error (like bad blocks)? Here's the output: linux-box# fsck.ext3 -c /dev/sdx1 e2fsck 1.40.2 (12-Jul-2007) Checking for bad blocks (read-only test): done Pass 1: Checking inodes, blocks, and sizes Pass 2: Checking directory structure Pass 3: Checking directory connectivity Pass 4: Checking reference counts Pass 5: Checking group summary information Volume (/dev/sdx1): ***** FILE SYSTEM WAS MODIFIED ***** Volume (/dev/sdx1): 5132/245760 files (1.2% non-contiguous), 178910/1959896 blocks

    Read the article

  • TCP 30 small packets per second flood connection with server

    - by Denis Ermolin
    I'm testing connection with flash client and cloud server(boost::asio for software) over TCP connection. My connection with server already is really poor - 120 ms ping in average. I found when i start to send packets with 2 bytes size (without tcp header) with speed 30 packets/s - ping grow to 170-200 average. I think that it's really bad and my bad connection and bad cloud provider is reason for this high ping without any load. What do you think? (I tested my software - it can compute about 50k small packets/s so software is not a problem). I measure my ping through flash client - send packet with timestamp and immediatly send from server to client.

    Read the article

  • What is the procedure to replace a failing hard drive in a RAID array?

    - by slayton
    3 years ago a co-worker setup a software RAID-6 array on Ubuntu 9.04 and I'm getting messages from the OS that the drive has bad sectors and should be replaced. I'd like to remove this drive and replace it with a new drive, however, I have never done this before and I'm terrified that in the process of fixing the array I'm going to end up ruining it. I know the device ID of the array and I know the device IDs of the individual drives in the array. Additionally I physically have the bad drive. What are the steps to replace the bad drive with a new drive and get the array running again?

    Read the article

  • can power supply affect I/O

    - by user101289
    I have a dev server machine running Ubuntu 12.04. For a long while it's been throwing intermittent errors where it would suddenly tell me "File system is read only" or drop into a GRUB error console on boot. I've done disk checks, bad blocks, etc. and no real problems with the main SATA drive were detected. Finally the drive would not be detected at all-- but neither would other drives I plugged in (via SATA). I plugged the supposedly "bad" drive into another server and it worked fine, no issues, for days-- so I assumed the motherboard had a bad SATA controller, and replaced the motherboard with an identical model. I replaced the drive into the original machine with the new motherboard, rebooted-- and the same issues-- I/O errors, failure to read the drive at all, dropping into GRUB, etc. I'm wondering if there could be some other issue with this machine, that's not related to the drive-- possibly power supply? Thanks for ideas

    Read the article

  • Fix corrupt NTFS partition without Windows

    - by Capt.Nemo
    MY NTFS Partition has gotten corrupt somehow (it's a relic from the days when I had Windows installed). I'm putting the debug output of fdisk and blkid here. At the same time, any OS is unable to mount my root partition, which is located next to my NTFS partition. I'm not sure if this has anything to do with it, though. I get the following error while trying to mount my root partition (sda5) mount: wrong fs type, bad option, bad superblock on /dev/sda5, missing codepage or helper program, or other error In some cases useful info is found in syslog - try dmesg | tail or so ubuntu@ubuntu:~$ dmesg | tail [ 1019.726530] Descriptor sense data with sense descriptors (in hex): [ 1019.726533] 72 03 11 04 00 00 00 0c 00 0a 80 00 00 00 00 00 [ 1019.726551] 1a 3e ed 92 [ 1019.726558] sd 0:0:0:0: [sda] Add. Sense: Unrecovered read error - auto reallocate failed [ 1019.726568] sd 0:0:0:0: [sda] CDB: Read(10): 28 00 1a 3e ed 40 00 01 00 00 [ 1019.726584] end_request: I/O error, dev sda, sector 440331666 [ 1019.726602] JBD: Failed to read block at offset 462 [ 1019.726609] ata1: EH complete [ 1019.726612] JBD: recovery failed [ 1019.726617] EXT4-fs (sda5): error loading journal When I open gparted (using live CD), I get an exclamation next to my NTFS drive which states Is there a way to run chkdsk without using windows ? My attempt to run fsck results in the following : ubuntu@ubuntu:~$ sudo fsck /dev/sda fsck from util-linux-ng 2.17.2 e2fsck 1.41.14 (22-Dec-2010) fsck.ext2: Superblock invalid, trying backup blocks... fsck.ext2: Bad magic number in super-block while trying to open /dev/sda The superblock could not be read or does not describe a correct ext2 filesystem. If the device is valid and it really contains an ext2 filesystem (and not swap or ufs or something else), then the superblock is corrupt, and you might try running e2fsck with an alternate superblock: e2fsck -b 8193 <device> Update : I was able to fix the NTFS partition running chkdsk off HBCD, but it seems that the superblock problem still remains. *Update 2: * Fixed superblock issue using e2fsck -c /dev/sda5

    Read the article

  • Missing Operating System after trying to upgrade to Ubuntu 11

    - by Mauricio
    there! After trying to upgrade from Ubuntu 10.04 to 11, the upgrading process stopped when running and then I got an "out of disk, grub rescue" message when booting. After running Boot Repair, I got this results. Now I get "Missing Operating System" whent trying to boot. Bellow I show some results from some commands I gather from help foruns, but I still reached no solution. Could you please help me? Any enlightment will be very helpful! Disk Utility says "Disk has a few bad sectors". When trying to run the Self-test I get "FAILED (Read)" Here we have what Gparted says about the /dev/sda1 partition (ext4): Flags: boot Status: not mounted Warning: e2label: Attempt to read block from filesystem resulted in short read while trying to open /dev/sda1Couldn`t find valid filesystem superblockUnable to read the contents of this filesystem! From sudo fdisk -lI got: Disk /dev/sda: 320.1 GB, 320072933376 bytes 255 heads, 63 sectors/track, 38913 cylinders, total 625142448 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk identifier: 0x000e0596 Device Boot Start End Blocks Id System/dev/sda1 * 2048 607428607 303713280 83 Linux/dev/sda2 607430654 625141759 8855553 5 Extended/dev/sda5 607430656 625141759 8855552 82 Linux swap / SolarisDisk /dev/sdb: 320.1 GB, 320072933376 bytes255 heads, 63 sectors/track, 38913 cylinders, total 625142448 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x000c3c41 Device Boot Start End Blocks Id System /dev/sdb1 * 63 625137344 312568641 c W95 FAT32 (LBA) " and fromsudo fdisk /dev/sda1I got fdisk: unable to read /dev/sda1: Inappropriate ioctl for device` From sudo mount /dev/sda1 /mntI got: mount: wrong fs type, bad option, bad superblock on /dev/sda1, missing codepage or helper program, or other error In some cases useful info is found in syslog - try dmesg | tail or so From sudo update-grubI got: error: cannot read from `/dev/sda'. /usr/sbin/grub-probe: error: cannot find a device for / (is /dev mounted?).

    Read the article

  • Google analytics - drop in traffic

    - by Andy
    Bit of a general question here. We are in the process of converting a number of our clients from older web sites to new ones. The problem we are getting, and sorry for being so general here, is we are getting a sharp decline in traffic as reported on Google Analytics. It's not a gradual decline, it seems to hit almost as soon as the new site goes live. I've just got a few questions to see if there is something we are doing wrong: a) We are using the same analytics accounts going from old to new site. Is this a bad idea? b) The actual analytics code is integrated into the pages using a server-side include. IS this a bad idea? c) We structure our sites differently to our old site. IE. The old sites would pretty must have all the web pages in the root directory, and hyperlinks would be linked to the page files: EG. <a href="somepage.aspx">Link</a> Our new sites now have a directory structure that pretty much reflects the navigation structure, and hyper links link to the pages directory instead of the actual page: EG. <a href="/new-items/shoes/">New shoes</a> Is this a bad idea. I'm really searching for a needle in a haystack here. Would appriciate any help or advice as to why we are getting such a sharp and sudden drop in traffic. Again, so this is such a general question. Thanks in advance.

    Read the article

  • Google analytics - drop in traffic

    - by user1001421
    Bit of a general question here. We are in the process of converting a number of our clients from older web sites to new ones. The problem we are getting, and sorry for being so general here, is we are getting a sharp decline in traffic as reported on Google Analytics. It's not a gradual decline, it seems to hit almost as soon as the new site goes live. I've just got a few questions to see if there is something we are doing wrong: a) We are using the same analytics accounts going from old to new site. Is this a bad idea? b) The actual analytics code is integrated into the pages using a server-side include. IS this a bad idea? c) We structure our sites differently to our old site. IE. The old sites would pretty must have all the web pages in the root directory, and hyperlinks would be linked to the page files: EG. <a href="somepage.aspx">Link</a> Our new sites now have a directory structure that pretty much reflects the navigation structure, and hyper links link to the pages directory instead of the actual page: EG. <a href="/new-items/shoes/">New shoes</a> Is this a bad idea. I'm really searching for a needle in a haystack here. Would appriciate any help or advice as to why we are getting such a sharp and sudden drop in traffic. Again, so this is such a general question. Thanks in advance.

    Read the article

  • Algorithm to measure how "diffused" 5,000 pennies are in an economy?

    - by makerofthings7
    Please allow me to use this example/metaphor to describe an algorithm I need. Objects There are 5 thousand pennies. There are 50 cups. There is a tracking history (Passport "stamp" etc) that is associated with each penny as it moves between cups. Definition I'll define a "highly diffused" penny as one that passes through many cups. A "poorly diffused" penny is one that either passes back and forth between 2 cups Question How can I objectively measure the diffusion of a penny as: The number of moves the penny has gone through The number of cups the penny has been in A unit of time (day, week, month) Why am I doing this? I want to detect if a cup is hoarding pennies. Resistance from bad actors Since hoarding is bad, the "bad cup" may simply solicit a partner and simply move pennies between each other. This will reduce the amount of time a coin isn't in transit, and would skew hoarding detection. A solution might be to detect if a cup (or set of cups) are common "partners" with each other, though I'm not sure how to think though this problem. Broad applicability Any assistance would be helpful, since I would think that this algorithm is common to Economics The study of migration patterns of animals, citizens of a country Other natural occurring phenomena ... and probably exists as a term or concept I'm unfamiliar with.

    Read the article

  • Why does my root filesystem keep becoming read-only?

    - by Scott Severance
    I've lately been having an issue with my root filesystem becoming readonly. It happens some amount of time after boot. I don't know exactly when it happens, as I don't usually notice it until something such as suspending the computer or printing fails. It seems to be fairly random. Since most of my system is on that partition, I can't re-mount it without rebooting. After this happens, the system runs a fsck. Sometimes it prompts to fix problems; other times it apparently finds none. To troubleshoot, I've searched through the logs but found nothing relevant. This might be due in part to not knowing when the actual errors took place. The filesystem is apparently good to begin with, as when fsck runs its fixes it doesn't report any errors. I've scanned the disk with SpinRite. A while ago, SpinRite found and recovered from some bad sectors on the hard drive. I ran a level 4 scan (a thorough scan) after this probem appeared, but SpinRite found nothing. The SMART data reports that the disk is OK with 63 bad sectors. The number of bad sectors hasn't changed recently. I realize that the disk isn't in the best of conditions, and I have complete backups in case of catastrophic failure. Yet the lack of errors in the logs, combined with SpinRite's test results and the unchanged SMART data makes me think that this problem has some cause other than disk failure. Other than disk failure, what could cause my symptoms?

    Read the article

< Previous Page | 171 172 173 174 175 176 177 178 179 180 181 182  | Next Page >