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• Pointers in C vs No pointers in PHP

  - by AnnaBanana

  Both languages have the same syntax. Why does C have the weird * character that denotes pointers (which is some kind of memory address of the variable contents?), when PHP doesn't have it and you can do pretty much the same things in PHP that you can do in C, without pointers? I guess the PHP compiler handles this internally, why doesn't C do the same? Doesn't this add unneeded complexity in C? For example I don't understand them :)

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• The Ins and Outs of Effective Smart Grid Data Management

  - by caroline.yu

  Oracle Utilities and Accenture recently sponsored a one-hour Web cast entitled, "The Ins and Outs of Effective Smart Grid Data Management." Oracle and Accenture created this Web cast to help utilities better understand the types of data collected over smart grid networks and the issues associated with mapping out a coherent information management strategy. The Web cast also addressed important points that utilities must consider with the imminent flood of data that both present and next-generation smart grid components will generate. The three speakers, including Oracle Utilities' Brad Williams, focused on the key factors associated with taking the millions of data points captured in real time and implementing the strategies, frameworks and technologies that enable utilities to process, store, analyze, visualize, integrate, transport and transform data into the information required to deliver targeted business benefits. The Web cast replay is available here. The Web cast slides are available here.

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• The Benefits of Smart Grid Business Software

  - by Sylvie MacKenzie, PMP

  Smart Grid Background What Are Smart Grids?Smart Grids use computer hardware and software, sensors, controls, and telecommunications equipment and services to: Link customers to information that helps them manage consumption and use electricity wisely. Enable customers to respond to utility notices in ways that help minimize the duration of overloads, bottlenecks, and outages. Provide utilities with information that helps them improve performance and control costs. What Is Driving Smart Grid Development? Environmental ImpactSmart Grid development is picking up speed because of the widespread interest in reducing the negative impact that energy use has on the environment. Smart Grids use technology to drive efficiencies in transmission, distribution, and consumption. As a result, utilities can serve customers’ power needs with fewer generating plants, fewer transmission and distribution assets,and lower overall generation. With the possible exception of wind farm sprawl, landscape preservation is one obvious benefit. And because most generation today results in greenhouse gas emissions, Smart Grids reduce air pollution and the potential for global climate change.Smart Grids also more easily accommodate the technical difficulties of integrating intermittent renewable resources like wind and solar into the grid, providing further greenhouse gas reductions. CostsThe ability to defer the cost of plant and grid expansion is a major benefit to both utilities and customers. Utilities do not need to use as many internal resources for traditional infrastructure project planning and management. Large T&D infrastructure expansion costs are not passed on to customers.Smart Grids will not eliminate capital expansion, of course. Transmission corridors to connect renewable generation with customers will require major near-term expenditures. Additionally, in the future, electricity to satisfy the needs of population growth and additional applications will exceed the capacity reductions available through the Smart Grid. At that point, expansion will resume—but with greater overall T&D efficiency based on demand response, load control, and many other Smart Grid technologies and business processes. Energy efficiency is a second area of Smart Grid cost saving of particular relevance to customers. The timely and detailed information Smart Grids provide encourages customers to limit waste, adopt energy-efficient building codes and standards, and invest in energy efficient appliances. Efficiency may or may not lower customer bills because customer efficiency savings may be offset by higher costs in generation fuels or carbon taxes. It is clear, however, that bills will be lower with efficiency than without it. Utility Operations Smart Grids can serve as the central focus of utility initiatives to improve business processes. Many utilities have long “wish lists” of projects and applications they would like to fund in order to improve customer service or ease staff’s burden of repetitious work, but they have difficulty cost-justifying the changes, especially in the short term. Adding Smart Grid benefits to the cost/benefit analysis frequently tips the scales in favor of the change and can also significantly reduce payback periods.Mobile workforce applications and asset management applications work together to deploy assets and then to maintain, repair, and replace them. Many additional benefits result—for instance, increased productivity and fuel savings from better routing. Similarly, customer portals that provide customers with near-real-time information can also encourage online payments, thus lowering billing costs. Utilities can and should include these cost and service improvements in the list of Smart Grid benefits. What Is Smart Grid Business Software? Smart Grid business software gathers data from a Smart Grid and uses it improve a utility’s business processes. Smart Grid business software also helps utilities provide relevant information to customers who can then use it to reduce their own consumption and improve their environmental profiles. Smart Grid Business Software Minimizes the Impact of Peak Demand Utilities must size their assets to accommodate their highest peak demand. The higher the peak rises above base demand: The more assets a utility must build that are used only for brief periods—an inefficient use of capital. The higher the utility’s risk profile rises given the uncertainties surrounding the time needed for permitting, building, and recouping costs. The higher the costs for utilities to purchase supply, because generators can charge more for contracts and spot supply during high-demand periods. Smart Grids enable a variety of programs that reduce peak demand, including: Time-of-use pricing and critical peak pricing—programs that charge customers more when they consume electricity during peak periods. Pilot projects indicate that these programs are successful in flattening peaks, thus ensuring better use of existing T&D and generation assets. Direct load control, which lets utilities reduce or eliminate electricity flow to customer equipment (such as air conditioners). Contracts govern the terms and conditions of these turn-offs. Indirect load control, which signals customers to reduce the use of on-premises equipment for contractually agreed-on time periods. Smart Grid business software enables utilities to impose penalties on customers who do not comply with their contracts. Smart Grids also help utilities manage peaks with existing assets by enabling: Real-time asset monitoring and control. In this application, advanced sensors safely enable dynamic capacity load limits, ensuring that all grid assets can be used to their maximum capacity during peak demand periods. Real-time asset monitoring and control applications also detect the location of excessive losses and pinpoint need for mitigation and asset replacements. As a result, utilities reduce outage risk and guard against excess capacity or “over-build”. Better peak demand analysis. As a result: Distribution planners can better size equipment (e.g. transformers) to avoid over-building. Operations engineers can identify and resolve bottlenecks and other inefficiencies that may cause or exacerbate peaks. As above, the result is a reduction in the tendency to over-build. Supply managers can more closely match procurement with delivery. As a result, they can fine-tune supply portfolios, reducing the tendency to over-contract for peak supply and reducing the need to resort to spot market purchases during high peaks. Smart Grids can help lower the cost of remaining peaks by: Standardizing interconnections for new distributed resources (such as electricity storage devices). Placing the interconnections where needed to support anticipated grid congestion. Smart Grid Business Software Lowers the Cost of Field Services By processing Smart Grid data through their business software, utilities can reduce such field costs as: Vegetation management. Smart Grids can pinpoint momentary interruptions and tree-caused outages. Spatial mash-up tools leverage GIS models of tree growth for targeted vegetation management. This reduces the cost of unnecessary tree trimming. Service vehicle fuel. Many utility service calls are “false alarms.” Checking meter status before dispatching crews prevents many unnecessary “truck rolls.” Similarly, crews use far less fuel when Smart Grid sensors can pinpoint a problem and mobile workforce applications can then route them directly to it. Smart Grid Business Software Ensures Regulatory Compliance Smart Grids can ensure compliance with private contracts and with regional, national, or international requirements by: Monitoring fulfillment of contract terms. Utilities can use one-hour interval meters to ensure that interruptible (“non-core”) customers actually reduce or eliminate deliveries as required. They can use the information to levy fines against contract violators. Monitoring regulations imposed on customers, such as maximum use during specific time periods. Using accurate time-stamped event history derived from intelligent devices distributed throughout the smart grid to monitor and report reliability statistics and risk compliance. Automating business processes and activities that ensure compliance with security and reliability measures (e.g. NERC-CIP 2-9). Grid Business Software Strengthens Utilities’ Connection to Customers While Reducing Customer Service Costs During outages, Smart Grid business software can: Identify outages more quickly. Software uses sensors to pinpoint outages and nested outage locations. They also permit utilities to ensure outage resolution at every meter location. Size outages more accurately, permitting utilities to dispatch crews that have the skills needed, in appropriate numbers. Provide updates on outage location and expected duration. This information helps call centers inform customers about the timing of service restoration. Smart Grids also facilitates display of outage maps for customer and public-service use. Smart Grids can significantly reduce the cost to: Connect and disconnect customers. Meters capable of remote disconnect can virtually eliminate the costs of field crews and vehicles previously required to change service from the old to the new residents of a metered property or disconnect customers for nonpayment. Resolve reports of voltage fluctuation. Smart Grids gather and report voltage and power quality data from meters and grid sensors, enabling utilities to pinpoint reported problems or resolve them before customers complain. Detect and resolve non-technical losses (e.g. theft). Smart Grids can identify illegal attempts to reconnect meters or to use electricity in supposedly vacant premises. They can also detect theft by comparing flows through delivery assets with billed consumption. Smart Grids also facilitate outreach to customers. By monitoring and analyzing consumption over time, utilities can: Identify customers with unusually high usage and contact them before they receive a bill. They can also suggest conservation techniques that might help to limit consumption. This can head off “high bill” complaints to the contact center. Note that such “high usage” or “additional charges apply because you are out of range” notices—frequently via text messaging—are already common among mobile phone providers. Help customers identify appropriate bill payment alternatives (budget billing, prepayment, etc.). Help customers find and reduce causes of over-consumption. There’s no waiting for bills in the mail before they even understand there is a problem. Utilities benefit not just through improved customer relations but also through limiting the size of bills from customers who might struggle to pay them. Where permitted, Smart Grids can open the doors to such new utility service offerings as: Monitoring properties. Landlords reduce costs of vacant properties when utilities notify them of unexpected energy or water consumption. Utilities can perform similar services for owners of vacation properties or the adult children of aging parents. Monitoring equipment. Power-use patterns can reveal a need for equipment maintenance. Smart Grids permit utilities to alert owners or managers to a need for maintenance or replacement. Facilitating home and small-business networks. Smart Grids can provide a gateway to equipment networks that automate control or let owners access equipment remotely. They also facilitate net metering, offering some utilities a path toward involvement in small-scale solar or wind generation. Prepayment plans that do not need special meters. Smart Grid Business Software Helps Customers Control Energy Costs There is no end to the ways Smart Grids help both small and large customers control energy costs. For instance: Multi-premises customers appreciate having all meters read on the same day so that they can more easily compare consumption at various sites. Customers in competitive regions can match their consumption profile (detailed via Smart Grid data) with specific offerings from competitive suppliers. Customers seeing inexplicable consumption patterns and power quality problems may investigate further. The result can be discovery of electrical problems that can be resolved through rewiring or maintenance—before more serious fires or accidents happen. Smart Grid Business Software Facilitates Use of Renewables Generation from wind and solar resources is a popular alternative to fossil fuel generation, which emits greenhouse gases. Wind and solar generation may also increase energy security in regions that currently import fossil fuel for use in generation. Utilities face many technical issues as they attempt to integrate intermittent resource generation into traditional grids, which traditionally handle only fully dispatchable generation. Smart Grid business software helps solves many of these issues by: Detecting sudden drops in production from renewables-generated electricity (wind and solar) and automatically triggering electricity storage and smart appliance response to compensate as needed. Supporting industry-standard distributed generation interconnection processes to reduce interconnection costs and avoid adding renewable supplies to locations already subject to grid congestion. Facilitating modeling and monitoring of locally generated supply from renewables and thus helping to maximize their use. Increasing the efficiency of “net metering” (through which utilities can use electricity generated by customers) by: Providing data for analysis. Integrating the production and consumption aspects of customer accounts. During non-peak periods, such techniques enable utilities to increase the percent of renewable generation in their supply mix. During peak periods, Smart Grid business software controls circuit reconfiguration to maximize available capacity. Conclusion Utility missions are changing. Yesterday, they focused on delivery of reasonably priced energy and water. Tomorrow, their missions will expand to encompass sustainable use and environmental improvement.Smart Grids are key to helping utilities achieve this expanded mission. But they come at a relatively high price. Utilities will need to invest heavily in new hardware, software, business process development, and staff training. Customer investments in home area networks and smart appliances will be large. Learning to change the energy and water consumption habits of a lifetime could ultimately prove even more formidable tasks.Smart Grid business software can ease the cost and difficulties inherent in a needed transition to a more flexible, reliable, responsive electricity grid. Justifying its implementation, however, requires a full understanding of the benefits it brings—benefits that can ultimately help customers, utilities, communities, and the world address global issues like energy security and climate change while minimizing costs and maximizing customer convenience. This white paper is available for download here. For further information about Oracle's Primavera Solutions for Utilities, please read our Utilities e-book.

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• C++ Pointers: Number of levels of Indirection

  - by A B

  In a C++ program that doesn't contain legacy C code, is there a guideline regarding the maximum number of levels of indirection that should be used in the source code? I know that in C (as opposed to C++), some programmers have used pointers to pointers for a multiple dimension array, but for the case of arrays, there are data structures in C++ that can be used to avoid the pointers to pointers. Are users who still create pointers to pointers (or more than this) trying to use pointers to pointers only for performance ETC. reasons? I have tried NOT to use any more than a pointer to a pointer, only in the case that a pointer needed modification; does anyone have any other official or unofficial guidelines or rules regarding the number of levels of indirection?

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• Smart Help with UPK

  - by [email protected]

  A short lesson on how awesome Smart Help is. In Oracle UPK speak, there are targeted and non-targeted applications. Targeted applications are Oracle EBS, PeopleSoft, Siebel, JD Edwards, SAP and a few others. Non-targeted applications are either custom built or other third party off the shelf applications. For most targeted applications you'll see better object recognition (during recording) and also Help Integration for that application. Help integration means that someone technical modifies the help link in your application to call up the UPK content that has been created. If you have seen this presented before, this is usually where the term context sensitive help is mentioned and the Do It mode shows off. The fact that UPK builds context sensitive help for its targeted applications automatically is awesome enough, but there is a whole new world out there and it's called "custom and\or third party apps." For the purposes of Smart Help and this discussion, I'm talking about the browser based applications. How does UPK support these apps? It used to be that you had to have your vendor try to modify the Help link to point to UPK or if your company had control over the applications configuration menus, then you get someone on your team to modify this for you. But as you start to use UPK for more than one, two or three applications, the administration of this starts to become daunting. Multiple administrators, multiple player packages, multiple call points, multiple break points, help doesn't always work the same way for every application (picture the black white infomercial with an IT person trying to configure a bunch of wires or something funny like that). Introducing Smart Help! (in color of course, new IT person, probably wearing a blue shirt and smiling). Smart help eliminates the need to configure multiple browser help integration points, and adds a icon to the users browser itself. You're using your browser to read this now correct? Look up at the icons on your browser, you have the home link icon, print icon, maybe an RSS feed icon. Smart Help is icon that gets added to the users browser just like the others. When you click it, it first recognizes which application you're in and then finds the UPK created material for you and returns the best possible match, for (hold on to your seat now) both targeted and non-targeted applications (browser based applications). But wait, there's more. It does this automatically! You don't have to do anything! All you have to do is record content, UPK and Smart Help do the rest! This technology is not new. There are customers out there today that use this for as many as six applications! The real hero here is SMART MATCH. Smart match is the technology that's used to determine which application you're in and where you are when you click on Smart Help. We'll save that for a one-on-one conversation. Like most other awesome features of UPK, it ships with the product. All you have to do is turn it on. To learn more about Smart Help, Smart Match, Targeted and Non-Targeted applications, contact your UPK Sales Consultant or me directly at [email protected]

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• WD1000FYPS harddrive is marked 0 mb in 3ware (and no SMART)

  - by osgx

  After reboot my SATA 1TB WD1000FYPS (previously is was "Drive error") is marked 0 mb in 3ware web gui. Complete message: Available Drives (Controller ID 0) Port 1 WDC WD1000FYPS-01ZKB0 0.00 MB NOT SUPPORTED [Remove Drive] SMART gives me only Device Model and ATA protocol version 1 (not 7-8 as it must be for SATA) What does it mean? Just before reboot, when is was marked only with "Device Error", smart was: Device Model: WDC WD1000FYPS-01ZKB0 Serial Number: WD-WCASJ1130*** Firmware Version: 02.01B01 User Capacity: 1,000,204,886,016 bytes Device is: Not in smartctl database [for details use: -P showall] ATA Version is: 8 ATA Standard is: Exact ATA specification draft version not indicated Local Time is: Sun Mar 7 18:47:35 2010 MSK SMART support is: Available - device has SMART capability. SMART support is: Enabled SMART overall-health self-assessment test result: PASSED SMART Attributes Data Structure revision number: 16 Vendor Specific SMART Attributes with Thresholds: ID# ATTRIBUTE_NAME FLAG VALUE WORST THRESH TYPE UPDATED WHEN_FAILED RAW_VALUE 1 Raw_Read_Error_Rate 0x000f 200 200 051 Pre-fail Always - 0 3 Spin_Up_Time 0x0003 188 186 021 Pre-fail Always - 7591 4 Start_Stop_Count 0x0032 100 100 000 Old_age Always - 229 5 Reallocated_Sector_Ct 0x0033 199 199 140 Pre-fail Always - 3 7 Seek_Error_Rate 0x000e 193 193 000 Old_age Always - 125 9 Power_On_Hours 0x0032 078 078 000 Old_age Always - 16615 10 Spin_Retry_Count 0x0012 100 100 000 Old_age Always - 0 11 Calibration_Retry_Count 0x0012 100 253 000 Old_age Always - 0 12 Power_Cycle_Count 0x0032 100 100 000 Old_age Always - 77 192 Power-Off_Retract_Count 0x0032 198 198 000 Old_age Always - 1564 193 Load_Cycle_Count 0x0032 146 146 000 Old_age Always - 164824 194 Temperature_Celsius 0x0022 117 100 000 Old_age Always - 35 196 Reallocated_Event_Count 0x0032 199 199 000 Old_age Always - 1 197 Current_Pending_Sector 0x0012 200 200 000 Old_age Always - 0 198 Offline_Uncorrectable 0x0010 200 200 000 Old_age Offline - 0 199 UDMA_CRC_Error_Count 0x003e 200 200 000 Old_age Always - 0 200 Multi_Zone_Error_Rate 0x0008 200 200 000 Old_age Offline - 0 What can be wrong with he? Can it be restored? PS new smart is === START OF INFORMATION SECTION === Device Model: WDC WD1000FYPS-01ZKB0 Serial Number: [No Information Found] Firmware Version: [No Information Found] Device is: Not in smartctl database [for details use: -P showall] ATA Version is: 1 ATA Standard is: Exact ATA specification draft version not indicated Local Time is: Mon Mar 8 00:29:44 2010 MSK SMART is only available in ATA Version 3 Revision 3 or greater. We will try to proceed in spite of this. SMART support is: Ambiguous - ATA IDENTIFY DEVICE words 82-83 don't show if SMART supported. Checking for SMART support by trying SMART ENABLE command. Command failed, ata.status=(0x00), ata.command=(0x51), ata.flags=(0x01) Error SMART Enable failed: Input/output error SMART ENABLE failed - this establishes that this device lacks SMART functionality. A mandatory SMART command failed: exiting. To continue, add one or more '-T permissive' options. PPS There was a rapid grow of " 192 Power-Off_Retract_Count " before dying. The hard was used in raid, with several hards from the same fabric packaging box (close id's). The hard drives were placed identically. Rapid means almost linear grow from 300 to 1700 in 6-7 hours. Maximal temperature was 41C. (thanks to munin's smart monitoring)

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• C++ smart pointers: sharing pointers vs. sharing data

  - by Eli Bendersky

  In this insightful article, one of the Qt programmers tries to explain the different kinds of smart pointers Qt implements. In the beginning, he makes a distinction between sharing data and sharing the pointers themselves: First, let’s get one thing straight: there’s a difference between sharing pointers and sharing data. When you share pointers, the value of the pointer and its lifetime is protected by the smart pointer class. In other words, the pointer is the invariant. However, the object that the pointer is pointing to is completely outside its control. We don’t know if the object is copiable or not, if it’s assignable or not. Now, sharing of data involves the smart pointer class knowing something about the data being shared. In fact, the whole point is that the data is being shared and we don’t care how. The fact that pointers are being used to share the data is irrelevant at this point. For example, you don’t really care how Qt tool classes are implicitly shared, do you? What matters to you is that they are shared (thus reducing memory consumption) and that they work as if they weren’t. Frankly, I just don't undersand this explanation. There was a clarification plea in the article comments, but I didn't find the author's explanation sufficient. If you do understand this, please explain. What is this distinction, and how are other shared pointer classes (i.e. from boost or the new C++ standards) fit into this taxonomy? Thanks in advance

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• What's a nice explanation for pointers?

  - by Macneil

  In your own studies (on your own, or for a class) did you have an "ah ha" moment when you finally, really understood pointers? Do you have an explanation you use for beginner programmers that seems particularly effective? For example, when beginners first encounter pointers in C, they might just add &s and *s until it compiles (as I myself once did). Maybe it was a picture, or a really well motivated example, that made pointers "click" for you or your student. What was it, and what did you try before that didn't seem to work? Were any topics prerequisites (e.g. structs, or arrays)? In other words, what was necessary to understand the meaning of &s and *, when you could use them with confidence? Learning the syntax and terminology or the use cases isn't enough, at some point the idea needs to be internalized. Update: I really like the answers so far; please keep them coming. There are a lot of great perspectives here, but I think many are good explanations/slogans for ourselves after we've internalized the concept. I'm looking for the detailed contexts and circumstances when it dawned on you. For example: I only somewhat understood pointers syntactically in C. I heard two of my friends explaining pointers to another friend, who asked why a struct was passed with a pointer. The first friend talked about how it needed to be referenced and modified, but it was just a short comment from the other friend where it hit me: "It's also more efficient." Passing 4 bytes instead of 16 bytes was the final conceptual shift I needed.

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• Praise for Europe's Smart Metering & Conservation Efforts

  - by caroline.yu

  Recently, a writer at the Home Energy Team praised the UK for its efforts towards smart metering and energy conservation, with an article entitled UK Blazing A Trail With Smart Metering At Home? The article highlighted that the Department of Energy and Climate Change has announced that smart metering will be introduced in the next decade and that all UK households will have smart meters by the year 2020. In fact, the UK is not the only country striving to achieve carbon reduction targets, as many of its European counterparts have begun to take positive steps towards tackling the issue of energy conservation by implementing innovative new metering and billing technologies as well as promoting alternative energy solutions, such as wind and solar power. Since 1997, the states of the European Union, including France, Germany and Spain, have been working towards achieving a target of 12 percent renewable energy electricity by 2010. Germany in particular has made a significant achievement so far, having surpassed the target early in 2007. This success is largely due to the German Renewable Energy Act (EEG), which promoted the use of renewable energy. Recently, analysis from the European Wind Energy Association (EWEA) found that 21 of the EU Member States are meeting or exceeding their national target to achieve 20 percent renewable energy by 2020. However, six states - Belgium, Italy, Luxembourg, Malta, Bulgaria and Denmark - say they will not manage to reach their target through domestic action alone. Bulgaria and Denmark believe that with fresh national initiatives they could meet or exceed their targets, but others, including Italy, may need to import renewable energy from neighboring non-EU countries. Top achievers, according to the EWEA report, are Spain, which believes its renewable energy will reach 22.7 percent by 2020, as well as Germany, Estonia, Greece, Ireland, Poland, Slovakia and Sweden, who will all exceed their targets. "Importantly, the way that this renewable energy is controlled and distributed must be addressed in order to ensure its success," said Bastian Fischer, vice president and general manager EMEA, Oracle Utilities. "A smart gird infrastructure can enable utilities to deal with load distribution in times of increased need and ensure power is always available from these means. A smart grid also underpins the success of metering and billing technologies, such as smart metering, and allows utilities to deal with increased usage data and provide accurate billing." Outside of Europe, Australia has made significant steps towards improving water conservation. The Australian Department of Sustainability and Environment took some of the recent advancements made in the energy sector, including new metering and billing solutions, and applied them to the water industry, enhancing customer service and reducing consumption as a result. The adoption of smart metering in Europe is mainly driven by regulation, but significant technological improvements are being made the world over to change the way we use all kinds of energy. However, the developing markets are lagging behind. One of the primary reasons for this is the lack of infrastructure in place to use as a foundation for setting up energy-saving solutions, which is slowing the adoption of technologies such as smart meters. However, these countries do benefit from fewer outdated infrastructure and legacy systems, which is often cited by others as a difficult barrier to deploying new solutions. As a result, some countries should find new technologies easier to implement and adapt to in the immediate future, without this roadblock.

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• char pointers & integer pointers (++)

  - by benjamin button

  i have two pointers, char *str1; int *str2; if i look at the size of both the pointers lets assume str1=4 bytes str2=4 bytes str1++ will increment by 1 byte but if str2++ will increment 4 byte could anybody tell e the concept behind this?

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• What's So Smart About Oracle Exadata Smart Flash Cache?

  - by kimberly.billings

  Want to know what's so "smart" about Oracle Exadata Smart Flash Cache? This three minute video explains how Oracle Exadata Smart Flash Cache helps solve the random I/O bottleneck challenge and delivers extreme performance for consolidated database applications. Exadata Smart Flash Cache is a feature of the Sun Oracle Database Machine. With it, you get ten times faster I/O response time and use ten times fewer disks for business applications from Oracle and third-party providers. Read the whitepaper for more information. var gaJsHost = (("https:" == document.location.protocol) ? "https://ssl." : "http://www."); document.write(unescape("%3Cscript src='" + gaJsHost + "google-analytics.com/ga.js' type='text/javascript'%3E%3C/script%3E")); try { var pageTracker = _gat._getTracker("UA-13185312-1"); pageTracker._trackPageview(); } catch(err) {}

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• How to enable SMART?

  - by Pratik Koirala

  I want to conduct a SMART test on my drive but it was disabled. So, i used sudo smartctl -s on /dev/sda but the result was smartctl 5.41 2011-06-09 r3365 [i686-linux-3.2.0-26-generic] (local build) Copyright (C) 2002-11 by Bruce Allen, http://smartmontools.sourceforge.net === START OF ENABLE/DISABLE COMMANDS SECTION === Error SMART Enable failed: scsi error aborted command Smartctl: SMART Enable Failed. A mandatory SMART command failed: exiting. To continue, add one or more '-T permissive' options. How to overcome this problem?

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• Smart pointers and polymorphism

  - by qwerty

  hello. I implemented reference counting pointers (called SP in the example) and im having problems with polymorphism which i think i shouldn't have. In the following code: SP<BaseClass> foo() { // Some logic... SP<DerivedClass> retPtr = new DerivedClass(); return retPtr; } DerivedClass inherits from BaseClass. With normal pointers this should have worked, but with the smart pointers it says "cannot convert from 'SP<T>' to 'const SP<T>&" and i think it refers to the copy constructor of the smart pointer. How to i allow this kind of polymorphism with reference counting pointer? I'd appreciate code samples cause obviously im doing something wrong here if im having this problem. Thanks! :) [p.s., plz don't tell me to use standart liberary with smart pointers cuz that's impossible at this moment.]

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• pointers to functions

  - by DevAno1

  I have two basic Cpp tasks, but still I have problems with them. First is to write functions mul1,div1,sub1,sum1, taking ints as arguments and returning ints. Then I need to create pointers ptrFun1 and ptrFun2 to functions mul1 and sum1, and print results of using them. Problem starts with defining those pointers. I thought I was doing it right, but devcpp gives me errors in compilation. #include <iostream> using namespace std; int mul1(int a,int b) { return a * b; } int div1(int a,int b) { return a / b; } int sum1(int a,int b) { return a + b; } int sub1(int a,int b) { return a - b; } int main() { int a=1; int b=5; cout << mul1(a,b) << endl; cout << div1(a,b) << endl; cout << sum1(a,b) << endl; cout << sub1(a,b) << endl; int *funPtr1(int, int); int *funPtr2(int, int); funPtr1 = sum1; funPtr2 = mul1; cout << funPtr1(a,b) << endl; cout << funPtr2(a,b) << endl; system("PAUSE"); return 0; } 38 assignment of function int* funPtr1(int, int)' 38 cannot convertint ()(int, int)' to `int*()(int, int)' in assignment Task 2 is to create array of pointers to those functions named tabFunPtr. How to do that ?

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• SMART Status Data Interpretation - Disk Utility

  - by Mah

  Last week my external harddisk (Seagate Barracuda 1.5TB in a custom enclosure) showed signs of failure (Disk Utility SMART Pre-failure status - several bad sectors) and I decided to change it. I bought a new HDD (Seagate Barracuda 2TB) and connected it to my Ubuntu box with a SATA to USB cable that could not report SMART status. I copied all the contents of the old HDD to the new HDD (one partition with rsync, the other with parted cp) and then gently replaced the old HDD with the new one inside my aluminum enclosure. For obscure reasons after reconnecting the new HDD through the old enclosure, the Linux box could not detect my partitions. I recovered the partitions with testdisk and restarted the computer. After the restart I checked the SMART status of the new HDD an I get this: Read Error Rate --------------- Normalized 108 Worst 99 Threshold 6 Value 16737944 I got a high value on the Seek Error Rate as well. Wondering why this happens I copied 2 GB directory from one partition to the other and rechecked the SMART status (5 minutes later). This time I got the following: Read Error Rate --------------- Normalized 109 Worst 99 Threshold 6 Value 24792504 As you see there has been an increase in the error rate. I am unable to interpret these numbers. Is my new hard disk already dying? What are the acceptable values in these fields for Seagate hard disks? Then why the assessment is still good? While I could get temperature and airflow temperature data from my old HDD, I can not fetch them for the new one. I noticed that my old hdd had got really hot sometimes. Is it possible that the enclosure is killing the harddisks due to high temperature?... Thanks

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• Using pointers in PHP.

  - by Babiker

  I ask this question because i learned that in programming and designing, you must have a good reason for decisions. I am php learner and i am at a crossroad here, i am using simple incrementation to try to get what im askin across. I am certainly not here to start a debate about the pros/cons of pointers but when it comes to php, which is the better programming practice: function increment(&$param) { $param++; } Or function increment($param){ return $param++; } $param = increment($param);

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• Oracle Database Smart Flash Cache: Only on Oracle Linux and Oracle Solaris

  - by sergio.leunissen

  Oracle Database Smart Flash Cache is a feature that was first introduced with Oracle Database 11g Release 2. Only available on Oracle Linux and Oracle Solaris, this feature increases the size of the database buffer cache without having to add RAM to the system. In effect, it acts as a second level cache on flash memory and will especially benefit read-intensive database applications. The Oracle Database Smart Flash Cache white paper concludes: Available at no additional cost, Database Smart Flash Cache on Oracle Solaris and Oracle Linux has the potential to offer considerable benefit to users of Oracle Database 11g Release 2 with disk-bound read-mostly or read-only workloads, through the simple addition of flash storage such as the Sun Storage F5100 Flash Array or the Sun Flash Accelerator F20 PCIe Card. Read the white paper.

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• Smart View és az Office verziók

  - by Fekete Zoltán

  A Smart View többek között az Oracle Essbase (Hyperion) lekérdezo-elemzo-kontrolling-adatbeviteli stb felülete is. A Smart View egy MS Excel add-in-ként áll rendelkezésre. Teljes mértékben támogatja a tervezési, költségvetéskészítési, kontrolling és elemzési munkát. Az Essbase a kontrollerek szívéhez és kezéhez közelálló OLAP szerver, ami a Hyperion Planningnek is az alapja. Milyen MS Office verziókat támogat a Smart View? MS Office 2000 (XP), 2003, 2007 verziókat. Ezt az információt az Oracle Enterprise Performance Management Products - Supported Platforms Matrices helyen felsorolt dokumentumok írják le. Az Oracle Enterprise Performance Management aktuális verziójának 11.1.1.3 teljes dokumentácója megtalálható itt.

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• handling refrence to pointers/double pointers using SWIG [C++ to Java]

  - by Siddu

  My code has an interface like class IExample { ~IExample(); //pure virtual methods ...}; a class inheriting the interface like class CExample : public IExample { protected: CExample(); //implementation of pure virtual methods ... }; and a global function to create object of this class - createExample( IExample *& obj ) { obj = new CExample(); } ; Now, I am trying to get Java API wrapper using SWIG, the SWIG generated interface has a construcotr like - IExample(long cPtr, boolean cMemoryOwn) and global function becomes createExample(IExample obj ) The problem is when i do, IExample exObject = new IExample(LogFileLibraryJNI.new_plong(), true /*or false*/ ); createExample( exObject ); The createExample(...) API at C++ layer succesfully gets called, however, when call returns to Java layer, the cPtr (long) variable does not get updated. Ideally, this variable should contain address of CExample object. I read in documentation that typemaps can be used to handle output parameters and pointer references as well; however, I am not able to figure out the suitable way to use typemaps to resolve this problem, or any other workaround. Please suggest if i am doing something wrong, or how to use typemap in such situation?

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• C++ simple arrays and pointers question

  - by nashmaniac

  So here's the confusion, let's say I declare an array of characters char name[3] = "Sam"; and then I declare another array but this time using pointers char * name = "Sam"; What's the difference between the two? I mean they work the same way in a program. Also how does the latter store the size of the stuff that someone puts in it, in this case 3 characters? Also how is it different from char * name = new char[3]; If those three are different where should they be used I mean in what circumstances?

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• C++ smart pointer for a non-object type?

  - by Brian

  Hi, I'm trying to use smart pointers such as auto_ptr, shared_ptr. However, I don't know how to use it in this situation. CvMemStorage *storage = cvCreateMemStorage(); ... use the pointer ... cvReleaseMemStorage(&storage); I'm not sure, but I think that the storage variable is just a malloc'ed memory, not a C++ class object. Is there a way to use the smart pointers for the storage variable? Thank you.

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• C++ smart pointer for non-object type?

  - by Brian

  Hi, I'm trying to use smart pointers such as auto_ptr, shared_ptr. However, I don't know how to use it in this situation. CvMemStorage *storage = cvCreateMemStorage(); ... use the pointer ... cvReleaseMemStorage(&storage); I'm not sure, but I think that the storage variable is just malloc'ed memory, not object. Is there a way to use the smart pointers for the storage variable? Thank you.

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• What's so bad about pointers in C++?

  - by Martin Beckett

  To continue the discussion in Why are pointers not recommended when coding with C++ Suppose you have a class that encapsulates objects which need some initialisation to be valid - like a network socket. // Blah manages some data and transmits it over a socket class socket; // forward declaration, so nice weak linkage. class blah { ... stuff TcpSocket *socket; } ~blah { // TcpSocket dtor handles disconnect delete socket; // or better, wrap it in a smart pointer } The ctor ensures that socket is marked NULL, then later in the code when I have the information to initialise the object. // initialising blah if ( !socket ) { // I know socket hasn't been created/connected // create it in a known initialised state and handle any errors // RAII is a good thing ! socket = new TcpSocket(ip,port); } // and when i actually need to use it if (socket) { // if socket exists then it must be connected and valid } This seems better than having the socket on the stack, having it created in some 'pending' state at program start and then having to continually check some isOK() or isConnected() function before every use. Additionally if TcpSocket ctor throws an exception it's a lot easier to handle at the point a Tcp connection is made rather than at program start. Obviously the socket is just an example, but I'm having a hard time thinking of when an encapsulated object with any sort of internal state shouldn't be created and initialised with new.

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• Making sense of S.M.A.R.T

  - by James

  First of all, I think everyone knows that hard drives fail a lot more than the manufacturers would like to admit. Google did a study that indicates that certain raw data attributes that the S.M.A.R.T status of hard drives reports can have a strong correlation with the future failure of the drive. We find, for example, that after their first scan error, drives are 39 times more likely to fail within 60 days than drives with no such errors. First errors in re- allocations, offline reallocations, and probational counts are also strongly correlated to higher failure probabil- ities. Despite those strong correlations, we find that failure prediction models based on SMART parameters alone are likely to be severely limited in their prediction accuracy, given that a large fraction of our failed drives have shown no SMART error signals whatsoever. Seagate seems like it is trying to obscure this information about their drives by claiming that only their software can accurately determine the accurate status of their drive and by the way their software will not tell you the raw data values for the S.M.A.R.T attributes. Western digital has made no such claim to my knowledge but their status reporting tool does not appear to report raw data values either. I've been using HDtune and smartctl from smartmontools in order to gather the raw data values for each attribute. I've found that indeed... I am comparing apples to oranges when it comes to certain attributes. I've found for example that most Seagate drives will report that they have many millions of read errors while western digital 99% of the time shows 0 for read errors. I've also found that Seagate will report many millions of seek errors while Western Digital always seems to report 0. Now for my question. How do I normalize this data? Is Seagate producing millions of errors while Western digital is producing none? Wikipedia's article on S.M.A.R.T status says that manufacturers have different ways of reporting this data. Here is my hypothesis: I think I found a way to normalize (is that the right term?) the data. Seagate drives have an additional attribute that Western Digital drives do not have (Hardware ECC Recovered). When you subtract the Read error count from the ECC Recovered count, you'll probably end up with 0. This seems to be equivalent to Western Digitals reported "Read Error" count. This means that Western Digital only reports read errors that it cannot correct while Seagate counts up all read errors and tells you how many of those it was able to fix. I had a Seagate drive where the ECC Recovered count was less than the Read error count and I noticed that many of my files were becoming corrupt. This is how I came up with my hypothesis. The millions of seek errors that Seagate produces are still a mystery to me. Please confirm or correct my hypothesis if you have additional information. Here is the smart status of my western digital drive just so you can see what I'm talking about: james@ubuntu:~$ sudo smartctl -a /dev/sda smartctl version 5.38 [x86_64-unknown-linux-gnu] Copyright (C) 2002-8 Bruce Allen Home page is http://smartmontools.sourceforge.net/ === START OF INFORMATION SECTION === Device Model: WDC WD1001FALS-00E3A0 Serial Number: WD-WCATR0258512 Firmware Version: 05.01D05 User Capacity: 1,000,204,886,016 bytes Device is: Not in smartctl database [for details use: -P showall] ATA Version is: 8 ATA Standard is: Exact ATA specification draft version not indicated Local Time is: Thu Jun 10 19:52:28 2010 PDT SMART support is: Available - device has SMART capability. SMART support is: Enabled === START OF READ SMART DATA SECTION === SMART overall-health self-assessment test result: PASSED SMART Attributes Data Structure revision number: 16 Vendor Specific SMART Attributes with Thresholds: ID# ATTRIBUTE_NAME FLAG VALUE WORST THRESH TYPE UPDATED WHEN_FAILED RAW_VALUE 1 Raw_Read_Error_Rate 0x002f 200 200 051 Pre-fail Always - 0 3 Spin_Up_Time 0x0027 179 175 021 Pre-fail Always - 4033 4 Start_Stop_Count 0x0032 100 100 000 Old_age Always - 270 5 Reallocated_Sector_Ct 0x0033 200 200 140 Pre-fail Always - 0 7 Seek_Error_Rate 0x002e 200 200 000 Old_age Always - 0 9 Power_On_Hours 0x0032 098 098 000 Old_age Always - 1468 10 Spin_Retry_Count 0x0032 100 100 000 Old_age Always - 0 11 Calibration_Retry_Count 0x0032 100 100 000 Old_age Always - 0 12 Power_Cycle_Count 0x0032 100 100 000 Old_age Always - 262 192 Power-Off_Retract_Count 0x0032 200 200 000 Old_age Always - 46 193 Load_Cycle_Count 0x0032 200 200 000 Old_age Always - 223 194 Temperature_Celsius 0x0022 105 102 000 Old_age Always - 42 196 Reallocated_Event_Count 0x0032 200 200 000 Old_age Always - 0 197 Current_Pending_Sector 0x0032 200 200 000 Old_age Always - 0 198 Offline_Uncorrectable 0x0030 200 200 000 Old_age Offline - 0 199 UDMA_CRC_Error_Count 0x0032 200 200 000 Old_age Always - 0 200 Multi_Zone_Error_Rate 0x0008 200 200 000 Old_age Offline - 0

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• Why Garbage Collection if smart pointers are there

  - by Gulshan

  This days, so many languages are garbage collected. Even it is available for C++ by third parties. But, C++ has RAII and smart pointers. So, what's the point of using garbage collection? Is it doing something extra? And in other languages like C#, if all the references are treated as smart pointers(keeping RAII aside), by specification and by implementation, will there be still any need of garbage collectors? If no, then why this is not so?

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