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• To SYNC or not to SYNC – Part 4

  - by AshishRay

  This is Part 4 of a multi-part blog article where we are discussing various aspects of setting up Data Guard synchronous redo transport (SYNC). In Part 1 of this article, I debunked the myth that Data Guard SYNC is similar to a two-phase commit operation. In Part 2, I discussed the various ways that network latency may or may not impact a Data Guard SYNC configuration. In Part 3, I talked in details regarding why Data Guard SYNC is a good thing, and the distance implications you have to keep in mind. In this final article of the series, I will talk about how you can nicely complement Data Guard SYNC with the ability to failover in seconds. Wait - Did I Say “Seconds”? Did I just say that some customers do Data Guard failover in seconds? Yes, Virginia, there is a Santa Claus. Data Guard has an automatic failover capability, aptly called Fast-Start Failover. Initially available with Oracle Database 10g Release 2 for Data Guard SYNC transport mode (and enhanced in Oracle Database 11g to support Data Guard ASYNC transport mode), this capability, managed by Data Guard Broker, lets your Data Guard configuration automatically failover to a designated standby database. Yes, this means no human intervention is required to do the failover. This process is controlled by a low footprint Data Guard Broker client called Observer, which makes sure that the primary database and the designated standby database are behaving like good kids. If something bad were to happen to the primary database, the Observer, after a configurable threshold period, tells that standby, “Your time has come, you are the chosen one!” The standby dutifully follows the Observer directives by assuming the role of the new primary database. The DBA or the Sys Admin doesn’t need to be involved. And - in case you are following this discussion very closely, and are wondering … “Hmmm … what if the old primary is not really dead, but just network isolated from the Observer or the standby - won’t this lead to a split-brain situation?” The answer is No - It Doesn’t. With respect to why-it-doesn’t, I am sure there are some smart DBAs in the audience who can explain the technical reasons. Otherwise - that will be the material for a future blog post. So - this combination of SYNC and Fast-Start Failover is the nirvana of lights-out, integrated HA and DR, as practiced by some of our advanced customers. They have observed failover times (with no data loss) ranging from single-digit seconds to tens of seconds. With this, they support operations in industry verticals such as manufacturing, retail, telecom, Internet, etc. that have the most demanding availability requirements. One of our leading customers with massive cloud deployment initiatives tells us that they know about server failures only after Data Guard has automatically completed the failover process and the app is back up and running! Needless to mention, Data Guard Broker has the integration hooks for interfaces such as JDBC and OCI, or even for custom apps, to ensure the application gets automatically rerouted to the new primary database after the database level failover completes. Net Net? To sum up this multi-part blog article, Data Guard with SYNC redo transport mode, plus Fast-Start Failover, gives you the ideal triple-combo - that is, it gives you the assurance that for critical outages, you can failover your Oracle databases: very fast without human intervention, and without losing any data. In short, it takes the element of risk out of critical IT operations. It does require you to be more careful with your network and systems planning, but as far as HA is concerned, the benefits outweigh the investment costs. So, this is what we in the MAA Development Team believe in. What do you think? How has your deployment experience been? We look forward to hearing from you!

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• Organization &amp; Architecture UNISA Studies &ndash; Chap 6

  - by MarkPearl

  Learning Outcomes Discuss the physical characteristics of magnetic disks Describe how data is organized and accessed on a magnetic disk Discuss the parameters that play a role in the performance of magnetic disks Describe different optical memory devices Magnetic Disk The way data is stored on and retried from magnetic disks Data is recorded on and later retrieved form the disk via a conducting coil named the head (in many systems there are two heads) The writ mechanism exploits the fact that electricity flowing through a coil produces a magnetic field. Electric pulses are sent to the write head, and the resulting magnetic patterns are recorded on the surface below with different patterns for positive and negative currents The physical characteristics of a magnetic disk   Summarize from book   The factors that play a role in the performance of a disk Seek time – the time it takes to position the head at the track Rotational delay / latency – the time it takes for the beginning of the sector to reach the head Access time – the sum of the seek time and rotational delay Transfer time – the time it takes to transfer data RAID The rate of improvement in secondary storage performance has been considerably less than the rate for processors and main memory. Thus secondary storage has become a bit of a bottleneck. RAID works on the concept that if one disk can be pushed so far, additional gains in performance are to be had by using multiple parallel components. Points to note about RAID… RAID is a set of physical disk drives viewed by the operating system as a single logical drive Data is distributed across the physical drives of an array in a scheme known as striping Redundant disk capacity is used to store parity information, which guarantees data recoverability in case of a disk failure (not supported by RAID 0 or RAID 1) Interesting to note that the increase in the number of drives, increases the probability of failure. To compensate for this decreased reliability RAID makes use of stored parity information that enables the recovery of data lost due to a disk failure.   The RAID scheme consists of 7 levels…   Category Level Description Disks Required Data Availability Large I/O Data Transfer Capacity Small I/O Request Rate Striping 0 Non Redundant N Lower than single disk Very high Very high for both read and write Mirroring 1 Mirrored 2N Higher than RAID 2 – 5 but lower than RAID 6 Higher than single disk Up to twice that of a signle disk for read Parallel Access 2 Redundant via Hamming Code N + m Much higher than single disk Highest of all listed alternatives Approximately twice that of a single disk Parallel Access 3 Bit interleaved parity N + 1 Much higher than single disk Highest of all listed alternatives Approximately twice that of a single disk Independent Access 4 Block interleaved parity N + 1 Much higher than single disk Similar to RAID 0 for read, significantly lower than single disk for write Similar to RAID 0 for read, significantly lower than single disk for write Independent Access 5 Block interleaved parity N + 1 Much higher than single disk Similar to RAID 0 for read, lower than single disk for write Similar to RAID 0 for read, generally  lower than single disk for write Independent Access 6 Block interleaved parity N + 2 Highest of all listed alternatives Similar to RAID 0 for read; lower than RAID 5 for write Similar to RAID 0 for read, significantly lower than RAID 5  for write   Read page 215 – 221 for detailed explanation on RAID levels Optical Memory There are a variety of optical-disk systems available. Read through the table on page 222 – 223 Some of the devices include… CD CD-ROM CD-R CD-RW DVD DVD-R DVD-RW Blue-Ray DVD Magnetic Tape Most modern systems use serial recording – data is lade out as a sequence of bits along each track. The typical recording used in serial is referred to as serpentine recording. In this technique when data is being recorded, the first set of bits is recorded along the whole length of the tape. When the end of the tape is reached the heads are repostioned to record a new track, and the tape is again recorded on its whole length, this time in the opposite direction. That process continued back and forth until the tape is full. To increase speed, the read-write head is capable of reading and writing a number of adjacent tracks simultaneously. Data is still recorded serially along individual tracks, but blocks in sequence are stored on adjacent tracks as suggested. A tape drive is a sequential access device. Magnetic tape was the first kind of secondary memory. It is still widely used as the lowest-cost, slowest speed member of the memory hierarchy.

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• Crime Scene Investigation: SQL Server

  - by Rodney Landrum

  “The packages are running slower in Prod than they are in Dev” My week began with this simple declaration from one of our lead BI developers, quickly followed by an emailed spreadsheet demonstrating that, over 5 executions, an extensive ETL process was running average 630 seconds faster on Dev than on Prod. The situation needed some scientific investigation to determine why the same code, the same data, the same schema would yield consistently slower results on a more powerful server. Prod had yet to be officially christened with a “Go Live” date so I had the time, and having recently been binge watching CSI: New York, I also had the inclination. An inspection of the two systems, Prod and Dev, revealed the first surprise: although Prod was indeed a “bigger” system, with double the amount of RAM of Dev, the latter actually had twice as many processor cores. On neither system did I see much sign of resources being heavily taxed, while the ETL process was running. Without any real supporting evidence, I jumped to a conclusion that my years of performance tuning should have helped me avoid, and that was that the hardware differences explained the better performance on Dev. We spent time setting up a Test system, similarly scoped to Prod except with 4 times the cores, and ported everything across. The results of our careful benchmarks left us truly bemused; the ETL process on the new server was slower than on both other systems. We burned more time tweaking server configurations, monitoring IO and network latency, several times believing we’d uncovered the smoking gun, until the results of subsequent test runs pitched us back into confusion. Finally, I decided, enough was enough. Hadn’t I learned very early in my DBA career that almost all bottlenecks were caused by code and database design, not hardware? It was time to get back to basics. With over 100 SSIS packages and hundreds of queries, each handling specific tasks such as file loads, bulk inserts, transforms, logging, and so on, the task seemed formidable. And yet, after barely an hour spent with Profiler, Extended Events, and wait statistics DMVs, I had a lead in the shape of a query that joined three tables, containing millions of rows, returned 3279 results, but performed 239K logical reads. As soon as I looked at the execution plans for the query in Dev and Test I saw the culprit, an implicit conversion warning on a join predicate field that was numeric in one table and a varchar(50) in another! I turned this information over to the BI developers who quickly resolved the data type mismatches and found and fixed “several” others as well. After the schema changes the same query with the same databases ran in under 1 second on all systems and reduced the logical reads down to fewer than 300. The analysis also revealed that on Dev, the ETL task was pulling data across a LAN, whereas Prod and Test were connected across slower WAN, in large part explaining why the same process ran slower on the latter two systems. Loading the data locally on Prod delivered a further 20% gain in performance. As we progress through our DBA careers we learn valuable lessons. Sometimes, with a project deadline looming and pressure mounting, we choose to forget them. I was close to giving into the temptation to throw more hardware at the problem. I’m pleased at least that I resisted, though I still kick myself for not looking at the code on day one. It can seem a daunting prospect to return to the fundamentals of the code so close to roll out, but with the right tools, and surprisingly little time, you can collect the evidence that reveals the true problem. It is a lesson I trust I will remember for my next 20 years as a DBA, if I’m ever again tempted to bypass the evidence.

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• Replicating between Cloud and On-Premises using Oracle GoldenGate

  - by Ananth R. Tiru

  Do you have applications running on the cloud that you need to connect with the on premises systems. The most likely answer to this question is an astounding YES!  If so, then you understand the importance of keep the data fresh at all times across the cloud and on-premises environments. This is also one of the key focus areas for the new GoldenGate 12c release which we announced couple of week ago via a press release. Most enterprises have spent years avoiding the data “silos” that inhibit productivity. For example, an enterprise which has adopted a CRM strategy could be relying on an on-premises based marketing application used for developing and nurturing leads. At the same time it could be using a SaaS based Sales application to create opportunities and quotes. The sales and the marketing teams which use these systems need to be able to access and share the data in a reliable and cohesive way. This example can be extended to other applications areas such as HR, Supply Chain, and Finance and the demands the users place on getting a consistent view of the data. When it comes to moving data in hybrid environments some of the key requirements include minimal latency, reliability and security: Data must remain fresh. As data ages it becomes less relevant and less valuable—day-old data is often insufficient in today’s competitive landscape. Reliability must be guaranteed despite system or connectivity issues that can occur between the cloud and on-premises instances. Security is a key concern when replicating between cloud and on-premises instances. There are several options to consider when replicating between the cloud and on-premises instances. Option 1 – Secured network established between the cloud and on-premises A secured network is established between the cloud and on-premises which enables the applications (including replication software) running on the cloud and on-premises to have seamless connectivity to other applications irrespective of where they are physically located. Option 2 – Restricted network established between the cloud and on-premises A restricted network is established between the cloud and on-premises instances which enable certain ports (required by replication) be opened on both the cloud and on the on-premises instances and white lists the IP addresses of the cloud and on-premises instances. Option 3 – Restricted network access from on-premises and cloud through HTTP proxy This option can be considered when the ports required by the applications (including replication software) are not open and the cloud instance is not white listed on the on-premises instance. This option of tunneling through HTTP proxy may be only considered when proper security exceptions are obtained. Oracle GoldenGate Oracle GoldenGate is used for major Fortune 500 companies and other industry leaders worldwide to support mission-critical systems for data availability and integration. Oracle GoldenGate addresses the requirements for ensuring data consistency between cloud and on-premises instances, thus facilitating the business process to run effectively and reliably. The architecture diagram below illustrates the scenario where the cloud and the on-premises instance are connected using GoldenGate through a secured network In the above scenario, Oracle GoldenGate is installed and configured on both the cloud and the on-premises instances. On the cloud instance Oracle GoldenGate is installed and configured on the machine where the database instance can be accessed. Oracle GoldenGate can be configured for unidirectional or bi-directional replication between the cloud and on premises instances. The specific configuration details of Oracle GoldenGate processes will depend upon the option selected for establishing connectivity between the cloud and on-premises instances. The knowledge article (ID - 1588484.1) titled ' Replicating between Cloud and On-Premises using Oracle GoldenGate' discusses in detail the options for replicating between the cloud and on-premises instances. The article can be found on My Oracle Support. To learn more about Oracle GoldenGate 12c register for our launch webcast where we will go into these new features in more detail.   You may also want to download our white paper "Oracle GoldenGate 12c Release 1 New Features Overview" I would love to hear your requirements for replicating between on-premises and cloud instances, as well as your comments about the strategy discussed in the knowledge article to address your needs. Please post your comments in this blog or in the Oracle GoldenGate public forum - https://forums.oracle.com/community/developer/english/business_intelligence/system_management_and_integration/goldengate

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• Observing flow control idle time in TCP

  - by user12820842

  Previously I described how to observe congestion control strategies during transmission, and here I talked about TCP's sliding window approach for handling flow control on the receive side. A neat trick would now be to put the pieces together and ask the following question - how often is TCP transmission blocked by congestion control (send-side flow control) versus a zero-sized send window (which is the receiver saying it cannot process any more data)? So in effect we are asking whether the size of the receive window of the peer or the congestion control strategy may be sub-optimal. The result of such a problem would be that we have TCP data that we could be transmitting but we are not, potentially effecting throughput. So flow control is in effect: when the congestion window is less than or equal to the amount of bytes outstanding on the connection. We can derive this from args[3]-tcps_snxt - args[3]-tcps_suna, i.e. the difference between the next sequence number to send and the lowest unacknowledged sequence number; and when the window in the TCP segment received is advertised as 0 We time from these events until we send new data (i.e. args[4]-tcp_seq = snxt value when window closes. Here's the script: #!/usr/sbin/dtrace -s #pragma D option quiet tcp:::send / (args[3]-tcps_snxt - args[3]-tcps_suna) = args[3]-tcps_cwnd / { cwndclosed[args[1]-cs_cid] = timestamp; cwndsnxt[args[1]-cs_cid] = args[3]-tcps_snxt; @numclosed["cwnd", args[2]-ip_daddr, args[4]-tcp_dport] = count(); } tcp:::send / cwndclosed[args[1]-cs_cid] && args[4]-tcp_seq = cwndsnxt[args[1]-cs_cid] / { @meantimeclosed["cwnd", args[2]-ip_daddr, args[4]-tcp_dport] = avg(timestamp - cwndclosed[args[1]-cs_cid]); @stddevtimeclosed["cwnd", args[2]-ip_daddr, args[4]-tcp_dport] = stddev(timestamp - cwndclosed[args[1]-cs_cid]); @numclosed["cwnd", args[2]-ip_daddr, args[4]-tcp_dport] = count(); cwndclosed[args[1]-cs_cid] = 0; cwndsnxt[args[1]-cs_cid] = 0; } tcp:::receive / args[4]-tcp_window == 0 && (args[4]-tcp_flags & (TH_SYN|TH_RST|TH_FIN)) == 0 / { swndclosed[args[1]-cs_cid] = timestamp; swndsnxt[args[1]-cs_cid] = args[3]-tcps_snxt; @numclosed["swnd", args[2]-ip_saddr, args[4]-tcp_dport] = count(); } tcp:::send / swndclosed[args[1]-cs_cid] && args[4]-tcp_seq = swndsnxt[args[1]-cs_cid] / { @meantimeclosed["swnd", args[2]-ip_daddr, args[4]-tcp_sport] = avg(timestamp - swndclosed[args[1]-cs_cid]); @stddevtimeclosed["swnd", args[2]-ip_daddr, args[4]-tcp_sport] = stddev(timestamp - swndclosed[args[1]-cs_cid]); swndclosed[args[1]-cs_cid] = 0; swndsnxt[args[1]-cs_cid] = 0; } END { printf("%-6s %-20s %-8s %-25s %-8s %-8s\n", "Window", "Remote host", "Port", "TCP Avg WndClosed(ns)", "StdDev", "Num"); printa("%-6s %-20s %-8d %@-25d %@-8d %@-8d\n", @meantimeclosed, @stddevtimeclosed, @numclosed); } So this script will show us whether the peer's receive window size is preventing flow ("swnd" events) or whether congestion control is limiting flow ("cwnd" events). As an example I traced on a server with a large file transfer in progress via a webserver and with an active ssh connection running "find / -depth -print". Here is the output: ^C Window Remote host Port TCP Avg WndClosed(ns) StdDev Num cwnd 10.175.96.92 80 86064329 77311705 125 cwnd 10.175.96.92 22 122068522 151039669 81 So we see in this case, the congestion window closes 125 times for port 80 connections and 81 times for ssh. The average time the window is closed is 0.086sec for port 80 and 0.12sec for port 22. So if you wish to change congestion control algorithm in Oracle Solaris 11, a useful step may be to see if congestion really is an issue on your network. Scripts like the one posted above can help assess this, but it's worth reiterating that if congestion control is occuring, that's not necessarily a problem that needs fixing. Recall that congestion control is about controlling flow to prevent large-scale drops, so looking at congestion events in isolation doesn't tell us the whole story. For example, are we seeing more congestion events with one control algorithm, but more drops/retransmission with another? As always, it's best to start with measures of throughput and latency before arriving at a specific hypothesis such as "my congestion control algorithm is sub-optimal".

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• What's wrong with my wireless?

  - by dazzle

  I am having issues with my wireless connection. My connection is constantly disconnecting, then attempting to reconnect, reconnecting momentarily, then disconnecting etc. on times scales that range from seconds to minutes. In the meantime, needless to say I'm having significant packet loss. I'm running Ubuntu 14.04 64bit, updated and upgraded to today. Here is my card and driver: delta@sager:~$ lspci -vq | grep -i wireless -B 1 -A 5 04:00.0 Network controller: Intel Corporation Wireless 7260 (rev 73) Subsystem: Intel Corporation Dual Band Wireless-AC 7260 Flags: bus master, fast devsel, latency 0, IRQ 47 Memory at f7d00000 (64-bit, non-prefetchable) [size=8K] Capabilities: Kernel driver in use: iwlwifi Here is my kernel: delta@sager:~$ uname -r 3.13.0-34-generic None of the other machines on my home network are having these issues. Windows Vista is networking without issue for goodness sake ;-) Here is a small clipping from the output of dmesg. As you can see, I am getting a cfg80211 message of some sort over and over again (FYI, I've replaced my MAC address with a series of dashes, so anytime there is a ---------------, that was where the MAC address was: [ 1881.739161] wlan1: authenticate with --------------- [ 1881.741561] wlan1: send auth to --------------- (try 1/3) [ 1881.743440] wlan1: authenticated [ 1881.746027] wlan1: associate with --------------- (try 1/3) [ 1881.749244] wlan1: RX AssocResp from --------------- (capab=0x411 status=0 aid=4) [ 1881.754727] wlan1: associated [ 1881.754827] cfg80211: Calling CRDA for country: US [ 1881.761552] cfg80211: Regulatory domain changed to country: US [ 1881.761559] cfg80211: (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp) [ 1881.761564] cfg80211: (2402000 KHz - 2472000 KHz @ 40000 KHz), (300 mBi, 2700 mBm) [ 1881.761568] cfg80211: (5170000 KHz - 5250000 KHz @ 40000 KHz), (300 mBi, 1700 mBm) [ 1881.761571] cfg80211: (5250000 KHz - 5330000 KHz @ 40000 KHz), (300 mBi, 2000 mBm) [ 1881.761574] cfg80211: (5490000 KHz - 5600000 KHz @ 40000 KHz), (300 mBi, 2000 mBm) [ 1881.761577] cfg80211: (5650000 KHz - 5710000 KHz @ 40000 KHz), (300 mBi, 2000 mBm) [ 1881.761580] cfg80211: (5735000 KHz - 5835000 KHz @ 40000 KHz), (300 mBi, 3000 mBm) [ 1881.761584] cfg80211: (57240000 KHz - 63720000 KHz @ 2160000 KHz), (N/A, 4000 mBm) [ 1882.391038] cfg80211: Calling CRDA to update world regulatory domain [ 1882.396254] cfg80211: World regulatory domain updated: [ 1882.396260] cfg80211: (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp) [ 1882.396265] cfg80211: (2402000 KHz - 2472000 KHz @ 40000 KHz), (300 mBi, 2000 mBm) [ 1882.396268] cfg80211: (2457000 KHz - 2482000 KHz @ 40000 KHz), (300 mBi, 2000 mBm) [ 1882.396271] cfg80211: (2474000 KHz - 2494000 KHz @ 20000 KHz), (300 mBi, 2000 mBm) [ 1882.396274] cfg80211: (5170000 KHz - 5250000 KHz @ 40000 KHz), (300 mBi, 2000 mBm) [ 1882.396277] cfg80211: (5735000 KHz - 5835000 KHz @ 40000 KHz), (300 mBi, 2000 mBm) [ 1886.148252] wlan1: authenticate with --------------- [ 1886.150005] wlan1: send auth to --------------- (try 1/3) [ 1886.151807] wlan1: authenticated [ 1886.154847] wlan1: associate with --------------- (try 1/3) [ 1886.158147] wlan1: RX AssocResp from --------------- (capab=0x411 status=0 aid=4) [ 1886.163464] wlan1: associated [ 1886.163520] wlan1: Limiting TX power to 30 (30 - 0) dBm as advertised by --------------- [ 1886.163588] cfg80211: Calling CRDA for country: US [ 1886.170500] cfg80211: Regulatory domain changed to country: US [ 1886.170508] cfg80211: (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp) [ 1886.170513] cfg80211: (2402000 KHz - 2472000 KHz @ 40000 KHz), (300 mBi, 2700 mBm) [ 1886.170517] cfg80211: (5170000 KHz - 5250000 KHz @ 40000 KHz), (300 mBi, 1700 mBm) [ 1886.170520] cfg80211: (5250000 KHz - 5330000 KHz @ 40000 KHz), (300 mBi, 2000 mBm) [ 1886.170523] cfg80211: (5490000 KHz - 5600000 KHz @ 40000 KHz), (300 mBi, 2000 mBm) [ 1886.170526] cfg80211: (5650000 KHz - 5710000 KHz @ 40000 KHz), (300 mBi, 2000 mBm) [ 1886.170529] cfg80211: (5735000 KHz - 5835000 KHz @ 40000 KHz), (300 mBi, 3000 mBm) [ 1886.170533] cfg80211: (57240000 KHz - 63720000 KHz @ 2160000 KHz), (N/A, 4000 mBm) [ 1887.200197] cfg80211: Calling CRDA to update world regulatory domain [ 1887.203655] cfg80211: World regulatory domain updated: [ 1887.203659] cfg80211: (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp) [ 1887.203662] cfg80211: (2402000 KHz - 2472000 KHz @ 40000 KHz), (300 mBi, 2000 mBm) [ 1887.203664] cfg80211: (2457000 KHz - 2482000 KHz @ 40000 KHz), (300 mBi, 2000 mBm) [ 1887.203666] cfg80211: (2474000 KHz - 2494000 KHz @ 20000 KHz), (300 mBi, 2000 mBm) [ 1887.203668] cfg80211: (5170000 KHz - 5250000 KHz @ 40000 KHz), (300 mBi, 2000 mBm) [ 1887.203670] cfg80211: (5735000 KHz - 5835000 KHz @ 40000 KHz), (300 mBi, 2000 mBm) I've poked around on AskUbuntu, and have not found any adequate solutions; have also found similar threads that were left unanswered. Any advice/experience/threads I might be able to pull on would be greatly appreciated. In your opinion, is this a kernel issue, hardware issue, etc.? Thanks in advance. EDIT: chili, here's the output of iwconfig: delta@sager:~$ iwconfig wlan1 IEEE 802.11abg ESSID:"LANbeforetime" Mode:Managed Frequency:2.412 GHz Access Point: ----------- Bit Rate=48 Mb/s Tx-Power=16 dBm Retry long limit:7 RTS thr:off Fragment thr:off Power Management:off Link Quality=44/70 Signal level=-66 dBm Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0 Tx excessive retries:0 Invalid misc:80 Missed beacon:0 eth0 no wireless extensions. lo no wireless extensions.

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• Randomely loosing wireless connexion with Cubuntu 12.04

  - by statquant

  I am presently experiencing random disconnections from my wireless network. It looks like it is more and more frequent (however I have not seen any clear pattern). This is killing me... Here is some information that should help (from ubuntu forums). Thanks for reading Machine : Acer Aspire S3 statquant@euclide:~$ lsb_release -d Description: Ubuntu 12.04.1 LTS statquant@euclide:~$ uname -mr 3.2.0-33-generic x86_64 statquant@euclide:~$ sudo /etc/init.d/networking restart * Running /etc/init.d/networking restart is deprecated because it may not enable again some interfaces * Reconfiguring network interfaces... statquant@euclide:~$ lspci 02:00.0 Network controller: Atheros Communications Inc. AR9485 Wireless Network Adapter (rev 01) statquant@euclide:~$ lsusb Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub Bus 002 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub Bus 001 Device 004: ID 064e:c321 Suyin Corp. Bus 002 Device 003: ID 0bda:0129 Realtek Semiconductor Corp. statquant@euclide:~$ ifconfig wlan0 Link encap:Ethernet HWaddr 74:de:2b:dd:c4:78 inet addr:192.168.1.3 Bcast:192.168.1.255 Mask:255.255.255.0 inet6 addr: fe80::76de:2bff:fedd:c478/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:913 errors:0 dropped:0 overruns:0 frame:0 TX packets:802 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:873218 (873.2 KB) TX bytes:125826 (125.8 KB) statquant@euclide:~$ iwconfig wlan0 IEEE 802.11bgn ESSID:"Bbox-D646D1" Mode:Managed Frequency:2.437 GHz Access Point: 00:19:70:80:01:6C Bit Rate=65 Mb/s Tx-Power=16 dBm Retry long limit:7 RTS thr:off Fragment thr:off Power Management:on Link Quality=56/70 Signal level=-54 dBm Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0 Tx excessive retries:0 Invalid misc:71 Missed beacon:0 statquant@euclide:~$ dmesg | grep "wlan" [ 17.495866] ADDRCONF(NETDEV_UP): wlan0: link is not ready [ 17.498950] ADDRCONF(NETDEV_UP): wlan0: link is not ready [ 20.072015] wlan0: authenticate with 00:19:70:80:01:6c (try 1) [ 20.269853] wlan0: authenticate with 00:19:70:80:01:6c (try 2) [ 20.272386] wlan0: authenticated [ 20.298682] wlan0: associate with 00:19:70:80:01:6c (try 1) [ 20.302321] wlan0: RX AssocResp from 00:19:70:80:01:6c (capab=0x431 status=0 aid=1) [ 20.302325] wlan0: associated [ 20.307307] ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready [ 30.402292] wlan0: no IPv6 routers present statquant@euclide:~$ sudo lshw -C network [sudo] password for statquant: *-network description: Wireless interface product: AR9485 Wireless Network Adapter vendor: Atheros Communications Inc. physical id: 0 bus info: pci@0000:02:00.0 logical name: wlan0 version: 01 serial: 74:de:2b:dd:c4:78 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list rom ethernet physical wireless configuration: broadcast=yes driver=ath9k driverversion=3.2.0-33-generic firmware=N/A ip=192.168.1.3 latency=0 link=yes multicast=yes wireless=IEEE 802.11bgn resources: irq:17 memory:c0400000-c047ffff memory:afb00000-afb0ffff statquant@euclide:~$ iwlist scan wlan0 Scan completed : Cell 01 - Address: 00:19:70:80:01:6C Channel:6 Frequency:2.437 GHz (Channel 6) Quality=56/70 Signal level=-54 dBm Encryption key:on ESSID:"Bbox-D646D1" Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 6 Mb/s 9 Mb/s; 12 Mb/s; 18 Mb/s Bit Rates:24 Mb/s; 36 Mb/s; 48 Mb/s; 54 Mb/s Mode:Master Extra:tsf=000000125fb152bb Extra: Last beacon: 40020ms ago IE: Unknown: 000B42626F782D443634364431 IE: Unknown: 010882848B960C121824 IE: Unknown: 030106 IE: IEEE 802.11i/WPA2 Version 1 Group Cipher : TKIP Pairwise Ciphers (2) : CCMP TKIP Authentication Suites (1) : PSK IE: WPA Version 1 Group Cipher : TKIP Pairwise Ciphers (2) : CCMP TKIP Authentication Suites (1) : PSK IE: Unknown: 2A0100 IE: Unknown: 32043048606C IE: Unknown: DD180050F2020101820003A4000027A4000042435E0062322F00 IE: Unknown: 2D1A4C101BFF00000000000000000000000000000000000000000000 IE: Unknown: 3D1606080800000000000000000000000000000000000000 IE: Unknown: DD0900037F01010000FF7F IE: Unknown: DD0A00037F04010000000000 And... finally, please note that I did the following (after looking for fixes of similar problems), but unfortunately it did not work sudo modprobe -r iwlwifi sudo modprobe iwlwifi 11n_disable=1

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• No Wireless Networks, BCM4313 [duplicate]

  - by TalonPlz

  This question already has an answer here: How to Install Broadcom Wireless Drivers (BCM43xx) 38 answers Just bought this little Asus 10 inch laptop that came with Ubuntu 12.04. Everything at my home was fine: Wireless identified and connected. As soon as I went to my girlfriend's house the trouble started. I couldn't connect to wireless (authentication... times out and asks for authentication) I started doing internet searching, tried a few solutions posted on line using terminal commands. No solutions. I decided to upgraded to 12.10-13.04 and that left me with a worse problem: I can no longer see ANY networks what so ever. Wireless card is ON, with out a doubt. Wired connection works. I have been fumbling with driver versions to no .avail, and have no idea which driver I am currently running I have a vague idea of what terminal lines to run: lshw: resources: irq:17 memory:f7d00000-f7dfffff *-network description: Wireless interface product: BCM4313 802.11b/g/n Wireless LAN Controller vendor: Broadcom Corporation physical id: 0 bus info: pci@0000:02:00.0 logical name: eth2 version: 01 serial: dc:85:de:56:c4:ea width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless configuration: broadcast=yes driver=wl0 driverversion=6.20.155.1 (r326264) latency=0 multicast=yes wireless=IEEE 802.11abg resources: irq:17 memory:f7d00000-f7d03fff iwconfig: eth1 no wireless extensions. eth2 IEEE 802.11abg ESSID:off/any Mode:Managed Access Point: Not-Associated Retry long limit:7 RTS thr:off Fragment thr:off Power Management:off lo no wireless extensions. I am new and excited to start my Ubuntu and Linux life and this is only the first of my few hic cups i am sure! :) Thanks all UPDATE: Report from 2nd answer talon@Black1015E:~$ sudo apt-get remove --purge bcmwl-kernel-source [sudo] password for talon: Reading package lists... Done Building dependency tree Reading state information... Done Package 'bcmwl-kernel-source' is not installed, so not removed 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded. talon@Black1015E:~$ wget http://us.archive.ubuntu.com/ubuntu/pool/restricted/b/bcmwl/bcmwl-kernel-source_5.100.82.112+bdcom-0ubuntu3_amd64.deb --2013-10-22 18:50:32-- http://us.archive.ubuntu.com/ubuntu/pool/restricted/b/bcmwl/bcmwl-kernel-source_5.100.82.112+bdcom-0ubuntu3_amd64.deb Resolving us.archive.ubuntu.com (us.archive.ubuntu.com)... 2001:67c:1562::15, 2001:67c:1562::13, 2001:67c:1562::14, ... Connecting to us.archive.ubuntu.com (us.archive.ubuntu.com)|2001:67c:1562::15|:80... connected. HTTP request sent, awaiting response... 200 OK Length: 1181334 (1.1M) [application/x-debian-package] Saving to: ‘bcmwl-kernel-source_5.100.82.112+bdcom-0ubuntu3_amd64.deb’ 100%[======================================>] 1,181,334 3.37MB/s in 0.3s 2013-10-22 18:50:33 (3.37 MB/s) - ‘bcmwl-kernel-source_5.100.82.112+bdcom-0ubuntu3_amd64.deb’ saved [1181334/1181334] talon@Black1015E:~$ arvh No command 'arvh' found, did you mean: Command 'arch' from package 'coreutils' (main) arvh: command not found talon@Black1015E:~$ arch x86_64 talon@Black1015E:~$ sudo dpkg -i bcmwl*.deb Selecting previously unselected package bcmwl-kernel-source. (Reading database ... 171895 files and directories currently installed.) Unpacking bcmwl-kernel-source (from bcmwl-kernel-source_5.100.82.112+bdcom-0ubuntu3_amd64.deb) ... Setting up bcmwl-kernel-source (5.100.82.112+bdcom-0ubuntu3) ... Loading new bcmwl-5.100.82.112+bdcom DKMS files... First Installation: checking all kernels... Building only for 3.8.0-32-generic Building for architecture x86_64 Building initial module for 3.8.0-32-generic Done. wl: Running module version sanity check. - Original module - No original module exists within this kernel - Installation - Installing to /lib/modules/3.8.0-32-generic/updates/dkms/ depmod........ DKMS: install completed. Error: Module b43 is not currently loaded Error: Module b43legacy is not currently loaded Error: Module ssb is not currently loaded Error: Module bcm43xx is not currently loaded Error: Module brcm80211 is not currently loaded Error: Module brcmfmac is not currently loaded update-initramfs: deferring update (trigger activated) Processing triggers for initramfs-tools ... update-initramfs: Generating /boot/initrd.img-3.8.0-32-generic rebooting now

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• Fun tips with Analytics

  - by user12620172

  If you read this blog, I am assuming you are at least familiar with the Analytic functions in the ZFSSA. They are basically amazing, very powerful and deep. However, you may not be aware of some great, hidden functions inside the Analytic screen. Once you open a metric, the toolbar looks like this: Now, I’m not going over every tool, as we have done that before, and you can hover your mouse over them and they will tell you what they do. But…. Check this out. Open a metric (CPU Percent Utilization works fine), and click on the “Hour” button, which is the 2nd clock icon. That’s easy, you are now looking at the last hour of data. Now, hold down your ‘Shift’ key, and click it again. Now you are looking at 2 hours of data. Hold down Shift and click it again, and you are looking at 3 hours of data. Are you catching on yet? You can do this with not only the ‘Hour’ button, but also with the ‘Minute’, ‘Day’, ‘Week’, and the ‘Month’ buttons. Very cool. It also works with the ‘Show Minimum’ and ‘Show Maximum’ buttons, allowing you to go to the next iteration of either of those. One last button you can Shift-click is the handy ‘Drill’ button. This button usually drills down on one specific aspect of your metric. If you Shift-click it, it will display a “Rainbow Highlight” of the current metric. This works best if this metric has many ‘Range Average’ items in the left-hand window. Give it a shot. Also, one will sometimes click on a certain second of data in the graph, like this:  In this case, I clicked 4:57 and 21 seconds, and the 'Range Average' on the left went away, and was replaced by the time stamp. It seems at this point to some people that you are now stuck, and can not get back to an average for the whole chart. However, you can actually click on the actual time stamp of "4:57:21" right above the chart. Even though your mouse does not change into the typical browser finger that most links look like, you can click it, and it will change your range back to the full metric. Another trick you may like is to save a certain view or look of a group of graphs. Most of you know you can save a worksheet, but did you know you could Sync them, Pause them, and then Save it? This will save the paused state, allowing you to view it forever the way you see it now.  Heatmaps. Heatmaps are cool, and look like this:  Some metrics use them and some don't. If you have one, and wish to zoom it vertically, try this. Open a heatmap metric like my example above (I believe every metric that deals with latency will show as a heatmap). Select one or two of the ranges on the left. Click the "Change Outlier Elimination" button. Click it again and check out what it does.  Enjoy. Perhaps my next blog entry will be the best Analytic metrics to keep your eyes on, and how you can use the Alerts feature to watch them for you. Steve 

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• Webcast On-Demand: Building Java EE Apps That Scale

  - by jeckels

  With some awesome work by one of our architects, Randy Stafford, we recently completed a webcast on scaling Java EE apps efficiently. Did you miss it? No problem. We have a replay available on-demand for you. Just hit the '+' sign drop-down for access.Topics include: Domain object caching Service response caching Session state caching JSR-107 HotCache and more! Further, we had several interesting questions asked by our audience, and we thought we'd share a sampling of those here for you - just in case you had the same queries yourself. Enjoy! What is the largest Coherence deployment out there? We have seen deployments with over 500 JVMs in the Coherence cluster, and deployments with over 1000 JVMs using the Coherence jar file, in one system. On the management side there is an ecosystem of monitoring tools from Oracle and third parties with dashboards graphing values from Coherence's JMX instrumentation. For lifecycle management we have seen a lot of custom scripting over the years, but we've also integrated closely with WebLogic to leverage its management ecosystem for deploying Coherence-based applications and managing process life cycles. That integration introduces a new Java EE archive type, the Grid Archive or GAR, which embeds in an EAR and can be seen by a WAR in WebLogic. That integration also doesn't require any extra WebLogic licensing if Coherence is licensed. How is Coherence different from a NoSQL Database like MongoDB? Coherence can be considered a NoSQL technology. It pre-dates the NoSQL movement, having been first released in 2001 whereas the term "NoSQL" was coined in 2009. Coherence has a key-value data model primarily but can also be used for document data models. Coherence manages data in memory currently, though disk persistence is in a future release currently in beta testing. Where the data is managed yields a few differences from the most well-known NoSQL products: access latency is faster with Coherence, though well-known NoSQL databases can manage more data. Coherence also has features that well-known NoSQL database lack, such as grid computing, eventing, and data source integration. Finally Coherence has had 15 years of maturation and hardening from usage in mission-critical systems across a variety of industries, particularly financial services. Can I use Coherence for local caching? Yes, you get additional features beyond just a java.util.Map: you get expiration capabilities, size-limitation capabilities, eventing capabilites, etc. Are there APIs available for GoldenGate HotCache? It's mostly a black box. You configure it, and it just puts objects into your caches. However you can treat it as a glass box, and use Coherence event interceptors to enhance its behavior - and there are use cases for that. Are Coherence caches updated transactionally? Coherence provides several mechanisms for concurrency control. If a project insists on full-blown JTA / XA distributed transactions, Coherence caches can participate as resources. But nobody does that because it's a performance and scalability anti-pattern. At finer granularity, Coherence guarantees strict ordering of all operations (reads and writes) against a single cache key if the operations are done using Coherence's "EntryProcessor" feature. And Coherence has a unique feature called "partition-level transactions" which guarantees atomic writes of multiple cache entries (even in different caches) without requiring JTA / XA distributed transaction semantics.

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• CUDA Driver API vs. CUDA runtime

  - by Morten Christiansen

  When writing CUDA applications, you can either work at the driver level or at the runtime level as illustrated on this image (The libraries are CUFFT and CUBLAS for advanced math): I assume the tradeoff between the two are increased performance for the low-evel API but at the cost of increased complexity of code. What are the concrete differences and are there any significant things which you cannot do with the high-level API? I am using CUDA.net for interop with C# and it is built as a copy of the driver API. This encourages writing a lot of rather complex code in C# while the C++ equivalent would be more simple using the runtime API. Is there anything to win by doing it this way? The one benefit I can see is that it is easier to integrate intelligent error handling with the rest of the C# code.

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• IIS 6.0 Server Too Busy HTTP 503 Connection_Dropped DefaultAppPool

  - by Shiraz Bhaiji

  We have a site which is running on a windows 2003 cluster with 2 64bit machines. The site needs to be able to cope with over 20,000 concurrent users One of the things that the site does is to allow the download of a 2MB file (which is cached in memory). We have low CPU and memory usage. We also have surplus bandwidth. It appears that we are running out of connections due the time it takes the user to download the file (some users have slow internet connections). In the IIS log we get HTTP 503 errors. In the HTTPErr log we get mainly Connection_Dropped DefaultAppPool with some Timer_EntityBody DefaultAppPool. Question is: How can we configure IIS to allow more connections? Or is there something that I am missing here? Thanks Shiraz

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• Setting up Metro 2.0 with Jetty 7

  - by trojanfoe

  This question relates to a previous question of mine. I am attempting to set-up a low overhead Web Container using Jetty 7 that I can deploy Web Services using Metro 2.0. I have installed the following Metro 2.0 libs into jetty/lib: webservices-extra-api.jar webservices-extra.jar webservices-rt.jar webservices-tools.jar And the following into a new jetty/lib/endorsed directory: jsr173_api.jar webservices-api.jar I start Jetty with the following script (Windows) to ensure that jetty/lib/endorsed is part of the 'endorsed library path' and to ensure that Jetty adds the webservices jars to its classpath: @echo off set JETTY_HOME=C:\dev\jetty-7.1.0 set JAVA_OPTS=-Xmx1024m -XX:MaxPermSize=512m -Djetty.home=%JETTY_HOME% -Djava.endorsed.dirs=%JETTY_HOME%\lib\endorsed -Djetty.class.path=%JETTY_HOME%\lib\webservices-rt.jar;%JETTY_HOME%\lib\endorsed\webservices-api.jar -DSTOP.PORT=8079 -DSTOP.KEY=jettykey pushd %JETTY_HOME% java %JAVA_OPTS% -jar start.jar popd However when I deploy a WebServices war file (for example Metro sample 'pricequote'), I get the following exception: java.lang.ClassNotFoundException: com.sun.xml.ws.transport.http.servlet.WSServletContextListener Can anyone help me with this please? I suspect it's related to the order of classes in Jetty's classpath?

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• Sending a Soap Header with a WSDL Soap Request with PHP

  - by Josh Smeaton

  I'm extremely new to SOAP and I'm trying to implement a quick test client in PHP that consumes a ASP.NET web service. The web service relies on a Soap Header that contains authorization parameters. Is it possible to send the auth header along with a soap request when using WSDL? My code: php $service = new SoapClient("http://localhost:16840/CTI.ConfigStack.WS/ATeamService.asmx?WSDL"); $service->AddPendingUsers($users, 3); // Example webservice [SoapHeader("AuthorisationHeader")] [WebMethod] public void AddPendingUsers(List<PendingUser> users, int templateUserId) { ateamService.AddPendingUsers(users, templateUserId, AuthorisationHeader.UserId); } How would the auth header be passed in this context? Or will I need to do a low lever __soapCall() to pass in the header? Also, am I invoking the correct soap call within PHP?

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• Where are the Entity Framework t4 templates for Data Annotations?

  - by JK

  I have been googling this non stop for 2 days now and can't find a single complete, ready to use, fully implemented t4 template that generates DataAnnotations. Do they even exist? I generate POCOs with the standard t4 templates. The actual database table has metadata that describes some of the validation rules, eg not null, nvarchar(25), etc. So all I want is a t4 template that can take my table and generate a POCO with DataAnnotations, eg public class Person { [Required] [StringLength(255)] public FirstName {get;set} } It is a basic and fundamental requirement, surely I can not be the first person in the entire world to have this requirement? I don't want to re-invent the wheel here. Yet I haven't found it after search high and low for days. This must be possible (and hopefully must be available somewhere to just download) - it would be criminally wrong to have to manually type in these annotations when the metadata for them already exists in the database.

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• MPMoviePlayerController on large videos causes massive memory spike, and a level 1 memory warning

  - by Shizam

  When viewing images my application hums along nicely with low memory consumption, once I try to watch a video using MPMoviePlayerController memory usage spikes way up, dwarfing the previous memory graph and if I play the video it causes a 'memory warning. Level=1' message. The video files (mp4) aren't even that big, 40MB or so, and it doesn't matter if I play the file streamed from a URL or loaded from a local file, actually the memory spike is even worse if I try to stream it. Here is the code I use to create the player: if (_photo.videoPath != nil) { _movieViewController=[[MPMoviePlayerViewController alloc] initWithContentURL:[NSURL fileURLWithPath:_photo.videoPath]]; } else { _movieViewController=[[MPMoviePlayerViewController alloc] initWithContentURL:[NSURL URLWithString:_photo.videoURL]]; } [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(videoMetaListener:) name:MPMovieDurationAvailableNotification object:_movieViewController.moviePlayer]; _movieViewController.moviePlayer.scalingMode=MPMovieScalingModeAspectFit; _movieViewController.moviePlayer.shouldAutoplay = YES; _movieViewController.moviePlayer.controlStyle = MPMovieControlStyleEmbedded; Anybody else running into issues playing video? Also I checked for leaks, there are none reported.

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• [Android] How to search and Highlight Text within an EditText

  - by marc

  I've searched high and low for something that seems to be a simple task. Forgive me, I am coming to Android from other programming languages and am new to this platform and Java. What I want to do is create a dialog pop-up where a user enters text to search for and the code would take that text and search for it within all the text in an EditText control and if it's found, highlight it. I've done this before, for example in VB and it went something similar to this pseudo code: grab the text from the (EditText) assign it to a string search the length of that string (character by character) for the substring, if it's found return the position (index) of the substring within the string. if found, start the (EditText).setSelection highlight beginning on the returned position for the length of Does this make sense? I just want to search a EditText for and when found, scroll to it and it'll be highlighted. Maybe there's something in Android/Java equivalent to what I need here? Any help / pointers would be greatly appreciated

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• Visual Studio 2008 maintenance mode - I can't remember my installation source drive letter!!!

  - by Dave

  I've searched high and low for this and can't find the answer anywhere. I installed VS2008, but my drive letters are all mapped differently now, and of course I need to add a component to my current installation (VC++). But since I don't know which drive letter it was installed from, and since I don't want to try to figure it out the brute force way, I was hoping that someone here knew how to figure that out. I poked through HKCU and HKLM in the registry, hoping to find the info there, but couldn't. Does anyone know how to get this to work? Right now, I get the error "A selected drive is no longer valid. Please review your installation path settings before continuing with setup".

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• ipad video format

  - by Mike

  When you use iTunes to sync your videos with the iPhone the videos are always saved with no more than 640 pixels wide, if I am not wrong. What about the iPad? What is the size of videos iTunes syncs with iPad? 1024x768? and what if the video has a dimension below 1024x768? Will it scale up? or will it keep the video at low res and scale when you play? The question is because I am using the MPMoviePlayerController and I need to know what resolutions to expect, so I can adjust the interface. thanks.

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• jQuery Cycle plugin z-index float problem

  - by Antony Carthy

  When I try to place an element on top of my jQuery Cycle element, it doesn't work. The element is always behind the jQuery cycle element. I use float: right; to position the element, and set its z-index to 100000, to no avail. Firebug sees the Cycle element and its children as having low z-indexes, and shows the floating element to be in the right place. The element never shows above the Cycling images. <!-- the cycling set --> <div id='headerimages'> <img src='images/header1.jpg' alt='' style='' /> <img src='images/header2.jpg' alt='' style='' /> <img src='images/header3.jpg' alt='' style='' /> </div> <!-- the floating element --> <img src='images/logotransparent.png' alt='' id='logo' />

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• Best way to learn iphone audio queue services, step by step tutorial

  - by optician

  Hi Everyone, I'm trying to learn how to handle audio at a fairly low level with audio queue services. I have been progrmaing in memory managed languages for quite a while, and have just completed the c programing tutorial by vtc (2007). This has left me comfortable with the understanding of pointers and memory allocation, but the apple documention still leaves me wanting for a simpler implenation and explaination. Maybe I need to learn objective c and cocoa better. I have heard that this book is good. Cocoa(R) Programming for Mac(R) OS X (3rd Edition) Could someone suggest a learning path that is going to help me get an better understanding of working with audio and an iphone. I want to be able to play mp3 files back and also alter the pitch of them as they are playing. I am prepared that I may have to temporarily convert the mp3 files into pcm files to do things like that to them. Thanks everyone.

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• Google Maps API v3: Can I setZoom after fitBounds?

  - by chris

  I have a set of points I want to plot on an embedded Google Map (API v3). I'd like the bounds to accommodate all points unless the zoom level is too low (i.e., zoomed out too much). My approach has been like this: var bounds = new google.maps.LatLngBounds(); // extend bounds with each point gmap.fitBounds(bounds); gmap.setZoom( Math.max(6, gmap.getZoom()) ); This doesn't work. The last line "gmap.setZoom()" doesn't change the zoom level of the map if called directly after fitBounds. Is there a way to get the zoom level of a bounds without applying it to the map? Other ideas to solve this?

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• Embedded Linux or eCos ?

  - by mawg

  One way to look at it - embedded Linux starts with desktop Linux & ditches the parts not needed for embedded systems (is this actually true?), whereas eCos is designed from the ground up for embedded systems. Now, assume an ARM processor, probably ARM 7 - does performance make a difference? Actually, we talking a very low load system, max 500 transactions a day. Any advantages of one over the other (or FreeRTOS, etc)? Stability, maturity, performance, development tools, anything else? All that I can think of is that if I am certain that I will never port to another o/s, then if I go with embedded Linux, I don't need an o/s abstraction layer to allow me to do unit testing on host (desktop Linux box). Any thoughts or comments? Thanks.

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• Nhibernate equivalent of LinqToEntitiesDomainService in RIA

  - by VexXtreme

  Hi, When using Entity Framework with RIA domain services, domain services are inherited from LinqToEntitiesDomainService, which, I suppose, allows you to make linq queries on a low level (client-side) which propagate into ORM; meaning that all queries are performed on the database and only relevant results are retrieved to the server and thus the client. Example: var query = context.GetCustomersQuery().Where(x => x.Age > 50); Right now we have a domain service which inherits from DomainService, and retrieves data through NHibernate session as in: virtual public IQueryable<Customer> GetCustomers() { return sessionManager.Session.Linq<Customer>(); } The problem with this approach is that it's impossible to make specific queries without retrieving entire tables to the server (or client) and filtering them there. Is there a way to make linq querying work with NHibernate over RIA like it works with EF? If not, we're willing to switch to EF because of this, because performance impact would be just too severe. Thanks

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• SIP and Java, where to start and with what?

  - by Senne

  I want to implement the SIP protocol in java and would want to be able to create different clients (5 or more) and make them connect to a proxy server. This is all for testing purposes so I would like to be able to see well what's happening on a rather low level. The clients should first be able to communicate trough text and later on maybe also by audio. (If I ever get that far) I already read a bit about the JAIN libraries and what I understood from that is that they are not really well suited for the server side? I also didn't really find any proxy server examples, tutorials, using JAIN. I also found this SIP Servlet Tutorial book, I used HTTP servlets in the past but should I prefer servlets or JAIN or ...? I'm quite new to SIP so I don't really know where to start or what to choose in combination with java.

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