Pareto Principle

The 80/20 Performance Rule

Vilfredo Pareto, an economist in the early 1900s, made a famous observation where 80% of the nation’s wealth belonged to 20% of the population. This was later generalized into what’s commonly referred to as the Pareto principle (also known as the 80-20 rule), which states for any phenomenon, 80% of the consequences come from 20% of the causes. We see this phenomenon in software engineering where 80% of the time is spent in only 20% of the code

referenced content

Canonical XML

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Canonical XML specifies a number of other details, some of which are:

  • the UTF-8 encoding is used

  • line-ends are represented using the character 0x0A

  • whitespace in attribute values is normalized

  • entity references are expanded

  • CDATA marked sections are not used

  • empty elements are encoded as start/end pairs, not using the special empty-element syntax

  • default attributes are made explicit

  • superfluous namespace declarations are deleted

According to the W3C, if two XML documents have the same canonical form, then the two documents are logically equivalent within the given application context (except for limitations regarding a few unusual cases).



MS Word Tip: Update References all across the document Ctrl+A, F9

Handy shortcut

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You can update linked fields by selecting them and then pressing F9. You can also select all (by using CTRL+A) and press F9 to update all your fields. However, Dani discovered that footnotes will only update using this method if you first put the cursor in the footnotes area. Then pressing CTRL+A and F9 will update everything. Odd, but it works.



SAP Integration: Initial Load and Delta Load

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From an ERP application perspective this is an extremely important aspect the data exchange among the systems is kind of back-bone and the crux of very existence of the application. This data exchange can be of following types between other systems and CRM:

  1. Initial data transfer which is also called as Initial Load in SAP terminology

  1. Intermediate synchronization of data among the applications also called as Delta Load in SAP terminology

  1. Synchronization



Hypervisor, zVM, VMM and virtualization

Hypervisor is a general computing term and not a brand name. IBM first coined this term back in 1960s. Very interesting to note forms of virtualization have existed since that time. Even more interesting to note that the IBM mainframe can even today, technically support binary compatibility of code developed in 1960s!

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In computing, a hypervisor, also called virtual machine manager (VMM), is one of many hardware virtualization techniques that allow multiple operating systems, termed guests, to run concurrently on a host computer. It is so named because it is conceptually one level higher than a supervisory program. The hypervisor presents to the guest operating systems a virtual operating platform and manages the execution of the guest operating systems. Multiple instances of a variety of operating systems may share the virtualized hardware resources. Hypervisors are installed on server hardware whose only task is to run guest operating systems. Non-hypervisor virtualization systems are used for similar tasks on dedicated server hardware, but also commonly on desktop, portable and even handheld computers.

Robert P. Goldberg classifies two types of hypervisor:[5]

  • Type 1 (or native, bare metal) hypervisors run directly on the host’s hardware to control the hardware and to manage guest operating systems. A guest operating system thus runs on another level above the hypervisor.
  • Type 2 (or hosted) hypervisors run within a conventional operating system environment. With the hypervisor layer as a distinct second software level, guest operating systems run at the third level above the hardware.

IBM provides virtualization partition technology known as logical partitioning (LPAR) on System/390, zSeries, pSeries and iSeries systems. For IBM’s Power Systems, the Power Hypervisor (PowerVM) functions as a native (bare-metal) hypervisor and provides EAL4+ strong isolation between LPARs. Processor capacity is provided to LPARs in either a dedicated fashion or on an entitlement basis where unused capacity is harvested and can be re-allocated to busy workloads. Groups of LPARs can have their processor capacity managed as if they were in a “pool” – IBM refers to this capability as Multiple Shared-Processor Pools (MSPPs) and implements it in servers with the POWER6 processor. LPAR and MSPP capacity allocations can be dynamically changed. Memory is allocated to each LPAR (at LPAR initiation or dynamically) and is address-controlled by the POWER Hypervisor. For real-mode addressing by operating systems (AIX, Linux, IBM i), the POWER processors (POWER4 onwards) have architected virtualization capabilities where a hardware address-offset is evaluated with the OS address-offset to arrive at the physical memory address. Input/Output (I/O) adapters can be exclusively “owned” by LPARs or shared by LPARs through an appliance partition known as the Virtual I/O Server (VIOS). The Power Hypervisor provides for high levels of reliability, availability and serviceability (RAS) by facilitating hot add/replace of many parts (model dependent: processors, memory, I/O adapters, blowers, power units, disks, system controllers, etc.)

Similar trends have occurred with x86/x86_64 server platforms, where open-source projects such as Xen have led virtualization efforts. These include hypervisors built on Linux and Solaris kernels as well as custom kernels. Since these technologies span from large systems down to desktops, they are described in the next section.




Ideas similar to my gospel of continuous deployment, architecture sustenance and operational excellence.

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DevOps” is an emerging set of principles, methods and practices for communication, collaboration and integration between software development (application/software engineering) and IT operations (systems administration/infrastructure) professionals.[1] It has developed in response to the emerging understanding of the interdependence and importance of both the development and operations disciplines in meeting an organization’s goal of rapidly producing software products and services.[2][3][4][5][6]

Illustration showing Devops as the intersection of development (software engineering), technology operations and quality assurance (QA)

The use of Devops integration can have profound results in product delivery, quality testing, feature development and maintenance releases (including the once special but now ubiquitous “hot fix“). Organizations without Devops capabilities can see problems emerge from the “gap” of information shared between development and operations. This occurs as operations request greater reliability and security, developers ask for faster infrastructure responsiveness, while business users ask for more application enhancements and releases made available faster.[citation needed]

Devops Impact on Application Releases

Reduced change scope
Increased release co-ordination



April’s Fools Day RFCs


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April Fools’ Day RFC

Almost every April Fools’ Day (1 April) since 1989, the Internet Engineering Task Force has published one or more humorous RFC (Request for Comments) documents, following in the path blazed by the June 1973 RFC 527 entitled ARPAWOCKY, which parodied Lewis Carroll‘s nonsense poem Jabberwocky. The following list also includes humorous RFCs published on other dates.

R. Callon (1 April 1996). The Twelve Networking Truths. RFC 1925. 
implemented on Facebook Ipv6 over Facebook.

[edit] Other humorous RFCs

[edit] Sources



Upgrading Ubuntu: Not a bug – E:Error, pkgProblemResolver::Resolve generated breaks, this may be caused by held packages

Looks like xserver issues are fairly common when attempting an upgrade from 10.4 to 10.10.

– Look at /var/log/dist-upgrade/apt.log file for errors.
– Remove the packages which say anything related to ‘held’

in my particular case it ended up being xserver-xorg-video-nouveau

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E:Error, pkgProblemResolver::Resolve generated breaks, this may be caused by held packages.

The error from apt.log is
Investigating xserver-xorg-video-all
Package xserver-xorg-video-all has broken Depends on xserver-xorg-video-tseng
  Considering xserver-xorg-video-tseng 1 as a solution to xserver-xorg-video-all 10005
  Added xserver-xorg-video-tseng to the remove list
  Fixing xserver-xorg-video-all via keep of xserver-xorg-video-tseng
ERROR:root:Installing/upgrading ‘xserver-xorg-video-all’ failed
ERROR:root:NvidiaDetector can not be imported No module named NvidiaDetector.nvidiadetector
MarkUpgrade() called on a non-upgrable pkg: ‘brasero’
ERROR:root:Upgrading ‘brasero’ failed
/usr/lib/python2.6/dist-packages/DistUpgrade/ DeprecationWarning: Deprecated, please use ‘get_changes()’ instead
  for pkg in self.getChanges():
/usr/lib/python2.6/dist-packages/DistUpgrade/ DeprecationWarning: Deprecated, please use ‘get_changes()’ instead
  for pkg in self.getChanges():
/usr/lib/python2.6/dist-packages/DistUpgrade/ DeprecationWarning: Deprecated, please use ‘marked_downgrade’ instead
  if pkg.markedDowngrade: