WeRecoverData.com - Solaris 10

By: Mr. John


Solaris is a UNIX-based operating system introduced by Sun Microsystems for desktops, laptops, servers and data centers. Solaris supports SPARC-based and x86-based workstations from Sun as well as other vendors.

Solaris 10 is an advanced version of Solaris. A major component of Solaris 10 is Sun's Java Desktop System (JDS), a GNOME-based application set. Some of the applications included in JDS are StarOffice and Sun’s office suite. Other important features included in this version are DTrace, Zones and the new Service Management Framework.

Solaris 10 codes have been released under the Common Development and Distribution License (CDDL) via OpenSolaris project.

Java Desktop System (JDS)

JDS provides a desktop system similar to Microsoft Windows. It comes with a full suite of office productivity software such as an office suite, a Web browser (Mozilla), email, instant messaging (IM) and calendar. Sun offers JDS as a platform for corporate users to deploy software written for Java platform.

DTrace
DTrace is a dynamic instrumentation system embedded in Solaris 10. DTrace is similar to Linux Trace Toolkit (LTT) and Dprobes. DTrace consists of ‘D’ scripting language and loadable kernel modules named providers. Providers are used to track and report system information. It has no effect on system performance when not in use.

Zones

Solaris Zones are similar to FreeBSD Jails. Each zone is a virtual operating system with IP address, separate configuration and a separate package DB. They share one kernel.

Service Management Framework
Service Management Framework (SMF) is introduced to replace the old sysV init. SMF can be split into the following different parts

  • Startups scripts.

  • XML manifests to store information about the services

  • svcs command, an importance interface to SMF that tells which services are started, which are failed or which are stopped.

  • svcadm, an administrative tool that can be used to add, delete, start, and stop services


Because of the above features, the init system on Solaris 10 work differently from the previous versions. It restarts a service in the event it fails to start or if it crashes. If the user stops a service which depends on another service, the second service also will be stopped. Similarly, if they start a service that depends on others, they all will be started. The init system also allows multiple services run parallel.

FireEngine
FireEngine is a new stack built with an aim to improve performance and support future networking technology. It is provided with a unique threading technology that could reduce resource contention.

x86 support

Solaris 10 supports x86 series of Intel microprocessors. Unlike in the previous versions, Solaris 10 offers greater speed and stability to x86. With Sun’s interest in other x-86 like platforms (like AMD Opteron) developers feel that Solaris will be further enhanced for such platforms.

Other important features of Solaris 10 include mdb, the Solaris modular debugger; libumem, a user-land slab allocator introduced in Solaris 9; and pTools, a utility set that extracts information from the /proc file system. Solaris 10 is also provided with Solaris Management Console, a toolbox of administration utilities such as user management, patch management, and performance monitoring.

Solaris 10’s general OS has been enhanced with several features, which focus on improving the speed. These changes, to an extent, help Solaris to get rid of its nickname ‘Slowlaris.’

WeRecoverData.com - Database normalization

Database normalization refers to a systematic way of organizing data in a database. The concept was introduced by E.F. Codd, the inventor of relational model of database. The purpose of normalization is to eliminate redundant data and ensure data integrity. By normalizing the database, the structure becomes suitable for general-purpose querying.

Normal Forms
Normal forms (NF) refer to a series of guidelines for database normalization. The normal forms are numbered one through six (1NF through 6NF). The first three normal forms are defined by Codd. Codd, along with Raymond F. Boyce, defined the Boyce-Codd normal form (BCNF). Sixth normal form, the latest one, is introduced by Chris Date, Hugh Darwen, and Nikos Lorentzos in 2002.

The most common normal forms defined in practical applications are 1NF, 2NF, and 3NF. As the forms progress from the first to the last, their restrictions increase. The first is the least restrictive, and the last is the most restrictive. Therefore, most database designers do not implement normalization beyond 3F or BCNF.

The purpose of 1NF was to permit data to be queried and manipulated using a universal data sub-language, such as SQL, grounded in first-order logic. In a non-normalized data structure, querying and manipulating of data adds more complexity. The first normal form was designed to eliminate duplicate columns from a table. It creates separate tables for related data. It also identifies each row with corresponding primary key.

Codd defined higher normal forms to further free the database from undesirable insertion, update and deletion dependencies. He also stressed on the importance of reducing the process of restructuring as and when new types of data are introduced.

Thus the second normal form again focuses on removing duplicate data. Apart from the guidelines included in the first form, it also removes subsets of data that apply to multiple rows of a table, rearranges them in separate tables and creates relationships between the new tables thus formed. The third form meets all guidelines of the second form. Also, it removes columns that are not dependent upon primary key.

The normalization guidelines are cumulative. It means that if a database belongs to a higher normal form, it has to adhere to the guidelines prescribed for the lower forms.

De-normalization
Typically, a database design mandates that the designer normalizes the design completely. However, if normalization results in performance issues, they are allowed to de-normalize certain places where doing so will address the performance issues. The need for de-normalization has reduced significantly as computers and RDBMS have become more powerful. However, they are still used in OLAP databases which have enormous data volume.
De-normalization is also used in smaller computers as in computerized cash-registers and mobile devices where they use data for look-up only. Another such use is when no RDBMS exists for a platform. Also, there are some modeling approaches such as dimensional modeling to data warehousing design that highly recommends non-normalized designs.

WeRecoverData.com - FreeBSD

FreeBSD is a free operating system designed for desktops, servers and embedded platforms. FreeBSD is derived from Berkeley Software Distribution (BSD), a UNIX derivative developed at the University of California, Berkeley. It is developed and maintained by more than 200 developers and thousands of contributors across the world. FreeBSD is known for its advanced networking capabilities and impressive security as well as compatibility features. It is used by some of the popular Web sites and embedded networking and storage devices.

Unlike Linux distributions, FreeBSD is developed as a complete operating system. The kernel, device drivers and all userland utilities are held in the same source code tracking tree. In Linux distributions, these are developed separately and then packed together by others.

FreeBSD 8.0 is the current version under development. An important enhancement in this version would be the ability for jails to have more than one IP, superpages, Xen DomU support, network stack virtualization, stack-smashing protection, enhanced ZFS support and a new USB stack. FreeBSD 8.0 is scheduled to be released in the third quarter of 2009.

Important features

Support for embedded platforms

FreeBSD’s integrated build and cross-build environments make it an ideal operating system for a number of embedded platforms. Examples of supported architectures are Intel x86 family (including Pentium and Athlon) IBM PC compatible computers, AMD64 (including Opteron, Athlon, EM64T), PowerPC, ARM, DEC Alpha, Sun UltraSPARC, IA-64, NEC PC-9801 and Microsoft Xbox. The software is also being used in networking appliances including routers, time servers and wireless access points. Under Berkeley open source license, companies are allowed to customize the product and contribute back to the FreeBSD project. Developers are keen to include more architecture in the future.

Support for third-party applications

FreeBSD acts as a repository of third-party applications. It has over 17,000 ported libraries and applications. These include applications for desktop, server, appliance, and embedded environments. FreeBSD acts as the framework for these programs to be installed. These applications can be installed either from the source (ports), or offered as compiled binaries (packages).

Linux Compatibility

FreeBSD can run most of the Linux software applications on it without the need for a compatibility layer. FreeBSD also offers binary compatibility with other UNIX-like operating systems, allowing Linux binaries to run on FreeBSD. Some of the common applications that can use Linux compatibility layer include the Linux version of Adobe Acrobat, RealPlayer, Oracle, WordPerfect, Firefox, and Skype.

Internet capabilities

FreeBSD is widely known for its robust network services which make it an ideal Internet or Intranet server. FreeBSD is capable of managing its memory efficiently to maintain good response times for thousands of simultaneous user processes.

Easy to install

FreeBSD can be installed from CD-ROM, DVD, and through file transfer protocol (FTP) or name server daemon (NSD).

FreeBSD is distributed under different licenses. The kernel code and the latest developed code are released under the BSD license which gives complete freedom to use and distribute FreeBSD. On the other hand, parts of FreeBSD are released under different licenses such as BSD, GPL, LGPL, ISC, CDDL and Beerware.

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