For those who had linux knowledge will have a lot of  advantage over IT field, due to linux is a open source, a lot of free application available in linux. One of the linux platform operating system I mention before is Ubuntu, You can actually request a Ubuntu Free CDs that deliver to your door step.

As mention on the free application, I do collect some Free Antivirus software for linux before, hope this Linux, The Complete Manual I share here will bring more benefit for those tech freak. (more…)

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Digital subscriber line
Digital subscriber line (DSL) is a high-speed method of transferring data over existing twisted-pair telephone lines. DSL is commonly available through your local telephone provider or a third-party provider, if the service is available in your area.

DSL encompasses various protocols, including asymmetric DSL (ADSL), rate adaptive DSL (RADSL), high bit-rate DSL (HDSL), and symmetric DSL (SDSL). It also includes different subvariations, such as CAP-encoding ADSL versus discrete multitone (DMT)- encoding ADSL. The acronym xDSL is used to refer to the set of DSL protocols, rather than to a specific protocol. (more…)

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In this coming topic, I am going to give some basic introduces on what is Integrated Services Digital Network (ISDN), digital subscriber line (DSL), and universal serial bus (USB) standards. It explains how each standard enables device communication, as well as its advantages and disadvantages.

ISDN overview
Integrated Services Digital Network (ISDN) refers to a set of communication protocols proposed by telephone companies to permit telephone networks to carry data, voice, graphics, music, and video. ISDN was developed to permit faster access over existing telephone systems without the additional call setup time. It enables the simultaneous transmission of voice and data signals using end-to-end digital connectivity. (more…)

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Last month was mention about the Linux Processes on PIDs , parent and child processes and using the ps command. In this part 2, let see how the background and foreground background process work.

Background and foreground processes
An interactive process can run in the foreground or background. To place a process in the background, you use the command bg or the ampersand symbol (&). This lets you do other jobs while waiting for the command to finish. Let’s say you use the syntax

$ find / filename 2 > /dev/null | grep filename | tee result

A command using this syntax could take a long time to execute, especially if you have a lot of files and are listing several network drives. Only one job at a time can run in the foreground, so no further commands can be issued until the prompt returns. To continue working on the command line while it processes, you can execute the same command in the background, using the ampersand. For example, you could enter the command using the following syntax:

$ find / filename 2 > /dev/null | grep filename | >result &

After the command has been issued, the shell displays a message, which looks similar to the following: (more…)

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After read some linux article, and having some basic knowledge, now can have basic understanding on linux processes, a process is a single program that is executed within its own virtual address space. For example, a shell is a process that is created each time a user logs in to the system. It creates a new process every time it implements a program such as a system command. A system command is an example of a collection of related commands called a job. Jobs create a series of separate processes from a single command line. So, in fact, every program running under Linux is a process.

The following table shows the three main categories of processes.

Linux can share its processing power, storage capabilities, and input and output mechanisms with several users, or with several processes created by one user. Processes such as user jobs, operating system tasks, mail, and background jobs like printing need to be monitored simultaneously by Linux. (more…)

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