Sunday, May 31, 2009

My Linux timeline

I decided to install Linux O/S on my PC on 2004 May because I read an article that saying Linux has every software that we want to use.
So when I went to Kandy city to pay our telephone bill, entered to a CD-Shop and then asked for Linux.

The sales person then given me Redhat-Linux-ver-9 and said it cost LKR250/= because it has 3 CDs. so I paid that fee and came home with Redhat-Linux-9. Then I placed redhat9-cd1 after booting my PC by XP.
Then what I see? The Cd doesn't contain any setup.exe file to install Redhat9 to my pc. Then I went through may folders to find the setup.exe. Where is it? Then I read the html file that introduces Redhat9. I didn't understand anything. So I decided to keep that cds away from my pc.

After some weeks , the CD-Rom on my pc didn't read any cd. So, I made a call to the dealer who sold it to me. Then they told me to open the casing and carry only the CD-ROM to them to check it. I'm new to computers. I didn't even opened a caing of a PC before, and there is a warrenty that given me from the

Dealer. So, I decided to carry whole CPU to the dealer. Then I asked them to install Linux on it and make my PC to dualboot with Linux and XP. They told me they could install Redhat9 and can't install XP to dualboot with it So, they given me some options. Keep my PC runing on XP without installing Redhat9 , dualboot with Redhat9 with windows 98. So, I decided to select the 2nd option because I want to
experience Linux. So, they installed Redhat and Windows 98 on my PC. When I came home , I started to experience the Redhat9. After sometimes I wanted to listen to a song. So, I searched for D:\> drive on my PC, because it's the partition that I copied my favorite music. Where is it? so I placed a MP3 disk and
tried to listen a MP3. It failed. So, what should I do? Said goodbye to Redhat9 and started windows 98. MP3s work well with 98. So, but I don't like the appearence on 98. I decided to format my pc and install windows XP on it. Redhat didn't live on my PC for more than 1 day and I didn't used it more than 1 hour.

Then it's May-2005 and saw an advertisement called a computer magazine cost LKR150/= bundled with free CDROM.

Then I bought that mag and got the free CD. It's knoppix. It made my mind to love Linux because it has many plugins and codecs. Unfortunately, Knoppix is only a Live CD and couldn't setup on a PC.
I remebered Redahat9 again because I can't forget the Look-&-Feel that brought by Knoppix. So, I installed it on my PC. Then waht is the secondary os? I don't have 98 bootable CD to install 98. Then I decided to install XP on my PC and made it dualboot with redhat9. But after some weeks, I got boared abaout Redhat because it couldn't play MP3s. so I said goodbye again to redhat.

I found Ubuntu5.04 from my colege friend. He took LKR200/= to give me Ubuntu5.04 because it has 2 CDs , LiveCD and Setup CD.I didn't know it's a free CD shipping with free of charge. Then I installed it on my PC. It didn't give feeling that I got with Knoppix. So, removed that also. But I collected many Ubuntu and Kubuntu versions by registering with Canonical but didn't used some CDs to boot my PC.
I'm a customer of the it mag which comes with free cd. So , I got a Mepis Linux CD from that mag (july-2005 issue). I stated my pc from it and made my mind to install it. So, I installed it on my PC. I didn't remove it till I found any other Linux.
After my A/L s, I wanted to find another Linux distro. So, I went through many CD shops in Kandy to find one. I got number of funny answers from sales persons. Someone told she didn't heared the word "linux" before I tell it to her.

Got Mandriva Corporate Server 4 for LKR200/= and installed it. But I didnt like it.
Then I found Fedora core 6 DVD for LKR250/= and RHEL5 5cds for LKR350/= on oct-2007. Why I pay for CDs when I could use DVDs. Then I bought FC6. It took my hours to install FC6 on my pc and bored about FC6 from the installation. Then I removed FC6 after using it for some hours and installed Mepis Linux again.Found openSUSE10.0 but sales person told it has some errors, and he didn't explained what are them
and he tried to sell windows XP pirated copy for LKR250/=.

Then I found Mandriva Free 2006 3CD's(on Dec-2006) from Buddhika sir who is in Asian Destination. So I copied that 3 CDs to another 3 CDs coz I must return that 1st copies I got from sir. Then I used that Linux version till I found openSUSE11.0 on Sep-2008.

Found openSUSE11.0, MandrivaFree2009, FC9. I bought openSUSE11.0 and Mandriva free 2009 both DVDs for LKR400/= because I couldn't forget the experience with Fedora. Then I tries to install MandrivaFree2009 because I used MandrivaFree2006 for months. But what I see when boot from MandrivaFree2009 DVD? it's a 64bit version that failed to run on my 32bit PC. Then I installed openSUSE11.0 successfully on my PC.
Till now I use openSUSE11.0 on my PC.
K.W.Roshan Herath - Gelioya , Sri Lanka.

Thursday, May 28, 2009

What is called Custom-Subnet-Mask ?

What is called Custom-Subnet-Mask ?

කස්ටම් සබ්නෙටි මාස්ක් යනු කුමක්ද ?

IP Addressපන්ති / classes in IP Addresses ජාලය localhost / loopback ලිපින සදහා වෙන්කර ඇත. network reserved for localhost /loopback addresses.

private address space / පුද්ගලික හෙවත් අභයන්තර ජාල සදහා වෙන්කර ඇති ලිපින

අපට IP Address ම‌ගින් ද පන්තියට පොදු සබ්නෙටි මාස්ක් එය අදාල ජාල පන්තිය හදුනා ගත හැක

නමුත් පරිගණකය එම ආකාර දෙකම භාවිතා කරමින් IP Address එක අදාල ජාල පන්තිය හදුනා ගැනීම සදහා AND යන බූලියානු ගණිත සමීකරණයට ආදේශ කිරීම සිදු කරයි

People could identify the Class that IP Address belongs to by octets of the IP Address and as well as by the Subnet mask.

For your computer to determine the network and subnet portion of an IP address it must “AND” the IP address with the subnet mask.

AND බූලියානු ගණිත සමීකරණය / ANDING Equations

1 AND 1 = 1

1 AND 0 = 0

0 AND 1 = 0

0 AND 0 = 0

ANDබූලියානු ගණිත සමීකරණය භාවිතා කර Custom සබ්නෙටි මාස්ක් සෑදීම.

Making custom subnet-masks using ANDING Equations.

අප ජාල 16 කට බෙදා ඇති යන ජාලය උදාහරණලෙස ලෙස සැලකූ විට ඇතුලත ජාලයෙහි /localnetwork එකෙහි පරිගණක හා ඇතුලත ජාලයට අදාල ජාලගතකිරීමේ උපකරණ මගින් එම උප ජාල හදුනාගත්තද ජාලයෙන් පිටත එනම් අන්තර්ජාලයේ (internet/www) පරිගණක හා ජාලගතකිරීමේ උපකරණ මගින් හදුනාගනුයේ ජාලය පමණි.

ඇතුලත ජාලය උප ජාල වලට බෙදිම සදහා custom සබ්නෙටි මාස්ක් යොදා ගත හැක. මේ සදහා සබ්නෙටි මාස්ක් එකෙහි Networkකොටසට host කොටසින් bits කිපයක් ලබා ගනි. පරිගණකය IP Address එක අදාල පන්තිය හදුනා ගැනිමට AND යන බූලියානු ගණිත සමීකරණයට ආදේශ කිරීම සිදු කරයි.

When you take a single network such as and divide it into 16 smaller networks ,the outside world still sees the network as, but the internal computers and routers see 16 smaller subnetworks. Each independent of the other. This can only be accomplished by using a custom subnet mask. A custom subnet mask borrows bits from the host portion of the address to create a subnetwork address between the network and host portions of an IP address. In this example each range has 14 usable addresses in it. The computer must still AND the IP address against the custom subnet mask to see what the network portion is and which subnetwork it belongs to. යන ජාලය උදාහරණලෙස ලෙස සැලකූ විට එක් උප ජාලයක පරිගණක 14 ක් සදහා IP Address ලැබී ඇත.

In this example ( each range has 14 usable addresses in it.

උප ජාල ගණන හා එක් උප ජාලයකට යෙදිය හැකි පරිගණක ගණන සොයාගන්නේ කෙසේද ?

How to determine the number of subnets and the number of hosts per subnet ?

උදාහරණලෙස bits 4 ක් ජාල / network කොටසට ගත්තේ නම් සෑදෙන උප ජාල ගණන 2 හි 4 වන හි ගුණාකාරය හෙවත් 2x2x2x2=16 කි.

මෙවිට host කොටසේ ඉතිරිව ඇති bit ගණන 8-4=4 කි. එනම් එක් උප ජාලයකට යෙදිය හැකි පරිගණක ගණන 2 හි 4 වන ගුණාකාරය හෙවත් 2x2x2x2=16 කි.

Both formulas calculate the number of hosts or subnets based on the number of binary bits

used. For example if you borrow three bits from the host portion of the address use the

number of subnets formula to determine the total number of subnets gained by borrowing the

three bits. This would be 2 x 2 x 2 x 2 = 16 subnets .

To determine the number of hosts per subnet you would take the number of binary bits used in

the host portion and apply this to the number of hosts per subnet formula If five bits are in the

host portion of the address this would be 2 x 2 x 2 x 2 x 2 = 32 hosts.

නමුත් මතක තබාගතයුතු කරුණක් වන්නේ මෙහිදී සෑදෙන උප ජාල ගණන හා එක් උප ජාලයකට යෙදිය හැකි පරිගණක ගණන සම්පූර්ණයෙන්ම ඒ සදහා යොදාගත නොහැකි බවයි.

ඒ සෑදෙන පළමු උප ජාලය එනම් න් ආරම්භ වී න් අවසන් වන ජාලය ද න් ආරම්භ වී න් අවසන් වන ජාලය ද පරිගණක සදහා යොදාගත නොහැක. ඊට හේතුව කුමක්දැයි තේරුමි ගැනීමට හා යන අගයන් දෙක පමණක් සෑහේ. යනු සම්පූර්ණ ජාලයටම අදාල ජාල ලිපිනයයි (Network Address). යනු සම්පූර්ණ ජාලයටම අදාල විකාශණ (broadcast) ලිපිනයයි. මේ ආකාරයටම සෑම උපජාලයකම ආරම්භක ලිපිනයද අවසාන ලිපිනයද එම උප ජාලයට අදාලව පිළිෙවලින් ජාල ලිපිනය (Network Address) හා ජාලයටම අදාල විකාශණ (broadcast) ලිපිනය වේ.

මේ නිසා යොදාගත හැකි උප ජාල ගණනද එම උප ජාලලෙස සදහා යොදාගත හැකි පරිගණක ගණනද සෑමවිටම ගණනයෙන් ලැබෙන අගයට වඩා 2කින් අඩු අගයකි.

එනම් මෙම ලිපිනයට අදාලව සෑදෙන උප ජාල ගණන 16 වුවද ඉන් උපජාල සදහා යොදාගත හැක්කේ උපජාල 14 කි. ඒ ආකාරයටම සෑදෙන උප ජාලයක භාවිතකල හැකි පරිගණක ගණන 14ක් වේ.

When dealing with the number of hosts per subnet you have to subtract two addresses from

the range. The first address in every range is the subnet number. The last address in every

range is the broadcast address. These two addresses cannot be assigned to any device in

the network which is why you have to subtract two addresses to find the number of usable

addresses in each range.

In some instances the first and last subnet range of addresses are reserved. This is similar to

the first and last host addresses in each range of addreses.

The first range of addresses is the zero subnet. The subnet number for the zero subnet is

also the subnet number for the classful subnet address.

The last range of addresses is the broadcast subnet. The broadcast address for the last

subnet in the broadcast subnet is the same as the classful broadcast address.

මෙහිදී යොදාගෙන අෑති යන ලිපිනයට අදාල ගණනයකිරිම් උදාහරණ ලෙස පමණක් යොදාගත් බව සලකන්න.

අයිතිය (copyright reserved to) / උපුටාගැනීම‌ - IP Addressing and Sub netting workbook ( Student version ) 2.0

created by Roshan Herath using OpenOffice.Org 3.0 on AMD AthlonXP system running by openSUSE Linux 11.0

Tuesday, May 26, 2009

shared bandwith service - GPRS

GPRS is a shared bandwith service offered by mobile service providers and they charge us for data that we downloaded and uploaded. service providers share the same line(ip address) to provide data access. so, they charge more than for data that used by me, when network got busy. i think they shares same ip as well as the data usage with others and thats why they charge for unused data from me.
i cant imagine another reason.

Sunday, May 17, 2009

we salute our heroes.

one flag , one country + one nation called SRILANKANS.
today is a historical day.

Thursday, May 7, 2009

do we need to buy what they sell and why we cudnt buy what we want if we pay for it?

when we want something , we enter to a shop and ask what we want. but salesman try to sell what we dont want by neglecting what we want.
is it marketting?
then why we pay for it if we select what we never want and dont like to use.
they controls the market by selling what they could get more profit. they never think about the quality of the items and what is the request of the customer. Y V CUDNT BUY AMD , instead of INTEL if WE PAY FOR IT?