April 25, 2008
Hello friends in this post i am going to discuss some interesting points about BIOS.
As if anybody belongs to the field of computer field then it will definitely aware of the term BIOS, first what BIOS means, it simply means Basic Input/Output System and sometimes it also known as Basic Integrated operating system, secondly what BIOS exactly is, in simple words we can say that it is the set of electronic instructions with the help of these instructions processor of any computer system successfully starts its operating system or we can say that it is used to successfully load your operating system into the RAM.
The main task of BIOS is to check your whole computer hardware and software parts whether they are properly attached to the computer and functions properly, in any case if these checks gave negative results then BIOS instructs the computer to gave a code that reveals the problem. It is the BIOS that manages the data flow between the operating system and the devices attached to it. BIOS is typically located inside the ROM chip and is placed in such a way that protects it from disk failure thats why sometimes it is called as ROM BIOS. But now a days flash memory cards are used to hold the BIOS the main reason behind why flash cards are used is flash card provides you an advantage that you can regularly update your BIOS as soon its new version is released.
April 24, 2008
Hello friends in the previous post i gave you an overview of the FAT file system, from where it is clear that today FAT file system is used in very special cases. In maximum of the it is replaced by the NTFS File system.
From its it is clear that it is the advanced version of FAT file system and covers all the drawback of FAT file system. The origin of NTFS came into existence when the Microsoft and IBM decided to made a joint project to improve the future generation operating system. When Microsoft starts working on their new operating system Windows NT(New Technology) then at that time they need an efficient file system that covers the major drawbacks of FAT file system. Hence the NTFS file system is developed, its development is totally depends on the HPFS file system of the IBM operating system OS/2,because its uses the same disk partitioning code as HPFS uses.
Yet five versions of NTFS has been released for their different operating systems. Their latest file system "NTFS V6.0" has been launched to support the Windows Vista. The third version of NTFS V3.0 also known as Encrypting File System. The third version of NTFS supports various new features that its predecessor did not contain. The main advantage of NTFS file system over FAT file system is that it provides you facility of greatly increased security, file–by–file compression, quotas, and even encryption. The most interesting thing about NTFS file system that you can easily convert your NTFS file system to FAT16 or FAT 32 while the opposite situation is not possible.
Now the million dollar question that arises here that when to use FAT or NTFS, the answer to this question is quite simple that means when you had more than one operating system on the same computer it is recommended that you must use FAT file system for your computer otherwise in all other cases you can frequently use NTFS File system.
April 23, 2008
Begin with the history of FAT file system it is developed in 1967 by Bill Gates and Marc McDonald. At that time this file system is assumed to be the primary file system for the majority of operating systems eg Microsoft Windows(up to ME), OPEN DOS, MS-DOS etc. The most common drawback that is found in FAT file system is that when old files are deleted and new files are written on the disk then after it directory fragments are scattered over the entire disk due to this some more advanced versions of FAT file system are developed like FAT12, FAT 16, FAT32 and exFAT.
The integer value that is associated with their name represents the version of the file system that means FAT12 represents 12 bit version and so on. The last one exFAT is the extended version of the 32 bit FAT file system. Now here i am going to discuss only FAT32 because it is the latest version of FAT, this version i s developed due to the volume size limit of the FAT16. In FAT32 the cluster values are held in the 32 bit field in which its 28 bits are used to hold the cluster number. About the future of FAT file system we can only say that it is limited to the volume of 32 GB, due to which users switch over the NTFS(New Technology File System) if they want to partition the drive into smaller volumes.
April 22, 2008
Hope you enjoying it.
From the last post it is clear that network security is dependent on the security of each layer of the computer network. Hence to make our network complete secure we had to make first every layer secure. Except physical layer, security of all the layers is based on the cryptographic principles. Now to understand the layer security we had to first understand the word Cryptography.
Cryptography comes from the Greek words for "secret writing". Historically, four groups of people have used and contributed to the art of cryptography: the military , the diplomatic corps, diarists and lovers. Cryptographic principles total deals with the ciphers and codes. First we had to understand the difference between ciphers and codes. A cipher is a character-for-character or bit-for-bit transformation , in contrast a code replaces one word another word or symbols. Now in cryptography various algorithms are used to encrypt the message and it totally depend on you which algorithm do you select for yourself.
For the few years ago no body is worried about the network security because at that time computer networks are primarily used by university researchers for sending e-mail and by corporate employees for sharing printers but now a day network security is an important factor for any computer network. Generally network security is concerned with people trying to access remote services that they are not authorized to use.
Network Security problem can be roughly divided into four closely intertwined areas: secrecy, authentication, non repudiation and integrity control. All these issues occur in traditional systems, too, but with some significant differences. Now we came to our main issue of network security, first of all we had to understand that where the network security belongs in the protocol stack. The answer is there is probably no one single place that means every network layer has something to contribute. In the case of data link layer, packets on a point to point line can be encrypted as they leave one machine and decrypted as they enter another. This solution also breaks down when packets have to traverse multiple routers because at each router the message is decrypted.
In the case of network layer, firewalls can be installed to keep good packets and bad packets out. In the transport layer, entire connections can be encrypted, end to end, that is process to process. As we discussed issues authentication and non-repudiation can only be handled in application layer. From all the above points it is clear that network security is dependent on each layer of network and it can be concluded that no computer network is 100% secure.