Tag: classification of computer

An IP address consists of 32 bits.

An IP address consists of 32 bits, often shown as 4 octets of numbers from 0-255 represented in decimal form instead of binary form. For example, the IP address: 168.212.226.204 in binary form is 10101000.11010100.11100010.11001100.

Internet Protocol version 4 (IPv4) defines an IP address as a 32-bit number. However, because of the growth of the Internet and the depletion of available IPv4 addresses, a new version of IP (IPv6), using 128 bits for the IP address, was developed in 1995, and standardized in December 1998.

The size of the prefix, in bits, is written after the oblique. This is called “slash notation”. There is a total of 32 bits in IPv4 address space. For example, if a network has the address “192.0.2.0/24”, the number “24” refers to how many bits are contained in the network. It means a single host address. That is called CIDR notation. 192.168.0.1 represents the IP and /32 represents the number of bits in the mask.

In Symmetric key cryptography same secret key is used by the sender and the receiver.

symmetric-key cryptography. An encryption system in which the sender and receiver of a message share a single, common key that is used to encrypt and decrypt the message. Contrast this with public-key cryptology, which utilizes two keys - a public key to encrypt messages and a private key to decrypt them.

Symmetric-key algorithms are algorithms for cryptography that use the same cryptographic keys for both encryption of plaintext and decryption of ciphertext. ... The keys, in practice, represent a shared secret between two or more parties that can be used to maintain a private information link.

The shared secret is either shared beforehand between the communicating parties, in which case it can also be called a pre-shared key, or it is created at the start of the communication session by using a key-agreement protocol, for instance using public-key cryptography such as Diffie-Hellman or using symmetric-key.

Mainframe computers use the 8 bit code called EBCDIC.

Mainframe computers (colloquially referred to as "big iron") are computers used primarily by large organizations for critical applications; bulk data processing, such as census, industry and consumer statistics, enterprise resource planning; and transaction processing.

For separating channels in FDM, it is necessary to use  Bandpass filters

A bandpass filter is an electronic device or circuit that allows signals between two specific frequencies to pass, but that discriminates against signals at other frequencies. Unlike the low pass filter which only pass signals of a low frequency range or the high pass filter which pass signals of a higher frequency range, a Band Pass Filters passes signals within a certain “band” or “spread” of frequencies without distorting the input signal or introducing extra noise.

Frequency Division Multiplexing (FDM) Frequency-Division Multiplexing (FDM) is a scheme in which numerous signals are combined for transmission on a single communications line or channel. It is analog multiplexing technique. ... FDM multiplexing technique is based on orthogonality of sinusoids.

The modulation can be AM,SSB, FM or PM . The modulated signals are then added together to form a composite signal which is transmitted over a single channel . The spectrum of composite FDM signal has been shown in fig.1 . Generally, the FDM systems are used for multiplexing the analog signals .

For separating channels in TDM, it is necessary to use  Time slots.

Time-division multiplexing (TDM) is a method of transmitting and receiving independent signals over a common signal path by means of synchronized switches at each end of the transmission line so that each signal appears on the line only a fraction of time in an alternating pattern.

Time-division multiplexing (TDM) is a method of putting multiple data streams in a single signal by separating the signal into many segments, each having a very short duration. Each individual data stream is reassembled at the receiving end based on the timing.

Time-division multiplexing (TDM) is a method of transmitting and receiving independent signals over a common signal path by means of synchronized switches at each end of the transmission line so that each signal appears on the line only a fraction of time in an alternating pattern. It is used when the bit rate of the transmission medium exceeds that of the signal to be transmitted.

Avalanche effect in encryption is Desirable.

Avalanche effect. ... In cryptography, the avalanche effect is the desirable property of cryptographic algorithms, typically block ciphers and cryptographic hash functions, wherein if an input is changed slightly (for example, flipping a single bit), the output changes significantly (e.g., half the output bits flip).

Avalanche effect, in physics, a sudden increase in the flow of an electrical current through a nonconducting or semiconducting solid when a sufficiently strong electrical force is applied.

Signal becomes weak with increase in distance travelled because of Attenuation.

Consequently, positive attenuation causes signals to become weaker when travelling through the medium. ... Causes of attenuation in both signal frequency and range between the end points of the medium, affect the amount of signal reduction. As the range increases, attenuation also increases.

In a nutshell, attenuation is the loss of transmission signal strength measured in decibels (dB). As attenuation increases, the more distorted and unintelligible the transmission (e.g. a phone call or email you're trying to send) becomes. Inherent attenuation can be caused by a number of signaling issues including:

Transmission medium - All electrical signals transmitted down electrical conductors cause an electromagnetic field around the transmission. ... Crosstalk from adjacent cabling causes attenuation in copper or other conductive metal cabling.

Attenuation is a general term that refers to any reduction in the strength of a signal. ... Sometimes called loss, attenuation is a natural consequence of signal transmission over long distances. The extent of attenuation is usually expressed in units called decibels (dBs).

The tracks on a disk which can be accessed without repositioning of read write head is Cylinder.

are vertically formed by tracks. In other words, track 12 on platter 0 plus track 12 on platter 1 etc. is cylinder 12. The number of cylinders of a disk drive exactly equals the number of tracks on a single surface in the drive.

So, in order to access a particular cylinder from a track we do not need to move read write head from that particular track. | | --- |