Sunday, October 27, 2013

Short Notes on Information Technology_DAIBB



 Important Short Notes on Information Technology in Financial Services_DAIBB (Paper-4)



 

ASCII

The American Standard Code for Information Interchange is a character-encoding scheme originally based on the English alphabet. ASCII codes represent text in computers, communications equipment, and other devices that use text. Most modern character-encoding schemes are based on ASCII, though they support many additional characters. It was only developed for communication and first adopted in 1963.

ASCII has been very popular in the computer world. It  contains seven bits to define each letter or character excluding eighth bit for error-checking function. There are 128 specific characters including capital letters, small letters, 0 to 9 digit, special symbols and some specific character having specific different functions.  Thirty-three codes  are used to represent things other than specific characters. The first 32 (0-31) codes represent a chime sound, used  to feed  line as well as to start of a header. The final code, 127 represents a backspace while the first 31 bits are the printable characters. Bits ranging from  48 to 57 represent the numeric digits and 65 to 90  represents the capital letters, while bits 97 to 122 are the lower-case letters. The rest bits represent symbols of punctuation, mathematical symbols, and other symbols such as the pipe and tilde.

Earlier ASCII was developed  only in six bits for a simpler character set. But  finally it has been reconstructed using seven bits for assimilating   lower-case letters, punctuation, and control character sets  to enhance its utility. No other than English characters  has been used in ASCII. ASCII is not used in IBM computers. IBM has its own built-in-code called EBCDIC code containing 256 character sets. Nowadays Unicode character set is replacing ASCII code very rapidly. ASCII is being famous in ASCII art phase that describes the use of the basic character set to create visual approximations of images.


'Personal Identification Number - PIN'


A personal identification number is a secret numeric password shared between a user and a system that can be used to authenticate the user to the system. Typically, the user is required to provide a non-confidential user identifier or token (the user ID) and a confidential PIN to gain access to the system. Upon receiving the user ID and PIN, the system looks up the PIN based upon the user ID and compares the looked-up PIN with the received PIN. The user is granted access only when the number entered matches with the number stored in the system. Hence, despite the name, a PIN does not personally identify the user.

PINs are most often used for automated teller machines (ATMs) but are increasingly used at the point of sale, for debit cards and credit cards. For example, when you take money out of an ATM, you enter your PIN number to prove that you're authorized to make the withdrawal. You might also enter a PIN number if you use your debit card at a retailer (only for POS transactions, not signature transactions).

UPS


Short for uninterruptible power supply, a power supply that includes a battery to maintain power in the event of a power outage. Typically, a UPS keeps a computer running for several minutes after a power outage, enabling you to save data that is in RAM and shut down the computer gracefully. Many UPSs now offer a software component that enables you to automate backup and shut down procedures in case there's a power failure while you're away from the computer.

There are two basic types of UPS systems: standby power systems (SPSs) and on-line UPS systems. An SPS monitors the power line and switches to battery power as soon as it detects a problem. The switch to battery, however, can require several milliseconds, during which time the computer is not receiving any power. Standby Power Systems are sometimes called Line-interactive UPSes.

An on-line UPS avoids these momentary power lapses by constantly providing power from its own inverter, even when the power line is functioning properly. In general, on-line UPSs are much more expensive than SPSs.

A UPS is typically used to protect computers, data centers, telecommunication equipment or other electrical equipment where an unexpected power disruption could cause injuries, fatalities, serious business disruption or data loss. UPS units range in size from units designed to protect a single computer without a video monitor (around 200 VA rating) to large units powering entire data centers or buildings

RDBMS


RDBMS stands for Relational Database Management System. RDBMS data is structured in database tables, fields and records. Each RDBMS table consists of database table rows. Each database table row consists of one or more database table fields. An important feature of relational systems is that a single database can be spread across several tables. This differs from flat-file databases, in which each database is self-contained in a single table.

RDBMS store the data into collection of tables, which might be related by common fields (database table columns). RDBMS also provide relational operators to manipulate the data stored into the database tables. Most RDBMS use SQL as database query language.

Relational database management system (DBMS) stores data in the form of related tables. Relational databases are powerful because they require few assumptions about how data is related or how it will be extracted from the database. As a result, the same database can be viewed in many different ways.



RAM


RAM is an acronym for random access memory, a type of computer memory that can be accessed randomly; any byte of memory can be accessed without touching the preceding bytes. RAM is the most common type of memory found in computers and other devices, such as printers.

RAM is a temporary storage for data. For instance, when you open Microsoft Word (or any program), it goes into RAM because your CPU can get it a lot faster from RAM, than if it tried to get it off of your hard drive. However, RAM is dynamic which means if the power is cut off then any data that is in RAM is lost. Let’s say you are typing a letter, each time you hit the keyboard that data is put into RAM until it can be transferred to your hard drive. If the power goes off then whatever is in RAM while you were typing will be lost.

In common usage, the term RAM is synonymous with main memory, the memory available to programs. For example, a computer with 8MB RAM has approximately 8 million bytes of memory that programs can use. In contrast, ROM (read-only memory) refers to special memory used to store programs that boot the computer and perform diagnostics. Most personal computers have a small amount of ROM (a few thousand bytes). In fact, both types of memory (ROM and RAM) allow random access. To be precise, therefore, RAM should be referred to as read/write RAM and ROM as read-only RAM.


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