HARDWARE-1

With the proliferation of micro-computers, the concept of distributed computing has emerged. In distributed computing, a number of computers are dispersed in different parts of an organization and inter-connected using special cables, telephone lines or other telecommunication media. This allows data and programmers to be shared and also provides for some new types of application such as electronic mail. Electronic Mail moves messages through inter-linked computers/terminals.

 

To support such networking special electronic devices such as modems an network inter-face cards are often fitted into micro-computers. For example, a blinds company who are selling vertical blinds and roman shades online, they are having inter-linked computers by which they are sending their marketing emails. Another example is a company who are providing term life insurance rates online, they are using lead management tools by which their online leads are transfer to their insurance software and from that insurance software they are distributing their leads.

 

As with large computers, micro-computers have operating systems to enable the user to easily interact with the machine. These operating systems are similar to those on large machines except that they are much simpler. This is because the majority of micro-computers are not multi-terminal machines – only one user has access to the machine at any time. In this situation the machine is the personal computer of the user. Personal computers are used for a variety of tasks. The most common applications are:

 

1. Word Processing
2. Financial Analysis
3. Data Base Access
4. Graphics
5. Accounting

HARDWARE

Micro-computers are structurally similar to large computers in that they have the same basic components – CPU main memory, secondary memory and input/output devices. The most popular secondary memory device are floppy disk drives and fixed disks. Floppy disks store between 140 K Bytes to 1 Mega Byte = 1024 K Bytes (MB) while hard disks store 10 MB to 40 MB.

 

The main memory is made from several chips. These may be ROM or RAM chips.  ROM (Read Only Memory) chips contain instructions permanently written in the memory. The contents of these chips cannot be altered. RAM (Random Access Memory) Chips provide the memory that can be read from, written into and cleared.

 

Most micro-computers have between 16 K bytes and IMB memory. The typical word-size of micro-computers when they were introduced in business in the late seventies was B-bits. Today, the most common word-size is 16-bits. It is virtually certain that in the next few years 32-bit micro-computers will be very common although today their numbers are somewhat limited due to cost and scarcity of software. Dot matrix and daisy-wheel printers are popular printing devices on micro-computers.

Personal Computer and its uses-1

INTRODUCTION OF PERSONAL COMPUTER AND ITS USES

Computers were first used in management and business applications in centralized data processing departments. These departments were manned by computer specialists who were the only persons allowed access to the machines. Later terminals were provided to users for certain applications. However, cost, complexity, size and the need for special environment control did not permit computer users to have computers at their work places. All this has changed with the advent of micro-computers. For example market type is also change now a day than before. New days companies are using trade show booths where they have banner stands, table skirts and pipe and drape. Same way, computers are changing day by day with the use of new technology being invented and introduced in the market. Marketing exhibitions and trades shows are best way to introduce new technology to people.

 

MICRO-COMPUTERS

Micro-computers are computers which have their entire Central Processing Unit (CPU) on single integrated circuit ‘chip’ (called a micro-processor). Today powerful micro-computers are available which cost as little as $ 500. These micro-computers can do many of the jobs earlier done by large computers which cost many times this amount. In addition, because they are small enough to sit on a desk and do not require extensive environmental control, they can be used in most reasonably dust-free environments. Field tests on machines used in projects such as the Computer Literacy Project for Secondary Schools of the Education Ministry have shown this.

 

This ready availability for users has enabled a large number of entirely new applications to be undertaken. It has also increased user interest in computing since users can be directly in control of their data unlike the situation with centralized computing. Due to these factors and the fact that micro-computers can be used at home and schools for education and entertainment there has been a spectacular increase in their numbers since their first arrival as hobby kits in the U.S. Several million micro-computers are used in management applications around the world today. In India the projections are that by 1990 a few lakhs of these machines will be installed.

Operating Systems-1

We are talking computers in management. We talked evaluation of computers and computer softwares in our previous talk. We talked about operating system in our last post, today we continue with that. We talked the drawback of idling the CPU was overcome with the introduction of overlapped processing.

For example why not take up input operation of job 2 and the output operation of job 1 simultaneously? This and similar considerations gave rise to the concept of multi-programming. A multi-programming operating system handles multiple jobs simultaneously by overlapping the input, output and processing cycles of various jobs.

This operating system was introduced along with third generation computers and is still very popular. It has replaced the earlier batch processing (serial) operating system. With multi-programming a CPU’s utilization is increased and hence jobs get executed faster on an average. However a multi-programming operating system is more complex hardware to support it.

Other types of operating systems which are popular today are multi-processing operating systems and real time operating systems. A multi-processing operating system uses multiple CPU’s to process multiple jobs. A real time operating system is a very different type of operating system, because it is used for different type of applications, i.e., real time applications such as airlines reservations, process control, etc.

Utilities

Utility programmes are those which are very often requested by many application programmes. mailing leads and marketing list are few example of such utility programmes which are used in large by industry. A few examples are:

SORT/MERGE for sorting large volumes of data and merging them into a single sort list like mortgage mailing list.

Transfer programmes for transforming contents from one medium to another, e.g., disk to tape, tape to disk, etc.

Operating Systems

An operating system is the most important system software and is required to operate a computer system. An operating system manages a computer’s resources very effectively, takes care of scheduling multiple jobs for execution and manages the flow of data and instructions between the input/output units and the main memory.

 

Operating systems became a part of computer software with the second generation computers. Since then operating systems have undergone several revisions and modifications in order to achieve a better utilization of computer resources. Advances in the field of computer hardware have also helped the development of more efficient operating systems.

 

The first operating system called batch processing (serial) operating system was developed for the second generation computers; This operating system executes jobs serially one after another from a batch of jobs submitted for execution. The central processing unit is kept busy only during the processing cycle of a job and it idles during the input and output operations.

 

The above drawback of idling the CPU was overcome with the introduction of overlapped processing. For example why not take up input operation of job 2 and the output operation of job 1 simultaneously? This and similar considerations gave rise to the concept of multi-programming. A multi-programming operating system handles multiple jobs simultaneously by overlapping the input, output and processing cycles of various jobs.

Language translators

A language translator is system software which will translate a computer programme written by humans into a machine understandable form. The most elemental form of programming uses only the binary digits 0, 1 which is directly understood by the electronic circuits. A programme written using only binary digits is called a machine language programme.

 

Assembly language provide a significant improvement over machine language. Assembly language programmes are written using mnemonic codes like ADD, STORE, etc., rather than their machine language representations in binary digits. Therefore programming in assembly language is easier. Active directory and active directory management or active directory tool can be made with such programming. However, it needs to be translated into machine language codes. This translation is done by an assembler. Both machine language and assembly language programmes are machine dependent. This means that a programme written for one machine cannot be used in another machine.

 

High level languages, which are closer to English overcame the drawback of machine dependence. A few high level languages are FORTRAN, BASIC, PASCAL, COBOL etc. These languages relive the programmers from being machine specific. However a programme written in a high level language needs to be translated into machine language codes before execution. This translation is done either through compilers or through interpreters.

 

A compiler is a translator which reads an entire programme written in a high level language and coverts it into machine language codes. An interpreter on the otherhand, is a translator which interprets statement by statement, any programme written in a high level language. An interpreter is a very effective tools for programme development as it checks for errors statement by statement in an interactive mode. Exchange Management and Exchange Tools require interpreter.  This allows the programmer to correct the errors statement by statement as he enters them. A compiler on the otherhand, will request the user to enter the entire programming statement and then it will check for errors. Basic language provides a compiler and an interpreter.

 

Other language such as Fortran, cobol and Pascal had only compolers initially. However interpreters for these high level languages are also becoming available, partly due to the popularity enjoyed by micro-computers in the field of computing.

COMPUTER SOFTWARE

Today we are going to discuss on Computer Software part. This is a most important topic for Computers. Computer software consists pf sets of programmed instructions which enable the hardware units to perform. Programming a computer to perform has always been a very difficult task. The first electronic computer was programmed using wired panels. Today’s computers are programmed using software.

 

Computer software can be broadly classified into two categories – System Software and Application Software. System software is a set of instructions to the machine hardware to interpret and execute application software. Application software is a set of programming instructions for specific applications like payroll accounting, inventory control, etc. System software consists of language translators [called compilers (compiles program-wise), interpreters (compiles like-wise) and assemblers (converts semi-machine-language, macro-instructions, to machine language)], operating systems, utilities and special purpose software.

 

Computer software or just software is a general term used to describe a collection of computer programs, procedures and documentation that perform some tasks on a computer system. “Software” is sometimes used in a broader context to mean anything which is not hardware but which is used with hardware, such as film, tapes and records. 

We will discuss on languages translator in next post.

blinds, roller shades, woven wood shades

Input and Output Devices-4

Still today we have discussed for different types of the computer hardware devices. Form last few days we are talking on input and output devices which is most important part of the computer hardware. The input or output units of a computer system establish the communication between the system and its users. A large number of input and output units are available in the market. A few of them are discussed in this note.

Most recent trend for data input is towards source data automation. The equipments used for source data automation capture data as a by-product of a business activity thereby completely eliminating manual input of data. Some examples are:

1. Magnetic ink character recognition devices are used by the banking industry to read the account numbers on cheques directly and do the necessary processing.
2. Optical mark recognition devices can sense marks on computer readable papers.

This king of device is used by academic and testing institutions to grade aptitude tests where candidates mark the correct alternatives on a special sheet of paper. These answer sheets are then directly read by the optical mark recognition devices and the information sent to a computer for processing.

Input and Output Devices-3

We talked about input or output units of a computer system. Input and output establish the communication between the system and its users. A large number of input and output units are available in the market. A few of them we are discussing here. We talked about hard disk in our previous post. Today we are going to talk about printer.

 

A printer is a peripheral which produces a hard copy of documents stored in electronic form, usually on physical print media. Printers are purely output devices. Printers are classified into line printers and dot matrix printers. A line printer prints one line of information simultaneously, whereas a dot matrix printer prints one character at a time. A dot matrix printer uses a 5 X 7 or 7 X 9 dot matrix formation to represent each character. Dot matrix printers therefore provide a broken appearance to the characters, whereas a line printer provides a better quality output. A line printer has a speed of about 2000 lines per minute whereas a dot matrix printer has a lower speed of approximately 100 characters per second. If we talke about credit card printer than they need to have a merchant accounts with which credit card processing done. In big shopping mall credit card machine are available there.  With credit card software  and credit card terminal they use credit card printer  to for day to day functions.

Daisy wheel printers and letter quality printers are also character printers. But they produce excellent quality output. However, they are more expensive and slower than dot matrix printers. All the printers discussed so far are called impact printers as they make physical contact with paper while printing. A no impact printer on the other hand transfers information to paper without any physical contact. Example of no impact printers is laser printers, xerographic printers, electrostatic printers, etc.

 

Many printers are primarily used as local peripherals, and are attached by a printer cable or, in most new printers, a USB cable to a computer which serves as a document source. Some printers, commonly known as network printers, have built-in network interfaces (typically wireless or Ethernet), and can serve as a hardcopy device for any user on the network. Individual printers are often designed to support both local and network connected users at the same time.

Input and Output Devices-2

Terminals have become very popular interactive input and output units. A terminal, when connected to a CPU, sends data and instructions directly into the computer. Terminals can be classified into two types, namely, hard copy terminals and soft copy terminals. A hard copy terminal provides a print out on paper whereas a soft copy terminal provides a visual display on a screen. A soft copy terminal is also known as a CRT (Cathode Ray Tube) terminal.

 

Key-to-tape, key-to-disk and key-to-diskette are stand alone data entry stations. There units usually have a small processor attached to a key board and a visual display unit. The processor checks for the accuracy of data at the time of entry. The screen displays what is being entered. There facilities are highly desirable for a data processing centre. Hence most of the data processing centres are switching over from punched card input to data entry stations.

 

A graphic display terminal displays information in both character and graphic forms. These are extensively used for CAD/CAM (computer aided design/computer aided manufacture) applications.

A potter is used to obtain printed copies of graphic outputs. It is used by architects and designers to produce blueprints of their design on paper.