What is a Database? Describe the advantages of a centralized database over separate files for specific applications.

Database is described in following points:

1. It takes less space for storing all data. If data for each application is stored in separate files, key fields must be kept in all the files and there by additional space is consumed. Suppose separate data files are there for promotion of employees are retirement of employees, then the key field employee-id may have to be duplicated in both files. Similarly name of employees also should be duplicated.
2. It is easy to make modification in a single file rather than multiple files. If an employees quits the job, then his details should be removed from all files where ever it occurs. If it is a centralised file then it need to be deleted only from one file.

What is Transaction Processing in industry ? Describe the role of computer network in keeping track of transaction.

Transaction processing systems are systems with large data bases and hundreds of concurrent users that are executing data base transactions. Examples of such systems include systems for reservations, banking, credit card processing, stock market etc. They require high availability and fast response time for hundreds of concurrent users. Computer network is essential to interconnect the hundreds of systems that are involved in transactions. Whenever a transaction is performed, the details of transactions are transferred to all the servers in the network and the data bases in the server must be updated messages are send from the point where transaction takes place to all servers for updating data bases in servers so that data integrity is preserved.

What are Control Lines?

Control Lines are used to receive signals that control various operations memory chip. Basic memory operations are read and write. Control Lines are used to receive read and write signals when read signal is received, the contents of selected memory location is transferred into data lines. When write signal is received, data from data lines is taken into selected memory location.

What are Data Lines?

Data lines are the lines through which data is entered or taken out. If each memory location contain 'm' bits then the number of data lines will be 'm'.

Role of Address lines in the architecture of the RAM of a computer?

Address lines are lines through which address of memory location (from where read or write operator is to be performed) is given. Each memory location has a unique address. If there are n address lines, then the number of memory location is 2n. Address in address lines must be valid until write or read operation is complete.