Abstract: A method of dynamically managing and sharing database in a mobile communication terminal and a server system is provided. By installing applications such as a database system and a user interface programs in the mobile communication terminal, a user forms a database arbitrarily in a form of his/her own preference, input data there, and forms a user interface in a form of their preference. Also, the data managed in the mobile communication terminal may be stored and managed in a mobile communication server system through a wireless network or in a computer through a wired network. The user can download database template a provider provides to the mobile communication terminal from the mobile communication server, use them without generating the database structure for him/herself, and graphs and numerical expressions the user produced using the data of database may be included.

Abstract: Provided is a portable electronic device having a removable hard disk drive in which the hard disk drive is adapted to have a slot-type removable shape, thereby allowing the hard disk drive to be conveniently mounted and used, and when the hard disk drive is detached, power is cut off before detaching the hard disk drive, and when the hard disk drive is mounted, power is automatically supplied after the hard disk drive is completely mounted, thereby preventing damage by a voltage shock.

Abstract: A method of scheduling jobs in real time using a database management system is provided. An application task classifies jobs as any one transaction type of a hot type and a normal type. A processing area in a memory pool that is a common resource is allocated to the application task, and the job is transferred to a database job manager through a client application program interface (API). The job manager loads a request node of the job in a list of a transaction type corresponding to the job, of a mailbox of the DB task, which classifies job request nodes as the hot type and the normal type with respect to the type of transaction and manages the nodes, so that the job request node can be scheduled in units of transactions.

Abstract: A method of efficiently recovering a database that can be applied to a mobile communication terminal employing a flash memory as a storage medium is provided. In the flash memory, a database (DB) storage area and a DB recovery area are separately allocated. Images of pages in the DB storage area that are objects to be changed are sequentially read and stored in a memory buffer, and the original images of the pages before change are assigned sequential serial numbers and backed up in the DB recovery area. Then, the images of the pages in the memory buffer are changed according to a transaction. This series of jobs is performed with respect to all pages that are the objects of change. Then, each page in the DB storage area that is the object of the change is updated with a corresponding changed page in the memory buffer.