What is the difference between normal exp/imp and datapump expdp/impdp?

What is the difference between normal exp/imp and datapump expdp/impdp?

Datapump is a server side utility whereas export/import is a user (CLIENT) process. 

Datapump improves the performance dramatically over old export/import utilities, because the

datapump processes running on the server have direct access to the datafiles and the SGA. They don’t have to go via session.

It is possible to launch a datapump job and then detach from it, leaving it running in the background. You can reconnect to the job to monitor its progress at any time.

Impdp/Expdp has self-tuning unities. Tuning parameters that were used in original Export and Import, such as BUFFER and RECORDLENGTH, are neither required nor supported by Data Pump Export and Import.

Data Pump represents metadata in the dump file set as XML documents rather than as DDL commands.

Impdp/Expdp use parallel execution rather than a single stream of execution, for improved performance.

In Data Pump expdp full=y and then impdp schemas=prod is same as of expdp schemas=prod and then impdp full=y where in original export/import does not always exhibit this behavior.

Expdp/Impdp operate on a group of files called a dump file set rather than on a single sequential dump file.

Sequential media, such as tapes and pipes, are not supported in oracle data pump.But in original export/import we could directly compress the dump by using pipes.

The Data Pump method for moving data between different database versions is different than the method used by original Export/Import.

When you are importing data into an existing table using either APPEND or TRUNCATE, if any row violates an active constraint, the load is discontinued and no data is loaded. This is different from original Import, which logs any rows that are in violation and continues with the load.

Expdp/Impdp consume more undo tablespace than original Export and Import.

If a table has compression enabled, Data Pump Import attempts to compress the data being loaded. Whereas, the original Import utility loaded data in such a way that if a even table had compression enabled, the data was not compressed upon import.

Data Pump supports character set conversion for both direct path and external tables. Most of the restrictions that exist for character set conversions in the original Import utility do not apply to Data Pump. The one case in which character set conversions are not supported under the Data Pump is when using transportable tablespaces.

There is no option to merge extents when you re-create tables. In original Import, this was provided by the COMPRESS parameter. Instead, extents are reallocated according to storage parameters for the target table.

NOTE: Data Pump does not work with utilities older than the 10g release 1