Oracle A423961 - Manual (Page 107)

SQL Ref.
5 – 11 Database Administration
SQL*Language Conventions
The Oracle7 Server SQL Reference describes all aspects of Oracle’s
implementation of the SQL language. Certain features of SQL have
operating system–specific variations.
ROWID Datatype
The ROWID datatype provides a hexadecimal address of each row in a
database table. The format of the ROWID datatype is:
block.row.file
where block, row, and file are hexadecimal addresses that indicate the
data block, row, and database file of the queried row. The hexadecimal
lengths for block, row, and file, are eight, four, and four, respectively.
These lengths do not vary with Oracle7 Server for Windows NT.
Additional Information: See Oracle7 Server SQL Reference for
more information on the ROWID datatype.