Release 4.5 and 5.0 of MPE/iX provide some new file types.
Here is a brief definition of them. Since these interfaces
are based on a commonly used standard, many textbooks are
available that contain a detailed discussion of their use.
Byte-Stream Files |
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Byte stream files are simply a sequence (stream) of
bytes. The term byte stream file is frequently used when
talking about files with the byte stream record type, even
though they are not a new file type. Byte stream files do
not have any record structure associated with them and have
a record size of 1 byte. Also, they allow reading and
writing of data in arbitrary sized chunks.
Symbolic Links on MPE/iX |
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A symbolic link is a type of file that contains another pathname. It is a permanent file in the system directory. This concept is similar to MPE/iX file equations.
A symbolic link file may contain a relative or absolute path
name. If a symbolic link to a relative path name is
encountered during path name traversal, the contents of the
symbolic link replaces the symbolic link component and is
expanded into the path name being interpreted. If a
symbolic link to an absolute path name is encountered, the
contents of the symbolic link replaces all components up to
and including the symbolic link and is expanded into the
remainder of the path name.
For example, if the path name /dir1/dir2/syml/file is being traversed
and the component syml is a symbolic link that points to
the relative path dir3/dir4, then the
final path name resolved is:
/dir1/dir2/dir3/dir4/file. However, if
syml contains the absolute path
/dir4/dir5, then the final pathname
resolved is: /dir4/dir5/file.
All symbolic links are interpreted in this manner except
when the symbolic link is the last component of a pathname
passed as a parameter to one of the following POSIX
functions: READLINK, RENAME, SYMLINK, UNLINK,
CHOWN, and LSTAT. With
these calls, the symbolic link itself is accessed or affected.
