HP ARPA File Transfer Protocol User's Guide (36957-90159)

72 AppendixA
MPE/iX and POSIX Differences
Filename Size Restrictions
Filename Size Restrictions
The file reference can be either in MPE/iX or POSIX namespace.
The MPE file domain consists of MPE accounts, MPE groups and files which reside in
these groups.accounts. The MPE file domain is a 3 level Hierarchical File System (HFS).
The POSIX file domain is considered a superset of the MPE file domain.
The POSIX file domain consists of a root (/) and POSIX directories, which can contain
additional directories or files. The POSIX file domain is a multi-level Hierarchical File
System.
POSIX is implemented on MPE/iX in such a manor that it is a superset of MPE. MPE
accounts are now under the POSIX root (/) and are treated as special directories; likewise
MPE groups are located under accounts and again are treated as special directories.
As a result of this implementation, files in the MPE file domain can be accessed by MPE
applications; and, since the POSIX file domain is a superset of the MPE file domain, POSIX
applications can also access these files. In general MPE applications cannot access files in
the POSIX file domain unless the application, or the file procedures it calls, are specifically
coded to do so.
MPE/iX Namespace
If the file reference does not begin with a dot or a slash, it is parsed according to the
MPE/iX syntax and has the following format:
filename [/lockword] [.groupname [.acctname]]
MPE/iX names must contain from one to eight alphanumeric characters, beginning with
an alphabetic character. If
acctname is specified, you must create directory (CD) access to
the target group in the account. The default
groupname and acctname are the logon group
and account. Filenames in MPE name space are not case sensitive, and are all shifted to
uppercase.
POSIX Namespace
If the file reference begins with a dot (.) or a slash (/), it is parsed according to the POSIX
syntax. In this case the file reference can be ./Directory 1/Directory 2/Directory 3/... .
The following syntax rules apply:
• File names are not shifted to uppercase.
• File names can be up to 254 characters in length for absolute pathnames, and 253
characters for relative pathnames.
• File names can begin with, and contain, any of the following characters:
a—z A—Z, 0—9, _, .
• File names can contain (but not begin with) a dash (-).
• File names are of the form (path/filename) where the path/filename combination can