Old SFTP clients regard
/ (slash) as
a directory separator, which requires the SFTP server to use some "tricks"
to fool the clients. The SFTP client generally does
not have any inherent knowledge of MVS datasets and accesses all files as
they were part of a hierarchical file system.
If an SFTP client tries to open the file
the MVS dataset is actually opened. Some SFTP clients remove all consecutive
slashes so that the file to be accessed becomes
The SFTP server will interpret this as the HFS file
FILE.NAME, located at the HFS root. To avoid this client
behavior, the SFTP server has other ways of naming MVS datasets. If a client
tries to access the file
/FTADV:X=BIN/__FILE.NAME, the SFTP server interprets these
as the dataset
//FILE.NAME. All these combinations are
needed as it may be necessary to make the SFTP clients pass the correct file
or dataset name to the server.
In z/OS, if a dataset name is not enclosed in single quotes, the user
prefix is added in front of the dataset name. For example, if user
USER1 has a dataset
DATASET.NAME1, the user can access
it using the dataset name
//DATASET.NAME1. It is also possible to
use an absolute prefixed name
Because single quotes are special characters in most environments, the
SFTP server introduces a new convention to use triple slashes to
access absolute prefixed dataset names. The name becomes
///USER1.DATASET.NAME1. All combinations of slashes
and underscores can be used. For example,
access his/her dataset using one of the following names:
//DATASET.NAME1 /_DATASET.NAME1 /FTADV:X=BIN/_/DATASET.NAME1 /FTADV:X=BIN/__DATASET.NAME1
//'USER1.DATASET.NAME1' /_'USER1.DATASET.NAME1' /FTADV:X=BIN/_/'USER1.DATASET.NAME1' /FTADV:X=BIN/__'USER1.DATASET.NAME1'
///USER1.DATASET.NAME1 //_USER1.DATASET.NAME1 /_/USER1.DATASET.NAME1 /__USER1.DATASET.NAME1 /FTADV:X=BIN/_/_USER1.DATASET.NAME1 /FTADV:X=BIN/_//USER1.DATASET.NAME1 /FTADV:X=BIN/__/USER1.DATASET.NAME1 /FTADV:X=BIN/___USER1.DATASET.NAME1
The choice of name type depends on the client. If
consecutive slashes are not sent to the server, "
/__" for a prefixed absolute dataset) is probably the best choice.
The SFTP client interprets the file path to be absolute and does not add
any directories in front of the name. If a file transfer advice string
(see Advice String) is
added in front of the file name, "
__" (or "
___" for a
prefixed absolute dataset) is a safe choice. The dataset name becomes
/FTADV:X=BIN/__DATASET.NAME1. The client interprets it as an
absolute path to the file and does not change it. The SFTP server on the
other hand recognizes the advice string
__DATASET.NAME1 to be the real name of the dataset
z/OS has also library datasets, whose members are accessed using the
Again, parentheses may be special characters in some environments. The
SFTP server introduces a new convention for accessing library members
using a single slash as a member separator. The name becomes
Tectia Server for IBM z/OS will not mount volumes or consider off-line devices when accessing datasets, instead it will issue an error message if the dataset is in the catalog but the volume is not available.
Many clients do not show the server's error message and will instead show "No such file".
Because of the new conventions for dataset names there are some
exceptions in the HFS filenames. HFS file or directory name cannot
start with an underscore if the file or directory is located in the
root directory. Also, if an advice string is used with absolute HFS
names, the HFS root must be written either as