ncsa

Basics

• What is UniTree?
• Where can I find on-line documentation on UniTree?
• How can I access the mass storage system (UniTree)?
• I use ssh to connect to NCSA's production machines; can I use scp to access UniTree?
• How can I save a file to UniTree?
• How can I retrieve a file from UniTree?
• How can I delete a file in UniTree?
• Are files transferred in binary or ascii mode by default?

What is UniTree?

UniTree (now known as DiskXtender) is an archival storage system that supports unlimited file size in a UNIX-like file system environment. UniTree manages the file system by automatically migrating files off local disk space onto tape when disk space becomes low or files have not been accessed in a certain length of time. Files that have previously been migrated to tape and purged off disk are automatically cached back to disk on demand.

A major benefit of UniTree is that it looks and feels like a UNIX file system. The FTP interface allows you to manipulate files and directories using standard UNIX commands and I/O libraries. This FAQ assumes that you are familiar with normal UNIX file operations such as listing and changing directories and moving and removing files.

Where can I find on-line documentation on UniTree?

The UniTree Hardware page has links to various sources of documentation.

How can I access the mass storage system (UniTree)?

You can access UniTree via the ftp utility. There are three ways to access UniTree.

1. ftp mss.ncsa.uiuc.edu

   This needs to be the kerberized ftp client (/usr/local/krb5/bin/ftp on NCSA production machines). See NCSA's Security page for information on installing kerberos on your local machine. mssftp and msscmd (described below) are recommended for accessing UniTree from NCSA production machines since they use the Gigabit Ethernet network by default.

2. mssftp

   mssftp is available on all NCSA production machines. mssftp will automatically connect you to UniTree without the need to enter a login name or password. mssftp is intended for interactive use. Use msscmd (below) in batch scripts.

3. msscmd

   msscmd is available on all NCSA production machines. msscmd is available both interactively and for use in batch scripts. See the man page for details and options. Its usage is:

    
   % msscmd ftp-commands 
   

   where ftp-commands is either a ftp command (e.g., ls, put, get, mkdir) or a list of ftp commands separated by commas. Here are some examples:

   % msscmd put file1
   % msscmd get file2
   % msscmd cd cfdjob, get file3
   

I use ssh to connect to NCSA's production machines; can I use scp to access UniTree?

No; UniTree does not run a ssh server, so access is limited to using a kerberized ftp client or mssftp/msscmd from the NCSA production systems.

How can I save a file to UniTree?

In UniTree, issue the command:

ftp> put filename

How can I retrieve a file from UniTree?

In UniTree, issue the command:

ftp> get filename

How can I delete a file in UniTree?

Issue the command

ftp> del filename

Are files transferred in binary or ascii mode by default?

Files are transferred in binary mode by default when using the kerberized ftp, mssftp, and msscmd.