© Copyright Robert Vasvari, 1993.

Trouble shooting, known errors, problems

Since RBrowser does not use any custom software on the remote end, it has to rely on various implementations of UNIX utilities, FTP servers. Some remote systems you are connecting to might not have a correct implementations of all the software RBrowser relies on for. This can cause errors in some operations. This document is my attempt to record all the various problems, wirdnesses etc..

FTP protocol:

1. Keeping continuous connection to the server:

By default, FTP connections have an optimization turned on: to keep continuous connection. This speeds up individual directory loads because RBrowser does not have to login every time it loads a directory. There is one possible problem with this. In this mode RBrowser will load the directories sequentially. If your home path is /home/me for instance, RB will load /, /home and /home/me in that order. It is possible that /home is huge (I have seen /home directories with more than 10000 entries) and in this case it will take a long time to load your browser window. The workaround: either turn off the continuous connection on the FTP Connection Preferences Panel, or turn on the Home Only option on the Login Panel before you log in the next time.

2. Opening/Copying to Local Host:

If the remote FTP server is a Windows box, be mindful of the following: even if the file is listed in the browser, it might not be accessible to you, because it may have the "hidden" attribute set. If you try to retrieve this file You will probably get an error like this:

"550 filename:The system cannot find the file specified"

3. Server to Server transfers:

The operations effected are: Copy and Move on the same machine, and remote to remote transfer. The operation may fail with an error message similar to this:

Server to Server transfer failed: 500 Illegal PORT command.

A possible explanation: Server to Server transfer requires one server to be in passive mode and another server to connect to it using the PORT command. On some sites this capability is disabled on purpose. On others they might be using a version wftp that has this feature disabled. If this is the case, you need to complain loudly to your system administrator.

SSH/UNIX protocol:

1. Connecting:

You are trying to connect to a remote host which is UNIX, you have an account, and the login still fails. You try login with FTP and it succeeds. This is most likely caused by the fact that some administrators disable the inetd service "rexec" by commenting out the appropriate line in /etc/inetd/conf. You should check if this is the case, if so, complain loudly to your system administrator.

2. .cshrc:

Even though RBrowser does not use a C shell, the rexec server does read it during login. The one thing that can really screw up a remote connection, if there are any 'stty xxx' commands in your .cshrc. These commands do not belong in .cshrc, so make sure to remove them.

3. Progress Reporting for copying files between hosts:

In the UNIX protocol the files are transferred the following way:

(Source host) [tar source files]->[compress]->[uuencode] ===== network ====>(Target host) [uudecode]->[uncompress]->[unarchive files]

Since the total number of bytes that are actually transferred over the network is not known before the operation because of compressing, it is not possible to accurately measure the percentage of the total that is actually transferred. RBrowser makes a good faith estimate here. Also note, that if multiple files or a directory tree is transferred, all source files are treated as one stream since tar is used (in the FTP protocol, all files transferred separately).

4. Error reporting:

Some of the operations fail silently. Deleting files is most prone to this. This is true in all of the protocols. For that reason, the directories that are potentially changed with the operation are always reloaded after the operation. One common way for a silent failure is when you are replacing a directory by dropping into its parent another directory with the same name. If some of the contents of the original directory are not writable the whole operation will (silently on some systems) fail. In this case, always check permissions!

Some copying between different hosts will fail due to incompatibilities between their versions of tar. The default in RBrowser is to use /usr/bin/gnutar. This is probably the best version out there, so if it is available on the remote system you are connecting to, you should use it (see Connection preferences).

5. No Home Directory:

Logging on with the UNIX protocol will fail onto certain systems (OpenStep for instance) if the user you are logging on as has no home directory. If this happens, you will get an error message like "no remote directory", and the login fails. Unfortunately, there is no workaround for this problem, as it is a limitation of the rexec server running on the remote machine. For these hosts you will have to use the FTP protocol.

6. Slow File Transfer to a remote host running OPENSTEP:

By default, RBrowser will try to find an 8bit clean shell on the remote host, in order to handle files with names that contain international (upper ASCII) characters. You most likely will end up using ksh or zsh (check the UNIX Connection Preferences Panel to see what shell you are using). Unfortunately, there is a problem with zsh on OPENSTEP/NEXTSTEP, which results in slow file transfer if the remote host is OPENSTEP and the remote shell is zsh. Workaround: use ksh or /bin/sh instead of zsh.

7. LINUX users:

By default, LINUX will not install uuencode/uudecode. These must be installed on the remote host, otherwise RBrowser cannot get the directory listings.

ALL protocols:

ON WINDOWS drag and drop works differently than on MACH. The cursor will NOT change during the drag operation. See the drag&drop rules on the File Operations page

What to do if you are trying to do something and get the beachBall?

Maybe the remote host you are connected to is not responding. Try logging in using telnet from the Terminal. If the host is not responding correctly, RBrowser may get stuck on trying to talk to it. These connection attempts will time out usually after 60 seconds. After that everything will operate normally. If the attempt does not time out, you may have to kill RBrowser using the Processes menu from the Workspace and restart it.

 

I tried to kill a background process, but it would not go away...

Depending on the reliability of your network connection some background processes can hang. If this happens, the only thing you can do is to restart RBrowser.

 


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