This file contains a set of frequently asked questions (with answers) concerning possible sources of difficulty using either the CMU AI Repository anonymous FTP site, WWW pages, and e-mail server, or the Prime Time Freeware for AI CD-ROMs. Last Updated: Wed May 3 18:13:57 1995 ---------------------------------------------------------------- Subject: The MSDOS versions of GZIP included in util/gzip/msdos/ don't work. These files are actually self-extracting archives. We renamed them to conform to ISO-9660 file name restrictions. Unfortunately, the name we chose (GZIP.EXE) is the same as the name of one of the files contained in the archive, causing the archives to fail to unpack properly. We have fixed the problem in the AI Repository. To work around the problem for the copies on the CD-ROM, simply rename the files before executing them to extract the MSDOS version of GZIP, or unpack the self-extracting archive into a different directory than the one containing the archive. ---------------------------------------------------------------- Subject: I tried FTPing to the site mentioned, but it said "permission denied" or some other error message. The most frequent errors by anonymous FTP users are: I tried to ftp to the cs.cmu.edu but ran into difficulties in trying to change to the /user/ai/ directory. I kept getting messages that said that access to these directories by guest users was not allowed. ==> The FTP host is ftp.cs.cmu.edu, not cs.cmu.edu. I have tried to download a program from the ftp site, but could not access the directory /usr/ai/areas/... ==> The main ftp directory for the repository is /user/ai/, not /usr/ai/. I'm accessing the ftp site correctly, but I still get "Permission denied". ==> Is your local directory writable? If it isn't, your ftp daemon won't be able to write the files it retrieves to your disk. Likewise, make sure your disk isn't full. ---------------------------------------------------------------- Subject: GZIP doesn't seem to decompress the correctly. Did you ftp in binary mode? ---------------------------------------------------------------- Subject: Emacs W3 mode complains "403 Forbidden Your client does not have permission to get URL /afs/cs.cmu.edu/project/ai-repository/ai/... from this server." This is apparently due to a bug in W3 mode, where it treats an absolute pathname as a relative pathname. To work around it, use the relative pathname /Web/Groups/AI/... which is linked to the proper location. ---------------------------------------------------------------- Subject: I sent mail to the query server, but got no response. The email address for the query server is ai+query@cs.cmu.edu not ai@cs.cmu.edu, ai+quary@cs.cmu.edu, or ai+queries@cs.cmu.edu. ---------------------------------------------------------------- Subject: I tried using the SEND command to retrieve a file, but it didn't work. File retrieval by email is not yet implemented, due to concerns about overloading our mail server. We recommend using DECWRL's ftpmail. Send a message with the word "help" in the body to ftpmail@decwrl.dec.com for instructions. ---------------------------------------------------------------- Subject: I tried to access the WWW page for the repository, but it tells me that the server is not accessible. Our WWW server is heavily used, and occasionally wedges due to the load. Wait a while and try again. If the problem persists for more than a day, send us mail, so we can ask the maintainer to restart the server. ---------------------------------------------------------------- Subject: GCL 1.0 seems to be missing the cmpinclude.h file. Make sure you're using the config script properly. The file is included in the tar file, and if you use the config script incorrectly, you're deleting the h/cmpinclude.h file after it is installed. ---------------------------------------------------------------- Subject: I'm having trouble gunzipping the files, and am getting a "invalid compressed data -- crc error". Did you ftp the files in binary mode? Note that web browsers need to be specificly told to transfer the file in binary mode, especially when the protocol is http. If you don't know how to do this, try substituting ftp://ftp.cs.cmu.edu/ for http://www.cs.cmu.edu/ in the URL. This sometimes forces the retrieval to be in binary mode. ---------------------------------------------------------------- Subject: The keys command didn't find any C++ code. The arguments to the keys command may be regular expressions, and + has special meaning in regular expressions, so you must escape it: keys neural "C\+\+" ---------------------------------------------------------------- Subject: MSDOS tar Two new additions to the AI Repository util/pax/ Pax is an implementation of tar for MSDOS systems that seems to work well. util/tar/pc/tar316us.zip This implementation of tar runs on DOS/UNIX with built-in compress, zip, and gzip support. There are other tar implementations for PCs in util/tar/pc/, but several users have had problems with them. ---------------------------------------------------------------- Subject: lang/lisp/impl/clisp/sybase/ This package is related to CLIPS, not CLISP. Since more recent versions of this package are included in areas/expert/systems/clips/sybase/ we've deleted it from the repository. ---------------------------------------------------------------- Subject: Truncates files in areas/learning/systems/learn_pl/ The following files appear to be truncated on the AI 1-1 CD-ROM: areas/learning/systems/learn_pl/discr/discr.pl areas/learning/systems/learn_pl/invers/invers.pl areas/learning/systems/learn_pl/vs/vs.pl They were truncated on the original site as well. The author has provided us with new copies, which are now available in the repository. ---------------------------------------------------------------- Subject: Problems accessing the AI Repository using Ange-ftp Users of Ange-ftp will have trouble accessing the AI Repository, because Ange-ftp tries to do ls "-la /user/ai/" Apparently using strings to pass extra arguments to ls runs into a ftpd security restriction when the string includes slash (/) characters, returning a "... is not accessible to guest users" message. Since passing extra arguments to ls in this fashion is non-standard, CMU Facilities will *NOT* be modifying our ftpd to fix this problem. It is up to ange-ftp to support existing standard ftp daemons, not vice versa. This problem occurs with version 19.23 of ange-ftp. Later versions may have fixed the problem. ---------------------------------------------------------------- Subject: How do I unpack a file with a .??? extension? The most common incarnation of this question is "How do I unpack a file with a tgz extension?" A .tgz file is a gzipped tar file. To unpack such a file, first gunzip it with 'gzip' or 'gunzip', then untar it with 'tar'. To gunzip the file, you can use either of the equivalent operations, gzip -d foo.x or gunzip foo.x depending on your system (PC users will use gzip with the -d switch). The extension x should be dgz (gzipped dvi file) gz (gzipped text/data file) pgz (gzipped PostScript file) --> ps sgz (gzipped shell archive) --> shr tgz (gzipped tar archive) --> tar txz (gzipped text file) --> txt In the case of the .tgz file, this will produce a .tar file. To untar a .tar file, use the tar command with the xf switch, tar xf foo.tar Some versions of 'tar' provide built-in support for gzipped files (especially on MS-DOS systems). ---------------------------------------------------------------- Subject: I'm having trouble accessing the repository. I keep getting the warning Access not allowed from guest users for path "cd/user/ai". There is a space between the cd and the /user/ai. For example, ftp> cd /user/ai/ ----------------------------------------------------------------