Known problems with Sim390 mainframe emulator  

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18 Feb 2005 - MUSIC/SP scheduler problem if up for > 50 days

Description: If a MUSIC/SP system is kept up for more than about 50 days, there is a problem in the scheduler, causing application programs which call the DELAY() routine to stop responding. This can cause server programs such as HTTPD and FTPD to stop working. The MUSIC system itself continues to work, and the problem can be corrected by cancelling all Btrm tasks and restarting them. The problem is believed to be caused by field $TCBTLAT (a 32-bit time value in units of 0.001024 seconds) wrapping to 0. It is not a Sim390 emulator problem. There is no fix available at this time.

Fix: None available. As a work-around, you should re-IPL MUSIC/SP before it has been up for 50 days. In any case, it is advisable to shut down MUSIC/SP at least once a month, in order to make backup copies of its volume files.

18 Feb 2005 - Sim390 TCP/IP problem for long writes to a socket

Description: This is a problem in Sim390's support for the IUCV-Socket interface used by MUSIC/SP application programs for TCP/IP. If the program does a write operation to a socket, with a length exceeding 20480 bytes (20K), e.g. by a call to write() or send(), only the first 20K is sent to the socket. The function return value is 20K. This is fine for an application socket in nonblocking mode, but for blocking mode all the data should be written before the function returns.

Fix: Apply Sim390 version 1.5 or later, when it becomes available.

18 Feb 2005 - MUSIC/SP FTP client: file transfer aborts on a slow connection

Description: If the MUSIC/SP FTP client program is used to upload (PUT) a binary file using a slow connection (e.g. telephone modem speed), the transfer often aborts part way through. This is due to a low timeout (10 seconds) used for writes to the socket. A larger timeout should be used, especially if a large socket buffer (such as 16K) is used by the application program. The FTP client issues an error message like "unable to write to file".

Fix: Apply the misc5.arc update to MUSIC/SP 6.1.

27 Nov 2004 - MUSIC/SP FTPD server - problem with passive mode

Description: MUSIC/SP's FTP server (FTPD) has a problem with passive mode (the PASV command) file transfers for some FTP clients, including the Firefox browser. FTPD gives response code 450 for some operations such as an attempt to GET a directory name; it should give response 550 instead. The client interprets 450 to mean that passive mode continues, while the server has actually terminated passive mode.

Fix: Apply the misc5.arc update to MUSIC/SP 6.1.

11 Aug 2004 - Problem with ESA/390 virtual memory

Description: Incorrect caching of virtual-to-real address translations in Sim390 can cause occasional errors. The problem occurs only in programs that use the IUCV socket interface, i.e. TCP/IP. Occurrence is unpredictable, but most MUSIC/SP TCP/IP utilities seem to be unaffected. This problem will be fixed in sim390.exe version 1.4, which will be available in a few days.

Fix: Download the latest version (1.4 or later) of sim390.exe.

16 Feb 2004 - Problems with MUSIC's Web server (HTTPD)

Description: (1) File $tcp:mime.support was missing from the 1-vol demo MUSIC system. This caused some file types, such as .gif and other image files, to not display correctly in browsers, because the file MIME type was not being set properly in the HTTP header. (2) MUSIC's web server (HTTPD) was not giving the correct date/time in the "Last-Modified:" header for served record-format U files. The date was always Jan 1, 1970.

Fix: Restore (with REPL=T,SETUI=T) the files from fix_http1.arc

16 Jan 2004 - Problem: TN3270 connection fails with some clients

Description: It has been reported that some TN3270 clients (e.g. QWS3270 and z/VM's Telnet) are unable to connect to Sim390's TN3270 server. The error message on the Sim390 operator console is "Remote 3270 session ended, dev=xxxx, unspecified condition (errn=0)". This occurs during the Telnet "handshake" negociation.

Fix: (Feb 2, 2004) A fix for this was tested via sim390_12beta.exe, and now has been incorporated into Sim390 1.2. The cause of the problem seems to be that the client is sending "WILL BT" and "WILL EOR" commands in separate packets.

06 Jan 2004 - Problem: TN3270 server is filtering IP addresses

Description: The Telnet 3270 (TN3270) server in the original Sim390 (distributed in the .zip file dated 2004-01-04) prevents connections from non-McGill IP addresses.

Fix: (Jan 12, 2004) This problem is fixed in Sim390 1.1 and later. Sim390 1.1 also allows the TN3270 IP address filtering to be set by adding remote3270filter statements to the Sim390 config file. For a description of the config statements, get file config.txt.