Path: utzoo!utgpu!attcan!uunet!lll-winken!lll-tis!helios.ee.lbl.gov!nosc!ucsd!ucbvax!DRACO.HAC.COM!MNK From: MNK@DRACO.HAC.COM (Michael N. Kimura) Newsgroups: comp.os.vms Subject: Re: Terminal name length problems Message-ID: <880808212618.24C186F3591@draco.HAC.COM> Date: 9 Aug 88 04:26:18 GMT Sender: daemon@ucbvax.BERKELEY.EDU Organization: The Internet Lines: 53 > > From: Mike Ardai > > Subject: Terminal name length problems > > To: John Hascall > > > > I just noticed some strangeness on our 8550. It has been up for > > 30 days, and the lat terminal numbers have just topped 999. It > > seems that 'show users' or something is using an 8-byte buffer > > to hold the terminal name and has just overflowed. I hope there > > is nothing important in the next byte :-} Does anyone know if this > > is just an ignorable nuisance, or is it a potential problem? > > > > /mike > > VAX/VMS Interactive Users > > 30-JUL-1988 10:43:14.44 > > Total number of interactive users = 3 > > > > Username Process Name PID Terminal > > ARDAI Ardai 20407260 LTA1009 LTA1009: > > ZELLER ZELLER985 20406522 LTA985: > > ZELLER ZELLER986 20406525 LTA986: > > > The same thing happens here, it seems that the show users buffer > is too small, hence the truncation. Also it looks at the last > character of the terminal name an if it is not at colon, it thinks > that it is a virtual terminal and so it looks for and displays the > "real live physical terminal" as well.... As it turns out SHOW USERS displays your terminal name from the PCB which is at offset PCB$T_TERMINAL and is a counted string (i.e. first byte is the length of the string) PCB$S_TERMINAL (8) bytes long. Therefore VMS can only hold a 7 byte terminal name in the PCB. You can verify that by calling $GETJPI with an item of JPI$_TERMINAL which will return PCB$T_TERMINAL. $ write sys$output f$getjpi("20407260","TERMINAL") LTA1009 Also, if the physical terminal name returned from $GETDVI (DVI$_TT_PHYDEVNAM) is not identical to the terminal name returned from $GETJPI (JPI$_TERMINAL) then the physical terminal name is also displayed. Usually this will be the case for a virtual terminal, but this is also the case when the PCB$T_TERMINAL name has had the colon truncated off and doesn't match the full name with the colon returned by $GETDVI --------------------------------------------------------------------------- Michael Kimura Internet: mnk%draco@hac2arpa.hac.com BITnet: mnk@draco.hac.com Telephone: (213) 615-9775 US Mail: Hughes Aircraft Company (RSG) P.O. Box 92426 MS: R2/A159 Los Angeles, CA 90009 ---------------------------------------------------------------------------