[daip] Problem Loading TV

[Eric Greisen]

Carver, David Christopher writes:
 > I am having problems running the TV display on AIPS. The data has been
 > loaded in using 'FITLD' and seems to appear fine. Then, I try to start
 > the TV with the following:<br>
 >       INP TVALL<br>
 >       INDI 1<br>
 >       GETNAME 1<br>
 > <br>
 > This seems to work, as it puts the correct file and other information
 > in the parameters. However, when I do 'TVALL', I get the following: <br>
 >       ZSSSL2: tcp/ssslock NOT A SERVICE<br>
 >       AIPS 1: ZSSSLK: ERROR   2 ON LOCK<br>
 >       AIPS 1: ON LOCK ERROR    6 FROM ZSSSLK<br>
 >       AIPS 1: YTVOPN: TV LOCK OPEN ERROR      6<br>
 >       AIPS 1: TV OPEN ERROR      6<br>
 > <br>
 > I am running Red Hat Linux and my computer appears to be on a 16-bit
 > display. I tried to change this to a 24-bit display, going by the
 > instructions on the Managers' Questions page. However, the only
 > XF86Config file is a write-protected buffer (listed as XF86Config~). I
 > found other information online about changing to a 24-bit diaplay
 > through the command line, but that did not work either. <br>

The specific error arises because you are using Inet sockets without
defining the system service numbers to be used.  From the aips manager
FAQ:

Problems with the TV, message, TEK and tape servers

The instructions to change your /etc/services file are often
overlooked. The Inet versions of XAS with its TVSERV lock daemon,
MSGSRV, and TEKSRV all require that predictable node numbers be
reserved for them. The remote tape services also require these and do
not offer a UNIX (non-network socket) option. In both cases, if you
need to communicate between two computers (or more), the following
must be installed in your /etc/services (or YP services):

sssin           5000/tcp        SSSIN      # AIPS TV server
ssslock         5002/tcp        SSSLOCK    # AIPS TV Lock
msgserv         5008/tcp        MSGSERV    # AIPS Message Server
tekserv         5009/tcp        TEKSERV    # AIPS TekServer
aipsmt0         5010/tcp        AIPSMT0    # AIPS remote FITS disk access
aipsmt1         5011/tcp        AIPSMT1    # AIPS remote tape 1
aipsmt2         5012/tcp        AIPSMT2    # AIPS remote tape 2
aipsmt3         5013/tcp        AIPSMT3
aipsmt4         5014/tcp        AIPSMT4
aipsmt5         5015/tcp        AIPSMT5
aipsmt6         5016/tcp        AIPSMT6
aipsmt7         5017/tcp        AIPSMT7

You do not need to install all the tape services unless you have a
large number of tape devices on some computer.

Other problems include shared memory size problems on Macs and Solaris
and Linux's insistence on 16-bit "TrueColor" as its default visual in
XWindows. Both of these are addressed below.

RedHat Enterprise and some other systems have shown a problem
characterized by TV cursor reading appearing sporadic. This issue
almost certainly arises from internal Internet loopback problems in
the operating system. We have found that the AIPS Inet TV works fine
on these systems when actually talking to a different computer; it
only goes bad when talking to itself. The aips command-line option
tv=local (see the man page or help aips or the CookBook chapter 2 for
details) uses a local Unix socket and does not seem to suffer from the
bad performance problems.

AIPS works, tekserver works, but the TV doesn't come up
 
    This is seen most often on Linux systems. Almost certainly your X
Windows configuration is set to use a 16-bit display. The AIPS TV can
only support 8 and 24 bit displays (32 and 24 should be equivalent).
Type "xdpyinfo | more" and if you see this:

          
            default visual id:  0x20
            visual:
              visual id:    0x20
              class:    TrueColor
              depth:    16 planes
          

    ... then this is the problem. If it says 8 or 24, then the TV
should work. If it says 16, then you should alter your X configuration
to allow either 8 or 24 bit display. You should use the supplied
tools, e.g. XConfigurator under Red Hat Linux, to do this; only edit
the XF86Config file directly if you know exactly what you're doing!


AIPS will not work with 16-bit TrueColor displays since that is simply
too few bits to do real science.  Your error messages above did not
reach the point at which it respnds to this issue.

Eric Greisen