SAOimage display of M-51

SAOimage on 16(or more)-bit Displays

SAO/TDC Home Page
John Ouellette 18 June 1998

For those people running Linux and who normally use a 16-bit or higher display, there is a possible workaround for the nuisance of having to start an 8-bit XServer whenever they want to use SAOtng (or XImtool). The IRAF FAQ suggests using XNest to start a nested XServer which runs inside your 16-bit display, but is itself an 8-bit display. Ideally, it would be possible to run an SAOtng within this nested XServer while still using various 'colour-intensive' applications, such as netscape, in the 16-bit Xserver. The unfortunate reality is that many video cards don't support multiple display depths: you can use XNest, but it has to run at the same depth as the main XServer....

Under Linux it is possible to use one of the virtual terminals (Ctrl-Alt-F1..12) as a second display. Normally when you start Xwindows, your display (usually :0.0) starts up on the virtual terminal accessed through Ctrl-Alt-F7. If you were to start second Xsession (called, say, :1.0) it would start under a different virtual terminal (usually Ctrl-Alt-F8). Here's what I do, which is probably not the most elegant solution:

This uses a fair bit of memory (each Xserver is going to be ~10MB, plus whatever utilities you start) but is still much faster and more convenient than logging off to start an 8-bit display.... The two servers can be treated like separate XTerminals running off the same server.

I have no idea if the XServers for Solaris, SunOs, Alphas, etc. allow virtual terminals, but it may be that XNest will work on their video cards.
John Ouellette

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