question regarding IRAF's 16 frame iis support

Jason Quinn · IRAF Guru Joined: 07 Apr 2006 Posts: 151

I'm curious what architectural limitations on the number of display frames that IRAF can support are. How difficult would it be to increase it to 32? 512? 1024? Why have a limitation at all? I'm not sure how the image servers manage memory but it seems like they could do it on a need-to-have-it basis and only complain if the user actually attempts to load more images than the video RAM can handle.

Jason

fitz · Posted: Fri May 16, 2008 7:21 am Post subject:

The limitations come from the IIS protocol itself (which is what the actual IIS frame buffer devices used ages ago). Specifically, the headers are a structure of 16-bit values, and the frame is passed as a bit flag in one of the registers. Both the clients and servers would need to be modified to take full advantage of the 16-bit integer range, it could be done but it would be better to just add a modernized protocol instead.

Note that the move to 16 buffers required that the client get some sort of version from the server to know whether it supports the larger number of frame buffers so adding another flavor in another version would be easier. The simple truth is, though, nobody's ever asked for more that 16 frame buffers.

Cheers,
-Mike