D0430@PUCC.BITNET (Paul Lansky) (01/15/87)
When running Vaxen and Suns with NFS what is the cost of a large amount
(e.g. 2mbyte) of conversion of floats from IEEE->VAX or the other way
around using xdp? I can see that it would be relatively painless for
small amounts of data but what happens under larger loads? Byte-swapping
I assume is cheap. Does anyone have a quicker solution?
Paul Lansky
Music Department
Princeton University uucp == princeton!winnie!paul
bitnet == d0430@puccmouse@mcgill-vision.UUCP (01/29/87)
In article <1567@PUCC.BITNET>, D0430@PUCC.BITNET (Paul Lansky) writes: > When running Vaxen and Suns with NFS what is the cost of a large > amount (e.g. 2mbyte) of conversion of floats from IEEE->VAX or the > other way around using xdp? XDR, it's called; I think it stands for eXternal Data Representation. > I can see that it would be relatively painless for small amounts of > data but what happens under larger loads? Byte-swapping I assume is > cheap. Does anyone have a quicker solution? It sounds as though you are afraid NFS will bog things down converting floats. Well, it will bog things down, but not because it's converting floats. There are very few floats involved in NFS (I can't recall any off-hand). If you are using XDR to transfer lots of floats around yourself, that's your lookout; but it's not NFS's problem. As I recall, converting between VAX and IEEE floats (or doubles) is fairly simple for the VAX; a few EXTV/EXTZV and INSV instructions. I don't know how time-consuming they are - does a VAX use a barrel shifter? der Mouse USA: {ihnp4,decvax,akgua,utzoo,etc}!utcsri!mcgill-vision!mouse think!mosart!mcgill-vision!mouse Europe: mcvax!decvax!utcsri!mcgill-vision!mouse ARPAnet: think!mosart!mcgill-vision!mouse@harvard.harvard.edu