[daip] writing fits files with dd

Patrick P Murphy pmurphy at NRAO.EDU
Thu Aug 1 14:38:16 EDT 2002


On Thu, 1 Aug 2002 13:46:54 -0500 (CDT), Michael Bietenholz
   <michael at polaris.phys.yorku.ca> said: 

> Do you know if this can be done so that they are readable by AIPS.
> Ie., if I have fits disk files called xxx.fits, yyy.fits, etc; do know
> the invocation of dd that will write these to a tape so I can then
> read them

> ie. "dd if=xxx.fits of=/dev/rmt/0ln bs=28800"
>      dd if=yyy.fits of=/dev/rmt/0ln bs=28800"

Looks good to me; this is what I'd do, assuming I had the right device
(Solaris I assume, from the name; use /dev/nst0 on Linux).

> (I assume I need some form of blocking into the FITS n*2880 blocks)

Yes, but I'd (a) check the header [either "more" in an 80- or 81-wide
window, or a shell script like my fitsprint; ask and I'll send it] to see
if BLOCKED=T or not.  If there's no BLOCKED keyword, use 2880.  Otherwise
I'd use 28800 as you suggested.

				- Pat
-- 
 Patrick P. Murphy, Ph.D.              Division Head, CV Computing, NRAO
 Home: http://www.chien-noir.com/    Work: http://www.nrao.edu/~pmurphy/
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