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vlafiller.tapeinput - Function

	Package	nrao
	Module	vla
	Tool	vlafiller

Specify the input tape device.

Synopsis
tapeinput(device, files)

Description

The tapeinput function specifies that the input data source is the specified files on the specified tape device.

VLA archive data is normally stored on tape. Each tape may contain numerous files with the data from different projects mixed within one file and/or spread across numerous tape files. The tape archive log will contain a summary of what data is on what tape file.

This function tells the vlafiller tool which tape device and which files to read from the specified tape device. The tape device is the standard Unix name. Typical examples are /dev/rmt/0ln for Solaris 2.x and /dev/nst0 for Linux.

The files are numbered beginning at one. The files that are to be read are specified with positive integers that are in ascending order. For example specifying files=[1,2,10] will read the first, second and tenth files from tape. ^1.4

Users of AIPS should note that the AIPS++ convention of explicitly specifying which files to read is different, and more flexible, than than using the NFILES adverb in the FILLM task. In FILLM the NFILES adverb specifies how many tape files to skip prior to reading to reading any data.

The vlafiller tool always rewinds the tape in order to know where the the tape is currently positioned when the files are specified using integers greater than zero. If you have manually positioned the tape to the start of the file you want to read you can specify that the filler should ``read the next file'' using files=0. The number zero in this case meaning ``read the next file''. In this case the filler will not rewind the tape prior to reading the data. It is also possible to specify files=[0,0,0] which means ``read the next three files'' and to mix zeros with absolute file numbers. For example files=[1,0,10] will read the first, second and tenth files, but files=[1,0,2] will produce an error message as the filler will not read file two twice.

This functions returns F if the specified tape is not readable.

Arguments

device		The tape device.
		Allowed:	string
		Default:	no default
files		The files to read.
		Allowed:	vector of integers
		Default:	[1]

Returns
T or F

Example

      include 'vlafiller.g'
      v := vlafiller() 
      v.tapeinput('/dev/nst0', files=1) 
      v.output('file1.ms') 
      v.selectsource(source='ngc1234', qualifier=1) 
      v.fill() 
      v.done()

This example is identical to that for the vlafiller constructor except that the input data is the first file on the specified tape and all the data of ngc1234 with qualifier will be copied.