How to read COMIC or SHARP2 data?

© European Southern Observatory

To read COMIC or SHARP II data from DAT, you need a programm called wdat.

This ANSI C program was written by F. Lacombe at Observatoire de Paris- Meudon.
Please contact F. Lacombe to report bugs.

wdat has been added to the eclipse data reduction software package and is also distributed separately for people who just want to read their Adonis DAT tapes.

Downloading wdat:

The source code is here: wdat.c (18kbytes)
The man page is here in HTML format: wdat man page in HTML

Compiling wdat:

To compile wdat.c, use the following command :

    CC CFLAGS -o wdat wdat.c

where CC is the name of your local ANSI C compiler, and CFLAGS are the flags you may need to make it compile ANSI. examples :

    with gcc:    gcc -ansi -o wdat wdat.c
    on Solaris:  cc -o wdat wdat.c
    on Sun4:     acc -o wdat wdat.c
    on HPUX:     cc -Aa -D_HPUX_SOURCE -o wdat wdat.c

Ask more details to your system administrer if you do not know how to compile ANSI C on your Unix machine.

wdat also compiles on VMS. To do this, first change in wdat.c the line:

#define VMS 0
to
#define VMS 1

To compile, you would type:

    cc/stan=vax wdat_2_0_Vms
    link/exe=wdat wdat_2_0_Vms

Using wdat:

Typing wdat -help yields help:

WDAT version 2.0 
Fast skipp
Wdat <options>
Options : 
-d <device> : selects a device, default is the TAPE environment variable
-nr         : do not rewind tape before first access
-l          : ONLY list tape contents 
-l= file    : ONLY list tape contents on file
-fits       : skipp files when not FITS
-log        : automatically translates logfiles (.LOG) from Os9
-e= file    : read exclusion masks in file
-e MASK     : excludes all files matching the mask
-s= file    : read selection masks in file
-s MASK     : select only files matching the mask
-q          : ask before copying

The same kind of help is accessible through wdat man page, if you have installed the eclipse library.

Examples:

with a DAT driver called /dev/nrst0 :

To write in the file "listing.lis" the content of the DAT:

    wdat -d /dev/nrst0 -l= listing.lis

To write on your account the data from the files selected in selection.lis:

    wdat -d /dev/nrst0 -s= selection.lis -w

Tips and tricks

The following tricks have been suggested by Andrei Tokovinin:

Check out if your workstation knows the 'mt' command. If if does not, modify the definition in the wdat.c source code to reflect this. The line to modify is:
```
#define MT_FSF 1
Should be changed to:
#define MT_FSF 0
	
```
It is better to use non-rewinding devices. On many brands of Unix, this is identified by device names ending with 'n'. Consult your local system administrator to know how to access your tape device in non-rewinding mode.
Answer y (not <CR>) when asked to confirm tape label.