1.4 How to Read Yohkoh Archive Tapes (GO_RDTAP)

The routine GO_RDTAP allows access to the Yohkoh archive tapes. Normally the archive data are written on Exabyte (8 mm) or DAT (4 mm) tapes. There is one archive tape for each week of data. The first step to accessing archive data are to determine which tape it is on. Use the WeekID table shown in the Reference Guide to figure out what tape you need. For example, if you wish to look at data on 27-Mar-92 you first determine that it is week 13 in 1992, so the weekID is 92_13. You can use the routine TIM2ORBIT with the /print option to get the week number. Put that tape into the tape drive.

You need to move to the directory where you want the data to be written.    

GO_RDTAP is a menu driven program to retrieve data from the archive tapes via a menu driven program. The ISAS and LPARL machines have a copy of the directory listing for each tape saved on the disk. This means that you can simply type:
IDL> go_rdtap
  and it will list all of the tapes that have been made. You need to select the tape that you are reading. If your system does not have the XBD files on-line, then type:
IDL> go_rdtap, /tape
after you have loaded the tape, and the program will read the directory listing from the tape.

1. A menu will appear with a series of weekly log files. If you do not need any of the weekly files, then just select QUIT/EXIT.
2. The next menu will be the file prefixes that are available. Click on each file prefix that you wish to copy to the disk.
3. When you have selected all of the prefixes you need, click on QUIT/EXIT.
4. The final menu is the FileIDs that are on the tape. Select the fileIDs you need, and then click on QUIT/EXIT.
5. You will be asked whether you are ready to read the tape. GO_RDTAP will also display the number of kilobytes that you have selected to read, so check the available space on the disk selected before continuing.

If the /ydb switch is used on the call to GO_RDTAP, then the weekly data files will be copied to their proper directories (the default is to copy them to the current directory).

See the Reference Guide appendix for more detailed information on the archive tapes.