Making a copy of a tape made on an MPE system using an HPUX system!

[Jamal Asi]

I have tapes that were created on an MPE system. I don't have that system anymore. I only have HPUX systems now. Is there a way to make copies of these tapes using an HPUX system?

[Rodney Hills]

If you want to copy tapes, then "dd" is the command. Do a "man dd" for more info.

You will have to take in account that tape formats are dependant on what generated them. If a cobol program used IBM standards, then you will have a tape header and a tape trailer. Also if the tape is EBCDIC, then "dd" does have an option for EBCDIC to ASCII. Also in cobol the records can be fixed or variable. This can be specified on dd also.

If the tape was generated with a backup utility on MPE, then you will have to know the layout of the tape to copy each block of data that is terminated by a tape EOF marker. You will have to be sure to use the "norewind" option of the tape device to keep the drives positioned correctly after each copy using dd.
But then only the backup utility that generated the tape would be able to restore.

My 2 cents.

Good Luck

-- Rod Hills

[Bill Hassell · Accepted solution]

Yes, you do need to know what format was used. Most MPE tapes are variable length records, 80byte records for the headers, data records in a variety of lengths and formats, and trailer of end-of-file records. This is a typical ANSI style tape format. As mentioned, the tape might be in a backup format, or it could be in fcopy format, ANSI format with ASCII or EBCDIC records, etc.

The problem is that dd expects a stream of data and tapes are unit record devices. So a true copy of a tape with variable data records will not be possible with dd. Only a program that is smart enough to reserve a maximum record length area, perform a read and check for the actual length, then write that same record length out, will work. Unfortunately, there is nothing native to HP-UX to perform this task.