Tape backup functions in NT/2000

OSR_Community_User · June 27, 2001, 5:05pm

Hello,

I am starting to create a system for backing up files to DDS tapes.
I’ve seen the Windows tape backup functions in Platform SDK, but that
functions are so hard to understand.
If have someone that worked with that functions, could you send any sample
code, justo to take a look. My system will make incremental backups, but I
still can’t figure out how the files are stored/retrieved in/from the tapes.

Thanks in advance

Raul Martins Fragoso
Sao Paulo - Brazil
raul@lm.com.br

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OSR_Community_User · June 28, 2001, 8:49am

Raul,
Its actually fairly simple. You read the data from the file with
BackupRead and write it to the tape with WriteFile (and the inverse for
restoring). I think your io has to be performed on multiples of the media
block size. Move around the tape with SetTapePosition. The various marks
(file marks, etc) are for organizing your media format - they are used to
quickly seek around the tape. There is a freeware c++ class library called
WFC which has a ‘wrapper’ for the tape api. I don’t know if its useful, but
here it is:

http://www.samblackburn.com/wfc/index.html

You can also download a win32 open source port of unix TAR from several
sources (I think from GNU’s site, check there first). The port uses the
tape api.

Microsoft’s Tape format is also availible on the web:
http://www.layton-graphics.com/mtf/MTF_100a.PDF

It doesn’t show you how to use tape api, but may give you some ideas when it
comes time to design your on media layout.
Hope this helps!

-Joel

-----Original Message-----
From: Raul M. Fragoso [mailto:xxxxx@yahoo.com]
Sent: Wednesday, June 27, 2001 5:04 PM
To: File Systems Developers
Subject: [ntfsd] Tape backup functions in NT/2000