Quasijarus 4.3BSD on 1600bpi magtape

From: Michael Sokolov <msokolov_at_ivan.Harhan.ORG>
Date: Sat Jan 25 10:40:01 2003

Jochen Kunz <jkunz_at_unixag-kl.fh-kl.de> wrote:

> Well, I had to use some programm to write the tapes, dd(1), maketape, or
> somthing else. I made good experiences with maketape to write 2.11BSD
> tapes, so I stayed with it and it worked very well.=20
>
> [...]
>
> The same for dd(1). There may some implementation differences in dd(1),
> say on SunOS or AIX, that may produce unusable tapes. Therefore I used
> maketape. I had a glance at the code and it seams that it does
> everything proper on every UNIX and Unix-like OS.
> Don't forget the chicken-egg problem. If I have no 4.3BSD-Quasijarus
> running, I have to use some random foreign OS to produce distribution
> tapes. (Or I have to bother somone else to do it for me.)

But dd is a standard general-purpose tool, as opposed to a highly specialized
program for installing 2.11BSD.

> I learnd that the bs=3D parameter of dd doesn't set the block size of the
> tape with an ioctl, it is only the buffersize parameter that is used in
> the write(2) syscall.=20

On every system I have used the sizes of records written on tapes are
determined precisely by how much you write with one write or writev syscall, no
ioctl needed. But if some weird system does require a special syscall, I can
bet that dd on *that* system will make it. On each system its native dd utility
will always do the right thing, as opposed to some special program ripped out
of a 2.11BSD distribution and used for something it was never intended for (to
write dist tapes for a completely different OS).

MS
Received on Sat Jan 25 2003 - 10:40:01 GMT