Accessing the ctc on a 3B2/400 from a program ?

[Leslie Mikesell]

In article <744 at ambush.UUCP> storm at ambush.UUCP (Kim F. Storm) writes:
>
>We have to port a program to backup large files (and disks) on the
>23 Mbyte cartridge tape on the 3b2/400.
>
>There is no problems in moving the code (isn't C+UNIX wonderful),
>but we cannot get any good performance out of the tape drive, because
>we cannot make it stream.
>
The "afio" program posted a while back included support for the 3B2
streaming tape by doing the following:

  the flags to open() are  O_RDWR | O_CTSPECIAL

  after the open, ioctl(fd,STREAMON) is used to enable streaming

  streaming mode writes (and reads) must multiples of a certain size.
  Afio uses 31 * 512, and limits the total output to 1469 such blocks instead
  of watching for EOT from the device.

  Les Mikesell