XT(4S)

NAME
xt - Xylogics 472 1/2 inch tape controller

CONFIG — SUN-3, SUN-4 SYSTEMS
controller xtc0 at vme16d16 ? csr 0xee60 priority 3 vector xtintr 0x64
controller xtc1 at vme16d16 ? csr 0xee68 priority 3 vector xtintr 0x65
tape xt0 at xtc0 drive 0 flags 1
tape xt1 at xtc1 drive 0 flags 1

DESCRIPTION

The Xylogics 472 tape controller controls Pertec-interface 1/2” tape drives such as the Fujitsu M2444 and the CDC Keystone III, providing a standard tape interface to the device see mtio(4). This controller is used to support high speed or high density drives, which are not supported effectively by the older Tapemaster controller (see tm(4S)).

The flags field is used to control remote density select operation: a 0 specifies no remote density selection is to be attempted, a 1 specifies that the Pertec density-select line is used to toggle between high and low density; a 2 specifies that the Pertec speed-select line is used to toggle between high and low density. The default is 1, which is appropriate for the Fujitsu M2444, the CDC Keystone III (92185) and the Telex 9250. In no case will the controller select among more than 2 densities.

The xt driver supports the character device interface.

  EOT Handling

The user will be notified of end of tape (EOT) on write by a 0 byte count returned the first time this is attempted. This write must be retried by the user. Subsequent writes will be successful until the tape winds off the reel. Read past EOT is transparent to the user.

  Ioctls

Not all devices support all ioctls. The driver returns an ENOTTY error on unsupported ioctls.

1/2” tape devices do not support the tape retension function.

FILES
/dev/rmt0
    low density operation, typically 1600 bpi
/dev/rmt8
    high density operation, typically 6250 bpi
/dev/nrmt*
    non-rewinding

SEE ALSO
mt(1), tar(1), mtio(4), st(4S), suninstall(8)

BUGS

Record sizes are restricted to an even number of bytes.

Absolute file positioning is not fully supported; it is only meant to be used by suninstall(8).