fftt -- Device Driver

Floppy-tape driver
/ddeevv/fftt

The device  driver fftt supports floppy-tape drives.  It  has major number 4.
Minor-number    assignments   are   documented    in   the    header   file
/uussrr/iinncclluuddee/ssyyss/fftt.hh.

fftt works  with QIC-40 and  QIC-80 drives from  Colorado, Archive, Mountain,
and Summit.

fftt offers the following features:

-> It uses  the bad-block  bitmap that  is written into  the first  two 32-
   kilobyte segments of tape at format time.

-> It uses  standard QIC-40/QIC-80 Reed-Solomon  error-checking code.  This
   technique uses three of every 32  blocks for error checking.  NB, a tape
   block is one kilobyte long.

-> It supports no-rewind-on-close.  This feature permits you to concatenate
   several archives onto a single tape cartridge.

-> It performs auto-configuration for users who do not know if their drives
   use soft select  A or soft select B, or hard  select on unit 0, 1, 2, or
   3, with manual override.

-> It lets you configure the size of the tape buffer, from 64 through 4,064
   kilobytes.

-> It  reads from  and writes  to buffer  space rather  than going  to tape
   whenever possible.

-> It works with  partially formatted tapes.  Some formatting utilities let
   you select the number of tape  tracks to format, in case you do not want
   to take the time to format an entire cartridge.

-> It recognizes both 205-foot and 307.5-foot tapes.

-> It works  with the COHERENT  command ttaappee with  the following arguments:
   rreewwiinndd, rreetteennssiioonn, sseeeekk, ssttaattuuss, and tteellll.

Please note that release 1.0 of fftt has the following limitations:

->   It  does not  format tapes.   For now,  we suggest  that you  buy pre-
     formatted  tapes, or  use formatting  utilities available  under other
     operating systems.

->   It does not support the QIC-80 formats for MS-DOS or UUCP file systems
     on tape.  These features do not  need to be part of the device driver,
     and can be implemented by user-level applications.

->   It does not perform data compression, as documented in QIC-122.  Other
     forms of data compression are presently available under COHERENT, such
     as the -zz option supported by the tape-archive command ggttaarr.

->   The device  driver is character-only: there  is no corresponding block
     device for floppy tape.

->   It does  not support 1,100-foot  tapes.  Although the  QIC-80 standard
     mentions this length, it is not in common use.

->   You cannot  access a floppy-disk  drive from COHERENT  while a floppy-
     tape drive  is in use.   Likewise, if a  floppy disk is in  use -- for
     example, if it is mounted -- you cannot access the floppy-tape drive.

->   Although a QIC-80 drive can read a tape that was formatted for QIC-40,
     it cannot write to such a tape.  The cartridge must be reformatted for
     QIC-80 before a QIC-80 drive can write to it.

_S_e_e _A_l_s_o
ddeevviiccee ddrriivveerrss, ffdd, ggnnuuccppiioo, ggttaarr, ttaappee
