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BIGDISC

   BIGDISC is a means by which Tripos users can get access to a
large amount of temporary disc space. It is hoped that this will
reduce the number of times the main disc fills up with large
temporary files. At least 60 megabytes of space should normally be
available for BIGDISC. Space used on BIGDISC is not subject to the
accounting mechanisms used for the main filing system.

   Users are given access to BIGDISC by setting up two assignments in
their profile, associating 'BIGDISC:' with the root directory on
the BIGDISC pack, and 'BD:' (a short name because this will be typed more
often) with their private user directory on that pack.

   The reason for making potential users ask for their profiles to be
updated is not so that access is restricted to the chosen few, but rather
to make sure that users of the BIGDISC facility are made aware of its
limitations.

   The limitations are roughly as follows:

 - The BIGDISC pack is not archived.  If it becomes damaged by
   hardware or software error, it is likely to be reinitialized rather than
   mended.

 - BIGDISC will be useless if it gets clogged up with old material. All
   users will be given access to the whole of it, and will be encouraged to
   keep it tidy by scratching files belonging to other users if necessary.
   Old files are likely to be purged regularly anyway. Users should so
   arrange their work that they never have the only copy of anything
   valuable on BIGDISC.

 - Since BIGDISC is on a different pack from the main filing system, it is
   not possible to rename objects between directories on BIGDISC and
   directories on the main pack.  Particular care should be taken when
   editing big files on BIGDISC, since there is a danger of creating large
   temporary files in 'T:' on the main pack. It may be appropriate to
   reassign 'T:' to a directory on BIGDISC before starting such edits.

 - The BIGDISC facility makes use of equipment which is at present not
   required for other purposes. In the future, more pressing demands on
   the fileserver equipment may mean that BIGDISC has to be withdrawn.

 - The BIGDISC pack may be taken out of service if a disc drive fails, or
   if fileserver equipment needs to be taken for other purposes.


