Date : Wed, 21 Jul 2004 12:12:21 GMT
From : "Thomas Harte " <thomasharte@...>
Subject: Re: bbcim/bbctape (a UEF/CSW perspective)
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UEF, the tape image
format I've long
been pushing and
which is now
supported to a
varying degree by
emulators on PC,
RiscOS and Mac OS
and by tools on
those platforms and
for platform neutral
systems such as Java
(particularly of
interest is
UEFReader -
http://uefreader.sourceforge.net/)
and PERL, has been
able to support so
called 'security
waves' for a while
now due to the work
of Fraser Ross's,
whose tool for
highly accurate UEF
creation will go
live when Dave M of
The Stairway to Hell
(http://www.stairwaytohell.com
- a massive UEF
resource) completes
his new project -
The Acorn
Preservation
Project, a new site
that will be at
least partly aimed
at collecting and
storing perfect tape
images in the UEF
format.
Main controversial
elements of the file
format are that it
is binary and
compressed.
The full spec can be
found at
http://electrem.acornelectron.co.uk/UEFSpecs.htm
, but to cut a long
story short
'security waves'
allow an encoding of
individual cycles of
the wave (so a
single cycle of a
2400Hz wave can be
included, for
example), and can be
bookended by half
cycles - i.e.
movements of the
wave from zero and
back to zero with
only one arch. Is
this the sort of
thing currently
under discussion?
My emulator,
ElectrEm (in its
new, 'Future'
incarnation), can
fully support these
UEFs, and on the MS
Windows version is
capable of
supporting also CSW
tapes. CSW is a
format from the
world of the ZX
Spectrum which
encodes tapes as
time counts between
zero crossings. This
is therefore able to
support the same
sort of variety as
UEF. Fraser has sent
me numerous
BBC/Electron tapes
encoded in CSW and
therefore I believe
the standard
conversion tools for
ZX Spectrum tapes at
World of Spectrum
(http://www.worldofspectrum.org/)
are perfectly usable
for Acorn cassettes.
-Thomas
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