Dear Saxena ji,
Thank you for inquiry.
West facing windows can be a big source of heat, first measure which you...
Why all these are not applicable to Tuticorin port or the one planned in AP or WB ?
What an eye opener! As an environmental engineer,disposal of sanitary napkins has always been a concern during waste...
A WHOLE new world of recording on a
blank compact disc (CD) is now emerging. Researchers in Japan and The
Netherlands are working on the concept
of using a CD recorder at home to copy
favourite music tracks on blank CDs or
record film sequences on blank video
Hi-fidelity cD recorders exist. But
they are priced at several lakhs of rupees
each, while blank CD discs cost about
Rs 400. The blanks are the "write once"
type, which means they cannot be
erased and reused. Erasable CDs also
exist. High-end personal computers use
them for mass storage or back up of
There are 2 different types of CD
recorders. Neither will work with the
laser optics in ordinary CD players.
Consequently, all the leading electronics, chemical and tape companies have
been trying to make an affordable
erasable CD that will work on existing CD
Reports in Britain and Japanese
publications, detailing these advances,
state that several years ago, Tandy
computers had claimed to have a
blank disc that would do the trick.
Called Thor, it was to be coated With a
mix of dye materials which changed
their optical character when hit with
laser light. Hit again, their original state
was restored. But Thor never saw the
light of day.
TDK, the Japanese tape company, is
reaping some success with
reversible dyes, but it admits
that the erase facility will work
only a limited number of times.
So the disc uses a tape which
can be erased and re-used only
a few dozen times.
The evolution of recording
on a blank CD involves working
With several kinds of discs, each
serving its own particular purpose. The personal computer is
the Trojan horse that is driving
recordable CD into the livingroom. It takes a long time
because record, film and computer industries have completely different cultures. The record companies and film studios see home copying of music
and films as a threat.
The idea of consumers
using a CD recorder to copy
favourite music tracks or, with
the plans for video CDs, film
sequences, is obviously anathema to
copyright owners. It also explains why
hi-fi CD recorders are so expensive, and
targeted at professional users.
Today's floppy disks do not have
enough storage capacity to work as mass
back-ups. Streamer tape is slow and
Clumsy. SO, CD recorders are being sold
for computer use and there is a race on
to drive the price down.
CD recorders for PCs now cost less
than us $1,500 in us, and the price of
blank write-once discs is falling to about
us $9. But, prices of both are expected a
halve within 2 years.
A computer software is already
available in the market that lets a
recorder make copies of music or video
tracks from a pressed cD on to
CD, which then plays on an ordinary
A new high-tech development in the
electronics industry has emerged where
companies are now demonstrating
new high-density versions Of Co. Pre
recorded discs will be able to store a full
length film on a single side of a
disc, with broadcast quality pictures
sound or as much computer data as sex
eral conventional CD-rom (read-only
Modern PCs are designed to play
multimedia CDs that mix data, music
and video. The prospect of stopping a
recorder from copying music and video
disks while still letting it copy computer
data, seems remote.
Audio and video tape, and floppy
discs, are now so cheap that it is often
easier to use a new one than to check
content of used media and take a dec
sion to erase. If blank write-once CDs
cheap enough, the same model appbeL
With the right marketing strategy
idea of paying a few hundred rupees
extra for a disc that will erase a
dozen times might well appeal to the
For computer applications, there is
much to be said in favour of no
erasable discs. If it is used to back-up
large quantities of database or
sheet files, the last thing the owner
wants is the risk of erasing in error.
For applications where erasability
becomes necessary, for instance,,the
temporary storage of data that is contain
ually being updated, the computer
industry is moving in the direction or
phase-change recording. This works
more like a tape recorder which can
overwrite one recording with another
without first having to erase it.