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Amiga Collections: MegaDisc
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MegaDisc 36 (1993-11)(MegaDisc Digital Publishing)(AU)(Disk 1 of 2)[m doscopy][WB].zip
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MegaDisc 36 (1993-11)(MegaDisc Digital Publishing)(AU)(Disk 1 of 2)[m doscopy][WB].adf
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CD32_&_CDROM
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About_CDRom
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About_CDRom
Wrap
Text File
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1993-10-29
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10KB
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201 lines
CDROM Technology
by
David Jacobs
David Jacobs is the editor of an Amiga publication called
"24-bits and pieces". It is a journal dedicated to 24-bit imaging
on the Amiga and is published quarterly.
David's background is varied with a Degree in Photography and
a Graduate Diploma in computer graphics. One of his main aims
currently is to make non- Amiga people aware of the options in
integrating the Amiga into their environment be it Mac or PC.
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The term Computer Disk Read Only Memory or CD ROM as it is
more commonly known, is a technology that has recently gained
prominence and renewed media attention. It is a technology that
has been around for many years but is only now achieving the
potential that was promised.
The ability to deliver huge amount of information (over 600MB)
in a compact and inexpensive medium is part of the attraction of
CD ROM. For many years, CD ROM technology was relegated to the
corporate and government area due to the high cost and relatively
specialised software titles available.
Recently however, computer applications have grown more
sophisticated and so have the storage requirements. CD ROM is
currently able to fulfil those requirements better than any other
medium and in a cost effective way.
The falling prices of CD mechanisms (due partly to an
increased demand) have also contributed to the resurgence of CD
ROM, as has the new area of Multimedia. Even in the games market,
the demand for better quality graphics and sound have fuelled
interest in CD ROM. Some software companies are even releasing
their software on CD ROM and are including the manual on the CD as
well.
To date, most of the development and sales have been in the
MS-DOS and Macintosh markets. Philips (CD-I) and Commodore (CDTV)
have both released stand alone CD ROM machines with a fairly small
impact on the market. Commodore's system was called Commodore
Dynamic Total Vision (or CDTV as it was marketed) was a machine
that never realised its potential. Overpriced and without many
good quality software titles, it has floundered and is not really
taken very seriously.
How can I use it?
As previously mentioned, the greatest benefit of CD ROM is the
huge storage capacity. This has led to many companies releasing
what I call "resource" disks that contain material that does not
always have to be on-line, but, nevertheless, has to be easily
accessible. Some examples of this include fonts, clip art, sound
files, background images, utilities, etc.
There are many such disks available for PC and Mac users but
relatively few specifically for the Amiga. This has led to many
Amiga users ignoring CD ROM. This is a great loss to them as
there is a wealth of material that is easily accessed by the Amiga
with very little effort.
How do I access CD ROM disks?
The first thing that is needed is, of course, a CD ROM drive.
There are a number of mechanisms and manufacturers available in a
number of interfaces. The ones that are of any interest to the
Amiga utilise the SCSI interface.
The drives vary in price partly due to the speed of the drive
and the transfer rate. Most average low cost drives are in the
300 to 600 millisecond average access time with a transfer rate of
150kB per second. Better (and more expensive) drives utilise
"Multispin" technology and have an access time of between 250 and
300 millisecond average access time with a transfer rate of 300kB
per second.
Drives are available as internally mounted units (for A2000
owners) or as external units in a housing with its own power
supply and connectors. Most utilise what is called a "caddy" to
hold the actual CD. This is essentially a housing that the disk
is placed into before inserting into the CD mechanism.
Connecting a CD ROM drive to a computer and inserting a CD ROM
title is not going to get one very far. Most CD ROM titles are
released in one of two "standard" formats. ISO 9660 and
Hierarchical File System (HFS) are the two most commonly used file
system. They correspond to MS-DOS and Macintosh platforms
respectively and they both require appropriate "drivers" or
interface software to access the information on the CD.
On the Amiga, there are three such packages available.
AsimCDFS from AsimWare, CDx from Xetec and CDROM-FS from Canadian
Prototype Replicas. Both AsimWare and Xetec include bonus CDs for
the Amiga and both will access ISO 9660 and HFS disks. The Xetec
driver also has the ability to play many CDTV titles via emulating
many of the CDTV internal functions.
Once the drive is connected to a SCSI controller card and the
driver software installed and mounted, you are ready to access the
data on a CD ROM. If the CD is designed for use by the Amiga, you
will be able to access the disk from Workbench and using icons.
If not, you will need to use a programme like Directory Opus,
Diskmaster or SID to traverse the directory structure of the disk.
Be aware that many of data files will have to converted to a
format that the Amiga can utilise.
What about CDTV?
The CDTV unit can also be used as a normal CD ROM drive.
However, the CDTV unit is not always compatible with some ISO 9660
disks and will cause the system to "crash". One solution to this
problem is to boot off a floppy drive with one of the above
mentioned CD drivers.
If you are going to use the CDTV unit with a keyboard based
Amiga, you will need to connect the unit to your computer with
something like ParNet. This will allow you to treat the CDTV unit
just like an external CD ROM drive.
Prices for CDTV units have dropped dramatically and this is
one option worth investigating, particularly if your budget is
very tight. At the recent WOC show in Sydney, units were selling
for under $400 new! Do be aware that the CD mechanisms in the
CDTV unit are NOT SCSI based and will not connect to a SCSI
controller card. Benefits of using a CDTV unit as a CD ROM
(besides cost) include the ability to play normal audio CD's and
the ability to serve as a backup Amiga (although limited in its
capability).
What is Photo CD?
Photo CD is a new CD ROM format developed by Kodak and Philips
for the storage of photographic images on CD ROM. It is a
marriage of traditional photographic and computer imaging and
storage technologies.
Essentially, you take your photographs as you normally would
(with a 35mm camera) and drop the film off at a processing house.
The film will be processed as usual and you will have the option
of transfering the images (slides or negatives) to CD ROM with up
to 100 images per CD. The images on the Photo CD disk can then be
viewed on a special Photo CD player through a television set or
monitor. A standard CD ROM drive can also be used (with
appropriate driver software) allowing manipulation of the
digitised images.
The Photo CD disk can also be used as a replacement for
negatives when reordering extra prints. The original images are
digitised at a relatively high resolution and are transfered to
prints digitally when required.
The advantages of the Photo CD system lie in the ability to
display your photos on a large screen such as a television set or
to send a set of images to friends or family on a CD and letting
then select what they want to print. The robustness of the CD is
also important considering the fragility of negatives.
Currently, most CD drives will allow what is called "single
session" retrieval.This means that you will only be able to access
the first set (or session) of images that is recorded on the CD.
Due to the nature of the new format, you can actually add new
images to the disk up to the limit of 100 images in multiple
sessions. To be able to access the extra sessions, you will need
a "multi-session" capable CD ROM drive.
As you can see, there is much more to CD ROM than meets the
eye. It is certainly a technology that you should be aware of.
We will see an increase in the usage of CD ROMs as applications
become more sophisticated and demanding on storage. There has
already been a PC game released on two CD ROM disks and we are
likely to see even more.
Full motion video on CD ROM is already a reality on other
platforms (and possibly very soon on the Amiga). Kodak's
involvement with Photo CD adds a new dimension to the medium.
Kodak has plans to release a professional version offering very
high resolution images as well as a multimedia format which will
include audio and graphics.
There have also been a number of "mastering" drives released
that allow you to create your own CD ROM. Although these drives
are in the $10-15,000 range, it is only a matter of time and
demand before we will be talking about floppy and hard drives as
quaint storage media.
For more information about Photo CD, contact the Kodak
Information Centre on (008) 333 194.
If you want more information on CD ROM for your Amiga, contact
me and I will try to help.
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