Most
Frequently Asked Questions about CD-ROM
Networking
Q1) What is the advantage of getting a
CD/Maxtet tower compared to just hooking
up multiple individ-ual CD-ROM drives to
my network?
A1) Two primary reasons: Expansion and
speed. A SCSI bus has just seven IDs. This
normally limits the number of CD drives
that can be supported to just six since
the hard drive takes up one address
leav-ing just six IDs for the CD drives.
However, the CD/Maxtet has a built-in RISC
processor that enables eight CD drives to
take up just one SCSI ID. This, in effect,
"extends" the network so that many more
CDs can be supported. In fact, you can put
multiple CD/Maxtet units on the primary
SCSI bus thus giving great expansion
capability.
Secondly, Optical Access' SuperCache
control software speeds access and data
retreival for CD infor-mation. It works in
tandem with the OS to provide maximum
performance in situations where multi-ple
people are accessing multiple CDs.
Q2) Can multiple users access the same
CD at the same time?
A2) Yes, with our SuperCache software,
we cache all the most frequently accessed
data such as icons, indexing, and
directory information onto the server's
hard drive which reduces constant seeks to
the drives for this information and, thus,
speeds up the performance of your network.
The number of users simultaneously
supported will depend on the type of
title. Note: CD/Maxtets and CD/Servets are
equipped with, at minimum, quad-speed
("4X") CD drives so that multiple users
can be handled quickly.
Q3) Which titles work well and which
don't?
A3) Most CDs will work over a network.
It is rare that a publisher has crippled a
CD so that multiple peo-ple can't use the
CD. Many are just now figuring out ways to
charge a varying amount for their CD
depending on the number of users having
access. And, while it is true that most
will work, some CDs will work (meaning:
perform quickly and efficiently while
supporting multiple users at once) better
than others.
However, there are a couple of
situations that you need to be aware of:
1. While the video clip portions of CDs
can be used over network, it is difficult
in most situations to sup-port more than
one video transmission across the network
at once. This is due to the need for a
con-tinuous, uninterrupted data path which
even an Ethernet 10 Mbits/second network
has difficulty pro-viding. So multiple
users on a video at the same time is
something to be avoided. Note: Even with
that limitation, our customers are very
successful even using titles such as
encyclopedias which do have video clips.
The video is only a small portion of the
overall content of these titles. They
recognize the trade-offs.
2. Another title type that should be
avoided is highly interactive game discs.
Most of these are restricted to a single
user and are most appropriately used on a
stand-alone computer equipped with its own
drive.
Text, photos, graphics, video stills
and animation perform extremely well on
the CD/Maxtet and CD/Servet CD-ROM towers.
Q4) What are the minimum requirements
of the server to attach the tower?
A4) Minimum speed of 33 Mhz, and
approximatley 1 Mbyte of hard disc space
for each CD on line. SuperCache software
itself uses only 250K RAM.
Q5) If I need capabiltity to operate
on another network OS, do I have to buy a
different tower?
A5) No. We recognise that customers
sometimes have varied systems in their
organization and it is impor-tant to have
the utmost flexibility in configurations.
The CD/Maxtet hardware and firmware is the
same for any system. When the CD/Maxtet is
linked to an alternate system, it only
necessitates new control software which
Optical Access will provide. We support
most of the major networks.
Q6) Do all the CDs appear as one
volume which the users will have to search
thru to retrieve individual titles?
A6) Normally, the CDs appear as
individual icons on the users' screens.
The user merely clicks on an icon (on
Apple systems) like any other volume and
instant access to the CD is attained. In
the case of PC based systems, separate
drive letters are assigned to each title
or, alternatively, can be remapped to
single drive letters.
Q7) Can I let some users see one set
of CDs and other users a different set?
A7) Yes. This is a function within the
OS. If you have enabled or disabled their
ability to see a volume, they will be able
or not to be able to see the CDs at your
choice.
Q8) Should we buy computers with
built-in CDs or buy towers?
It's not a question of either/or. Both
methods have their place in a well
organized system. Put those CDs which
everyone needs access to on the CD/Maxtet.
This way you only need to deal with a
single copy and you can assure all network
users of access to the most important CDs
all the time. (Plus, you only need to buy
and keep track of ONE copy!) Reserve
"sneaker net" to distribute special CDs to
which only one person at a time needs
access out to CD-ROM-equipped
workstations. Both approaches have their
place.
Q9) What is the difference between a
"jukebox" and a "tower"?
Night and day! This is probably the
most misunderstood area in CD land!. A
"jukebox"typically has a single reader
unit but holds multiple CD discs. Only one
CD is directlly on-line at once -- making
this technology most appropriate for
stand-alone situations with single users.
(Note: Many people's per-ceptions of
CD-ROM use were formed in the era when
jukeboxes and their limitations were the
only available solutions for multiple
CDs.)
The CD/Maxtet is a "tower" which
dedicates a drive to each CD title -
putting every CD directly on-line,
assuring immediate access to multiple
titles for multiple users. Clearly, a
better network solution!
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