Providing Access to External Databases - High-Performance Web Databases: Design, Development, and Deployment - page 489

Exhibit 33-2. LAN access to a modem pool.
$300, communication software cost $100, and a business line costs $50 per
month, the cost of providing ten employees individual modems, communi-
cations software, and business telephone lines is a one-time expenditure
of$4,000 and a monthly recurring cost of $500. Of course, all ten employees
with individual modems can simultaneously access the external database,
whereas, only five could simultaneously access modems in a five-modem
modem pool.
In most organizations, only a few employees usually access modems
simultaneously. Thus, a 2:1 ratio of employees to modems in a modem pool
is generally sufficient, and because a company saves each month on busi-
ness lines by using a modem pool, the infrequent inconvenience of an
employee not being able to access a modem immediately must be com-
pared to this savings. Purchasing fax modems can provide users additional
capabilities that further justify costs.
A method to reduce the cost of accessing external database information
on subscription-based optical and magnetic media products involves add-
ing a conventional or optical disk to the file server that enables multiple
LAN users to access information. The following example illustrates the eco-
nomics of disk access sharing. A database is available on a CD-ROM disk for
$300 per year; a site license for a LAN costs $1000. If CD-ROM readers cost
$400 and a Novell NetWare-compliant CD-ROM reader and software cost