CEMP-E
TI 811-12
18 August 1998
b. Write-once-read-many (WORM) disks use an organic dye thin film optical recording technique
and have typical storage capacities starting at 650 megabytes. Data can only be written to a WORM disk
until the disk capacity is filled one time, so there is no risk of accidentally destroying archived data on the
WORM disk by overwriting. WORM disks provide very secure archival of large files, such as the static
database of a UMCS island, a snapshot of the dynamic database, trend values or graphic display
diagrams, and have a life of more than fifteen years.
c. Compact disk read only memory (CD ROM) disks have a typical storage capacity of 650
megabytes. CD ROM disks can only be read from, not written to by an optical drive. A special purpose
CD ROM recorder is required to write files to the CD ROM disks. Because of this feature, CD ROM disks
are often used for software distribution (such as delivery of a complete system software update from the
UMCS manufacturer) instead of archiving. An important advantage of CD-ROM is standardization of the
recording format according to ISO guidelines.
d. The rewriteable (or erasable) optical drives have the advantage of high volume data storage
capacity (650 Mbytes or 1.3 Gbytes) coupled with the ability to erase and write again. Some
manufacturers offer multifunctional drives that will support both the write-once (archival) and erasable
(working storage) function. This removable media has a long shelf life of 30 years and is easy to handle
and store.
e. Specific optical drives are required for each type and size of disk. Multiple disk changers
(jukeboxes) can be provided for installations requiring greater storage capacity.
9.
PRINTERS.
a. Dot Matrix alarm printers will be provided for all island stations and central stations, connected to
the island/central station computer printer port. Dot matrix alarm printers utilize sprocket-fed fanfold
paper up to 11 inches wide, providing hard-copy record of all alarm activity including acknowledgment
and return-to-normal. Printing speed and character spacing will be specified for all dot matrix alarm
printers.
b. Laser printers with both automatic and manual feed of single sheets will be provided for all island
stations and central stations. The system will include dedicated laser printers connected to printer ports
on workstations as well as network laser printers. Network compatible laser printers which can be
accessed by the central/island station computer or any workstation on the LAN are used to provide
economy in cost and in required console areas. Laser printers provide letter quality (high resolution)
output suitable for reports. The laser printer resolution, random access memory capacity and printing
speeds will be specified for all UMCS.
c. Network Color printers will be included in the design, if required by the installation. Thermal ink
jet color printers which allow the use of standard laser printer paper will be used. Although color printers
can be used for text printing, they should not be used in place of dot matrix or laser printers because of
their slower speed and higher cost per page. Color printers will be connected to the LAN.
10. WORKSTATIONS.
a. A full color, microcomputer based graphic workstation is the primary operator-machine interface.
The workstation displays equipment schematics, system status, operating parameters, and equipment
operating data. The workstation includes a dedicated keyboard and mouse for entry of operator
commands. Graphic displays may be brought up automatically when an alarm is activated, or upon
operator command. Operator workstations are located in the central station or island station equipment
room. Additional workstations may be located in other areas of the installation based on the installation's
requirements. Location of workstations in maintenance shops, such as an HVAC shop, is encouraged.
The workstation software permits partitioning of alarms and other information so that, for example, an
operator workstation located in the electrical maintenance facility will only display alarms associated with
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