Hardware Considerations

Computer Architecture

Computer Operating System

System Backup

Physical Media

Output Devices

Computer Graphics and Monitors

Network Devices

Input Devices

Software Considerations

Data Formats

Operating System Compatibility

Application Packages

Software Licensing

Telecommunications

Network Protocols

LAN

WAN

Data Processes

The computer hardware must have the appropriate processing speed and display capability to run the application software adequately. The application software must perform specific tasks on the digital data that are required by the user. Rather than re-create the data, the appropriate computer networking system should allow the users to share data and resources, and telecommunications equipment should allow users to transfer digital data easily. After reading the NATO CALS Handbook, the project manager should have an implementation approach for data type, process, format, and delivery/access method. With this information, infrastructure requirements can be identified. Each decision will affect the life-cycle costs of a program and the cost of the program's computer infrastructure. Human-interpretable data formats, such as Page Description Language (PDL) and raster, may not be suitable as source data for other applications. Processable data formats can be integrated with other digital data to reduce the total life-cycle costs. The following topics are addressed as considerations for a computer infrastructure:

• Computer Architecture
• Computer Operating System
• Storage Devices
• Output Devices
• Computer Graphics and Monitors
• Network Devices
• Application Software
• Software Licensing
• Network Protocols
• Local Area Networks (LANs)
• Wide Area Networks (WANs)
• Data Process

The above topics are the basis of discussion in paragraph 7.3, Infrastructure Requirements, for specific hardware, software, and telecommunication requirements of a program. Also included are several decision diagrams to help the project manager.

Hardware Considerations

Computer hardware consists of the computer processor, memory, monitor, storage devices, and input devices. Each computer should be tailored to fit the need of the main application. Computational intensive applications such as mechanical solid modelling or engineering simulation will require a larger amount of memory than general text and 2-D graphics-based applications. Each application requires a distinct amount of hard disk space for data storage. Raster images and simulation models tend to require more disk space than vector-based databases such as Computer Graphics Metafile (CGM) or Computer Aided Design (CAD) files.

Computer Architecture

Each computer is designed to meet a specific requirement. In many cases, the computer architecture is driven by the choice of application software needed to perform a specific task. For this reason, the software selected may be the most important decision made. The Personal Computers (PC) are the most widely used computers and are ideal for non intensive applications that require low-to-medium graphic displays. The RISC workstations are widely used in engineering and technical publishing applications that require either a powerful processor for extensive calculations or a high-resolution graphics display for document editing. A "diskless" RISC workstation may provide a low-cost solution to some engineering computing needs. These workstations typically have a small hard disk for the operating system while the application software and user files are loaded from a server workstation that is connected by a network. A third option is a graphic display workstation that supports the X-window Motif standard. However, a PC with X-window emulation software may provide the same features at a lower cost. The standard options for each type of computer is presented in table 7-1.

 

TABLE 7-1. Standard Options for PC Types

	WINDOWS WORKSTATION TYPE 1	RISC WORKSTATION TYPE 2
Processor	PENTIUM, 486 DX 2, 69040 -	RISC
Memory	32 Mb	32 Mb
Media
Hard Drive	1 Gb	2 Gb
Floppy Drive	3.5	3.5
Tape Drive	Optional	Yes
CD Drive	Yes	Optional
WORM	Optional	Optional
Monitor	17"-19" Flat SVGA	19"-21" High Res

Computer Operating System

The operating system is the shell that interprets the user's commands and translates them into machine code to control the computer's resources. The computer's internal clock, memory, Central Processing Unit (CPU), terminal, and other peripherals are controlled by the operating system. The three major distinctions among operating systems are the internal throughput bit size, the amount of available memory, and the ability for multitasking. Each of these factors controls the effectiveness of a computer for a particular user. The Pentium PCs have a 32-bit internal bus as do most RISC workstations. A few of the high-end RISC workstations have a 64-bit internal bus and will be compatible with a 64-bit operating system. Two operating systems are available for Pentium-based PCs. Disk Operating System (DOS) was the first major operating system for a PC and continues to be the standard. DOS is only an 8-bit or 16-bit operating system and does not offer true multitasking. OS/2 was introduced a few years ago and offered users multitasking and a 32-bit operating system. Windows 95 and Windows NT is similar to System 7, discussed in following paragraph, and offers many advantages compared to DOS. The largest benefit is that Windows NT is available on PCs and RISC-based workstations. This will allow the engineering users access to the same application software on a RISC workstation that most business users have on a PC.

A popular operating system used for the 68000 series processor is System 7, which is a true windowing system with 32-bit multitasking capabilities. This operating system has attained popularity due to its ability to meet the demands of both beginner and expert computer users. The operating system has strict hardware/software standards that reduce compatibility and installation problems, although the cost of this system is generally higher than similar Windowing systems. Most RISC workstations currently have a UNIX operating system based on System V UNIX or Berkeley BSD 4.4 UNIX that is POSIX compliant. Each operating system provided with RISC workstations is unique, but most will run application programs that were compiled using System V or Berkeley BSD UNIX. The CAD2 program specifies a POSIX operating system with a Motif standard graphical user interface. OSF/1.0, OPEN VMS, and Windows NT are new operating systems that are designed to allow users a greater variety of application software. Windows NT is designed to allow users of the RISC-based computer and 80486-processor-based-computer to run the same operating system and the same versions of application software.

System Backup

System backup is very important to the project manager. If managed properly, systems can be designed such that even a catastrophic loss of data can be recovered in a relatively short period of time. To do this, the project manager should address areas such as hard drive or CPU failure, lightning strike, fire, or damaging storm in a disaster recovery plan. Backup of a system should include a practical means to back up system data. This is a function that should be easy to accomplish and convenient to the users. If a system does not have a convenient backup system, the user will be unlikely to back up regularly and, thus, risk catastrophic loss of program data. An acceptable means to archive system and program data is to use a tape backup system.

Physical Media

Each computer system needs the appropriate amount of data storage capacity to allow users access to all areas of project data. This disk space can reside on each computer or on a network file server. Storage technology is constantly changing, and the project manager should understand that the physical media addressed below is provided as a guideline but does not necessarily imply that only the following technology should be used in building infrastructure. When evaluating whether to use new technology, the project manager should assure compatibility with other equipment of the same technology or with older, less sophisticated media.

Magnetic Media

Magnetic disk drives are available for most computer systems. Magnetic disk drives can store from 200 to 4,000 megabytes and should be American National Standard Institute (ANSI), SCSI, or IDE compatible. SCSI provides compatibility and allows for expansion when greater disk space is required. Magnetic disks can be used to transfer data when required. The most common magnetic disk used to transfer data is the 3.5 inch diskette which can hold up to 1.44 Mb of data. Using magnetic disks to transfer data should only be considered when the total data does not exceed 10 Mb. When transferring over 10 Mb of data, a 9-track computer tape or Quarter Inch Cartridge (QIC) tape would be better suited (MIL-STD-1840). The standard 9-track tape can store approximately 240 Mb of data compared to 500 Mb with the QIC. The exact configuration of the tape format can greatly affect the capacity of the tape. Tape drives that accept tape cartridges are easier to obtain and integrate into a desktop computer system. However, the project manager should confirm that tape formats are compatible. An alternative technology to 9-track tape or an optical drive is the Digital Audio Tape (DAT) drive. DAT drives can store up to 5 Gigabytes (G-byte) of data. The tapes are small and are easily integrated into the desktop environment. This avoids capacity problems that are sometimes encountered in 9-track and optical drives.

Optical Media

Optical drives are readily available and come in many different types and sizes. The most common optical drive is the 5.25 inch Compact Disk (CD) Read Only Memory (ROM) drive. These drives are used for end user systems similar to the Advanced Technical Information Support (ATIS) system. A Write Once/Read Many (WORM) optical disk system should be considered for storing the final deliverable digital data for a large project. Optical disks can store up to 200 G-bytes. This will provide the project with a nonerasable copy of the data that can help in configuration control. However, all WORM optical disk systems do not produce the same format as CD, and compatibility with the end user should be verified.

Output Devices

Each computer user will need access to a printer and/or a plotter. These devices can be set up on a LAN rather than directly to a specific computer, so that network users can share the devices. Printers are generally used to produce "A" or "B" (ANSI Y14.1-80) size documents. Plotters are used to create up to "J" size documents. An "A" size PostScript compatible laser printer is the standard printer recommended for general use. The printer should have a minimum resolution of 300 by 300 Dots Per Inch (DPI) and a minimum print speed of four to eight pages per minute. An "A/B" size laser printer would be better suited to print engineering drawings. Most drawings are legible when printed on "B" size paper. The two main types of plotters are electrostatic and pen plotters. Electrostatic "E" size plotters are recommended for engineers involved in the creation and review of engineering documents or when there is a requirement to plot up to "E" size raster drawings. A pen plotter may suffice, but these plotters can take up to 30 minutes to print a vector drawing versus only 1 to 2 minutes for an electrostatic plotter. Pen plotters cannot be used to plot raster images.

Computer Graphics and Monitors

The resolution and monitor size are important considerations when choosing the proper monitor. Most users who work with graphical data such as engineering drawings or technical illustrations will be more efficient with a high-resolution, 19-inch monitor. This is especially true when working with raster files. A larger monitor may eliminate the need to zoom in on a section of the drawing or illustration. A 14- to 16-inch monitor is suited only for general Windows applications and is not recommended for reviewing drawings or illustrations. An option for some RISC-based workstations is real-time, 3-D graphic manipulations. This allows the user to rotate and/or scale the view of the object in real time. Any engineer performing solid modelling or finite element analysis will increase productivity on the workstation with this option. Screen redraws for complex images can take up to several minutes with a standard graphics option but can be performed instantaneously with the 3-D graphic processors.

Network Devices

Network devices include equipment that is required to connect a single user station to an existing network or to connect two or more networks together. Examples of this type of equipment usually are network cards, bridges, and routers.The basic requirements for creating a single LAN are a Network Interface Card (NIC) and the appropriate cable; for example, an Ethernet board for each computer and the coaxial or twisted-pair cable to connect each computer. Network bridges can be added to the LAN, to connect to other LANs or manage the LAN electronic message traffic. Network terminal servers allow terminals, modems, and printers to be connected into the LAN. Network routers enable remote LANs to be connected or the LAN to connect to a WAN. All network devices should support the Ethernet V2.0 and Institute of Electrical and Electronic Engineers (IEEE) 802.3 standards. Due to LAN configuration complexity and variety, the project manager should discuss infrastructure requirements with the supporting activity Automated Data Processing (ADP) manager before purchasing any LAN equipment.

Input Devices

There are many different ways to provide input to a computer system. One of the most basic input devices is a keyboard. There are many different arrangements; however, the industry standard is the 101-key type. Additional devices include mice, track balls, digitizing tablets, light pens, and scanners. With the exception of the scanner, all the previous devices generate data with the user's guidance. The technology of scanners has greatly increased in the past few years and can add speed in the generation of technical data.

The two basic types of scanners are page scanners and large-format scanners. Page scanners are designed to be implemented with text or graphics up to 8.5 by 11 inches. When scanning images for documents that are currently being created or updated, a single-page scanner should work well. Features for a single-page scanner include quality of scan and moderate speed. Sheet-fed scanners are generally used to archive large amounts of paper data. The features required are speed of scan and moderate resolution. Large-format scanners are used to generate raster images from paper drawings up to 60 inches wide with an unlimited length. The scanners are monochrome/gray scale and are a single-sheet feed operation. In recent years, the speed and cost have been significantly reduced while quality has been enhanced.

Large-format scanners can provide a means of converting old, deteriorating paper drawings into an electronic form that can be edited and restored, if required. Many activities and sites are currently using scanners. Although the cost has been reduced significantly, a large-format scanner is a major investment and is usually purchased by the software support activity as a shared resource.

Software Considerations

The project manager must consider how a specific software application fits into the complete data process. Configuration management software may be needed to control the access and revision of digital data files as well as the specific application software. Software applications and repository services already available should be considered before different software applications are examined. Another important question is whether the software import and export files are in a CALS format such as MIL-D-28000 Initial Graphics Exchange Specification (IGES) and MIL-M-28001 Standard Generalized Markup Language (SGML). This will ensure the data will be accessible by other users.

Data Formats

Digital data deliverables available in the CALS environment are extensive. The NATO/NATO nations project manager must evaluate the need to determine which format is appropriate at each stage of a specific program. The final deliverables must be in a standard CALS format while preliminary digital data may be in a format that is agreeable to the project manager and the contractor. Commercial word processing software with the capability of text attribute, style sheets, and imbedded graphics may be used to view and annotate preliminary TMs. A list of various digital data formats is shown in table 7-2.

TABLE 7-2. Standard Digital Data Formats

STANDARD DIGITAL FORMATS
MIL-D-28000 IGES /CALS
MIL-M-28001 SGML /CALS
MIL-R-28002 Raster graphics /CALS
MIL-D-28003 CGM for illustration data /CALS
Formatted American Standards Code for Information Interchange (ASCII) text
Page Description Language POSTSCRIPT
VHSIC Hardware Description Language (VHDL)/BBS
Electronic Design Interchange Format (EDIF)BBS
Institute for Interconnecting and Packaging (IPC)-D-350 /BBS
Native CAD Format

The project manager must consider who is going to use the data in the armed forces and ensure that the infrastructure matches each user's requirements and the function of the requirements. The required infrastructure will vary depending on the data use and the data format. Formats, such as Raster, will require a higher resolution monitor but less processing capability to view and modify compared to a solid-model-based CAD system. Raster and IGES data formats generally necessitate larger disk memory. Some data functions cannot be performed on all digital data formats.

Operating System Compatibility

The first consideration is which operating systems the program uses. A software application that supports both Disk Operating System (DOS) for the PCS and UNIX for the RISC-based workstations will allow greater flexibility than a program tied to a single operating system. This is especially true when business and engineering personnel need to review the digital data. Most business applications operate on a PC while most engineering applications operate on RISC-based workstation. X-window emulation software may solve some problems. The current generation of X-window emulation programs are quite robust and can be used to allow PC users access to UNIX X-window software from a PC. The PC emulation packages for RISC-based workstations are not as sophisticated as the X-window emulation programs.

Application Packages

General types of packages of application packages are shown in table 7-3.

TABLE 7-3. General Types of Application Packages

COMPUTER SOFTWARE	CAPABILITIES	EXAMPLES
Word Processing	Creating Text-Based Doc.	Documents
Spread Sheet	Calculations Data Manipulations Carts and Graphs	Financial Reports Engineering Calculations Data Reports
Desktop Publishing	Advanced Text and Graphics Integrated Documents	Advanced Documents and Publications
Mathematics	Symbolic Calculations Advanced Calculations 2-D, 3-D Plots	Engineering Calculations Technical Reports
Terminal Emulation	Emulates Specific Ternimals for PC's	X-Window Emulation on a PC
MCAD	3-D Solid Modeling Mechanical Drawing	Weapon Systems Model Ship Drawing
Schematic Capture	Electric Schematic Logic Checking	Wiring Diagrams Avionics System Designs
Printed Wiring Board (PWB) Layout	PWB Layout PWB Manufactoring Data	Computr Aided Manufactoring
Finite Element Analysis	Structural Simulation Vibration Simulation Thermal Simulation	Flight Safety Checks Cooling System Evaluations
Dynamic Simulation	Mechanism Simulation Dynamic Sysrem Simulation	Bomb Rack Mechanism Evaluations Vehicle Characteristic Simulations
Electrical Simulation	VHDL Analog Simulation ASIC Simulation	Computer Aided Engineering

Software Licensing

The type of software licensing available can affect the total cost to implement a software system. The four types of software licensing that are prevalent today are single-user license, single-computer license, network license, and a site license. Each licensing option has a proper use and can greatly affect the total life-cycle costs associated with the software procurement. A single-user license allows the software to be loaded on one computer, and one person has access to the program at a time. Most PC software programs are licensed to a single user. A single-computer license is licensed for a specific computer, and the vendor may charge to move the license to a different computer. This type of license can allow either a single user or multiple users access to the program. The multiple-user option is generally used when the software is operating on a mainframe computer or network server. A network license will allow a specific number of simultaneous users, who share a common network, access to the program. Single-computer and network licenses are usually offered on software available on UNIX workstations. These licenses can reduce the total cost of supplying the needed software for all of the users of an acquisition program. A site license allows the software to be used on any computer at a particular location.

Telecommunications

The standard equipment required for telecommunications is a modem. The modem is used to link two or more computer systems via a phone line. Normal uses could include connection to larger computer systems via a terminal emulation program, connection to a remote site to send/receive files, or to access Contractor Integrated Technical Information Service (CITIS). A more specialized modem that has become readily available is a modem capable of sending and receiving Facsimile (FAX) data as well as the standard CCITT (Consultative Committee for International Telegraphy and Telephony) information. The speed requirement of the modem is directly related to the size of the data files that will be transferred and frequency that the modem will be used. If data is only to be accessed and viewed remotely using a terminal emulation program, then a 9,600 baud (character per second) modem is probably acceptable. However, if there is a requirement to send/receive large data files, a faster modem with built-in data compression is required. Before purchasing a modem, the project manager should assure compatibility with the remote location.

Network Protocols

Network protocols are essentially the software standards that enable users to communicate over LANs or WANs. There are several types of network protocols that are acceptable in the CALS community. Factors to consider when choosing the type of network protocol needed include current facility LAN/WAN compatibility, interface requirements, data to be transferred, and distance of network. The following are common protocols and their capabilities.

• GOSIP: The Government nations Open Systems Interconnection Profile (GOSIP) is the standard for networking protocols. Its function is to provide interoperability among different equipment manufacturers.
• TCP/IP: Transmission Control Protocol/Internet Protocol (TCP/IP) is the general protocol (IEEE 802.3) for most engineering workstations and servers. It allows UNIX computers to connect to each other for remote login with 'rlogin' and 'rsh' UNIX commands. It also allows a PC with X-windowing software to establish an X-window session on a UNIX server.

LAN

A LAN is required when there are several users who need to share data, application software, and equipment. The LAN network devices commonly used are printers, disk drives, modems, and other Management Information System (MIS) equipment. As the name LAN suggests, this type of network is contained within a small area (usually within the same building or floor). LANs are based on the needs of the user. Some LANs may only need to be connected to share resources such as modems or printers. Another LAN function could be used for configuration management of large CALS databases. A common need for organizations is to transfer data from one LAN to another or to connect to a large mainframe computer. These functions can be achieved with what is commonly referred to as a bridge.

WAN

A WAN is required when there are several users who need to share data or equipment over a large area (usually many miles). A WAN should only be considered if there is a need to transfer large amounts of data for long periods of time. If occasional or limited use of access to remote data or equipment is needed, then a modem will suffice.

Data Processes

The project manager needs to determine what digital data functions are required and who is the data user. The infrastructure may vary for each use of the data, if the hardware, software, and network cost are to be minimized. Generally, certain data functions are performed with a specific format. Conversion software may need to be procured to ensure that the format of the data is also compatible with the end user's requirements. The user functions are divided in the following areas.

• View: Acceptance, verification, and review of acquired digital data sets.
• Comment/Annotate: Annotate or highlight for future reference, or make annotations and comments without the ability to change the original file. The annotations are associated with a specific item or location within a document.
• Update/ Maintain: Update and modification of digital data.
• Process/Transform: Categorize, extract, cross-reference, and modify the format, composition, and structure of the data into another usable form.
• Archive: Storage of the accepted data into a repository, managed by a central index or locator.