Power and People The environmental impact of computer operations - Part II
From "VS Workshop",  Access to Wang, May 1991
[ Prior Article ]     [ Return to the Catalog of articles ]     [ Next Article ]

Continuing our look into the environmental impact of computer use, here are some goals and possible strategies for reducing power usage and improving the physical comfort of computer users.

As before, the general goal will be followed by possible strategies for achieving that goal.

Goal #1: Reduce Power Usage

Strategy #1: Use smaller systems. The physical size of computer systems have been dropping with each new generation of CPUs. As these system get smaller their power needs have also been reduced. It is now possible to create an effective system that uses a fraction of the power required even a few years ago.

Smaller computer systems also require less cooling capacity, so they save power there as well. Many new systems are designed to work in the "office environment" - that is, without special cooling and power accommodations.

The chart in Figure 1 shows how the new systems compare through a comparison of three 10-user systems with approximately one gigabyte of disk storage and appropriate means for data backup. System A uses early disk systems and relies on large removable disks for backup. System B uses smaller fixed drives and a 9-track reel tape backup system. Finally, System C uses new-generation tape backup, SCSI drives, and asynchronous workstations.

Figure 2 shows the impact of these figures graphically. The startup power requirements assume that only one device is powered on at a time. Note particularly the startup power requirements of System A: this large short-term consumption has to be absorbed by the power regulation system each time the system is started.

Strategy #2: Use smaller disk drives. Newer disk drives resemble PC disks in their size but offer better storage and access times than older drives. When coupled with new-technology CPUs, these drives offer better performance and demand far less power. Since disk drives are typically the largest source of computer room heat, smaller drives can reduce the need for air conditioning -perhaps even eliminate that need.

Strategy #3: Shut down the computer when not in use. Most business computer operations remain powered on at all times. Some may be used intermittently during evenings and weekends; some require nightly use for backup or batch processing. At this time there are few means of shutting down a system without requiring the physical presence of an operator to bring the system back up.

The new smaller VS models - particularly the 5000 series - allow asynchronous terminals to act as the system console in addition to the more familiar serial models. It is comparatively easy to perform remote system operation on these systems, since nearly any 2110 or VT-100 terminal or emulation can be used to control the system. Larger VS systems may be controlled using the Wang Remote System Operation product, a product that allows communication with the PC system console for system control. Third-party vendors offer "smart" PCs that control batch updates, perform system backups, and (perhaps) shut down the system when it is not in use. To my knowledge, none of these options allow remote shutdown of physical devices - only the logical control of them.

PC laptop makers recognized the value of disk drives that power themselves off after a period of inactivity. Perhaps someday similar products will be produced for larger systems. In the meanwhile, a potentially valuable product awaits development.

Strategy #4: Shut down workstations when not in use. Workstation power consumption used to be less of the total than previously. The popularity of PCs as workstations has changed that; the newer workstations, such as the 4330, consume less power than a PC. It is also arguable whether PCs should be shut down every day, since hard disk drives and other components wear faster when powered on and off.

A compromise between service level and power usage is needed here. Your organization should determine acceptable service requirements establish a policy for shutting down workstations that balances power savings with reliable service from personal computers. Such a policy might be to power off monitors every weeknight and entire PC systems every weekend. (Beware Monday mornings if you accept this as your policy!)

This is another case where product development has not caught up with user need. Vendors?

Goal #2: Reduce the physical discomfort of end users

Strategy #1: Provide a comfortable work area. As those responsible for installing terminals, we can exert influence on the manner in which these devices are used. The comfort and safety of the end user should be considered before the workstation is dropped on their desk. Considerations in this category include:

• Correct monitor distance: The workstation should be set up so that the screen is at least sixteen inches from the user's eyes. The keyboard should be located immediately in front of the monitor so the user does not have to turn to see the screen. Modern partition furniture is usually too narrow for the deeper color monitors sold with today's PCs; a depth of three feet may be required to meet these specifications.

• Adjustable chair: The chair should adjust in height and tilt. Casters are best for workstation use. If arms are desired, they should be short.

• Keyboard height control: Control of typing height. This is not the same as desk height.

• Palm rest: Proper keyboard use requires that the palms rest comfortably on a surface so the weight of the user's hands are not absorbed by the arms.

• Glare control: The workstation should be arranged so that on-screen glare is minimized and the background behind the terminal is dark. Glare control devices should be used only when absolutely necessary, since they reduce resolution and contrast.

• Copy holder: For those entering text, a copy hold should be provided that holds material at the same plane as the workstation screen. This minimizes the amount of refocusing required when moving from the copy to the screen and lessens eyestrain caused by this.

Most of these specifications are mandated by law in European countries; the U.S. lags behind in placing importance on user comfort and safety. The large number of cases of Carpal Tunnel Syndrome in recent news stories and persistent stories of radiation emissions from VDTs should help change those attitudes.

It will take a combined effort on the part of users, employers, labor unions, furniture manufacturers, and the government to improve the working conditions of workstation users.

Strategy #2: Encourage good workstation habits. CRT displays have been known to cause eyestrain when used over a long period of time. The combination of poor image resolution, the pulsing light of the screen, and the compelling nature of computer work have caused discomfort in many users. Mixed with the usual hazards of the business environment - fluorescent lighting, stress, sedentary activities - they can have a negative impact on the overall health of the individual.

Most experts advise eye rests at intervals of a half hour of continuous activity. Changes in activity are also recommended. The technique of "palming" - covering the eyes with the palms for thirty seconds or more - can also help avoid the symptoms of eyestrain.

Experts on the employment environment suggest that computer users purchase a cheap digital watch that beeps on the hour and keep it near the workstation to remind themselves to take this rest. Some PC programs are also available to help encourage regular rests or changes in activities.

Other environmental considerations

• Toner, toner cartridges: The toner used in copiers and laser printers is an irritant to human mucous membranes. Modern laser printers use disposable cartridges to reduce user contact -producing wasteful throwaway containers. The cartridge recharging industry has shown spotty performance, so users are advised by equipment manufacturers to purchase new cartridges only. Manufacturers should look beyond their selfish needs and work to make reusable products work.

• Radio interference: Computer equipment generates radiation of many types. The Federal Communications Commission certifies equipment according to the amount of radio frequency interference present. Class A certification is acceptable for commercial use, while Class B equipment (stricter limits) can be used in the home. Make sure that your equipment meets the standard appropriate for its use.

Conclusion

By providing fast means of interchanging information without paper or land-based transportation, data processing is often an environmentally effective means of reducing resource usage. Attention to some by-products of data processing operations can further its benefit as an environmentally appropriate technology.

Figure 1: Comparison of Heat Output and Power Usage of Three 10-user Systems

Description	Quan.	Running Power	Starting Power	Heat Output
System A     VS 85     288 MB removable disk     2256C DP/WP terminals	1 4 10	1,540 1,700 195	1,730 8,350 195	4,470 4,830 565
System B     VS 65     9-track tape drive     314 MB fixed disk     4230 DP/WP terminals	1 1 4 10	650 720 410 100	750 720 410 100	1,885 2,090 1,190 290
System C     VS 5300     Streaming tape drive     320 MB fixed disk     2110A terminals	1 1 4 10	300 230 100 51	300 230 100 51	1,706 670 500 148