The creator of that little gem was Dick Hustvedt, a brilliant engineer with a wicked sense of humor. He was one of the inventors of VAXclusters, as well as of the SD730 Solar Horologue Option - see end of this post.
When in the VMS SYSGEN utility, and you asked for a list of the parameters, the list included the units. The TIMEPROMPTWAIT parameter was unusual in that values in one range did one thing, while values in another range did something else. Dick wanted to encourage users to go read the manual for the full explanation, so he had the units listed as microfortnights, hoping that puzzled readers would go search out the details.
Sadly, Dick suffered severe brain injury in a car accident many years ago, and was unable to return to work. The VMS team named a conference room in his honor at the Nashua, NH facility where VMS engineering lives, and if you visit it, you can see the prototype SD730, which was introduced as an April Fools joke one year. Here's the text from the "Product Information Sheet" for the SD730.
VAX-11/730
SD730 Fixed Head Solar Horologue
Overview
The SD730 is an option for the VAX-11/730(TM) that provides an inexpensive solution to the problem of setting system time correctly following a power failure. An astronomical reference is used to assure accuracy. Reliability is assured by the simple, elegant design which employs well-proven technology.
Description
The SD730 is a gnomonic high noon detector that provides a simple, but elegant solution to the problem of setting system time correctly following a power failure. This option is particularly valuable for processors lacking battery backup for their time-of-year (TOY) clock.
Highlights
- Gnomonic interference high noon detector
- High accuracy assured by low-drift astronomical reference
- Connects to existing DR-11C port on VAX-11/730
- Proprietary high-moon rejection design
- Offline mode for standalone time measurement
- User installable and maintainable
- Reliability assured by minimal component count and proven technology
- Heavy duty construction resists solar wind
- Anti-corrosion coating prevents gnomonic plague
Description
The SD730 provides a single bit of data via the DR-11C port of the VAX-11/730 that encodes all of its sensory information. Decoding is accomplished by measuring the on/off intervals of this sensor channel. Derivation of the time and date is accomplished by the SD730 Shadow Processing Support Software.
Accurate high-noon sensing is obtained by measuring the solar transit time and computing the midpoint. This algorithm also corrects for variations in gnomon width, latitude and season. In the event that a cloudless night permits a high full moon to be seen, it will be differentiated from an authentic high noon by comparing observed transit time against a reference solar transit time.
Within 24 hours following power restoration, the SD730 driver software will restore the correct system time.
Power outages in excess of 24 hours can be accomodated once a reference year has been accumulated. Day length, solar transit time and their rates of change are used to recognize the day within the year.
Installation
The SD730 is user installable and comes complete with an installation kit consisting of a lensatic compass. All software is self-installing and self-calibrating. The only requirement is that system time be set correctly and that at least one clear day be allowed for self calibration.
The SD730 will not operate reliably when installed at latitudes greater than 60 degrees.
Maintenance
While the SD730 is simple and reliable, some environments may necessitate periodic cleaning of the gnomon and photo-detector. Although the gnomon shields the photo-detector from debris, this may not be sufficient for particularly hazardous locations subject to overflights by large flocks of migratory birds. To assist in problem detection, error log entries will be made for days without sunshine and weeks without a high noon.
Support Software
A driver and other support software are supplied with the SD730. All software runs on VAX/VMS.
An optional package is available to produce a local almanac sprinkled liberally with gnomic sayings and weather predictions, all derived from one year's solar date.
Options
For severe or hostile environments, a conversion kit consisting of a fiber-optic cable and adapters is available to convert the SD730 to an SD730-Tempest.
Specifications
I/O Adapter
DR-11C Connector (single bit)
Power Requirements
9 volt battery (alkaline recommended)
Battery not included
Optional solar cells available
Physical Characteristics
Packaging Free Standing Unit
Weight 4.5kg (10 lbs)
Height 86cm (34 inches)
Width 32cm (12.5 inches)
Depth 32cm (12.5 inches)
Operating Environment
Temperature 5 to 32 degrees C (41 to 90 F)
Relative Humidity 0 to 90%
Maximum Altitude 4.5km (15000 ft)
Latitude 0 to 60 degrees North (*)
Performance
Long Term Accuracy 1 second per year
Operational Reliability Consult your local weather service
*NOTE For installation in the southern hemisphere, order model SL730-SL.