Sym

Sym may refer to:

SYM may refer to:

SYM-1

The SYM-1 was a single board "trainer" computer produced by Synertek circa 1978. It was designed by Ray Holt who also designed the first microprocessor chip set used in the CADC for the F-14 Tomcat. Originally called the VIM-1 (Versatile Input Monitor), that name was changed for SYM-1 when Synertek bought our Microcomputer Associates around 1978.

The SYM-1 was a competitor to the popular MOS Technology KIM-1 system, with which it was compatible to a large extent. Compared to the KIM-1, enhancements included the ability to run on a single +5 volt power supply, an enhanced monitor ROM, three configurable ROM/EPROM sockets, RAM expandable on board to 4 kB, an RS-232 serial port, and a "high speed" (185 bytes/second, the KIM-1 supported about 8 bytes/second) audio cassette storage interface. It also featured on-board buffer circuits to ease interfacing to "high voltage or high current" devices.

One rather distinctive capability of the SYM-1 was its ability to allow an oscilloscope to be added to provide a 32 character display under software control. As explained in Chapter 7 of the "SYM Reference Manual", the vertical input, ground and trigger input of the oscilloscope were to be connected to the "Scope Out" connector AA on the SYM-1 board. The "Oscilloscope Output Driver Software" code provided in this chapter of the manual was to be entered into the SYM-1's memory and executed to enable the oscilloscope display. This code provided control of the oscilloscope display, as well as a rudimentary character set. Resistors R42 and R45 were to be adjusted to refine the displayed image.

Symmetry454

The Symmetry454 Calendar (Sym454) is a proposal for calendar reform. It is a perennial solar calendar that conserves the traditional 7-day week, has symmetrical equal quarters, and starts every month on Monday.

Calendar year

The proposed calendar is laid out as follows:

The idea of months having 4 or 5 whole weeks is not new, having been proposed in the 1970s by Chris Carrier for the Bonavian Civil Calendar and by Joseph Shteinberg for his "Calendar Without Split Weeks". Whereas the former has 5 + 4 + 4 weeks per quarter, and the latter has 4 + 4 + 5 weeks per quarter, the Symmetry454 Calendar has a symmetrical 4 + 5 + 4 weeks per quarter, which is why it is named Symmetry454. (Note that there is no space between "Symmetry" and "454".)

Balanced quarters are desirable for businesses because they aid in fiscal planning and analysis.

All months have a whole number of weeks, so no month ever has a partial week. Each day number within a month falls on the same weekday in all months and years; in particular, Friday the 13th never occurs under this calendar.