Who invented the calendar?

China began to have a calendar about four thousand years ago, according to a page of oracle bones in the oracle bone calendar, proving that the calendar of the Yin Dynasty has a considerable level, this page of oracle bone calendar is the oldest calendar of all mankind in kind, this page of oracle bone calendar is also called the calendar.

The real calendar, about one thousand one hundred years ago in the Tang Shunzong Yongzhen year, the palace has been using the imperial calendar. The imperial calendar not only recorded dates, but was also an important source for compiling state history. In those days, the calendar divided the year into 12 books, determined the number of pages in each book according to the number of days in each month, and wrote the month and date on each page, which was then handed over to the eunuchs who served the emperor for temporary safekeeping, pending the eunuchs to write down the emperor's words and deeds on the daily empty pages and hand them over to the emperor at the end of each month to be reviewed and approved by him, and then send them to the historians to be filed.

A calendar is a publication used daily to record dates and other relevant information. Each page showing information about a day is called a calendar, each page showing information about a month is called a monthly calendar, and each page showing information about a whole year is called an annual calendar. There are various forms, such as wall calendars, desk calendars, yearly calendar cards, etc., and nowadays there are electronic calendars.

Manufacturing calendar's role:

The basis for attendance calculations, the basis for determining the start date and the completion date when calculating the master production plan and the operation plan based on the lead time in the MPS and the MRP, the basis for calculating the date of the capacity load of the work center, and the identification of the date of the realization of the funds. There are two types of manufacturing calendars, single manufacturing calendars and complex manufacturing calendars.

For an enterprise that uses the same manufacturing calendar for both the production and management departments, and for both the work centers that perform surface processing operations and the work centers that complete product assembly operations, the manufacturing calendar for such an enterprise is called a single manufacturing calendar. In an enterprise, due to environmental constraints such as energy consumption, etc., and management needs such as equipment maintenance, etc., it is possible for different departments and work centers to have different manufacturing calendars due to the use of different production dates and rest dates. The manufacturing calendar of such a company is called a complex manufacturing calendar.

For companies that use complex manufacturing calendars, manufacturing calendars at different organizational levels have different priorities. Work centers at the lowest organizational level have the highest priority manufacturing calendars, and companies at the highest organizational level have the lowest priority manufacturing calendars. That is, if a manufacturing calendar is defined on a work center, then that work center uses its own manufacturing calendar. If a work center does not have its own manufacturing calendar defined, then it uses the manufacturing calendar of the department to which it belongs. If the department does not have a manufacturing calendar either, then the work center uses the corporate manufacturing calendar.

The suggestion that manufacturing calendars should be organized by serial number to facilitate lead time calculations is inappropriate. First, the complexity of calculating lead times is virtually indistinguishable for computers, whether by date or by number, and second, if they are numbered, the management of the calendar numbering resource is an additional human endeavor.

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