1. A non-transitory computer-readable memory which may be random access memory or read only memory, said memory having stored thereon a conventional non-database file system specially structured so as to act as a data warehouse which can be searched using regular expressions, said data warehouse storing performance metric data numerical values characterizing the performance of a system being monitored which has one or more resources, each resource having one or more attributes each of which is measured during sampling intervals contiguous in time to generate a time-series of performance metric data numerical values which have been mapped to Unicode values, each said performance metric data numerical value having dimensions comprising the date and time of its measurement, the resource from which it was measured, and the attribute of which it is a measurement, part of said special structuring including storage in files of one time-series of Unicode characters mapped to a corresponding time-series of performance metric data numerical values for each attribute of each resource of said system being monitored, said special structuring of said conventional non-database file system encoding the dimensions of each performance metric data numerical value in the structure of said conventional non-database file system itself thereby eliminating the need to use separate memory locations to store dimension data for each performance metric data numerical value, said conventional non-database file system comprising the following data structure: a separate top-level directory storing all the Unicode characters mapped to performance metric data numerical values measured during a single day, said top-level directory having a name which includes the date of the day to which said top-level directory is dedicated, said top-level directory having one or more single-resource subdirectories, each said single-resource subdirectory containing one or more files, said files storing one or more time-series of Unicode characters Wig-mapped to one or more time-series of performance metric data numerical values measured from one or more attributes of the single resource to which said single-resource subdirectory is dedicated, each of said one or more files in a single resource subdirectory storing Unicode characters for a group of attributes of said single resource to which said single-resource subdirectory is dedicated, each said text-file in a single-resource subdirectory divided into N sections, each section storing a single time-series of M Unicode characters, said Unicode characters in each said time-stream stored in adjacent locations which represent adjacent timeslots of said day to which said top level directory is dedicated so that regular expressions can be used to search through any time-stream of Unicode characters, each Unicode character mapped to one performance metric data numerical value in a time-series of M performance metric data numerical values measured for one attribute to which said section is devoted, said M performance metric data numerical values representing all the measurements of the attribute to which said section is devoted for the entire day to which said top-level directory containing said single resource subdirectory containing said file is dedicated and wherein M may be different or the same for each different attribute of each different section; and wherein said time of day dimension of each said Unicode character is represented by the position of said Unicode character in the time-series of M Unicode characters of which said Unicode character is a part.