Abstract: To enhance data structure processing performance, data is organized bi-directionally in a data structure. That is, depending on the value of a data key associated with an entry, the entry is stored either from a low end or from a high end of the data structure. For example, the low end of the data structure may store entries having even-valued keys, while the high end of the data structure may store entries having odd-valued keys. Subsequent data structure processing can be facilitated by searching the data structure in either a forward direction starting with the low end or a reverse direction starting with the high end, depending on whether a search key is even or odd.

Abstract: A plurality of versions of software application programs can be handled by a single server serving multiple user-clients who each need access to specific ones of the plurality of versions. Thus such different versions can run simultaneously without requiring upgrading of early versions and no interference between versions. A particular version is given a SiteID that a user request calls, and a table in the server is consulted to keep track of which SiteID corresponds to which version and to assign each request to the appropriate version. A directory or registry must be set up to accommodate the table which must be consulted for each request. No significant change need be made in any version of the software application program since the table is created at installation time on the server and the SiteID's are assigned to the users when they get rights to the particular version of interest by an administrator.