A separate cachable-in-virtual-cache attribute bit (CV) is maintained for each page of memory in the translation table maintained by the operating system. The CV bit indicates whether the memory addresses on the page to which the translation table entry refers are cachable in virtually indexed caches. According to a first embodiment, when there are two or more aliases which are not offset by multiples of the virtual cache size, all of the aliases are made non-cachable in virtually indexed caches by deasserting the CV bits for all aliases. With regards to the contents of the translation lookaside buffer (TLB), the translations for all aliases may simultaneously coexist in the TLB because no software intervention is required to insure data coherency between the aliases. According to second and third embodiments of the present invention, when there are two or more aliases which are not offset by multiples of the virtual cache size, only one of those aliases may remain cachable in virtual caches. For the other aliases, the CV bits for the translation pages containing those aliases are deasserted. The operating system has the responsibility of flushing data from the virtually indexed internal cache before deasserting the CV attribute for a page. The second embodiment allows the newer mapping to a physical address is allowed to remain in the first level cache, while the third embodiment allows the older alias to remain in the first level cache when a newer alias is mapped.

The invention provides a polling process software module operating on a host computer which polls a network interface by examining a virtual or "alias" register (602) that mirrors the network interface's status register (502). Such an alias register serves as an alternative path (e.g. address) by which to read the status register. Therefore, when an indicator (504-508) changes state to indicate a specific event or condition in the network interface, the corresponding indicator (604-608) in the alias register also changes. When the network interface is polled, if an indicator in the alias register is set to a state indicating the transfer of a packet, the polling module processes the waiting packet(s). Because the polling module reads the alias register instead of the status register, the alias register is cleared each time the polling module reads the network interface. When the alias register is cleared, one or more indicators in the status register may also be cleared, as determined by a programmable mask (610). The value in each mask entry determines whether an associated status register indicator is cleared when a corresponding alias register indicator is cleared.

Module for building a query on a database 3, comprising a client-side module part 1 and a server-side module part 4, creating an abstract query object 8 given user-defined query criteria, whereby the user-defined query criteria comprises alias names for elements of data tables 11 contained in the database, sending 5a the abstract query object 8 to a parse and validate entity 4a, the server-side module part comprises means for extracting mapping information between the alias names and real names of the elements of the data tables 11 from a private configuration table 10, the said private configuration table 10 storing the mapping information according to a valid internal structure of the database at the time of extraction, creating a query on the database 3 by extracting a query configuration from the abstract query object and resolving the alias names contained in the said query configuration by searching the mapping information of the private configuration table, performing the query on the data tables 11, adapting the query results to changes made in said internal structure of the database, extracting 5c a list of available alias names from the mapping information, forwarding the list of the available alias names to the client-side module part, forwarding 5b query results to the client-side module part 1.