Abstract: A method and apparatus identifies the existence of differences between two files on a personal computer, such as two versions of a Windows registry file. Portions of each of the files are hashed into a four byte value per portion to produce a set of hash results, and the set of hash results is combined with a four byte size of the portion of the file from which the hash was generated to produce a signature of each file. If the two files are different versions of a Windows registry file, the portion of the file hashed are the values of the Windows registry file. If the two files are different, there is a high probability that the signatures of the two files will be different. The signatures may be compared to provide a strong indicator whether the two files are different. Each four-byte hash from one file can be compared against its counterpart from the other file to determine the portion or portions of the files that differ.

Abstract: A method and apparatus identifies the existence of differences between two files on a personal computer, such as two versions of a Windows registry file. Some or all of each of the files are hashed into a four byte value per file, and each hash is combined with a four byte size of the portion of the file from which the hash was generated to produce a fingerprint of each file. If the two files are different versions of a Windows registry file, the portion of the file hashed are the values of the Windows registry file. If the two files are different, there is a high probability that the fingerprints of the two files will be different. The fingerprints may be compared to provide a strong indicator whether the two files are different.

Abstract: A system and method allows a host computer to operate as a server in a client-server arrangement in response to requests from client computer systems. The system and computer program product performs reads, reads for update, update and deletes on some or all records in a file, depending on the type of file. Record or file locking is provided when applicable. Security is provided at the file level. Abnormal ends of communication with the client computer system are detected to allow resources and record or file locks to be freed in such event. A counter is incremented at the time a client computer system logs into the host computer system to enforce limits on the number of concurrent users, and ordinary log off as well as abnormal ends of communication decrement the counter to maintain its accuracy.