Abstract: Files stored on a hard disk drive are scanned for a predefined pattern, such as a virus definition. For each one of a plurality of files, predetermined select portion(s) (e.g., likely sites of infection) are stored in a common file. After storing the predetermined select portions, the portions are tested without accessing the file to determine whether content of the predetermined select portion corresponds to the predefined pattern.

Abstract: A sender prepares a message, then transmits an e-mail notice to the receiver and the e-mail message to a forwarding server. The “e-mail notice” is a short message, including a message ID and specifically does not include the complete prepared message. The “e-mail message” is in binary format and also includes the message ID of the corresponding e-mail notice. The receiving user receives the e-mail notice, then contacts the forwarding server to receive the e-mail message corresponding to the message ID within the received e-mail notice.

Abstract: Files from a client are backed up over the internet onto a back-up storage area. The client gathers identifying information for each file, including file size and file checksum. A client server estimates whether the information matches that present in a database including identifying information from multiple clients. When the information for a given file is present, the matched information is stored in the back-up storage area. When the information is not present, the given file is received from the client computer. The given file and the associated identifying information then are stored in the back-up storage area. The backed-up files are accessible in online storage, and may be archived. The client accesses the backed-up files over the internet in a restore operation, or as a virtual hard disk, a virtual CD image or a virtual DVD image. The backed-up files are accessible offline on a CD or DVD.

Abstract: A method and apparatus for error detection and correction in the storage and retrieval of digital data on magnetic storage systems includes converting the digital data into analog waveforms, multiplexing the analog waveforms with reference values and storing same as a data stream, demultiplexing the reference values from the data stream and using the retrieved reference values to detect and reduce distortion or other errors in the data stream. Assignment of data to analog waveforms includes option of assigning arbitrary quantities of data to a compact analog waveform representation. Analog errors may be detected and corrected statistically, while digital errors may be detected and corrected using standard signal processing techniques.