New technology to improve image transmission speed emerges

The emergence of digital imaging has necessitated companion technologies capable of transmitting large files at high speeds over available networks.

One of the newest file transfer methods is HST, or HyperSpeed Transport, a patent-pending technology said to offer major improvement on the flow of medical images, with image compression neither required nor necessary.

HST will be released initially for NT/2000 environments. It allows Windows clients to fetch files from storage on remote Windows servers at 130 MBps using standard Windows interfaces.

Developed by Baydel, a U.K. and San Jose, CA, supplier of high-performance RAID storage systems and other technologies, HST technology runs on standard 2-Gb fiber LAN using third-party SAN (storage area network) systems from informatics vendors such as Brocade, Qlogic, and Agilent.

"Using standard NT network file sharing, a single client can read files at a sustained rate of over 130 MBps from high-speed RAID platters attached to the NT server head," said Michael Smith, former head of clinical trial imaging at Covance, a Princeton, NJ, pharmaceutical firm, and now consulting to Baydel.

Like Microsoft's WinSock Direct, a new protocol that integrates server applications into SAN environments, HST uses fiber channel as the physical network layer. But while WinSock Direct is a socket technology designed to allow clustered servers to communicate with each other, HST was designed to allow ordinary, low-cost clients to access remote server storage at previously unheard of transfer rates.

HST speed is nearly five times faster than what a typical Gigabit Ethernet achieves today and more than double that of the fastest Gigabit Ethernet cards with TCP offline load engines (TOEs), Smith said.

HST's 130-MBps speed is measured from the time the client makes a file request until the requested data return from the rotating platters of the server storage. It is not simply a memory-to-memory socket rate in which no mechanical motion is involved. Running the same test, FastEthernet measures 8 MBps, commodity GigE cards run 25 MBps, and the fastest TOE cards measure 66 MBps, Smith said.

Since the fiber host bus adapters used are dual-port devices, the technology can nearly double available bandwidth by implementing a second LAN path on the same channel. Recent tests indicate single client file transfers can reach 250-plus MBps at distances of up to 10 km.

The new technology has been tested extensively with DICOM and HDTV signals. Baydel says it is in contact with several curious PACS vendors, who are always on alert for technologies that could enhance their market position or threaten the appeal of their more expensive Unix-based PACS.

"In PACS, our application rides piggyback on communication infrastructure and standards," said Henri 'Rik' Primo, director of Medical Solutions in Siemens' IS/PACS department. "If HST makes it in this world, we will be highly interested to benefit from its advantages for transferring large files, fast and reliably, over networks, the same as we benefit from Gigabit Ethernet, JPEG compression, and other technologies."