ADIC simplifies Fibre-to-SCSI conversion

ADIC's FCR100 Fibre Channel-to-SCSI converter enables users to run SCSI and fibre side by side, and to evaluate and run applications designed to interface with SCSI devices.

Fibre Channel is a very reliable 1Gbps interface technology using common storage and network protocols. It allows for concurrent communications among mainframes, servers and data storage systems.

It also provides an interconnection system for multiple topologies - SCSI, TCP, video, etc - that can scale to a total system bandwidth in the order of 1Tbps. It delivers a high level of reliability even though its physical layer uses 20 per cent of the bandwidth for flow control.

The conversion from Fibre Channel can be complex, which is why ADIC has launched the FCR range. The converters enable IT managers to mix-and-match SCSI- and fibre-based storage devices and servers. They are designed to help preserve a company's investment in infrastructure and ensure interoperability with legacy software and operating systems that are not necessarily fibre-aware.

Fibre Channel offers data transfer rates of 100MBps compared to SCSI's 40MBps. It also supports data transports over far greater distances than SCSI - supporting links of up to 10km between nodes. SCSI supports only 25m overall bus length. Distances of 10km can only be supported over single-mode fibre, which is an expensive option. However, 500m between nodes is easily reached over multi-mode fibre - more affordable at approximately #1 per metre.

Fibre Channel also offers the user greater connectivity in the amount of nodes or devices that can be linked. Typically you can connect 126 nodes together in a Fibre Channel Arbitrated Loop, where 126 devices share the 100MBps bandwidth. On a switched fabric network, it is possible to connect up to 16 million nodes. These nodes can all be addressed with a mixture of bandwidths and connections per loop.

Fibre Channel brings the speed of a computer bus together with the connectivity of a network to give the end user a more reliable, flexible and powerful interface than they could previously use.

For this review, we equipped two Compaq servers with Emulex LightPulse 7000 host bus adaptors (HBAs) and connected these via 50m of multi-mode fibre to an ADIC FCR100 router. This in turn was connected to ADIC's Scalar 218M (a two-drive, 18-cartridge DLT library) featuring a fast-wide SCSI interface.

The test network of two servers connected to one tape library was simple to install and use. In a real-world scenario, there could be several more servers connected via a fibre switch or hub to a much larger tape library.

The mainstream storage software vendors are all expected to release support for storage area networks very soon. Fibre Channel is seen as the main network transport for this topology. It is possible to have a San using SCSI, but this is limited by the factors of bandwidth, distance and the number of connectable nodes.

The FCR100 is a simple Fibre Channel loop to SCSI bus converter, encompassing any mixture of single-mode or multi-mode fibre or copper on the fibre side, and single-ended or differential on the SCSI side. ADIC also offers the FCR200, which has two SCSI buses, enabling the 100MBps bandwidth of Fibre Channel to be more efficiently distributed over two 40MBps SCSI buses. The ADIC FCR400 can connect two Fibre Channel loops with four SCSI buses.

The FCR100 is available in the UK at just #3,700. It comes at a time when many organisations will be evaluating Fibre Channel to cope with the ever-increasing amounts of data they need to store.

ADIC's FCR range enables the implementation of Fibre Channel alongside an existing network infrastructure. ADIC is also integrating the FCR100 technology into its range of tape libraries to produce native Fibre Channel products. The first of these is the Scalar 218FC, a Fibre Channel version of the popular Scalar 218M desktop or rack-mountable library.

Fast Facts

What is it? ADIC FCR100

What does it do? Fibre Channel-to-SCSI multiplexor

Pros: Provides connectivity between conventional SCSI devices and Fibre Channel Sans, offers easy installation and versatility.

Cons: Not everybody needs or can afford Fibre Channel right now.

Availability: ADIC (0118) 979 1944

Price: #3,700.