S T 3 9 1 7 3 F C SEAGATE Native| Translation ------+-----+-----+----- Form 3.5"/SLIMLINE Cylinders | | | Capacity form/unform 9100/ MB Heads 10| | | Seek time / track 7.1/ 1.2 ms Sector/track | | | Controller SCSI3 FIBRE/SCA Precompensation Cache/Buffer 1024 KB MULTI-SEGMEN Landing Zone Data transfer rate 15.000 MB/S int Bytes/Sector 512 100.000 MB/S ext Recording method EPR4 16/17 operating | non-operating -------------+-------------- Supply voltage 5 V Temperature *C 5 50 | -40 70 Power: sleep W Humidity % 5 90 | 5 95 standby W Altitude km | idle 13.0 W Shock g 10 | 75 seek W Rotation RPM 7200 read/write W Acoustic dBA spin-up W ECC Bit ON THE FLY,SMART MTBF h 1000000 Warranty Month 60 Lift/Lock/Park YES Certificates ********************************************************************** J U M P E R S ********************************************************************** SEAGATE ST39173FC Jumper Setting ============== Jumpers are not used on the drive. Drive ID/option selection ------------------------- All drive options are made through the interface connector (J1). LED connections --------------- A connector, J6, is provided on the printed circuit board assembly (PCBA) to provide port bypass, drive active, and drive fault LED connections. J6 connector requirements ------------------------- Recommended mating connector part number: Berg receptacle, 6-position, Berg part number 690-006. ********************************************************************** I N S T A L L ********************************************************************** SEAGATE ST39173FC PRODUCT MANUAL 77767522, REV. B Notes on installation ===================== Installation direction ---------------------- horizontally vertically +-----------------+ +--+ +--+ | | | +-----+ +-----+ | | | | | | | | | +-+-----------------+-+ | | | | | | +---------------------+ | | | | | | | | | | | | | | | | | | +---------------------+ | +-----+ +-----+ | +-+-----------------+-+ +--+ +--+ | | | | +-----------------+ The drive will operate in all axis (6 directions). Shielded I/O cables may be required if the enclosure does not provide adequate shielding. If the I/O cables are external to the enclosure, shielded cables should be used, with the shields grounded to the enclosure and to the host controller. Electromagnetic susceptibility ------------------------------ As a component assembly, the drive is not required to meet any susceptibility performance requirements. It is the responsibility of those integrating the drive within their systems to perform those tests required and design their system to ensure that equipment operating in the same system as the drive or external to the system does not adversely affect the performance of the drive. Electromagnetic compliance -------------------------- Seagate uses an independent laboratory to confirm compliance with the directives/standards for CE Marking and C-Tick Marking. The drive was tested in a representative system for typical applications. The selected system represents the most popular characteristics for test platforms. The system configurations include: - 486, Pentium, and PowerPC microprocessors - 3.5-inch floppy disc drive - Keyboard - Monitor/display - Printer - External modem - Mouse Although the test system with this Seagate model complies with the directives/standards, we cannot guarantee that all systems will comply. The computer manufacturer or system integrator shall confirm EMC compliance and provide the appropriate marking for their product. Electromagnetic compliance for the European Union If this model has the CE Marking it complies with the European Union requirements of the Electromagnetic Compatibility Directive 89/336/EEC of 03 May 1989 as amended by Directive 92/31/EEC of 28 April 1992 and Directive 93/68/EEC of 22 July 1993. Cache operation --------------- Note. Refer to the Fibre Channel Interface Manual for more detail concerning the cache bits. Of the 1,024 Kbytes physical buffer space in the drive, 967.5 Kbytes can be used as a cache. The cache can be divided into logical segments from which data is read and to which data is written. The drive keeps track of the logical block addresses of the data stored in each segment of the cache. If the cache is enabled (see RCD bit in the Fibre Channel Interface Manual), data requested by the host with a read command is retrieved from the cache, if possible, before any disc access is initiated. Data in contiguous logical blocks immediately beyond that requested by the Read command can be retrieved and stored in the cache for immediate transfer to the initiator on subsequent read commands. This is referred to as the prefetch operation. Since data that is prefetched may replace data already in the cache segment, an initiator can limit the amount of prefetch data to optimize system performance. The drive never prefetches more sectors than the number specified in bytes 8 and 9 of Mode page 08h. If the cache is not enabled, 967.5 Kbytes of the buffer are used as a circular buffer for read/writes, with no prefetch operation and no segmented cache operation. Shipping -------- When transporting or shipping a drive, use only a Seagate-approved container. Keep your original box. Seagate approved containers are easily identified by the Seagate Approved Package label. Shipping a drive in a non-approved container voids the drive warranty. Seagate repair centers may refuse receipt of components improperly packaged or obviously damaged in transit. Contact your authorized Seagate distributor to purchase additional boxes. Seagate recommends shipping by an air-ride carrier experienced in handling computer equipment. Hot plugging the drive ---------------------- Inserting and removing the drive on the FC-AL will interrupt loop operation. The interruption occurs when the receiver of the next device in the loop must synchronize to a different input signal. FC error detection mechanisms, character sync, running disparity, word sync, and CRC are able to detect any error. Recovery is initiated based on the type of error. The disc drive defaults to the FC-AL Monitoring state, Pass-through state, when it is powered-on by switching the power or hot plugged. The control line to an optional port bypass circuit (external to the drive), defaults to the Enable Bypass state. If the bypass circuit is present, the next device in the loop will continue to receive the output of the previous device to the newly inserted device. If the bypass circuit is not present, loop operation is temporarily disrupted until the next device starts receiving the output from the newly inserted device and regains synchronization to the new input. The Pass-through state is disabled while the drive performs self test of the FC interface. The control line for an external port bypass circuit remains in the Enable Bypass state while self test is running. If the bypass circuit is present, loop operation may continue. If the bypass circuit is not present, loop operation will be halted while the self test of the FC interface runs. When the self test completes successfully, the control line to the bypass circuit is disabled and the drive enters the FC-AL Initializing state. The receiver on the next device in the loop must synchronize to output of the newly inserted drive. If the self-test fails, the control line to the bypass circuit remains in the Enable Bypass state. Note. It is the responsibility of the systems integrator to assure that no temperature, energy, voltage hazard, or ESD potential hazard is presented during the hot connect/disconnect operation. Discharge the static electricity from the drive carrier prior to inserting it into the system. Caution. The drive motor must come to a complete stop prior to changing the plane of operation. This time is required to insure data integrity. Shock and vibration ------------------- Shock and vibration limits specified in this document are measured directly on the drive chassis. If the drive is installed in an enclosure to which the stated shock and/or vibration criteria are applied, resonances may occur internally to the enclosure resulting in drive movement in excess of the stated limits. If this situation is apparent, it may be necessary to modify the enclosure to minimize drive movement. The limits of shock and vibration defined within this document are specified with the drive mounted in a vertical or horizontal position. Shock ----- a. Operating (normal) The drive, as installed for normal operation, will operate error free while subjected to intermittent shock not exceeding 2.0 Gs at a maximum duration of 11 msec (half sinewave). Shock may be applied in the X, Y, or Z axis. b. Operating (abnormal) Equipment as installed for normal operation will not incur physical damage while subjected to intermittent shock not exceeding 10 Gs at a maximum duration of 11 msec (half sinewave). Shock occurring at abnormal levels may promote degraded operational performance during the abnormal shock period. Specified operational performance will continue when normal operating shock levels resume. Shock may be applied in the X, Y, or Z axis. Shock is not to be repeated more than two times per second. c. Non-operating The limits of non-operating shock apply to all conditions of handling and transportation. This includes both isolated drives and integrated drives. The drive subjected to non-repetitive shock not exceeding 75 Gs at a maximum duration of 11 msec (half sinewave) will not exhibit device damage or performance degradation. Shock may be applied in the X, Y, or Z axis. The drive subjected to non-repetitive shock not exceeding 140 Gs at a maximum of 2 msec (half sinewave) will not exhibit device damage or performance degradation. Shock may be applied in the X, Y, or Z axis. Installation ------------ Barracuda 9LP FC disc drive installation is a plug-and-play process. There are no jumpers, switches, or terminators on the drive. Simply plug the drive into the host's 40-pin Fibre Channel backpanel connector (FC-SCA)- no cables are required. Use the FC-AL interface to select drive ID and all option configurations for devices on the loop. If multiple devices are on the same FC-AL and physical addresses are used, set the device selection IDs (SEL IDs) on the backpanel so that no two devices have the same selection ID. This is called the hard assigned arbitrated loop physical address (AL_PA). There are 125 AL_PAs available. If you set the AL_PA on the backpanel to any value other than 0, the device plugged into the backpanel's SCA connector inherits this AL_PA. In the event you don't successfully assign unique hard addresses (and therefore have duplicate selection IDs assigned to two or more devices), the FC-AL generates a message indicating this condition. If you set the AL_PA on the backpanel to a value of 0, the system issues a unique soft-assigned physical address automatically. Loop initialization is the process used to verify or obtain an address. The loop initialization process is performed when power is applied to the drive, when a device is added or removed from the Fibre Channel loop, or when a device times out attempting to win arbitration. - Set all option selections in the connector prior to applying power to the drive. If you change options after applying power to the drive, recycle the drive power to activate the new settings. - It is not necessary to low-level format this drive. The drive is shipped from the factory low-level formatted in 512-byte logical blocks. You need to reformat the drive only if you want to select a different logical block size. Drive orientation ----------------- The drive may be mounted in any orientation. All drive performance characterizations, however, have been done with the drive in horizontal (discs level) and vertical (drive on its side) orientations, which are the two preferred mounting orientations. Cooling ------- Cabinet cooling must be designed by the customer so that the ambient temperature immediately surrounding the drive will not exceed temperature conditions. Specific consideration should be given to make sure adequate air circulation is present around the printed circuit board assembly (PCBA) to meet the requirements. Air flow -------- The rack, cabinet, or drawer environment for the drive must provide cooling of the electronics and head and disc assembly (HDA). You should confirm that adequate cooling is provided using the temperature measurement guidelines described below. The drive should be oriented, or air flow directed, so that the least amount of air-flow resistance is created while providing air flow to the electronics and HDA. Also, the shortest possible path between the air inlet and exit should be chosen to minimize the travel length of air heated by the drive and other heat sources within the rack, cabinet, or drawer environment. The air-flow patterns are created by one or more fans, either forcing or drawing air as shown in the illustrations. Other air-flow patterns are acceptable as long as the temperature measurement guidelines are met. Drive mounting -------------- Mount the drive using the bottom or side mounting holes. If you mount the drive using the bottom holes, ensure that you do not physically distort the drive by attempting to mount it on a stiff, non-flat surface. The allowable mounting surface stiffness is 80 lb/in (14.0 N/mm). The following equation and paragraph define the allowable mounting surface stiffness: where K is the mounting surface stiffness (units in lb/in or N/mm) and X is the out-of-plane surface distortion (units in inches or millimeters). The out-of-plane distortion (X) is determined by defining a plane with three of the four mounting points fixed and evaluating the out-of-plane deflection of the fourth mounting point when a known force (F) is applied to the fourth point. Grounding --------- Signal ground (PCBA) and HDA ground are connected together in the drive and cannot be separated by the user. Maximizing the conductive contact area between HDA ground and system ground may reduce radiated emissions. If you do not want the system chassis to be connected to the HDA/PCBA ground, you must provide a nonconductive (electrically isolating) method of mounting the drive in the host equipment; however, this may increase radiated emissions and is the system designer's responsibility. K x X = F < 15lb = 67N FC-AL physical interface ------------------------ The operational aspects of Seagate's Fibre Channel drives are provided in the Fibre Channel Interface Manual. Physical description -------------------- FIbre Channel drives may be connected in a loop together or with other compatible FC-AL devices. A maximum of 127 devices may have addresses; however, one of the addresses is reserved for a fabric port switch device. This means 126 addresses are available for FC-AL devices. More FC-AL compatible devices may physically reside on the loop, but they will not be functional because they would not be able to obtain valid addresses. Port bypass circuits (PBCs) allow devices to be inserted into unpopulated locations or removed from the loop with loop operation recovery after a brief interruption. These PBCs are located external to the FC-AL device. ********************************************************************** F E A T U R E S ********************************************************************** SEAGATE ST39173FC PRODUCT MANUAL 77767522, REV. B Applicable standards and reference documentation ------------------------------------------------ The drive has been developed as a system peripheral to the highest standards of design and construction. The drive depends upon its host equipment to provide adequate power and environment in order to achieve optimum performance and compliance with applicable industry and governmental regulations. Special attention must be given in the areas of safety, power distribution, shielding, audible noise control, and temperature regulation. In particular, the drive must be securely mounted in order to guarantee the specified performance characteristics. Standards --------- The Barracuda 9LP FC family complies with Seagate standards as noted in the appropriate sections of this manual and the Seagate Fibre Channel Interface Manual, part number 77767496. The Barracuda 9LP FC disc drive is a UL recognized component per UL1950, CSA certified to CAN/CSA C22.2 No. 950-95, and VDE certified to VDE 0805 and EN60950. Electromagnetic compatibility ----------------------------- The drive, as delivered, is designed for system integration and installation into a suitable enclosure prior to use. As such the drive is supplied as a subassembly and is not subject to Subpart B of Part 15 of the FCC Rules and Regulations nor the Radio Interference Regulations of the Canadian Department of Communications. The design characteristics of the drive serve to minimize radiation when installed in an enclosure that provides reasonable shielding. As such, the drive is capable of meeting the Class B limits of the FCC Rules and Regulations of the Canadian Department of Communications when properly packaged. However, it is the user's responsibility to assure that the drive meets the appropriate EMI requirements in their system. General description ------------------- Barracuda 9LP FC drives are random access storage devices designed to support the Fibre Channel Arbitrated Loop (FC-AL) and SCSI Fibre Channel Protocol as described in the ANSI specifications, this document, and the Fibre Channel Interface Manual (part number 77767496) which describes the general interface characteristics of this drive. ST39173FC drives are classified as intelligent peripherals and provide level 2 conformance (highest level) with the ANSI SCSI-1 standard. You can view the Fibre Channel interface simply as a transport vehicle for the supported command set (ST39173FC drives use the SCSI command set). In fact, the Fibre Channel interface is unaware of the content or meaning of the information being transported. It simply packs the SCSI commands in frames, transports them to the appropriate devices, and provides error checking to ensure that the information reaches its destination accurately. The head and disc assembly (HDA) is environmentally sealed at the factory. Air recirculates within the HDA through a non-replaceable filter to maintain a contamination-free HDA environment. The drive contains no parts replaceable by the user and opening the HDA for any reason voids your warranty. Barracuda 9LP FC drives use a dedicated landing zone at the innermost radius of the media to eliminate the possibility of destroying or degrading data by landing in the data zone. The heads automatically go to the landing zone when power is removed from the drive. An automatic shipping lock prevents potential damage to the heads and discs that results from movement during shipping and handling. The shipping lock disengages and the head load process begins when power is applied to the drive. The drives also use a high-performance actuator assembly design that provides excellent performance with minimum power dissipation. Standard features ----------------- Barracuda 9LP FC drives have the following standard features: - Integrated dual port FC-AL controller - Concurrent dual port transfers - Support for FC arbitrated loop and private loop attachment - Differential copper FC drivers and receivers - Downloadable firmware using the FC-AL interface - Drive selection ID and configuration options are set on the FC-AL backpanel or through interface commands. Jumpers are not used on the drive. - Fibre Channel worldwide name uniquely identifies the drive and each port - User-selectable logical block size (512 to 4,096 bytes) - Selectable frame sizes from 128 to 2,112 bytes - Industry standard 3.5-inch low profile (1 inch high) form factor dimensions - Programmable logical block reallocation scheme - Flawed logical block reallocation at format time - Programmable auto write and read reallocation - Reed-Solomon error correction - Sealed head and disc assembly (HDA) - No preventive maintenance or adjustments required - Dedicated head landing zone - Automatic shipping lock - Embedded Grey Code track address to eliminate seek errors - Self-diagnostics performed at power on - 1:1 interleave - Zone bit recording (ZBR) - Vertical, horizontal, or top down mounting - Dynamic spindle brake - 1,024 Kbyte data buffer - Embedded servo design - Supports SCSI enclosure services via interface connector - Supports up to 32 initiators - Reallocation of defects on command (Port Format) - Fibre Channel interface transports SCSI protocol Media description ----------------- The media used on the drive has a diameter of approximately 95 mm (approximately 3.7 inches). The aluminum substrate is coated with a thin film magnetic material, overcoated with a proprietary protective layer for improved durability and environmental protection. Performance ----------- - 106 Mbytes/sec maximum instantaneous data transfers per port - 7,200 RPM spindle; average latency = 4.17 msec - Command queuing of up to 128 commands - Background processing of queue - Supports start and stop commands - Adaptive seek velocity; improved seek performance Factory-installed accessories ----------------------------- OEM standard drives are shipped with the Barracuda 9LP FC Installation Guide (part number 77767523). Factory-installed options ------------------------- You may order the following items which are incorporated at the manufacturing facility during production or packaged before shipping: - Single-unit shipping pack. The drive is normally shipped in bulk packaging to provide maximum protection against transit damage. Units shipped individually require additional protection as provided by the single unit shipping pack. Users planning single unit distribution should specify this option. User-installed accessories -------------------------- The following accessories are available. All kits may be installed in the field. - Evaluation kit, part number 73473641. This kit provides an adapter card ("T-card") to allow cable connections for two FC ports and DC power. Two twin axial cables, 6 feet in length, are included for the input and output connections to the FC interface. Start/stop time --------------- If the Motor Start option is disabled, the drive becomes ready within 25 seconds after DC power is applied. If arecoverable error condition is detected during the start sequence, the drive executes a recovery procedure and the time to become ready may exceed 25 seconds. During the start sequence, the drive responds to some commands over the FC-AL interface. Stop time is less than 25 seconds (maximum) from removal of DC power. If the Motor Start option is enabled, the internal controller accepts the commands listed in the Fibre Channel Interface Manual less than 3 seconds after DC power has been applied. After the Motor Start command has been received, the drive becomes ready for normal operations within 13 seconds (excluding the error recovery procedure). The Motor Start command can also be used to command the drive to stop the spindle. There is no power control switch on the drive. Prefetch/multi-segmented cache control -------------------------------------- The drive provides a prefetch/multi-segmented cache algorithm that in many cases can enhance system performance. To select this feature the host sends the Mode Select command with the proper values in the applicable bytes in page 08h. Default is prefetch and read cache enabled. If the Prefetch feature is enabled, data in contiguous logical blocks on the disc immediately beyond that which was requested by a Read command are retrieved and stored in the buffer for immediate transfer from the buffer to the host on subsequent Read commands that request those logical blocks (this is true even if cache operation is disabled). To enable Prefetch, use Mode Select page 08h, byte 12, bit 5 (Disable Read Ahead - DRA bit). DRA bit = 0 enables prefetch. Since data that is prefetched replaces data already in some buffer segments, the host can limit the amount of prefetch data to optimize system performance. The Max Prefetch field (bytes 8 and 9) limits the amount of prefetch. The drive does not use the Prefetch Ceiling field (bytes 10 and 11). Cache operation --------------- Note. Refer to the Fibre Channel Interface Manual for more detail concerning the cache bits. Of the 1,024 Kbytes physical buffer space in the drive, 967.5 Kbytes can be used as a cache. The cache can be divided into logical segments from which data is read and to which data is written. The drive keeps track of the logical block addresses of the data stored in each segment of the cache. If the cache is enabled (see RCD bit in the Fibre Channel Interface Manual), data requested by the host with a read command is retrieved from the cache, if possible, before any disc access is initiated. Data in contiguous logical blocks immediately beyond that requested by the Read command can be retrieved and stored in the cache for immediate transfer to the initiator on subsequent read commands. This is referred to as the prefetch operation. Since data that is prefetched may replace data already in the cache segment, an initiator can limit the amount of prefetch data to optimize system performance. The drive never prefetches more sectors than the number specified in bytes 8 and 9 of Mode page 08h. If the cache is not enabled, 967.5 Kbytes of the buffer are used as a circular buffer for read/writes, with no prefetch operation and no segmented cache operation. The following is a simplified description of the prefetch/cache operation: Case A-read command is received and the first logical block is already in cache: 1. Drive transfers to the initiator the first logical block requested plus all subsequent contiguous logical blocks that are already in the cache. This data may be in multiple segments. 2. When a requested logical block is reached that is not in any segment, the drive fetches it and any remaining requested logical block addresses from the disc and puts them in a segment of the cache. The drive transfers the remaining requested logical blocks from the cache to the initiator in accordance with the "buffer-full" ratio specification given in Mode Select Disconnect/Reconnect parameters, page 02h. 3. The drive prefetches additional logical blocks contiguous to those transferred in step 2 above and stores them in the segment. The drive stops filling the segment when the maximum prefetch value has been transferred. Case B-read command is received and the first logical block address requested is not in any segment of the cache. 1. The drive fetches the requested logical blocks from the disc and transfers them into a segment, and then from there to the initiator in accordance with the "buffer-full" ratio specification given in Mode Select Dis-connect/Reconnect parameters, page 02h. 2. The drive prefetches additional logical blocks contiguous to those transferred in Case A, step 2 above and stores them in the segment. The drive stops filling the segment when the maximum prefetch value has been transferred. During a prefetch, the drive crosses a cylinder boundary to fetch data only if the Discontinuity (DISC) bit is set to 1 in bit 4 of byte 2 of the Mode Select parameters page 08h. Default is zero for bit 4. Each cache segment is actually a self-contained circular buffer whose length is an integer number of logical blocks. The wrap-around capability of the individual segments greatly enhances the cache's overall performance, allowing a wide range of user-selectable configurations. The drive supports operation of any integer number of segments from 1 to 16. Divide the 967.5 Kbytes in the buffer by the number of segments to get the segment size. Default is 3 segments. Note. The size of each segment is not reported by Mode Sense command page 08h, bytes 14 and 15. The value 0XFFFF is always reported regardless of the actual size of the segment. Sending a size specification using the Mode Select command (bytes 14 and 15) does not set up a new segment size. If the STRICT bit in Mode page 00h (byte 2, bit 1) is set to one, the drive responds as it does for any attempt to change an unchangeable parameter. Caching write data ------------------ Write caching is a write operation by the drive that makes use of a drive buffer storage area where the data to be written to the medium is stored while the drive performs the Write command. Write caching is enabled independently of read caching. Write caching is enabled by default. To disable the write cache, use the Write Caching Enable (WCE) bit. For write caching, the same buffer space and segmentation is used as set up for read functions. When a write command is issued, the cache is first checked to see if any logical blocks that are to be written are already stored in the cache from a previous read or write command. If there are, the respective cache segments are cleared. The new data is cached for subsequent read commands. If a 10-byte CDB Write command (2Ah) is issued with the data page out (DPO) bit set to 1, no write data is cached, but the cache segments are still checked and cleared, if need be, for any logical blocks that are being written. If the number of write data logical blocks exceeds the size of the segment being written into when the end of the segment is reached, the data is written into the beginning of the same cache segment, overwriting the data that was written there at the beginning of the operation. However, the drive does not overwrite data that has not yet been written to the medium. S.M.A.R.T --------- S.M.A.R.T. is an acronym for Self-Monitoring Analysis and Reporting Technology. This technology is intended to recognize conditions that indicate imminent drive failure and is designed to provide sufficient warning of a failure to allow you to back up the data before an actual failure occurs. Note. The drive's firmware monitors specific attributes for degradation over time but can't predict instantaneous Each monitored attribute has been selected to monitor a specific set of failure conditions in the operating performance of the drive and the thresholds are optimized to minimize "false" and "failed" predictions. Product warranty ---------------- Beginning on the date of shipment to the customer and continuing for a period of five years, Seagate warrants that each product (including components and subassemblies) that fails to function properly under normal use due to defect in materials or workmanship or due to nonconformance to the applicable specifications will be repaired or replaced, at Seagate's option and at no charge to the customer, if returned by customer at customer's expense to Seagate's designated facility in accordance with Seagate's warranty procedure. Seagate will pay for transporting the repair or replacement item to the customer. For more detailed warranty information, refer to the standard terms and conditions of purchase for Seagate products on your purchase documentation. The remaining warranty for a particular drive can be determined by calling Seagate Customer Service at 1-800-468-3472. You can also determine remaining warranty using the Seagate web site (www.seagate.com). The drive serial number is required to determine remaining warranty information. Defect and error management --------------------------- The drive, as delivered, complies with this product manual. The read error rates and specified storage capacities are not dependent upon use of defect management routines by the host (initiator). Defect and error management in the SCSI protocol involves the drive internal defect/error management and FC-AL system error considerations (errors in communications between the initiator and the drive). Tools for use in designing a defect/error management plan are briefly outlined in this section. References to other sections are provided when necessary. Drive internal defects/errors ----------------------------- During the initial drive format operation at the factory, media defects are identified, tagged as being unusable, and their locations recorded on the drive primary defects list (referred to as the "P" list and also as the ETF defect list). At factory format time, these known defects are also reallocated, that is, reassigned to a new place on the medium and the location listed in the defects reallocation table. The "P" list is not altered after factory formatting. Locations of defects found and reallocated during error recovery procedures after drive shipment are listed in the "G" list (defects growth list). The "P" and "G" list may be referenced by the initiator using the Read Defect Data command. Details of the SCSI commands supported by the drive are described in the Fibre Channel Interface Manual. Also, more information on the drive error recovery philosophy is presented in the Fibre Channel Interface Manual. ********************************************************************** G E N E R A L ********************************************************************** SEAGATE FC-AL INTERFACE An Overview of Fibre Channel --------------------------- Introduction ------------ Everyone has accepted the fact that we have moved into the Age of Information. In this paradigm information itself is a commodity, and therefore there is great value in its efficient disbursement. Unfortunately, industry has placed greater value in creating information, than distributing it. We often hear about new machines which are capable of performing prodigious calculation at the blink of an eye. New reports of ever faster computers are commonplace. Sharing this information, however, has become a priority only recently. It seems that although we have moved into the Age of Information, one of our biggest challenges is to efficiently distribute the information for everyone to use. Luckily, a viable solution is at hand. Conceived and supported by such industry giants as IBM, Hewlett-Packard, and Sun Microsystems, the Fibre Channel is aimed at providing an inexpensive, flexible and very high-speed communications system. Most of the popular network implementations today can claim to have any two of these elements. Since Fibre Channel encompasses all three, it has everything necessary to become a resounding success. Not the Network Fibre Channel has significant advantages over common networks. The first difference is speed. The fastest network implementations today support transfer data at a little over 100 megabits per second. For smaller data files, where a single computer is directly communicating with a file server, such speeds are adequate. However, for realtime video and sound, or systems where two machines must operate on common data even 200 megabits per second is hopelessly inadequate. Fiber Channel provides significantly higher rates, from 10 to 250 times faster than a typical Local Area Network (LAN). In fact, Fibre Channel can transfer data at speeds exceeding 100 megabytes, or 800 megabits, per second. This speed is sufficient to allow transfer of a 1024x768 image with 24-bit color at 30 frame per second, and CD- quality digital sound. This overcomes the bandwidth limitation, which is probably the most serious impediment for LAN performance. As the number of computers communicating on a common network increases, the amount of data packets increases accordingly. This is because data on a LAN is common to all computers on that network. The software must decide if a particular message is relevant for a particular machine. When several machines are communicating with one another, every other machine on the network must contend with all of the messages. As the number of messages increases, the load for the entire system is increased. Fiber channel is a switched system. Much like a telephone system, a connection is established between only the parties that need to communicate. These parties can share the entire bandwidth of Fibre Channel, since they do not have to contend with messages not relevant to their communication. LANs attempt to compensate for this by increasing the transfer speed, which places an even greater burden on the software. Since all protocol for Fibre Channel is handled by the hardware, the software overhead is minimal. Fibre Channel also supports full parallelism, so if greater capacity is needed, more lines can be added. The common analogy for showing the advantages of parallelism is the effect of doubling the number of lanes on a freeway instead of doubling the speed limit. The physical distance between computers is another limiting factor for conventional LANs. Ethernet cables usually have a limit of 1000 feet between machines whereas Fibre Channel can support a link between two up to 10 kilometers apart. Finally, Fibre Channel is not software intensive. All of the essential functions are handled by hardware, freeing the computer's processor to attend to the application at hand. Even the error correction for transmitted data is handled by the Fibre Channel hardware. In standard LANs this requires precious processor resources. Advantages for Computing ------------------------ The obvious advantage for Fibre Channel is to facilitate communication between machines. Several workstations clustered together already surpass the speed and capacity of a VAX, and begin to rival the power of a super computer, at a much lower cost. The power of concurrent processing is awesome. For example, a single neuron inside our brain is much less complex, and operates far slower than a common 286 processor. However, millions of neurons working in parallel can process information much faster than any processor known today. Networking simple logical units, and operating them in parallel offers advantages simply unavailable for the fastest single processor architectures. These shared architectures require a huge amount of communication and data sharing which can only be handled by high-speed networks. Fibre Channel not only meets these requirements, but meets them inexpensively. The hardware industry is partly responsible for the I/O bottleneck. By using the processor speed as the primary focus for their sales efforts, the bus speeds have languished. With respect to the new class of processors, current system bus speeds are greatly lagging. This is something like building a mill which can process 1000 pounds of grain a day, and supplying that mill with a single donkey. There is little use for a fast processor that spends most of its time waiting for data to act upon. Whether this data comes from disc drives, peripherals, or even other processors, today's bus speeds would leave most processors idle, and the next generation of processors will be many times faster. Fiber Channel provides the data transfer capability which can keep current and upcoming processors busy. Impact on Mass Storage ---------------------- Today's fastest interfaces are capable of transferring data at around 20 megabytes per second. However, this speed rating is only for transferring data. All protocol intercommunication occurs at much slower speeds, resulting in a lower effective data transfer rates, typically around 11 megabytes per second. This represents about one-tenth of Fibre Channel's current capability. Fibre Channel drives do not suffer from device protocols occurring at slower speeds, since all communication occurs at 100 megabytes per second, including device intercommunication. In addition to this, the drive itself can be placed up to 10 kilometers away from the computer. This would have two effects on the way mass storage is implemented. First, the amount of data a machine could receive would only be limited to the transfer speed of the drive. For high performance disc arrays this could exceed 50 megabytes per second. Machine and disc storage could finally work to provide real-time, full motion video and sound for several machines simultaneously. With Fibre Channel's ability to work across long distances, these machines could conceivably reside many miles apart. For medical applications, computer design centers, and real-time networks such as reservations systems, this capability would be invaluable. Second, such support for transmitting data over large distances would allow disc drives to be placed away from the computer itself. This would allow for centralized data resource areas within a business office, simplifying everything from site planning to maintenance procedures. Indeed a centralized data resource center would be possible for an entire office complex. The development of the Loop will also provide a huge advantage in implementing large capacity disc sub systems. The Fast/Wide SCSI specification has a theoretical upper limit of 16 total devices attached to a single host. The practical maximum is 6 devices. Fibre Channel supports a theoretical limit of 256 devices for a common host, with a practical implementation of 64 devices. This practical limit is a very conservative figure, and implementation with more devices are easily possible. The Loop allows system designers to build high capacity configurations, well into the terabyte range, with much lower overall cost. Finally, Fibre Channel is a serial communications device which has two immediate advantages. First, the cabling necessary to interconnect Fibre Channel devices is very inexpensive when compared to SCSI cabling. Fibre Channel cabling is also much easier to connect, and replace than SCSI cables, which simplifies the entire process of integration and maintenance for a high capacity data storage system. For corporations that are currently grappling with a the complexity of installation, and high-cost of SCSI cables, this feature will prove invaluable for cutting costs and simplifying installation and upkeep. Secondly, implementing Fibre Channel requires less space on the circuit board than SCSI drives. This reduced space requirement would allow the drive designers to include extended features which cannot currently be implemented. For example, a 3.5-inch form-factor drive with Fibre Channel could be designed with dual-port capability, a feature necessary for use with many mainframes and mini-computers. The space saved on the circuit board by using Fibre Channel would allow for the extra connector and additional circuitry needed for dual-port drives. Conclusion ---------- The Fibre Channel will provide the corporations with data in much the same way the freeway system provided motorists mobility. Access to a vast, interconnected information network which is fast, inexpensive, and flexible. With the adoption of Fibre Channel as an open ANSI standard, its effect on the horizon of computing will be nothing short of revolutionary. We have become very good at processing data; Fibre Channel allows us to move it. The ability to share information will provide the impetus for communication, design and development on a scale not previously possible. By facilitating the fabled data-highway, Fibre Channel will accelerate to the Age of Information, as the steam engine moved us into the Age of Industry.