Chapter 1 Introduction
1.4Support for Partitioned Tapes
Some operating systems provide support for tape partitions. With these systems, the tape drive can read and write tapes containing either one or two partitions. Partitions provide an efficient way to maintain a directory on a tape without the risk of overwriting data when updating the directory. For additional information, refer to the operating manuals that support your system.
1.5Enhanced Performance
Assuming an average 2:1 compression ratio, the tape drive can achieve a sustained transfer rate of approximately 1 MByte per second when writing in EXB-8500c format. The maximum SCSI data transfer rate is up to 5.0 MBytes/second for a synchronous burst and up to 2.5 MBytes/second for an asynchronous burst. (Achievement of these performance numbers is dependent on the system configuration into which this tape drive is installed).
Data interchange is maintained through full read and write compatibility with the EXB-8500c, EXB-8500, EXB-8205, EXB-8200, and EXB-8200SX 8mm Cartridge Tape Drives.
1.6Intelligent Data Compression
When writing in its default EXB-8500c format, the tape drive uses the established Improved Data Recording Capability (IDRC) algorithm. Licensed from IBM, this algorithm is a de facto standard in mainframe environments. It uses the EXABYTE Compression Integrity Check™ feature to ensure that data is accurately compressed and decompressed into the original form sent by the host computer.
The compression algorithm is completely contained in an EXABYTE proprietary integrated circuit. When data compression is enabled by the user, the tape drive invokes the compression algorithm intelligently, constantly monitoring the compression ratio to determine whether compressing the data will actually decrease the size of the data set. When compression is turned on, the tape drive sends compressed data to tape only when it benefits the user's storage capacity and throughput.
1.7Sophisticated Error Correction Procedures
The tape drive performs on-board error correction code (ECC) and error-recovery procedures, along with full read-after-write verification to ensure data integrity. The drive also contains a logical-block-CRC (cyclic redundancy check) feature. By adding two bytes of CRC data to every logical block on a compressed format tape, the drive can check that user data is compressed and decompressed accurately.
1.8Additional Features
The tape drive contains a single-ended SCSI controller. Additional features include SCSI-2 compatibility, synchronous data transfer, an integrated 1-MByte speed-matching buffer, full disconnect/reconnect arbitration support, and logical block packing. The tape drive is an easily integrated solution to your journalizing, archiving, data interchange, software distribution, imaging, data acquisition, and backup/restore needs.
