A high density magnetic tape cartridge storage system

Abstract

A magnetic tape data storage system called the High Capacity Mini-Recorder has been designed and is in manufacture for Bell System applications. It can be operated in either the streaming or the incremental (start/stop) mode. It uses the recently available DC600 1/4 inch, 600 foot, high density tape cartridge manufactured by 3M Corp. Data are written in blocks of 2K bytes on five serpentine tracks at a linear density of 10,000 flux transitions/in. (ftpi) using Modified Frequency Modulation (MFM) encoding. The total user capacity is 26 Mbytes. The addition of a binary head positioning mechanism increases the number of tracks to 10 and the capacity to 52 Mbytes. Burst error correction capability up to several thousand bits is provided by an Interlaced Sum-set code. Tape speed for read or write is 50 inches/sec. (ips), and for search is 100 inches/sec. The average data rate is 37 Kbytes/sec. for streaming. The data electronics incorporates write precompensation for peak shift and provides data recovery using phase-locked loop decoding techniques. A controller based on an 8086 microprocessor with an 8 MHz clock allows the system to be operated using a high level command set.