AN-413 Disk Interface Design Guide and Users Manual
COP820CJ,COP840CJ,COP880C,COP884BC, COP888CF,COP888CL,COP888EK,COP888FH, COP888GW,COP8ACC5,COP8AME9,COP8CBE9, COP8CBR9,COP8CCE9,COP8CCR9,COP8CDR9, COP8SAA7,COP8SAC7,COP8SBR9,COP8SCR9, COP8SDR9,COP8SGE5,COP8SGE7,COP8SGG5, COP8SGH5,COP8SGK5,COP8SGR5,COP8SGR7, COP912C AN-413 Disk Interface Design Guide and Users Manual Literature Number: SNOA710 Disk Interface Design Guide and Users Manual AN-413 National Semiconductor Disk Interface Application Note 413 Design Guide and James Cecil Ramachandran Gopalan Users Manual William Llewellyn Shakeel Masood Pat Tucci Larry Wakeman January 1986 CHAPTER 1 DISK DRIVE TECHNOLOGYÐOVERVIEW 1.0 INTRODUCTIONÐWINCHESTER sectoring: hard sectored discs and soft sectored discs. The DRIVES hard sectored discs have sectors demarcated by the manu- facturer and are identified by a sector pulse at the start of From the start, digital computers have required some form each sector while the soft sectored discs have only an index of data storage as an adjunct to their relatively sparse main- pulse signifying the start of a track. storage facilities. Some of the early forms of storage were The more recent hard disk drives have a number of platters punched cards, paper tape and the magnetic tape storage. on the same spindle, with one head per surface. In such This was the principal storage medium, until faster-transfer, cases similar track position on each platter constitutes a higher-capacity media became available and a direct link cylinder, e.g. cylinder 0 is the cylinder corresponding to was established between the computer's main memory and track 0 on both sides of all the platters. The reading or writ- the mass storage device. This link was the rotating memo- ing of data is accomplished by the read/write head.
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