This part of ISO/IEC 9318 dcscribcs thc Logicai Level 2 (device level) Interface for disk drives. Sce clause 6 of ISO/IEC 9318-1 for explanation of thc lcvcls.
The physical, electrical, and configuration characterisiics and the transmission prolocol of this interface are in accordance with ISO/IEC 9318-1. The interface is eapablc of handling data rates from 0 to at least 10 Moctets/s, depending on driver and receiver classcs.
The purpose of this part of ISO/IEC 9318 is to facilitatc thc dcvclopmcnt and utilization of a device level interface which permits thc interconnection of disk slave pcriphcrals to a controllcr.
This part of ISO/IEC 9318 does not replaee any existing standard, but it docs complemcnt othcr Intelligent Peripheral Interface (IPI) standards (sec clause 2).
This part of ISO/IEC 9318 provides a definition of thc device specifie portion of a family of standards callcd thc Intelligent Peripheral Interface (IPI), a high performance, gcncral-purposc parallel peripheral interface.
The intent of thc IPI is to isolate thc host (CPU), both hardware and software, from changes in peripherals by providing a "funclion gencric" command set to allow thc connection of multiple types of peripherals (disks, printers, tapes, Communications). To smooth thc transition from the current methods to thc gencric approach, thc IPI supports devicc-specifie command sets, such as this one, lo aid in bridging thc gap between the two approaches.
To accomplish this set of goals, the design of the IPI includes dcvice-spccific and dcvicc-gcneric command sets, both utilizing a common physical bus. Thc dcvice-spccific command set provides:
Dcvicc-oricnted control; Physical Data Addressing; Timing Critical Operations; Lowcr Device Cosl.
Thc dcvicc-gcneric command set provides a higher level of functionality and portability. It includes:
Host/Device Indcpendcncc; Logicai Data Addressing; Timing Indepcndence; Command Qucuing Capability.
A system is not restricted to the use of one level of command set or thc othcr. Il is possiblc thai both lcvcls of command sets will be utilizcd with a given system's architccturc to balance such parameters as system performance, cost, and
DS/ISO/IEC 9318-2:1991 history
1991DS/ISO/IEC 9318-2:1991 Information technology - Intelligent Peripheral Interface - Part 2: Device specific command set for magnetic disk drives