Browse Prior Art Database

Hard File Assembly for a Diskette-Based Data Processing System

IP.com Disclosure Number: IPCOM000041682D
Original Publication Date: 1984-Feb-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 3 page(s) / 80K

Publishing Venue

IBM

Related People

Lerom, GA: AUTHOR [+2]

Abstract

A hard file assembly containing a magnetic hard file of high capacity is attached to a diskette-based data processing system via the normal diskette cable and diskette adapter to increase the system's storage. The hard file assembly is set up as a field replaceable unit and can physically replace a normal diskette drive. From the processing system the hard file assembly is considered as an enlarged diskette. Thus, the storage capacity of such a diskette-based system can easily be upgraded in different steps, and the system may use diskette as well as hard file drives. Fig. 1 shows schematically the main parts of the data processing system. The system contains the system memory and a bus 2 to which a printer adapter, a communication adapter, a keyboard/display adapter and a diskette adapter 3 might be attached.

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Hard File Assembly for a Diskette-Based Data Processing System

A hard file assembly containing a magnetic hard file of high capacity is attached to a diskette-based data processing system via the normal diskette cable and diskette adapter to increase the system's storage. The hard file assembly is set up as a field replaceable unit and can physically replace a normal diskette drive. From the processing system the hard file assembly is considered as an enlarged diskette. Thus, the storage capacity of such a diskette-based system can easily be upgraded in different steps, and the system may use diskette as well as hard file drives. Fig. 1 shows schematically the main parts of the data processing system. The system contains the system memory and a bus 2 to which a printer adapter, a communication adapter, a keyboard/display adapter and a diskette adapter 3 might be attached. Via normal diskette cables 4, a hard file assembly 5 and a diskette drive 6 are attached to diskette adapter 3. More hard file assemblies and/or diskette drives might be attached via additional diskette cables 4. The hard file assembly 5 comprises a diskette cable interface 7, a microprocessor 8, a buffer 9, a hard file interface logic 10 and the hard file 11 itself. A separate power supply (not shown) is also contained in hard file assembly 5. Diskette adapter 3 encompasses the system interface logic 12, diskette interface logic 13, microprocessor 14 and an associated read-only storage (ROS) 15. Hard file assembly 5 receives commands and data from the system and transfers data and status to it. This information is passed over the standard diskette interface, especially diskette adapter 3 and cable 4, by simulating a diskette data stream in the hard file assembly 5. The commands for the hard file assembly 5 are sent as a control block embedded in a diskette record written to a predefined diskette location. The diskette record format contains ID areas and data areas interleaved with gaps, as shown in Fig. 2. Fig. 3 shows how the ID area looks, and Fig. 4 shows how the data area looks. In simulating the diskette data stream, the hard file command is included in the data area as the first four bytes, as indicated in Fig. 4 and shown in more detail in Fig.
5. This command block is generated and placed in these first four bytes by the system, i.e., the program control realized by microprocessor 14 in cooperation with the instructions con...