Browse Prior Art Database

Miniservice for Active Control Blocks

IP.com Disclosure Number: IPCOM000041844D
Original Publication Date: 1984-Mar-01
Included in the Prior Art Database: 2005-Feb-03
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Clauson, RA: AUTHOR [+3]

Abstract

This technique allows a plurality of inexpensive byte-by-byte printers to be attached on the same printer attachment card as faster, more expensive, blocked data printers with minimal impact to the existing printer attachment card. In order to connect and service several printers with a byte-by-byte interface, it is necessary to service the printer control blocks (PCB) associated with each printer data set sufficiently often to maintain a data rate adequate to keep the printers busy. To provide this capability, extra service (miniservice) is provided to each data set which indicates the need for such service between normal control block service. A bit is provided in each PCB which, when set, indicates that the PCB needs miniservice.

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Miniservice for Active Control Blocks

This technique allows a plurality of inexpensive byte-by-byte printers to be attached on the same printer attachment card as faster, more expensive, blocked data printers with minimal impact to the existing printer attachment card. In order to connect and service several printers with a byte-by-byte interface, it is necessary to service the printer control blocks (PCB) associated with each printer data set sufficiently often to maintain a data rate adequate to keep the printers busy. To provide this capability, extra service (miniservice) is provided to each data set which indicates the need for such service between normal control block service. A bit is provided in each PCB which, when set, indicates that the PCB needs miniservice. After normal service to a PCB without the bit set, all control blocks with the bit set are serviced. Then, the next control block without need for miniservice is serviced followed again by service to all control blocks requiring miniservice. In the figure, the miniservice bits of printer control blocks 3 and 5 are set. Between normal service of PCB1 and PCB2 miniservice is provided to PCB3 and PCB5. After PCB2 is serviced, miniservice is again provided for PCB3 and PCB5. After this, normal service jumps to PCB4 since PCB3 is being serviced by miniservice. This progression continues until all of the blocks have been serviced by normal service. Miniservice continues until none of the PCB blocks have...