JPS5769434A - Command prefetching system - Google Patents

Command prefetching system

Info

Publication number
JPS5769434A
JPS5769434A JP14520680A JP14520680A JPS5769434A JP S5769434 A JPS5769434 A JP S5769434A JP 14520680 A JP14520680 A JP 14520680A JP 14520680 A JP14520680 A JP 14520680A JP S5769434 A JPS5769434 A JP S5769434A
Authority
JP
Japan
Prior art keywords
bit
command
ccw2
prefetched
ccw4
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP14520680A
Other languages
Japanese (ja)
Inventor
Masahiro Nagai
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NEC Corp
Original Assignee
NEC Corp
Nippon Electric Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by NEC Corp, Nippon Electric Co Ltd filed Critical NEC Corp
Priority to JP14520680A priority Critical patent/JPS5769434A/en
Publication of JPS5769434A publication Critical patent/JPS5769434A/en
Pending legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F9/00—Arrangements for program control, e.g. control units
    • G06F9/06—Arrangements for program control, e.g. control units using stored programs, i.e. using an internal store of processing equipment to receive or retain programs
    • G06F9/30—Arrangements for executing machine instructions, e.g. instruction decode
    • G06F9/38—Concurrent instruction execution, e.g. pipeline or look ahead
    • G06F9/3802—Instruction prefetching

Landscapes

  • Engineering & Computer Science (AREA)
  • Software Systems (AREA)
  • Theoretical Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Advance Control (AREA)

Abstract

PURPOSE:To obtain a command control system suitable for an IO device and the attributes of its commands, by providing a bit showing whether a command one bit later or a command after the next one is to be prefetched in a command control word. CONSTITUTION:Since a bit PF at the bit position 15 of a command control word CCW0 is a ''0'', a data channel device prefetches the next command CCW1. Similarly, since the bit PF is the ''0'' even during the execution of the CCW1, the next CCW2 is prefetched, but since the bit PF is a ''1'' even during the execution of the CCW2, the command CCW4 following the next one is prefetched. On receiving the status ''1'' of a bit MOD from a magnetic disk device as information on the completion of the CCW2, the data channels sends the instruction of the execution of the prefetched CCW4 to the magnetic disk device, thereby performing chain actuation smoothly. When the status of the bit MOD is the ''0'', the CCW4 is discarded to perform TIC operation and the reexecution of the CCW2.
JP14520680A 1980-10-17 1980-10-17 Command prefetching system Pending JPS5769434A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP14520680A JPS5769434A (en) 1980-10-17 1980-10-17 Command prefetching system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP14520680A JPS5769434A (en) 1980-10-17 1980-10-17 Command prefetching system

Publications (1)

Publication Number Publication Date
JPS5769434A true JPS5769434A (en) 1982-04-28

Family

ID=15379844

Family Applications (1)

Application Number Title Priority Date Filing Date
JP14520680A Pending JPS5769434A (en) 1980-10-17 1980-10-17 Command prefetching system

Country Status (1)

Country Link
JP (1) JPS5769434A (en)

Similar Documents

Publication Publication Date Title
EP1158398A3 (en) Information recording apparatus, information recording system and information recording medium
EP0788115A3 (en) Electronic apparatus including a memory device and method of reprogramming the memory device
JPS57111792A (en) Program copying preventing system
JPS5769434A (en) Command prefetching system
ES487251A1 (en) Methods of operating direct access storage means.
JPS5330841A (en) Control method of computer
EP0195091A3 (en) Method of controlling automatic drawing machine
JPS57105061A (en) Advanced seek control system of floppy disk device
JPS5240108A (en) Controlling method for recording medium
JPS545636A (en) Input/output control system for electronic computer
JPS5226131A (en) Method of making out the operation control signal in microprograming c ontrol system computer
JPS57106937A (en) Prefetch controller
JPS57210483A (en) Origin returning method for head of magnetic disk device
JPS57111625A (en) Input and output system for controlling microprocessor
JPS55110357A (en) Control system for recorder
JPS5421811A (en) Magnetic recorder-reproducer
JPS57174740A (en) Memory controlling method
JPS57123581A (en) Pre-fetch control system
JPS53136448A (en) Information processor
JPS6410468A (en) Formatting method for magnetic disk device
JPS51140433A (en) Write data checking system
JPS6473561A (en) Buffer controller for magnetic tape device
JPS5416947A (en) Input/output action control syste for data channel device
JPS564855A (en) Control system for command retrial
JPS5757329A (en) Controller of virtual input-output device