JES2/JES3

Key Characteristics

• • Job queuing and scheduling
  • SPOOL management
  • Print and punch services
  • Job output management
  • Multi-system support
• JES2 vs JES3:
• JES2:
  • Decentralized architecture
  • Simpler configuration
  • Better for independent systems
  • Job-level management
  • More commonly used
• JES3:
  • Centralized scheduling
  • Advanced device management
  • Global resource management
  • Complex scheduling requirements
  • Deadline scheduling
• JES Functions:
  • Input Processing: Receive and queue jobs
  • Job Selection: Choose jobs for execution
  • Output Processing: Manage job output
  • SPOOL Management: Temporary storage for I/O
  • Device Allocation: Manage printers and devices
• Job Processing Flow:
  1. Job submitted to JES 2. Job placed in input queue 3. Initiator selects job for execution 4. Programs execute with JES managing I/O 5. Output captured in SPOOL 6. Output printed or purged 7. Job completion and cleanup
• JES Commands:
  • $DJQ: Display job queue
  • $PI: Purge input job
  • $PO: Purge output
  • $S: Start initiator or writer
  • $P: Stop initiator or writer
  • $D: Display status

Use Cases

• • Managing batch workload
  • Print and report distribution
  • Job scheduling and prioritization
  • Multi-system work distribution
  • Output management

Related Concepts