Figure 1.
FiJure 2.
Figure 3. Figure 4. Fi;Iure 5.
Figure 6.
Figu:r:e 7. Figure 8.
I'igure 9.
Figure 10. Figure 11. Figure 12.
Figure 13.
Figure 14. CftS File System ••••••••••••• 2-6
Devices Supporte1 by a virtual 5achine •••••••••••• 2-13 CftS Storage ftap •••••••••••• 2-16 CftS (and Request; processing ••••••••••••••••• 2-30 PSi Fields when :alled Routine Starts ••••••••••••• 2-31
Register Conte&ts when :alled
Routine Starts ••••••••••••• 2-31 Simulated os Supervisor Calls ••••••••••• __ .========2-31 An Overview of the Functional
Areas CKS ••••••••••••••• 2-52
Details of CftS Systea Functions and the Routines that
Perform Them ••••••••••••••• 2-53 PSi Fields when Callea Routine is Started ••••••••• 2-69
Register Contents when :alled Routine is Started ••••••••• 2-10 How CMS File Records are
Chained Togehter ••••••••••• 2-86
Format of a File Status Block; Format of a rile Status rable •••••••••••••••••••••• 2-86
For.at of the First Chain
Link and Nth Links ••• 2-89 15.
Figure 16.
Figure 17. Figure 18. Figure 19. FIGURES of Fixed-Length Recoras and Variable-Length Re=oris in Files ••••••••••• 2-B9
structure of the Master File Directort ••••••••••••• 2-92
Disk Storage Allocation Using the QMSK Data Block •••••••• 2-92
Flow of Control for Unit Recora I/O processing •••••• 2-94
Relationships in storage
between the CMS Interface and the CMSAMS ana CHSVSAM DCSSs •••••••••••••••••••• Figure 20. The Relationships in storage between the User Program and the ana CMSVSAft DCSSs ••••••••• 2-111
Figure 21. Relationship in storage
between the User Program, the os Simulation and
Interface Routines, and the CMSDOS ana CMSVSAft DCSSs •• 2-118 figure 22. OS Functions that CMS Simulates ••••••••••••••••• 2-123
Figure 23. Devices Supported by a Virtual Machine ••••••••••• 2-239
Figure 24. CBS Abend Codes ••••••••••• 2-243 Contents vii

viii IBM VM/370 System Logic and Program Determination--Voluae 2