



CARE AND FEEDING OF FILES 11 DISK VOLUMES - OUTLINE

	R. B. DENNY
	L. M. FRASER

Morning Session - Definition and Description
or How the beast is supposed to work.

I. Introduction
	o General description of file systems
	o What they do for us
	o Types of file systems
		single/multiple directory
		contiguous vs segmented vs mapped files.

II.  Static structure of ODS1 volume.
	o Two views of file system, user vs system
	o Index file
		home block
		index bitmap
		file headers
	o Storage Bitmap file
	o Master file Directory
	o Directory structures
	o Inter-relationship of static files
	o Limitations on different structures

III.  Dynamic changes in on disk structure as result of file
activity, i.e. all of the ACP functions.
	o File creation
	o Directory enter
	o File extension
	o File deletion
	o Directory remove
Look at effects on directories, file headers, index file
bitmap, storage bitmap.

IV. Runtime core resident structures used by the ACP and relationship
to disk resident data.  Discuss VCB, FCB, and WDB creation and
maintenance during operation.
	o volume mount
	o file access

Short Q&A prior to lunch.






Afternoon Session - Enhancement and repairs.
or Damn!! My pack won't boot! What now??

V.  File system optimization. Selecting appropriate values for
	o Index file position
	o Maximum number files
	o Default extension size
	o Directory Cache size
	o Maximum retrieval pointers

VI.  Preventative maintenance.
	o Full pack backups - BRU, DSC, PRESRV
	o Incremental backups - BRU
	o Zero block/empty files - PUG
	o Lost files - VFY
	o Volume fragmentation
	o Huge directories & problems w/large disks
	o Save volume keys in safe place

VII.  Weak spots in the Files 11 structure and problem repair or
 recovery.
	o Boot block - Priv task qios to wrong lun or device
	o Bad file headers
	o Corrupted storage bitmap
	o Overwritten home block
	o Multiple entries to same file not interlocked
	o Physically bad sectors develop

VIII. Tools and procedures for disk fixing.

	o CVL, HOME	- change defaults of existing volume.
	o DMP, OD	- File/Disk dump utilities
	o DDT, ZAP	- File/Disk Bit Twiddler
	o REI, UND, RECOVER - Deleted file Utilities
	o DSKPAT, DBM	- General disk dumper/modifiers
	o FILES		- Find file with specific block(s)
	o Stand alone, bootable tape RSX with tools fixed in core


Q&A and hands-on time if available.

