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Chapter 4. SafeAccess CMS Component
SafeAccess CMS Interception Operation
SafeAccess modifies CMS behavior by loading up SafeAccess CMS nucleus extensions in each user's virtual machine. Each user loads the SafeAccess CMS component with the SACUC utility. SafeAccess intercepts the CMS commands or functions listed below and, in the cases where SafeAccess simulated minidisks are involved, modifies the behavior of the command to simulate a normal minidisk. When SafeAccess simulated minidisks are not involved, SafeAccess calls the appropriate CMS command or function so that it can process it as normal. Listed below are the CMS commands and functions that are intercepted and a description of the SafeAccess processing that occurs.
ACCESS
SafeAccess determines if the target of the ACCESS command is a virtual device and also a SACDISK. If it is, then SafeAccess retrieves the corresponding SFS Directory from the SafeAccess database, modifies the ACCESS command an SFS directory instead of a vdev and issues the transformed ACCESS command. SafeAccess always specifies FORCERO or FORCERW depending on the linkmode.
FORMAT
SafeAccess determines if the target of the FORMAT is a SACDISK and if so, it will erase all the files from the corresponding directory (if applicable), update the SafeAccess database with the new label, and access the SACDISK at the given mode. SafeAccess ignores the blocksize after verifying that it is a valid one. Note that SFS only supports a 4K blocksize.
LISTFILE
SafeAccess determines if the target of the LISTFILE contains a SACDISK and if so examines the options on the LISTFILE command. If the LABEL option is present, then it runs the CMS LISTFILE command, changing the label column to contain the minidisk label from the SafeAccess database for the SACDISK.
QUERY
SafeAccess passes all non-QUERY DISK commands to CMS. It then determines if any SACDISKs are accessed and if any are to be included in the QUERY DISK output. If so, it runs the CMS QUERY DISK and translates lines that correspond to SACDISKs with information from SFS and from the SafeAccess database for the SACDISK.
The fields in the QUERY DISK output and where the information is obtained for a SACDISK:
LABEL SafeAccess Database
VDEV CMS QUERY DISK output
M CMS QUERY DISK output
STAT CMS QUERY DISK output
CYL SafeAccess Database
TYPE SafeAccess Database
BLKSZ Always set to 4096
FILES CMS QUERY DISK output
BLKS USED-(%) CMS QUERY LIMITS "4K Blocks Committed"
BLKS LEFT CMS QUERY LIMITS "4K Block Limit" - "4K Blocks Committed"
BLK TOTAL CMS QUERY LIMITS "4K Block Limit"
SafeAccess keeps a table in each user's virtual machine of currently accessed SACDISKs.
RELEASE
SafeAccess updates the table of accessed SACDISKs and releases the directory.
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