WasteBasket

Wouldn’t it be nice to easily recover purged files on a Tandem system, instead of restoring them from the archive? Windows supports this function, while Tandem does not — until today. GreenHouse designed and developed a Tandem/GUARDIAN based WasteBasket, from which a purged file can be easily and hassle-free restored.

And what about purging an open file, e.g. to replace a program file with a new one? This makes a program upgrade much easier: simply purge the existing file (keeping its functionality intact) and move the new file into place. The ability to purge even open files is one of the features of WasteBasket.

How it works

The product is based on a library (WBLIB) attached to programs performing the PURGE function, such as FUP, TACL or other — even user-written — programs. The library intercepts the FILE_PURGE_ and PURGE procedure calls and saves the files to be purged in a subvol named $vol.WASTEGHS. For performance reasons, purged files are always saved on the original volume, while restoring allows a target location different from the original. WBLIB also intercepts User_Authenticate_ to detect when the User-ID of the process has changed (mainly to catch the logon in TACL).

Components

• WBSRV — a $ZZKRN controlled server that creates monotone file numbers, updates the WBDIT directory file, checks purge access rights and collects statistics (moving all privileged actions here keeps WBLIB small and license-free)
• WBLIB — the intercepting library attached to purging programs
• WBCOM — the command interpreter for managing the WasteBasket and restoring files; supports BACKUP, REALPURGE (purge of open files) and administrative commands (ACCESS, LISTOPENS, REMOVEACL, STATISTICS, USERS)
• WBDOG — a $ZZKRN controlled watchdog that checks the WasteBasket daily and deletes files older than a configurable number of days (execution time and file lifetime are set in the EDIT file WBCONFIG)

Version 2.00 supports up to 21,767,823,360 files in the WasteBasket system. Available for a two-month free test period — please contact info@greenhouse.de.