August 06, 2012
What You Need to Do and Check for SLTs
At a recent visit to a customer's shop, VEsoft's Vladimir Volokh spread the word about System Load Tapes. The SLTs are a crucial component to making serious backups of HP 3000s. Vladimir saw a commonplace habit at the shop: Skipping the reading of the advice they'd received.
"I don't know exactly what to do about my SLT," the manager told him. "HP built my first one using a CD. Do I need that CD?"
His answer was no, because HP was only using the most stable media to build that 3000's first SLT. But Vladimir had a question in reply. Do you read the NewsWire? "Yes, I get it in my email, and my mailbox," she said. But like other tech resources, ours hadn't been consulted to advise on such procedures, even though we'd run an article about 10 days ago covering CSLTs. That tape's rules are the same as for SLTs. Create one each time something changes in your configuration for your 3000.
Other managers figure they'd better be creating an SLT with every backup. Not needed, but there's one step that gets skipped in the process.I always say, "Do and Check," Vladimir reports. The checking of your SLT for an error-free tape can be done with the 3000's included utilities. The venerable TELESUP account, which HP deployed to help its support engineers, has CHECKSLT to run and do the checking.
There's also the VSTORE command of MPE/iX to employ in 3000 checking. If your MPE references come from Google searches instead of reading your NewsWires, you might find it a bit harder to locate HP's documentation for VSTORE. You won't find what you'd expect in a 7.5 manual. HP introduced VSTORE in MPE/iX 5.0, so that edition of the manual is where its details reside for your illumination.
It's also standard practice to include VSTORE in every backup job's command process.
There's another kind of manager wouldn't be doing SLTs. That's the one who knows how, but doesn't do the maintenance. You can't make this kind of administrator do their job, not any more than you can make a subscriber read an article. There's lots to be gained by learning skills that keep that 3000 stable and available, even in the event of a disk crash. Management might not respect the 3000's ability to take on new developments. But a company always respects the 3000's reliability.
CHECKSLT, and care and feeding of SLTs, are well-covered in a NewsWire column written by John Burke almost 13 years ago. His advice still holds today.
HP’s documentation tells us we need to have a current SLT. And that it can be created using the TAPE command within SYSGEN. If you look hard enough you will also find the warning that the CSLT you may have created when doing an update or manage patch is not adequate. That is about it for SLT recommendations.
Is this recommendation correct? Well, in the sense that it is necessary to have an SLT created by the TAPE command, then, yes, it is correct. You can re-install your system in the event you lose a drive in the system volume set using this SLT and appropriate other backups. But is this recommendation complete? I think not.
As has been proven countless times, the people who write manuals (and not just at HP) are not out in the real world. They are not running shops where if you get a six-hour maintenance window once a month you consider yourself lucky. They are not running shops where you have to have procedures that can be understood and followed by someone with only basic training in system operation. They are not running shops where cell phones go off like July 4th fireworks as soon as anything unusual happens.
You can find HP's VSTORE page in that 5.0 command manual online, just like the NewsWire's advice. Vladimir, you find him in your office, if he's traveling your way. But managers also find that he recommends our advice -- perhaps because we first get the instructions to do it, and then have our reports checked. Do and Check are words to live by, not just for managing 3000s.
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