Copyright 1995-2016 by Kevin G. Barkes All rights reserved. This article may be duplicated or redistributed provided no alterations of any kind are made to this file. This edition of DCL Dialogue is sponsored by Networking Dynamics, developers and marketers of productivity software for OpenVMS systems. Contact our website www.networkingdynamics.com to download free demos of our software and see how you will save time, money and raise productivity! Be sure to mention DCL Dialogue! DCL DIALOGUE Zapped Again Originally published August, 1995 By Kevin G. Barkes Having just completed a thorough check of my new UPS systems and surge suppressors (see my May column), I felt a bit, well, invincible. I had employed all the marvels available through modern technology to shield myself from the vagaries of the power company and Mother Nature. I hardly even noticed the rumbling outside as a typical summer thunderstorm lumbered down upon my house. In the summer it's not uncommon for the local power company to have two or three "mini-blackouts" a week. These interruptions of power are impressive technical works of art. They appear to be carefully timed so as to be short enough not to tax uninterruptible power supplies but long enough to require resetting all the clocks and VCRs in the house. These man-made glitches are in addition to the periodic outages caused by summer thunderstorms. Whatever. Secure as I was in my inpenetrable fortress, I just kept puttering along, ignoring the increasing backround noise of torrential rain and thunder. There's a saying I once read in a piece of Star Trek fan fiction. Scotty was upset because of some hare-brained scheme Spock had employed to save the universe, which, of course, had been totally successful but had reduced the poor Scotsman's engineering department to a pile of smoking debris. "Ye canna stick a 15 ampere tap inta God, ye crazy Vulcan!" Scotty had cried indignantly. That's about the best description I can think of for what happened next. A nearby lighting discharge apparently induced a massive electromagnetic pulse in the area of my son's bedroom, literally blowing out the modem and telephone connected to his computer. Amazingly, his computer suffered no damage other than a scrambled CMOS memory. His new Sega Saturn game computer, which shared an electrical outlet with the telephone, was not as fortunate. It became a futuristic looking paperweight. The strike also nailed the house telephone in my son's room, frying its innards so it was still warm to the touch an hour later. The pulse evenly distributed itself throughout the house phone circuits, taking out the remaining five units of the AT&T System 2000 phone system. (AT&T no longer makes or repairs the System 2000, but offered me $25 for each of their smoking carcasses.) This is where it gets interesting. The house phone line runs directly parallel to a fax machine, which actually made a "poof" noise as its modem gave up the ghost. The surge from my son's room also passed into a two-line phone in my office, jumping from the house line to my office line. It travelled a few feet to another two-line phone, and jumped over to a second line I use for dialing out. This dialout line is connected by an old modem to my main PC; I use the modem to dial the phone via software control from a phone manager program. The voltage traveled through the modem, frying it; into the PC, blowing out the serial I/O card; and down the thinwire Ethernet, whacking all four PC nodes of my Pathworks network. In the meantime, my office looked like the bridge of a starship under full enemy attack. Various alarms, klaxons and beepers screamed in terror. The lights went off and on, and two incandescent bulbs gave off a loud pop, flashed an actinic glare and plunged the office into near darkness, the sole light coming from a desktop halogen lamp powered by its own UPS. The smell of ozone and burned insulation filled the air. Then the turmoil ended. The power came back on. The UPS systems winked off. Those systems, lights, and pieces of office equipment not damaged by the strike returned to normal. While the damage was significant, it was limited. None of the other electrical appliances in the house was affected. The VAXstation continued its charmed existence, complaining only that the nodes downstream on the Ethernet had mysteriously vanished. As my electrician pointed out, most of the suppressors and protection devices had worked. Total cost of this little lesson in humility? About $5,000, not counting the time lost making repairs, ordering parts and marveling in silent awe at the charred remains of three high-grade telephone line surge suppressors, which had been reduced to hunks of nondescript plastic and metal. Scotty was right. You can't stick a 15 ampere tap into God. Unfortunately, God doesn't always give you a choice in the matter. ******************* A couple years ago I wrote a column about how most people have "holes" in their DCL knowledge. That's because relatively few learn DCL in a structured setting. Most times you were plunked down in front of a terminal, told to type "HELP HELP", and you were on your own. Things haven't changed much since then. In fact, an argument can be made that things have worsened, since even less formal VMS training is given these days. Even oldtimers suffer lapses. I recalled how I was embarassed at a customer site when someone pointed out to me the queue-name parameter in the DELETE/ENTRY command is optional, and had been for some time. When I looked it up, I also discovered the existence of the special $ENTRY symbol. How the heck did I miss that one? Sheesh. Some DCL whiz, eh? Still, there are some really basic features of DCL and VMS which some users have never learned. Traveling from site to site, I've compiled a list of common "forgotten" DCL features. Don't be too condescending; you may be surprised at your own blind spots. When I present this list at my training sessions, everyone laughs heartily; after all, many of these items are absurdly obvious. But invariably a few people approach me privately afterward and confess they were caught by one or two of these nuggets: -- Control-t. This constantly surprises me, but a lot of people are unaware of this stat display. It occurs mostly at sites where users remain primarily within a custom application and the manager has disabled control-t to keep the screen displays from being messed up. --The DEALLOCATE command has an /ALL qualifier which permits you to deallocate all devices which your process has allocated, without specifying device names. --File specification flexibility. You can get prior versions of files by specifying a version offset instead of an explicit version number. For example, EDIT FILE.DAT;-1 will edit the file one version number lower than the highest available version number. The version number ;0 specifies the highest version number; ;-0 specifies the oldest. So, if you wanted to delete the latest version of a file, keeping prior versions intact, and you didn't know the actual version number, you could enter DELETE FILE.DAT;0. -- Command line continuation. A user once complained to me he couldn't enter a line on a command file he was writing because TPU kept breaking it. He'd never heard about the hyphen continuation character. -- Command prompting. Many are unaware VMS will ask for required parameters. -- Control-b recalls previously entered command lines. Especially helpful on hardcopy terminals. And command recall is also available from within a number of VMS utility programs. --For that matter, just about all the other control key combinations: control-a (switches between insert and overstrike mode); control-d (move cursor to the left); control-f (move cursor to the right); control-e (move cursor to end of line); control-h (move cursor to beginning of line); control-r (repeats command line); control-u (cancels current input line); control-x (cancels current line and all data in typeahead buffer), among others. --/CONFIRM options. Commands like DELETE, which have a /CONFIRM option, generally prompt the user prior to each operation, but the only prompt you get is the default [N]. You can enter Y, T or 1 for positive responses, N, F and 0 for negative responses; typing the word QUIT or entering control-z aborts the remainder of the command; and if you enter ALL, the command stops prompting and processes the rest of the command. --Instead of creating a new directory, copying files into it and deleting the original files, you can just RENAME the .DIR file (provided the directories are on the same disk, of course). You can find these kinds of tricks just by perusing the DCL Dictionary or the online help. Once a week, find yourself a new DCL shortcut. ******************* Kevin G. Barkes is an independent consultant who recently learned the correct name for a redneck demon is Beelzebubba. Kevin lurks on comp.os.vms and can be reached at kgbarkes@gmail.com.