Copyright 1990-2016 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 Originally published October, 1990 By Kevin G. Barkes DSNlink: On-Demand Software Support You're working on a complex DCL command procedure and you're having problems. Some of your code isn't behaving properly. Despite repeated searches through the DCL Dictionary, you just can't seem to locate the cause of the glitch. What do you do? You send a VMS Mail message containing the irksome command file fragment to the magical address DSN%VMS-DCL. The odds are pretty good that by the end of the day you'll have the answer. SON OF DSIN The rapid response is possible because of DSNlink, Digital's "on-demand" network linking DEC's Customer Support Center with participating customer sites. DSNlink is "free" to sites having at least a Basic VMS Support license. Essentially, it's an automated version of DSIN, the Digital Software Information Network. But calling DSNlink an automated DSIN is like calling a VAX 9000 a big calculator. DSNlink is like having a resident VMS wizard lurking in the bowels of your VAX. On-demand networks are fairly common nowadays. For example, my computer bulletin board system (BBS), SYS$OUTPUT, is part of the international FidoNet amateur network, which has over 7,000 member nodes around the world. FidoNet is a prototypical on-demand network. Unlike DECnet networks, which are in constant communication, FidoNet nodes call each other over regular phone lines only when they have electronic mail or files to exchange. DSNlink works the same way. The DSNlink software goes in easily with VMSINSTAL and requires a minimum of fiddling to configure. All it requires is a dedicated serial port and modem. DSNlink is completely managed by a single detached process named DSN$NETWORK. When a user issues DSN commands, they're piped into DSN$NETWORK, which controls the modem and all communications operations. Up to 32 users on your system can be connected through a single DSNlink channel to DEC, although the practical considerations of 2400 bps throughput limits things a bit. DSNlink offers four major functions: Mail, File Copy, Flash Mail and Interactive Text Search. DSNlink Mail permits the transmission of service requests to DEC using the regular VMS Mail utility. Mail sent to DSN%-nnnn (nnnn is the software product name) "wakes up" DSN$NETWORK, which then dials DEC and passes the message on. An acknowledgement is e-mailed back to you via DSNlink, and, depending on the nature of the request, a response from CSC personnel follows shortly thereafter. I've never had to wait more than two hours for a response, but then I have a tendency to make requests in the wee hours of the morning and on weekends. Your mileage may vary. DSNlink mail can only handle ASCII files up to 30 blocks in length. For large text files or binary files such as images, DSNlink File Copy can be used. A close relative to DSNlink Mail is Flash Mail, which enables Digital to send important product notices and image patches. The only downside to Flash Mail, at least from my standpoint, is that it eliminates my major source of free TK50 cartridges. Such is progress. Mail, Flash Mail and File Copy run in batch mode. However, DSNlink does permit interactive access to the DSNlink host and its impressive collection of databases. This final DSNlink application, appriopriately named Interactive Text Search, is somewhat similar to the DSIN interface, but is much easier to use and far more versatile. The databases you can access depend upon the software support licenses you have with DEC. But even with VMS-only access, you can get to nearly a dozen databases covering just about everything in VMS; 20,000 articles in all. With a simple SEARCH command you can reduce hours of searching through "the big grey wall" to just a few minutes. Articles can be printed out to your system printer, extracted to a file on your local system and otherwise manipulated. The DSNlink software buffers its i/o quite well. While you're reading a screen, DSNlink keeps transmitting in the background. If you decide to extract a file you've read, the process is practically instantaneous. It's much easier than using DSIN, where you have to capture your on-line session to a file and later edit out the extraneous information. NOTHING'S PERFECT Despite its marvelous capabilities, DSNlink does have a few shortcomings which DEC, to its credit, is working to correct. Some of these problems may be resolved by the time this column is published. The initial DSNlink release could work only with specific DEC-manufactured modems. This was a major inconvenience. Many sites don't purchase DEC modems because of their cost, which is several times that of "generic" units. The proprietary Digital Modem Command Language is a roadblock as well, although DEC modems also have a Hayes-compatible "AT" command set. User reaction to the lack of Hayes compatibility was so strong DEC developed a special script file which permitted DSNlink to work with "regular" modems. At the last DECUS Symposium in New Orleans, the DSNlink folks spent most of their time telling users of the availability of the script file and their intention to bundle a Hayes compatibility option into a future release of the software. Some DEC folk appear to have been left out of the loop, so if you're told a Hayes script isn't available, be insistent and don't take "no" for an answer. DSNlink currently supports only 2400 bps. Support for faster modems would be nice, especially when more than one user is connected to the network. Despite built-in data compression, it takes time to scroll through a large listing of database entries or to copy a large file. DSNlink supposedly requires a port with full modem control capability. I say "supposedly" because I was able to get DSNlink to run off a DEC Scholar Plus modem on one of the serial ports of my VAXstation 3100, which doesn't have modem flow control. My permanent DSNlink connection will be off a terminal server, though. DEDICATED LINE Another drawback is the need to dedicate a port and a telephone line to DSNlink. DEC says it needs a constant dial-in line in order to be able to deliver FLASH messages. In the two months I've had DSNlink connected, the only unsolicited mail I received was a note advising me that a telephone problem at the support center had been corrected. I hadn't even been aware of one. Of course, since DEC is paying for the phone calls (DSNlink uses toll-free 800 numbers), its request for a port and dedicated phone line isn't that unreasonable. If you're really tight on serial ports, it's a simple operation to create a command file which can stop and start the DSNlink software automatically to provide others with access to the line. SECURITY ISSUES Some sites with a paranoid bent may also feel uneasy about giving an "outsider" access to their system, despite DEC's assurances that DSNlink is secure and cannot be used for any scurrilous activity. A proprietary communications protocol is used by the software; it can talk only with DEC's CSC. When DSNlink is running, it will talk only with the CSC. And when the DSN$NETWORK process is idle, the port is set to NOTYPE_AHEAD, which prevents unsolicited input from initiating a login sequence. If you're using a DEC modem, DSNlink exploits its built-in passwording capabilities for even greater security. Nonetheless, a system manager acquaintance was put off by the DSNlink startup command file, which creates the startup process by using $RUN LOGINOUT with /PRIVILEGES=ALL. TEMPORAL DISPLACEMENT The other major problem deals with DSNlink's Interactive Text Search (ITS) facility. With thousands of entries in several databases, it's not unusual for a SEARCH command to produce hundreds of "hits". This is especially true when your query covers a broad topic, such as BACKUP utility problems. The /SINCE qualifier ostensibly serves as a filter to block database entries created prior to a specified date. Unfortunately, it doesn't work properly. DEC's database software detects the date the entry was last modified, not the original date of the actual entry. CSC routinely goes through its databases, correcting typographical errors and performing minor updates. These are detected by the ITS software as new entries. For example, when I searched for the word "VMS" and used the /SINCE qualifer to restrict the search to entries created in the past week, I received a listing of over 240 titles. There weren't 240 new bugs reported in VMS in seven days, thank goodness. Rather, CSC had been busy cleaning up typos and modifying the release numbers of VMS. ITS picked up each change as a new entry. This problem will take a while to correct. DEC is planning to revamp its database software, but it's a long-term effort. In the meantime, one workaround is to issue searches one day at a time, starting at the current date and working backward. Since ITS has command buffer recall, it isn't as onerous as it sounds. Despite these hitches, DSNlink is a real winner. I used to complain about the monthly support costs for VMS. DSNlink makes it worth every penny. ---------- Kevin G. Barkes is an independent consultant. He publishes the KGB Report newsletter, operates the www.kgbreport.com website, lurks on comp.os.vms, and can be reached at kgbarkes@gmail.com.