Priority Interrupt by Steve Ciarcia Update or Die

I don't remember exactly the reason, but recently I needed to check the pinout for an XR2211 PLL chip. The part number rung a bell, and rather than dig through a pile of dusty and obsolete EXAR manuals, I grabbed an early Ciarcia's Circuit Cellar book off the shelf. Ah, lets see. Way back then I wrote an article titled, "A Build-It-Yourself Modem for Under $50." It used an XR2211 phase-locked loop chip and the voltage-controlled oscillator section of an NE567 connected to an acoustic coupler. Today, I cringe when I look at the complexity of some of those early brute-force designs, but they worked exceedingly well for their time.

Back then, I think I was still working for Control Data Corporation as one of their consulting engineers. I didn't consult to them. It was the other way around. They had a professional services division where they used engineers at a customer site to consult to the customers. As long as we didn't criticize the sanctity of massive centralized computer control schemes and didn't create more messes than we solved, job security was good. Unfortunately, my after-hours activities put me on a collision course with such absurd technical dogma.

My personal system was a Digital Group Z-80. For its time it was a powerful machine and had everything. The Z-80 had tape drives (later upgraded to floppies), memory-mapped ASCII terminal, 64 KB of memory, an operating system with BASIC, and even a Votrax speech synthesizer board. Best of all, it had a modem.

Back then, 300 bps was king. There was no Internet, no web, nothing. Except for a few military geeks, cyberspace was still science fiction. There were no hubs or routers. One computer simply picked up the phone and called another. If that computer was outfitted with a bunch of telephone lines (or a service like Telenet) and message-logging software, it became a bulletin board system (BBS) resembling something like today's single-subject chat groups. BBSs were typically local because of flat-rate telephone billing. Anything outside the local area was an expensive call. There wasn't any of this penny a minute stuff we have now. Occasionally you'd venture out to other BBSs but you took your chances. The meter started running when the other computer answered, but you never knew how long it would take or even if you would eventually get in.

The good news was that we all spoke the same data rate. Initially, it was 300 bps. There was no spam, trash messages, or viruses, just smooth ASCII characters streaming in at human speed. Everything was text or graphics built from ASCII characters, and it simply scrolled down the screen. In truth, 30 characters per second got old fast and 1200 bps became the standard for a longer time. There were many experts who even thought that 1200 or 2400 bps was the limit for our 100-year-old copper-wired telephone system. Until they broke the barriers, Hayes modems were kings.

These early years were innocent times. Because everything was ASCII text or limited text graphics, BBS users concentrated on communication without crap (often misspelled, mis-punctuated, and sometimes all caps). Yes, there were the commercial interruptions, but those things deemed as interruptions were easily remedied. If someone posted an unwanted commercial message, the BBS moderator would simply remove it. There was none of this sending a thousand individual spam messages to everyone on the BBS.

If it seems that I'm rambling, I agree. I guess that I'm merely lamenting the fact that this early period may have been the last time that serious personal computer users got the benefit of the full bandwidth. As limiting as 30 or 120 characters per second may seem, it was one-on-one and it worked.

Yes, we've had a lot of evolution since then. However, the real change is not the data rate, but how we have changed using it. Low data rates dictated a privately controlled network with limited participation. Higher data rates have allowed a portion of the bandwidth to be utilized in making everything into a public highway and a public communications system. If the message is simply "you need an XR2211," you could hardly tolerate a couple thousand bytes of header and routing information at 1200 bps.

Today, with 500 kbps or greater connection speeds, a few kilobytes of routing information is not only innocuous, but you probably don't even mind that this simple 17-character message comes displayed on 200 KB of custom-graphic virtual stationary. While simpler technology offered emotional security, today we've all gotten used to surfing for practically everything; and there is no going back. Moreover, I have come to expect that what I find on the web will be detailed and plentiful. Any personal computer system able to support those lofty ambitions has a price as well as a penalty. The penalty we pay for an unrestricted cyberspace is that sometimes it's like living in the old Wild West. The price for keeping pace with all these bandwidth-intensive Internet functions is, upgrade or die.

steve.ciarcia@circuitcellar.com

Published: August-2002