Path: utzoo!attcan!uunet!zephyr.ens.tek.com!uw-beaver!mit-eddie!mintaka!olivea!samsung!zaphod.mps.ohio-state.edu!ncar!umigw!mthvax!wb8foz From: wb8foz@mthvax.cs.miami.edu (David Lesher) Newsgroups: comp.sys.ibm.pc.hardware Subject: Re: Wild claims about copy protection--true? Message-ID: <1990Oct28.141112.23619@mthvax.cs.miami.edu> Date: 28 Oct 90 14:11:12 GMT References: <5946@nisca.ircc.ohio-state.edu> <8951@pitt.UUCP> <1990Oct28.023321.12232@ecst.csuchico.edu> Reply-To: wb8foz@mthvax.cs.miami.edu (David Lesher) Distribution: na Organization: NRK Clinic for habitual NetNews Abusers Lines: 55 >I'm not an expert, but I know enough about electronics and TV/monitor theory >to know that the worst thing that will happen to a monitor if you send it >the wrong frequency is that it will not lock on the picture. The sync >circuits are oscillators that have their frequency controlled by receiving >sync signals from the computer. If the signal is not within the frequency >range of the oscillator, the oscillator will run free, and the picture will >be garbage, but no damage to the circuits will occur. I've heard lots of wild claims about how some secret c.p. scheme will blow up {your hard disk, computer, house, the free world} and I give them the due that other urban legends get. Most are spread by employees such a serviceman trying to preserve a monopoly. They may or may not have been told these stories as fact by their supervisors. But there is ONE that is true. It was NOT a copy protection scheme, though. The original IBEAM mono monitor was NOT built for the PeeCee. It was lifted from the old Displaywriter, an ugly box if there ever was one. That is also why the TTL mono scan rate was 50 hz, different from the 60 hz CGA. The only problem was, the horizontal sweep oscillator won't! In the absence of sync pulses, it stalls. When it stops, the flyback smokes, as virtually any TV set will. Now on a Displaywriter, this is no problem. The monitor is hardwired to the main box, and everything is controlled via one power switch. But on a PeeCee, you could turn off the CPU, and the monitor (plugged into another outlet) would keep on running, for a few seconds...... Now, you or I might have just fixed the stupid horizontal oscillator so it did what it was supposed to, but not IBEAM. Instead, they put an IEC switched outlet on the back, and fitted the monitor with a matching plug, so no one could plug it into an outlet. Presto, it went on and off with the PeeCee. There were, of course, several problems with this hack fix. First, if you wanted the CPU on the floor, the cord was too short. Second, if for some reason, the video card in the PeeCee stopped sending out horz. sync. pulses, the monitor smoked anyhow. Also, the color monitor IBEAM sold drew too much current to run off that outlet, so it HAD to come with a normal plug.... So yes, if you had an IBEAM MDA monitor, and screwed around with the display driver code for your wizz-bang-boom X-657 video card, you could smoke it. Yet another present from the folks that brought you EBCDIC, DB-25's used as Centronics ports, DB-9's used as serial ports and other such standardbreakers...... -- A host is a host from coast to coast.....wb8foz@mthvax.cs.miami.edu & no one will talk to a host that's close............(305) 255-RTFM Unless the host (that isn't close)......................pob 570-335 is busy, hung or dead....................................33257-0335