David.Plummer@f70.n140.z1.FIDONET.ORG (David Plummer) (11/28/90)
Personally, I think viruses blowing up your monitor sounds a little extreme, but the ability to cause damage to CTRs via software isn't new (at least certainly APPEAR to cause damage). Try this on a SP9000 (SuperPet for all you neophites out there): for a=1 to 100:for b=1 to 255:poke 59521,b:next b,a (I think it's 59521, it's been about 4 years). It shifts the video so badly that you get a BACKWARDS display reflected off the inside of your display tube, and the letters are about 4 times as big because they have to travel faster. It also makes sounds that I was worried could cause sterility. I'm sure it can't be good for it. Point being, nothing can instantly destroy your monitor. Even if you could damage it, I don't think anything could be so severe as to do damage before you could turn it off. -- David Plummer - via FidoNet node 1:140/22 UUCP: ...!herald!weyr!70!David.Plummer Domain: David.Plummer@f70.n140.z1.FIDONET.ORG Standard Disclaimers Apply...
peterk@cbmger.UUCP (Peter Kittel GERMANY) (11/30/90)
In article <964.2754A82B@weyr.FIDONET.ORG> David.Plummer@f70.n140.z1.FIDONET.ORG (David Plummer) writes: > Try this on a SP9000 >(SuperPet for all you neophites out there): ^^^^^^^^ (a normal CBM 8032 would already do) >for a=1 to 100:for b=1 to 255:poke 59521,b:next b,a > >(I think it's 59521, it's been about 4 years). It shifts the video >so badly that you get a BACKWARDS display reflected off the inside of >your display tube, and the letters are about 4 times as big because >they have to travel faster. It also makes sounds that I was worried >could cause sterility. I'm sure it can't be good for it. I had a similar effect with a software running harakiri. Afterwards the monitor image was only half height/half width for five minutes before it slowly recovered. Didn't feel like healthy for the monitor. >Point being, nothing can instantly destroy your monitor. Even if you >could damage it, I don't think anything could be so severe as to do >damage before you could turn it off. I doubt that strongly. There are enough stories about blowing up even a Multisync with a properly set up Amiga, because that monitor wants to resynchronize every frame and switches an internal relay at that speed. Or think about those stories about Atari STs connected to the wrong monitor type or using the wrong resolution. In general, monitors are very vulnerable. With their high-voltage parts and their horizontal deflection circuitry that must be tuned to the correct frequency, they are sensible for changes in that frequency. That may put them into totally unspecified states where everything may happen. One should be carefull. -- Best regards, Dr. Peter Kittel // E-Mail to \\ Only my personal opinions... Commodore Frankfurt, Germany \X/ {uunet|pyramid|rutgers}!cbmvax!cbmger!peterk
scot@amigash.UUCP (Scot L. Harris) (12/01/90)
>In article <964.2754A82B@weyr.FIDONET.ORG> David.Plummer@f70.n140.z1.FIDONET.ORG (David Plummer) writes: >Personally, I think viruses blowing up your monitor sounds a little >extreme, but the ability to cause damage to CTRs via software isn't new >Point being, nothing can instantly destroy your monitor. Even if you >could damage it, I don't think anything could be so severe as to do >damage before you could turn it off. >David Plummer - via FidoNet node 1:140/22 I used to belive this also until one of the engineers at a place I used to work for came in and said he blew up his monitor with a program. I did not belive him even after he explained what happened. Later on I got confirmation that this could indeed happen. He had an IBM and a hercules graphics card that he was poking registers at. Seems that you can poke some values in that card (possibly others) that cause it to put out I belive a much higher frequency signal to the monitor than the monitor can handle. A few seconds of that and he had smoke curlying out the top of the monitor and the monitor was dead. I would suspect that the new graphics modes and monitors get into these frequency ranges and if you have the wrong monitor attached the possibility of it going poof is fairly high. -- _ /// /_\ Scot L. Harris ...!tarpit!bilver!amigash!scot \XX/ / \ M I G A Orlando, FL (407)273-1759 [Prodigy censor messages? Nah, they wou
thad@cup.portal.com (Thad P Floryan) (12/02/90)
David.Plummer@f70.n140.z1.FIDONET.ORG (David Plummer)
in <964.2754A82B@weyr.FIDONET.ORG> writes:
[...]
Point being, nothing can instantly destroy your monitor. Even if you
could damage it, I don't think anything could be so severe as to do
damage before you could turn it off.
On the early IBM-PCs (and maybe still for all I know about "those" systems),
it was possible to change video attributes by altering the values written to
the registers in the video controller chip. An errant program (or a malicious
Trojan Horse) could also change the value in the register all the way down to
ZERO. Just imagine what used to happen when, say, an expected 15KHz AC signal
on the CRT coil(s) is now pure DC. Yes, it WOULD and DID destroy the CRT.
*PO*O*F*
On the Amiga, we see numerous instances in this newsgroup about the battery-
backed clock getting clobbered by errant programs ... the clock's registers
are sitting in the address space easily touchable by any program.
And guess what ALSO is vulnerable to errant programs: your SCSI interface.
Does anyone STILL doubt the value of an MMU to protect one's system and other
processes?
Protection not only from "normal" programming bugs during development, but
from virii such as the LAME-BRAINER or whatever?
Thad Floryan [ thad@cup.portal.com (OR) ..!sun!portal!cup.portal.com!thad ]DXB132@psuvm.psu.edu (12/03/90)
In article <36456@cup.portal.com>, thad@cup.portal.com (Thad P Floryan) says: >On the early IBM-PCs (and maybe still for all I know about "those" systems), >it was possible to change video attributes by altering the values written to Yes, on anything that used a 6845 (very common), this was possible. But if it destroys a monitor, the monitor was not designed properly. I've written all sorts of random garbage to a Hercules card (6845 based) and it never hurt my monitor (but of course I rebooted right away :-) :-)) >On the Amiga, we see numerous instances in this newsgroup about the battery- >backed clock getting clobbered by errant programs ... the clock's registers >are sitting in the address space easily touchable by any program. This is one of my pet peeves. It SEEMS like every crash messes up the clock. I'm lucky if my clock is still set properly at the end of a busy day. >And guess what ALSO is vulnerable to errant programs: your SCSI interface. This I'm not too concerned with, as it's hard for a program writing random garbage to get the common command set just right. :-) >Protection not only from "normal" programming bugs during development, but >from virii such as the LAME-BRAINER or whatever? Problem is, viruses don't do much that legitimate programs don't also do. -- Dan Babcock
peterk@cbmger.UUCP (Peter Kittel GERMANY) (12/03/90)
In article <36456@cup.portal.com> thad@cup.portal.com (Thad P Floryan) writes: >David.Plummer@f70.n140.z1.FIDONET.ORG (David Plummer) >in <964.2754A82B@weyr.FIDONET.ORG> writes: > > [...] > Point being, nothing can instantly destroy your monitor. Even if you > could damage it, I don't think anything could be so severe as to do > damage before you could turn it off. > >On the early IBM-PCs (and maybe still for all I know about "those" systems), >it was possible to change video attributes by altering the values written to >the registers in the video controller chip. An errant program (or a malicious >Trojan Horse) could also change the value in the register all the way down to >ZERO. Just imagine what used to happen when, say, an expected 15KHz AC signal >on the CRT coil(s) is now pure DC. Yes, it WOULD and DID destroy the CRT. Yes, and you know why? Because PCs use the same 6845/6545 video controller chip as in the SuperPET (or also 8032) mentioned in the original posting! This 6845 appears also today as subset in the registers of every PC video card. Was a quite useful part. -- Best regards, Dr. Peter Kittel // E-Mail to \\ Only my personal opinions... Commodore Frankfurt, Germany \X/ {uunet|pyramid|rutgers}!cbmvax!cbmger!peterk
johnhlee@sol.cs.cornell.edu (John H. Lee) (12/04/90)
In article <606@cbmger.UUCP> peterk@cbmger.UUCP (Peter Kittel GERMANY) writes: >In article <36456@cup.portal.com> thad@cup.portal.com (Thad P Floryan) writes: >>David.Plummer@f70.n140.z1.FIDONET.ORG (David Plummer) >>On the early IBM-PCs (and maybe still for all I know about "those" systems), >>it was possible to change video attributes by altering the values written to >>the registers in the video controller chip. An errant program (or a malicious >>Trojan Horse) could also change the value in the register all the way down to >>ZERO. Just imagine what used to happen when, say, an expected 15KHz AC signal >>on the CRT coil(s) is now pure DC. Yes, it WOULD and DID destroy the CRT. > >Yes, and you know why? Because PCs use the same 6845/6545 video controller >chip as in the SuperPET (or also 8032) mentioned in the original posting! >This 6845 appears also today as subset in the registers of every PC video >card. Was a quite useful part. Was? I've looked extensively into the 6845 because my old Heathkit H89's terminal section (the H19 portion) used it. So does a Perkin-Elmer terminal I have. It looks like a pretty nifty chip--relatively compact, yet generates almost everything you need, plus is configurable in almost anyway you want including 0Hz refresh rate. In fact, I'm thinking about designing a simple graphics board with it. Anyways, the 6845 isn't the reason for monitors being destroyed. It's low-cost design. My H89's analog video subsystem was designed to be an independent monitor. It had a simple local vertical oscillator with a free-running frequency of ~60Hz that just reset itself to vertical-sync's. It essentially acted like a simple phase-locked loop. You couldn't destroy the monitor by incorrect programming of the 6845 controller. (You could reprogram the terminal since it was basically a Z-80 computer with firmware. In fact, mine has a 3rd-party ROM which added a couple of features.) ------------------------------------------------------------------------------- The DiskDoctor threatens the crew! Next time on AmigaDos: The Next Generation. John Lee Internet: johnhlee@cs.cornell.edu The above opinions of those of the user, and not of this machine.
za011@zeus.unomaha.edu (12/08/90)
> Point being, nothing can instantly destroy your monitor. Even if you > could damage it, I don't think anything could be so severe as to do > damage before you could turn it off. You're right in that nothing in software can instantly destroy a monitor, but instantly doesn't always matter. I remember reading an article about computer viruses a couple of years back in which the author told of an IBM clone lab at a university that was hit by a virus attack at night. A number of monitors actually burned, according to the writer. ------------------------------------------------------------------------------- Kurt Krueger | BITNET: ZA011@UNOMA1 | //\ MBA student | Internet: ZA011@ZEUS.UNOMAHA.EDU | \X/--\ M I G A ------------------------------------------------------------------------------- Your message here -------------------------------------------------------------------------------