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Vintage Computers Any vintage computer systems, calculators, video games etc., but with an emphasis on 1980s and earlier equipment. |
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16th May 2020, 7:51 pm | #41 | |
Hexode
Join Date: Nov 2009
Location: Chertsey, Surrey, UK.
Posts: 456
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Re: How long can a computer last?
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I think many Banks only got rid of their heirloom computers due to y2k! Didn't the internet use pdp-11 for DNS until late 1999? |
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16th May 2020, 7:59 pm | #42 | |
Dekatron
Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
Posts: 11,570
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Re: How long can a computer last?
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With Microcontrollers the default behaviour is that you can read the code out of them as easily as you can program it in, but devices which feature 'code protection' have a 'flag' which can be set at programming time to stop the 'read out' feature from working. In this case the programmer programs the code, reads it back (verifies it) to confirm that it has programmed correctly and then sets the 'protect' flag so that the code can no longer be read out by a device reader/programmer. This feature is intended to stop the code, which may have taken many man-hours to write and debug, from being stolen by a competitor. They may be able to clone your hardware but without the code to programme into the microcontroller, the copy will be useless. Usually the only way to clear the protection flag is to erase the device, which allows you to read it once more. Of course if you do that, there is no longer any code to read out of the device. |
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16th May 2020, 8:04 pm | #43 |
Dekatron
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 14,005
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Re: How long can a computer last?
I know that there were some early "Fusible Link" type PROMs that had an issue with a sort of re-growth effect whereby a 'blown' location would sometimes become un-blown after a few years. We had some RACAL-Milgo leased-line modems built in the 70s which suffered badly with this.
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16th May 2020, 8:10 pm | #44 | |
Hexode
Join Date: Nov 2009
Location: Chertsey, Surrey, UK.
Posts: 456
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Re: How long can a computer last?
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I had to Google the Decola, it would probably make an excellent amp hooked to a CD player, it has so meny small speakers! and must weigh a ton! The Decola hooked to a good bluetooth adapter could be controlled by your phone and have a nearly infinite playlist! Some valve radios have a pa input that can be used with a simple adapter made with a resistor and 2 y class caps, or a plug in Bluetooth receiver, thow the DAC90A dose not, but a Pico am transmitter can be used to connect it to anything! Old teck can be extended |
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16th May 2020, 8:17 pm | #45 | |
Hexode
Join Date: Nov 2009
Location: Chertsey, Surrey, UK.
Posts: 456
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Re: How long can a computer last?
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But I can set the voltage, I was surprised to be able to find the original dos software! I think you can just re blow the Fusible Link" type PROMs but best at a higher voltage and current, as long as the codes the same. How did you fix it? Last edited by audion_1908; 16th May 2020 at 8:43 pm. |
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16th May 2020, 8:21 pm | #46 | ||
Hexode
Join Date: Nov 2009
Location: Chertsey, Surrey, UK.
Posts: 456
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Re: How long can a computer last?
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How common is it to add copy protection? |
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16th May 2020, 8:21 pm | #47 | |
Heptode
Join Date: Oct 2015
Location: Gloucestershire, UK.
Posts: 720
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Re: How long can a computer last?
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Can't say why the PSU died, but my guess is electrolytics failure being a SMPSU. I'm dreading hard drive failure because I know life is going to become interesting then and there is no equivalent PC application that I have found. |
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16th May 2020, 8:24 pm | #48 |
Hexode
Join Date: Nov 2009
Location: Chertsey, Surrey, UK.
Posts: 456
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Re: How long can a computer last?
Can custom firmware be used to convert multi bit per cell SSD to 1 bit per cell for much greater data retention reliability, but also a large drop in capacity?
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16th May 2020, 8:26 pm | #49 | ||
Dekatron
Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
Posts: 11,570
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Re: How long can a computer last?
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I know this does happen, I have helped several people 'rescue' old computer systems by programming replacement bipolar PROMs for them after the original ones had failed. Which brings us to another problem. You have a replacement blank device <check> You have the code which need to go into it <check> Now, how do you get the code into the device? Taking the example of the Fusible-Link PROMs, these are now truly historic and almost no modern, reasonably priced programmer can program them. (There are about three or four eye-wateringly expensive programmers in current production which still support them). If you have the need to program such devices every now and again, you may find yourself having to acquire and maintain the entire equipment infrastructure necessary to do the job - an ancient device programmer and an ancient PC to run its support software. Both of these items (the ancient programmer and the ancient PC) may themselves contain antique programmed devices which may fail at any moment... and so on and so forth. Quote:
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16th May 2020, 8:36 pm | #50 |
Dekatron
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 14,005
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Re: How long can a computer last?
After complaining to Racal-Milgo, who reminded us that the offending modems were now several years out of support, we 'fixed it' by replacing all the modems with some current-production ones (which took up less rack-space and also had vastly better automatic line-equalisation).
Problem solved! |
16th May 2020, 8:46 pm | #51 | ||
Hexode
Join Date: Nov 2009
Location: Chertsey, Surrey, UK.
Posts: 456
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Re: How long can a computer last?
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16th May 2020, 8:47 pm | #52 | |||
Hexode
Join Date: Nov 2009
Location: Chertsey, Surrey, UK.
Posts: 456
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Re: How long can a computer last?
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16th May 2020, 8:50 pm | #53 | |
Hexode
Join Date: Nov 2009
Location: Chertsey, Surrey, UK.
Posts: 456
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Re: How long can a computer last?
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That's how a lot is fixed now, dump and replace, as it's cheaper but more wasteful, and not very green Last edited by audion_1908; 16th May 2020 at 9:09 pm. |
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16th May 2020, 8:53 pm | #54 | |
Dekatron
Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
Posts: 11,570
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Re: How long can a computer last?
Quote:
As mentioned before, the code protect feature on microcontrollers has not always worked perfectly, ways have sometimes been found to make the microcontroller cough up its internal code despite it being 'protected'. I would imagine most modern microcontrollers will not respond to that sort of attack. As for reverse engineering software, there are some tremendously clever people around who, starting with the circuit diagram, the datasheets of all the ICs and full knowledge of what the product is supposed to do, can create replacement firmware with equivalent, sometimes even improved functionality from scratch. For this to happen, there either has to be a lot of demand, or there has to be some kind of reward / bounty involved for the programmers concerned, or the programmers have to have some kind of obsessive love for the equipment and a desire to get it working again no matter what. Amazingly, the latter scenario is much more common than you might imagine. |
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16th May 2020, 8:58 pm | #55 |
Dekatron
Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
Posts: 11,570
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Re: How long can a computer last?
The company I work for still has archived copies of every version of every bit of firmware they have ever produced. They have been going since the mid 70s, I think.
As a repair technician I still draw on those archives from time to time, if we get an old piece of equipment back for repair with a failed EPROM, Microcontroller or PLD. |
16th May 2020, 9:04 pm | #56 |
Nonode
Join Date: Jan 2016
Location: Stafford, Staffs. UK.
Posts: 2,532
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Re: How long can a computer last?
Regarding getting code out of protected controllers, there have been extreme ways, including machining the tops off the IC's and using weird voltages on programming pins. I guess that these days ways of bypassing the protection are significantly harder as protecting the intellectual property is very important. I did once come across an application, PIC based, where the originator hadn't set any code protection. This though was a non commercial product. It was useful that they hadn't because they dissapeared completely, but it was possible to make a few more by simply reproducing the circuit and cloning the firmware. The information was freely available to create the device from scratch, but having the code left freely available saved a lot of time and testing!
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16th May 2020, 9:06 pm | #57 | |||
Hexode
Join Date: Nov 2009
Location: Chertsey, Surrey, UK.
Posts: 456
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Re: How long can a computer last?
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I think the eproms I needed for my old commodore need 12 volts and the newer the eprom burner the lower the voltage it could output, but why are modern EPROM programmers that support the old proms so expensive? |
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16th May 2020, 9:12 pm | #58 | |
Hexode
Join Date: Nov 2009
Location: Chertsey, Surrey, UK.
Posts: 456
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Re: How long can a computer last?
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16th May 2020, 9:14 pm | #59 | |
Hexode
Join Date: Nov 2009
Location: Chertsey, Surrey, UK.
Posts: 456
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Re: How long can a computer last?
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16th May 2020, 9:17 pm | #60 | |
Dekatron
Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
Posts: 11,570
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Re: How long can a computer last?
Quote:
My high-end device programmer also dates from the mid-nineties and I bought that one specifically because it programmed Bipolar PROMs, which, even then, only the high end models still did. The support software is DOS, so I keep not just one, but two DOS computers working to ensure that I will be able to keep using it for the forseeable future. I've noticed that some of the newest, cheap 'universal' EPROM programmers can not generate a VPP (programming voltage) of 25V. The designers are assuming that virtually no-one wants to be able to programme first and second generation EPROMs any more. |
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