1 Oct
2007
1 Oct
'07
6:31 a.m.
Over on comp.terminals someone wrote this about the VT100:
"The power-on operation does a "destructive" read of the
ROM-based firmware. After so many power-ups, the ROM becomes
unreadable. This was a design issue at the time - the technology
to fix it did not evolve until the VT200 series."
Is this true? I've never heard of a ROM being damaged by reading it a
lot.
--
"The Direct3D Graphics Pipeline" -- DirectX 9 draft available for download
<http://www.xmission.com/~legalize/book/download/index.html>
Legalize Adulthood! <http://blogs.xmission.com/legalize/>
1 Oct
1 Oct
6:32 a.m.
On Monday 01 October 2007 14:31:15 Richard wrote:
Over on comp.terminals someone wrote this about the
VT100:
"The power-on operation does a "destructive" read of the
ROM-based firmware. After so many power-ups, the ROM becomes
unreadable. This was a design issue at the time - the technology
to fix it did not evolve until the VT200 series."
Is this true? I've never heard of a ROM being damaged by reading it a
lot.
A comment like the above would merit an uncharitable response on some of the
straight-talking, no-nonsense automotive lists I'm on.
Gordon
1:19 p.m.
On Mon, 1 Oct 2007, Richard wrote:
Over on comp.terminals someone wrote this about the
VT100:
"The power-on operation does a "destructive" read of the
ROM-based firmware. After so many power-ups, the ROM becomes
unreadable. This was a design issue at the time - the technology
to fix it did not evolve until the VT200 series."
Is this true? I've never heard of a ROM being damaged by reading it a
lot.
Then we'll have to send John Titor back to get some "fresh" VT100s!
2:10 p.m.
> "The power-on operation does a
"destructive" read of the
> ROM-based firmware. After so many power-ups, the ROM becomes
> unreadable. This was a design issue at the time - the technology
> to fix it did not evolve until the VT200 series."
> Is this true? I've never heard of a ROM being damaged by reading it a
> lot.
It seems not a matter of reading, but reading it with a wrong VPP
voltage applied or something like that. As stated, this is a design issue.
3:36 p.m.
In article <007301c80470$379810a0$f0fea8c0 at alpha>,
"Alexandre Souza" <alexandre-listas at e-secure.com.br> writes:
Sure, but the poster on comp.terminals is making it sound like if
you've used a VT100 for any reasonable period of time, this will have
happened to you. They even go so far as to say that if you turn on
your VT100 you should leave it on until the next power bump.
That sort of advice just sounds fishy to me, as I've not heard of
this being said about a VT100 before. But hey, I could easily be
wrong. I'm looking for confirmation of this behavior ON A VT100.
--
"The Direct3D Graphics Pipeline" -- DirectX 9 draft available for download
<http://www.xmission.com/~legalize/book/download/index.html>
Legalize Adulthood! <http://blogs.xmission.com/legalize/>
> "The
power-on operation does a "destructive" read of the
> ROM-based firmware. After so many power-ups, the ROM becomes
> unreadable. This was a design issue at the time - the technology
> to fix it did not evolve until the VT200 series."
> Is this true? I've never heard of a ROM being damaged by reading it a
> lot.
It seems not a matter of reading, but reading it with a wrong VPP
voltage applied or something like that. As stated, this is a design issue. 
3:29 p.m.
Over on comp.terminals someone wrote this about the VT100:
"The power-on operation does a "destructive" read of the
ROM-based firmware. After so many power-ups, the ROM becomes
unreadable. This was a design issue at the time - the technology
to fix it did not evolve until the VT200 series."
The polite reply, I believe, is B*llsh*t!
AFAIK, based on reading the VT100 schematics, there's nothing special
about the power-on operation. It just reads the ROMs like any other ROM
read. And the VT100 firmware is run from ROM all the time, it's not
copied into RAM at power-up or anything like that. So presumably, if this
were true, the ROM would die if the terminal is left on.
There ahd been semiconductor ROMs for about 10 years before the VT100, it
was not new technology at the time. And AFAIK none of them had this problem.
Now, there is an EAROM in the VT100 to store the configuration settings.
It has a limited number of write cycles (i.e. saving new configurations),
but AFAIK no limit to reads (and it is read on power-up to restore the
configuration, of course). Maybe that's where this story originates.
-tony
6244
days inactive
6244
days old
5 comments
5 participants
participants (5)
-
alexandre-listas＠e-secure.com.br -
ard＠p850ug1.demon.co.uk -
cisin＠xenosoft.com -
gordonjcp＠gjcp.net -
legalize＠xmission.com