EPROM

R

richard

Could someone of proper knowledge and intelligence enlighten me as to which
computers today use EPROM's?
Erasable Programmable Read Only Memory.
One person is claiming that no computers today use them at all.
But from what I gather from some research, EPROM's are rather common.
As they are used in various applications such as storing BIOS.
I can see where these chips should have numerous responsibilities in
today's market.
Kind of like, how can you manage without them?
 
W

Wolf K

Could someone of proper knowledge and intelligence enlighten me as to which
computers today use EPROM's?
Erasable Programmable Read Only Memory.
One person is claiming that no computers today use them at all.
But from what I gather from some research, EPROM's are rather common.
As they are used in various applications such as storing BIOS.
I can see where these chips should have numerous responsibilities in
today's market.
Kind of like, how can you manage without them?
Click to expand...

http://en.wikipedia.org/wiki/EPROM

Wolf K.
 
D

DanS

Could someone of proper knowledge and intelligence
enlighten me as to which computers today use EPROM's?
Erasable Programmable Read Only Memory.
One person is claiming that no computers today use them at
all. But from what I gather from some research, EPROM's are
rather common. As they are used in various applications
such as storing BIOS. I can see where these chips should
have numerous responsibilities in today's market.
Kind of like, how can you manage without them?
Click to expand...
Looking at 10 different random motherboards @ NewEgg, I see no
EPROMS.
 
A

Andy Burns

richard said:
Could someone of proper knowledge and intelligence enlighten me as to which
computers today use EPROM's?
Click to expand...
Virtually none.

EPROMs pre-date EEPROMs and FLASH memory, you need a UV eraser to blank
them before re-writing, they were typically used in prototypes where the
eventual chip used in production would be a PROM or ROM, of course for
some small production runs, EPROMs did get released.
 
P

Paul

richard said:
Could someone of proper knowledge and intelligence enlighten me as to which
computers today use EPROM's?
Erasable Programmable Read Only Memory.
One person is claiming that no computers today use them at all.
But from what I gather from some research, EPROM's are rather common.
As they are used in various applications such as storing BIOS.
I can see where these chips should have numerous responsibilities in
today's market.
Kind of like, how can you manage without them?
Click to expand...
EPROMs were made obsolete by EEPROMs, due to the ability to
field upgrade (Electrically Erase) them. The existence of EEPROMs,
also made it possible to store several types of info in the BIOS chip.
Some of the contents of a BIOS chip are shown in the following table.
The middle three, require erasing the chip on a moment's notice.

Boot block (useful, if main BIOS block is "bricked")
Main BIOS code (upgradeable by end user)
DMI (potentially updated during POST)
ESCD (potentially updated during POST)
Microcode cache segment (updated when new processor detected)

http://en.wikipedia.org/wiki/Desktop_Management_Interface

http://en.wikipedia.org/wiki/ESCD

Modern EEPROMs are segmented, so you can erase only a portion of
it and reprogram it.

The main BIOS code, may even include a subroutine which knows how
to re-program the chip. To flash the entire chip safely, they can
"shadow" the BIOS in RAM, while the various parts of the chip are
updated. But since the chip is split into segments, just particular
segments can be programmed as well.

I programmed the microcode on my 440BX based motherboard, about
ten years ago, so I've actually done one of those. The microcode
cache concept, doesn't exist on all brands of BIOS designs.

Another change, is the package they come in. My most recent
motherboard, uses a "serial EEPROM" in an 8 pin DIP. This
is quite a bit smaller than the previous generations of parallel
interface devices. Example of the package type, here.

http://www.c-stamp.com/images/CS450000.jpg

At one time, serial EEPROMs had a tiny capacity, but now they have
large enough internal capacities, to take the place of the
bigger packaged parts. A nuisance aspect of them, is the manufacturers
have taken to soldering them to the motherboard, which makes buying a
replacement, a nuisance. The generations before the present time,
had a socket for the chip, so it could be removed for maintenance.
(Maintenance being, buying a programmed chip from an Internet vendor,
if the current BIOS chip is "bricked" or accidentally erased without
being properly re-programmed).

Paul
 
R

richard

EPROMs were made obsolete by EEPROMs, due to the ability to
field upgrade (Electrically Erase) them. The existence of EEPROMs,
also made it possible to store several types of info in the BIOS chip.
Some of the contents of a BIOS chip are shown in the following table.
The middle three, require erasing the chip on a moment's notice.

Boot block (useful, if main BIOS block is "bricked")
Main BIOS code (upgradeable by end user)
DMI (potentially updated during POST)
ESCD (potentially updated during POST)
Microcode cache segment (updated when new processor detected)

http://en.wikipedia.org/wiki/Desktop_Management_Interface

http://en.wikipedia.org/wiki/ESCD

Modern EEPROMs are segmented, so you can erase only a portion of
it and reprogram it.

The main BIOS code, may even include a subroutine which knows how
to re-program the chip. To flash the entire chip safely, they can
"shadow" the BIOS in RAM, while the various parts of the chip are
updated. But since the chip is split into segments, just particular
segments can be programmed as well.

I programmed the microcode on my 440BX based motherboard, about
ten years ago, so I've actually done one of those. The microcode
cache concept, doesn't exist on all brands of BIOS designs.

Another change, is the package they come in. My most recent
motherboard, uses a "serial EEPROM" in an 8 pin DIP. This
is quite a bit smaller than the previous generations of parallel
interface devices. Example of the package type, here.

http://www.c-stamp.com/images/CS450000.jpg

At one time, serial EEPROMs had a tiny capacity, but now they have
large enough internal capacities, to take the place of the
bigger packaged parts. A nuisance aspect of them, is the manufacturers
have taken to soldering them to the motherboard, which makes buying a
replacement, a nuisance. The generations before the present time,
had a socket for the chip, so it could be removed for maintenance.
(Maintenance being, buying a programmed chip from an Internet vendor,
if the current BIOS chip is "bricked" or accidentally erased without
being properly re-programmed).

Paul
Click to expand...
Thanks for the information.
Perhaps I should have said EEPROM to begin with.
 
G

G. Morgan

richard said:
Could someone of proper knowledge and intelligence enlighten me as to which
computers today use EPROM's?
Click to expand...
None.

If anything its an EEPROM [Electronically Erasable Programmable Read
Only Memory]

--

"I don't like to discriminate against terrorists based on nationality.
If you declare war on the United States and you want to kill us,
We're going to kill you first, period."

October 19, 2011 - Ali Soufan (Colbert Report)
 
E

Evan Platt

Could someone of proper knowledge and intelligence enlighten me as to which
computers today use EPROM's?
Click to expand...
About a dozen people 'of proper knowledge' already did school you,
bullis.
Erasable Programmable Read Only Memory.
One person is claiming that no computers today use them at all.
Click to expand...
One person? Try about a dozen.
But from what I gather from some research, EPROM's are rather common.
Click to expand...
No, they aren't.
As they are used in various applications such as storing BIOS.
I can see where these chips should have numerous responsibilities in
today's market.
Kind of like, how can you manage without them?
Click to expand...
You also claimed EPROM's lose their data when power is lost, which is
also incorrect.

How many people need to tell you that you're wrong?
 
J

John Williamson

Evan said:
About a dozen people 'of proper knowledge' already did school you,
bullis.


One person? Try about a dozen.


No, they aren't.
Click to expand...
Not common, but still in use, depending on your defnition of computer.
I'm sitting here looking at one.

The Psion II and 3 series personal organisers from the late '80s/ early
'90s used (Massive for the time up to 8 Megabyte) EPROMs for data
storage, and Psion sold a special "formatter" for them, which is
basically a UV tube in a box.
 
D

Desk Rabbit

Not common, but still in use, depending on your defnition of computer.
I'm sitting here looking at one.

The Psion II and 3 series personal organisers from the late '80s/ early
'90s used (Massive for the time up to 8 Megabyte) EPROMs for data
storage, and Psion sold a special "formatter" for them, which is
basically a UV tube in a box.
Click to expand...
Or you could just leave them on a sunny windowsill ;-)
 
A

Andy Burns

John said:
The Psion II and 3 series personal organisers from the late '80s/ early
'90s used (Massive for the time up to 8 Megabyte) EPROMs for data
storage, and Psion sold a special "formatter" for them, which is
basically a UV tube in a box.
Click to expand...
Ah that reminds me, I never posted that cable ...
 
D

Desk Rabbit

Virtually none.

EPROMs pre-date EEPROMs and FLASH memory, you need a UV eraser to blank
them before re-writing, they were typically used in prototypes where the
eventual chip used in production would be a PROM or ROM, of course for
some small production runs, EPROMs did get released.
Click to expand...
For many years I worked for a company that produced a device called the
TelexBox (A PC interface to the Telex network). These devices had their
firmware in a removeable EPROM. Engineers could just download the latest
firmware from the development system (A PDP11 if I recall) and burn a
set of EPROMS (There were PC ASCII and IBM EPSIDIC versions). Devices
were then upgraded in the field by replacing the EPROM and then the old
EPROM was erased in a UV eraser before being loaded with new firmware.

I even recall making changes to the code to fix a bug by using an EPROM
programmer to alter individual bits in the EPROM ;-)
 
A

Andy Burns

Desk said:
For many years I worked for a company that produced a device called the
TelexBox
Click to expand...
I worked for a company that produced software that used Hasler telex modems
(A PC interface to the Telex network). These devices had their
firmware in a removeable EPROM. Engineers could just download the latest
firmware from the development system (A PDP11 if I recall) and burn a
set of EPROMS (There were PC ASCII and IBM EPSIDIC versions). Devices
were then upgraded in the field by replacing the EPROM and then the old
EPROM was erased in a UV eraser before being loaded with new firmware.
Click to expand...
Yes, we used to burn EPROMs with customers' answerbacks in them, and
different versions for SPC or crossbar exchanges, or foreign networks.
 
J

John Williamson

Andy said:
Ah that reminds me, I never posted that cable ...
Click to expand...
No rush, I'm still working through a proper fix for the button bar. The
rest works fine now I've replaced *all* the batteries, though.
 
D

Desk Rabbit

I worked for a company that produced software that used Hasler telex modems


Yes, we used to burn EPROMs with customers' answerbacks in them, and
different versions for SPC or crossbar exchanges, or foreign networks.
Click to expand...
<Nods>
 
A

Andy Burns

I assume it was DCE that you worked for? I did pay them a visit once,
but there was no advantage for us to support the hardware ...
 
D

Desk Rabbit

I assume it was DCE that you worked for? I did pay them a visit once,
but there was no advantage for us to support the hardware ...
Click to expand...
Yes it was. Depending when you visited I was either a bench engineer or
the manager of the entire support operation ;-)
 
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