On (22 Mar 96) Bill Grimsley wrote to Keith Richardson...



 BG> Keith, at 21:08 on Mar 21 1996, you wrote to Bill Grimsley...



BG> What's the story with EPROM copying these days, do you need highly

BG> specialised equipment, or what?



KR> you need an eprom programmer, some are plugins to a pc others are

KR> standalone, usually with an rs232 port. you also need a uv source of the

KR> correct wavelength to erase the eprom first.



 BG> The EPROMs I had in mind are probably only electrically erasable (if

 BG> at all) as they have no window on them.  An EEPROM perhaps?  I also

 BG> presume that some of them are only programmable the once, and can't be

 BG> erased after that, right?



most probably one time programmable, same as the ones with the window,

only without it (: the thing to do with these is to copy their contents

into another chip, that aint a bad idea anyway, you dont really want to

change the original.



BG> The Sportie's EPROM appears to be a fairly standard 256Kb job, and

BG> I wonder, do they generally copy first time, every time without

BG> any problems?



KR> depends on the manufacturer, some are better than others, it also can

KR> very from piece to piece, but generally these days most are ok.



 BG> You can see how much I've had to do with EPROMs, can't you?  :)



never would have guessed (:



BG> Also, can they be altered slightly, if required?



KR> if you mean can an eprom be changed, as you erase to all
"1"s you can

KR> change "1"s to "0"s but not vice versa. some
people leave an area of

KR> "1"s as a patch area, but its usually better to erase the
whole thing

KR> and start again. if you mean can the data be changed, then thats easy

KR> all the programming systems that i've used have edit capabilities, as

KR> long as you dont want to do inserts there is no problem.



 BG> I meant does the original image go to disk first, where it is then

 BG> editable, or is it copied directly into the new EPROM from the

 BG> original?  It may not matter either way, I was just covering all

 BG> aspects of what may be required.



thats no problem, the only constraints are that inserts are a problem,

and, as brenton pointed out, some roms have checksums. i reburnt the

bios roms in my old '286 in order to facilitate using ide drives, the

thing winged every time that i booted up coz the checksum didn't.



                        Keith



... An elephant is a mouse with an operating sys.



--- PPoint 1.96