It appears that they were all read as 27256s, as per your second paragraph below. Anders' original reads resulted in 32KB files, the size of a 27256. (as you know) This would've resulted in a read of only half of the data in the two 27512s. This is for the 4.22 set.
As for your first paragraph below, the 4.21 set consists of all 64KB images. I don't know if 4.21 actually is a mix of 27256 and 27512, as I've not looked at that release, but if it is, then your first paragraph would be correct for the 4.21 images, while the second would be correct for the original 4.22 images from Anders.
-Dave
toggle quoted message
Show quoted text
On 5/15/24 11:09, Chuck Harris wrote:
Hi Dave,
Wouldn't the mistake have to have been assuming one or more
of the 27256 EPROMS was a 27512? That would cause the hex file
for the misidentified EPROM to contain a double copy of the
27256's data.... which was noted earlier.
If the mistake went the other way, and was caused by assuming
that a 27512 was a 27256, that would have given a hex file that
contained half of the 512's data. That would result in the newly
burned 27512 containing half data, and half 'FF's.... which I
don't believe has been observed.
-Chuck Harris
On Wed, 15 May 2024 10:28:59 -0400 "Dave McGuire"
<mcguire@...> wrote:
On 5/15/24 01:49, Anders wrote:
If you compare the files with mine, then what did I do wrong all
those years ago? Did I miss that not all EEPROMS were the same type
or perhaps not supported by the GalepIII?
It was a simple and natural mistake to make; no one is looking to
assign blame. Apparently you had assumed they were all 27256s and
read them as such, thus truncating the data from the two 27512s.
Anyway. Last time I played with eproms was on the ZX81. Did not
even have a proper eraser so I used a Philips tanning lamp with the
IR emitters removed :) The Sinclairs had a tokenised BASIC so you
could translate it to swedish by changing just a table of keywords
:) Years later we programmed different fonts for PC graphics cards
and hacked NEC printers that could not print the letter ?.
Neat!
-Dave
--
Dave McGuire, AK4HZ
New Kensington, PA
Dave McGuire