Elfen
Well-known member
This has been on my mind for years, and have never acted on it. But where does it say that an LC or Classic is stuck at 10 Megs of RAM? Most II Series data bus is 32 bits, thus making a 4MB address into 16MB of RAM in 32 bit.
But the LC and a couple of others are 16 bits, which would make a 4MB address into 8MB of RAM in 16 bit. Thus the 10MB RAM size in an LC is just in 16 bits. If the bus can be expanded to 32 bits, it increases the RAM size to double!
Since finding the Classic II and comparing it to the SE/30, there is very little difference between 16 bit Classic II and the 32 bit SE/30. The SIMMs share many lines. Thus is one can pull out the lines into a separate board to add RAM into the missing 16 bits, I believe one can expand the RAM to double on these machines.
Looking at the Classic II, there are 4 - 4 bit X 1 Meg Chips - 44C1000-8, giving the board 2 MB in 16 bits. On a separate board with 4 more 44C1000-8, and have them share all but the Data Bus Lines and then line up each data bus line to the missing bits, you have just increased the RAM from 2 MB in 16 bits to 4 MB in 32 bits. Doing the same with 2 added SIMM sockets on the same board, you can now increase the RAM on the Classic II from 10MB to 20MB!
Question is, would ROM Routines stop this? The ROMs themselves are in 32 bits - 4 - 27C010 EPROMS on my board; each 27C010 is 8 bits wide. 4 X 8 is 32. This is also true with the LCs
So the question is, can it be done? In theory it can. In my mind I believe it can. So I provide a simple diagram from which a board can be drawn up. If you think that it can't, explain what you know. Don't just say that it can't, prove from what you know why it can't.
Given time and money I will try to build such a board and try it on the Classic II. If successful, then I can design and create another for the LC's.
But the LC and a couple of others are 16 bits, which would make a 4MB address into 8MB of RAM in 16 bit. Thus the 10MB RAM size in an LC is just in 16 bits. If the bus can be expanded to 32 bits, it increases the RAM size to double!
Since finding the Classic II and comparing it to the SE/30, there is very little difference between 16 bit Classic II and the 32 bit SE/30. The SIMMs share many lines. Thus is one can pull out the lines into a separate board to add RAM into the missing 16 bits, I believe one can expand the RAM to double on these machines.
Looking at the Classic II, there are 4 - 4 bit X 1 Meg Chips - 44C1000-8, giving the board 2 MB in 16 bits. On a separate board with 4 more 44C1000-8, and have them share all but the Data Bus Lines and then line up each data bus line to the missing bits, you have just increased the RAM from 2 MB in 16 bits to 4 MB in 32 bits. Doing the same with 2 added SIMM sockets on the same board, you can now increase the RAM on the Classic II from 10MB to 20MB!
Question is, would ROM Routines stop this? The ROMs themselves are in 32 bits - 4 - 27C010 EPROMS on my board; each 27C010 is 8 bits wide. 4 X 8 is 32. This is also true with the LCs
So the question is, can it be done? In theory it can. In my mind I believe it can. So I provide a simple diagram from which a board can be drawn up. If you think that it can't, explain what you know. Don't just say that it can't, prove from what you know why it can't.
Given time and money I will try to build such a board and try it on the Classic II. If successful, then I can design and create another for the LC's.