billdeg
Technician
I have been testing RAM cards lately. I have a good number of RAM cards, and I want to start separating the good from the bad. My test machine is an IMSAI 8080 with a lot of Processor Technologies cards, all working fine and it's a stable system. I use CUTTER to dump memory to the screen and if there's a test program listed in the RAM documentation, I run it. Some RAM cards are a little flakey, but I am happy that most of these cards have aged well.
Here is my question...
When I dump a page, for example 0000 -->0FFF, often I see a pattern something like FF 33 FF 33 FF 33 FF 33 etc.
Is this done by 74L chips on the RAM card just to make it easier to visually observe and differentiate that the RAM is "clear but available" verses FF FF FF FF - depicting that nothing is present in that location/range? In short, what's responsible? Static RAM would not hold memory, so it must be happening when the system initiates.
Are there any mag articles about this topic?
Thanks.
Bill
Here is my question...
When I dump a page, for example 0000 -->0FFF, often I see a pattern something like FF 33 FF 33 FF 33 FF 33 etc.
Is this done by 74L chips on the RAM card just to make it easier to visually observe and differentiate that the RAM is "clear but available" verses FF FF FF FF - depicting that nothing is present in that location/range? In short, what's responsible? Static RAM would not hold memory, so it must be happening when the system initiates.
Are there any mag articles about this topic?
Thanks.
Bill