Carlos E. R. wrote:
The Thursday 2005-07-21 at 21:12 -0400, James Knott wrote:
Carlos E. R. wrote:
And no, I do not accept naming HD memory as RAM memory, for one thing: it is not directly addressable by the processor, thus it is not even "memory". Reading from HD requires a program, as it resides in a peripheral device. I call it "long term external storage space" ;-)
That's the case for modern computers, but back in the dark ages, some computers used a drum or disk for memory.
Which was directly addressable for that architecture ;-)
Just think, how could you run a program to read a byte from the drum, if that program has to run in drum memory! Impossible, it has to be read directly, or otherwise, it needs other type of memory.
That's how it work. The computer directly addressed the locations on the drum. Many years ago, I used to maintain an ancient (it was older than I was) "computer" (it was called a computer, even though it wasn't programable and could only perform the one function), that was built with vacuum tubes and relays. It used a drum for memory and to access a location, it would specify the desired track and counters were used to locate the position on that track. There were no sectors or even files, just data stored at locations on the drum surface. One thing you have to bear in mind, was that the earliest computers, were little more than programable calculators.