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12

The 1955 manual for the IBM 704 on page 7 talks about data representation in the computer. When a word is interpreted as numerical data, the zero position acts as the sign of the word. (…) When a logical operation is performed on a word, the word is interpreted as a 32-bit signless number. As an algebraic (signed) binary number, a word can represent (…) In ...


6

(Another "what was the first" question where it's basically impossible to answer it unless one goes through all computer instruction sets ...) One example of the usage of "logical" is the IBM 7090 (1959), as one can verify in the manual where the shift instructions are listed starting on page 31: ALS Accumulator Left Shift ARS ...


0

The answer lies in the contrast between ROM and RAM. When you turn a computer off, the RAM(random access memory) looses all it's contents. All variants of ROM do not. Some are programmable more than once. "pure" ROM is programmed once at the factory and and can never change.


2

I will give you an answer from a programmer's point of view: An EEPROM is called a ROM despite being writable because its INTERFACE is that of a ROM. In other words, from the point of view of your board, and from the point of view of software running on the board, it is memory that cannot be written to, therefore it is ROM. The fact that we can actually ...


8

RAM is designed to be quickly written many trillions of times without wearing out. Flash and EEPROM devices, by contrast, are designed to be quickly read many trillions of times without degradation, but writing will be orders of magnitude slower and impose significant wear; an EEPROM device that can reliably endure 10,000,000 write operations without ...


26

EEPROM can't be "written to." It can be programmed. Programming is different. When there's EEPROM in a CPU's physical address space, ordinary write cycles will not affect it. Something out of the ordinary has to happen in order to change the EEPROM's contents. The oldest PROMs and EEPROMs had to be physically removed from the system and programmed ...


80

Look at the development: ROM = read-only memory = can only be read when on the board, programmed in the chip factory. PROM = programmable read-only memory = can be programmed with a special programmer, but read-only when on the board. EPROM = erasable programmable read-only memory = can be repeatedly programmed with a special programmer, after erasing it ...


13

It can't be 'written to' in the sense of storing useful information written by a running program in the computer. It can be erased and re-programmed, which generally requires a special ROM programmer (rather than erasing and rewriting in place). So, the readonly-ness is from the viewpoint of the computer in which it's used. These days the line between that ...


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